Replace ID based TokenMap with proper relative text-ranges / spans

80 files changed, 1819 insertions, 2049 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 5a8d971c3d4..90ee0810fa6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1263,6 +1263,7 @@ dependencies = [
  "serde_json",
  "snap",
  "stdx",
+ "text-size",
  "tracing",
  "triomphe",
  "tt",
@@ -2010,6 +2011,7 @@ version = "0.0.0"
 dependencies = [
  "smol_str",
  "stdx",
+ "text-size",
 ]
 
 [[package]]
diff --git a/crates/base-db/src/fixture.rs b/crates/base-db/src/fixture.rs
index 3da555a47ac..7236b56f6d4 100644
--- a/crates/base-db/src/fixture.rs
+++ b/crates/base-db/src/fixture.rs
@@ -8,11 +8,12 @@ use test_utils::{
     ESCAPED_CURSOR_MARKER,
 };
 use triomphe::Arc;
-use tt::token_id::{Leaf, Subtree, TokenTree};
+use tt::{Leaf, Subtree, TokenTree};
 use vfs::{file_set::FileSet, VfsPath};
 
 use crate::{
     input::{CrateName, CrateOrigin, LangCrateOrigin},
+    span::SpanData,
     Change, CrateDisplayName, CrateGraph, CrateId, Dependency, DependencyKind, Edition, Env,
     FileId, FilePosition, FileRange, ProcMacro, ProcMacroExpander, ProcMacroExpansionError,
     ProcMacros, ReleaseChannel, SourceDatabaseExt, SourceRoot, SourceRootId,
@@ -539,10 +540,10 @@ struct IdentityProcMacroExpander;
 impl ProcMacroExpander for IdentityProcMacroExpander {
     fn expand(
         &self,
-        subtree: &Subtree,
-        _: Option<&Subtree>,
+        subtree: &Subtree<SpanData>,
+        _: Option<&Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<Subtree, ProcMacroExpansionError> {
+    ) -> Result<Subtree<SpanData>, ProcMacroExpansionError> {
         Ok(subtree.clone())
     }
 }
@@ -553,10 +554,10 @@ struct AttributeInputReplaceProcMacroExpander;
 impl ProcMacroExpander for AttributeInputReplaceProcMacroExpander {
     fn expand(
         &self,
-        _: &Subtree,
-        attrs: Option<&Subtree>,
+        _: &Subtree<SpanData>,
+        attrs: Option<&Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<Subtree, ProcMacroExpansionError> {
+    ) -> Result<Subtree<SpanData>, ProcMacroExpansionError> {
         attrs
             .cloned()
             .ok_or_else(|| ProcMacroExpansionError::Panic("Expected attribute input".into()))
@@ -568,11 +569,11 @@ struct MirrorProcMacroExpander;
 impl ProcMacroExpander for MirrorProcMacroExpander {
     fn expand(
         &self,
-        input: &Subtree,
-        _: Option<&Subtree>,
+        input: &Subtree<SpanData>,
+        _: Option<&Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<Subtree, ProcMacroExpansionError> {
-        fn traverse(input: &Subtree) -> Subtree {
+    ) -> Result<Subtree<SpanData>, ProcMacroExpansionError> {
+        fn traverse(input: &Subtree<SpanData>) -> Subtree<SpanData> {
             let mut token_trees = vec![];
             for tt in input.token_trees.iter().rev() {
                 let tt = match tt {
@@ -595,13 +596,13 @@ struct ShortenProcMacroExpander;
 impl ProcMacroExpander for ShortenProcMacroExpander {
     fn expand(
         &self,
-        input: &Subtree,
-        _: Option<&Subtree>,
+        input: &Subtree<SpanData>,
+        _: Option<&Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<Subtree, ProcMacroExpansionError> {
+    ) -> Result<Subtree<SpanData>, ProcMacroExpansionError> {
         return Ok(traverse(input));
 
-        fn traverse(input: &Subtree) -> Subtree {
+        fn traverse(input: &Subtree<SpanData>) -> Subtree<SpanData> {
             let token_trees = input
                 .token_trees
                 .iter()
@@ -613,7 +614,7 @@ impl ProcMacroExpander for ShortenProcMacroExpander {
             Subtree { delimiter: input.delimiter, token_trees }
         }
 
-        fn modify_leaf(leaf: &Leaf) -> Leaf {
+        fn modify_leaf(leaf: &Leaf<SpanData>) -> Leaf<SpanData> {
             let mut leaf = leaf.clone();
             match &mut leaf {
                 Leaf::Literal(it) => {
diff --git a/crates/base-db/src/input.rs b/crates/base-db/src/input.rs
index e4f78321e21..2fa5c25c91e 100644
--- a/crates/base-db/src/input.rs
+++ b/crates/base-db/src/input.rs
@@ -13,9 +13,10 @@ use la_arena::{Arena, Idx};
 use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::SmolStr;
 use triomphe::Arc;
-use tt::token_id::Subtree;
 use vfs::{file_set::FileSet, AbsPathBuf, AnchoredPath, FileId, VfsPath};
 
+use crate::span::SpanData;
+
 // Map from crate id to the name of the crate and path of the proc-macro. If the value is `None`,
 // then the crate for the proc-macro hasn't been build yet as the build data is missing.
 pub type ProcMacroPaths = FxHashMap<CrateId, Result<(Option<String>, AbsPathBuf), String>>;
@@ -255,10 +256,10 @@ pub enum ProcMacroKind {
 pub trait ProcMacroExpander: fmt::Debug + Send + Sync + RefUnwindSafe {
     fn expand(
         &self,
-        subtree: &Subtree,
-        attrs: Option<&Subtree>,
+        subtree: &tt::Subtree<SpanData>,
+        attrs: Option<&tt::Subtree<SpanData>>,
         env: &Env,
-    ) -> Result<Subtree, ProcMacroExpansionError>;
+    ) -> Result<tt::Subtree<SpanData>, ProcMacroExpansionError>;
 }
 
 #[derive(Debug)]
diff --git a/crates/base-db/src/lib.rs b/crates/base-db/src/lib.rs
index 40cfab88afd..6dc1629c3be 100644
--- a/crates/base-db/src/lib.rs
+++ b/crates/base-db/src/lib.rs
@@ -5,6 +5,7 @@
 mod input;
 mod change;
 pub mod fixture;
+pub mod span;
 
 use std::panic;
 
diff --git a/crates/base-db/src/span.rs b/crates/base-db/src/span.rs
new file mode 100644
index 00000000000..1072d937a3b
--- /dev/null
+++ b/crates/base-db/src/span.rs
@@ -0,0 +1,166 @@
+use std::fmt;
+
+use salsa::InternId;
+use vfs::FileId;
+
+pub type ErasedFileAstId = la_arena::Idx<syntax::SyntaxNodePtr>;
+
+// The first inde is always the root node's AstId
+pub const ROOT_ERASED_FILE_AST_ID: ErasedFileAstId =
+    la_arena::Idx::from_raw(la_arena::RawIdx::from_u32(0));
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub struct SyntaxContext;
+
+pub type SpanData = tt::SpanData<SpanAnchor>;
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+pub struct SpanAnchor {
+    pub file_id: HirFileId,
+    pub ast_id: ErasedFileAstId,
+}
+
+impl fmt::Debug for SpanAnchor {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("SpanAnchor").field(&self.file_id).field(&self.ast_id.into_raw()).finish()
+    }
+}
+
+impl tt::Span for SpanAnchor {
+    const DUMMY: Self = SpanAnchor { file_id: HirFileId(0), ast_id: ROOT_ERASED_FILE_AST_ID };
+}
+
+/// Input to the analyzer is a set of files, where each file is identified by
+/// `FileId` and contains source code. However, another source of source code in
+/// Rust are macros: each macro can be thought of as producing a "temporary
+/// file". To assign an id to such a file, we use the id of the macro call that
+/// produced the file. So, a `HirFileId` is either a `FileId` (source code
+/// written by user), or a `MacroCallId` (source code produced by macro).
+///
+/// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
+/// containing the call plus the offset of the macro call in the file. Note that
+/// this is a recursive definition! However, the size_of of `HirFileId` is
+/// finite (because everything bottoms out at the real `FileId`) and small
+/// (`MacroCallId` uses the location interning. You can check details here:
+/// <https://en.wikipedia.org/wiki/String_interning>).
+///
+/// The two variants are encoded in a single u32 which are differentiated by the MSB.
+/// If the MSB is 0, the value represents a `FileId`, otherwise the remaining 31 bits represent a
+/// `MacroCallId`.
+#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct HirFileId(u32);
+
+impl From<HirFileId> for u32 {
+    fn from(value: HirFileId) -> Self {
+        value.0
+    }
+}
+
+impl From<u32> for HirFileId {
+    fn from(value: u32) -> Self {
+        HirFileId(value)
+    }
+}
+
+impl From<MacroCallId> for HirFileId {
+    fn from(value: MacroCallId) -> Self {
+        value.as_file()
+    }
+}
+
+impl fmt::Debug for HirFileId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.repr().fmt(f)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct MacroFile {
+    pub macro_call_id: MacroCallId,
+}
+
+/// `MacroCallId` identifies a particular macro invocation, like
+/// `println!("Hello, {}", world)`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct MacroCallId(salsa::InternId);
+crate::impl_intern_key!(MacroCallId);
+
+impl MacroCallId {
+    pub fn as_file(self) -> HirFileId {
+        MacroFile { macro_call_id: self }.into()
+    }
+
+    pub fn as_macro_file(self) -> MacroFile {
+        MacroFile { macro_call_id: self }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+pub enum HirFileIdRepr {
+    FileId(FileId),
+    MacroFile(MacroFile),
+}
+
+impl fmt::Debug for HirFileIdRepr {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::FileId(arg0) => f.debug_tuple("FileId").field(&arg0.0).finish(),
+            Self::MacroFile(arg0) => {
+                f.debug_tuple("MacroFile").field(&arg0.macro_call_id.0).finish()
+            }
+        }
+    }
+}
+
+impl From<FileId> for HirFileId {
+    fn from(FileId(id): FileId) -> Self {
+        assert!(id < Self::MAX_FILE_ID);
+        HirFileId(id)
+    }
+}
+
+impl From<MacroFile> for HirFileId {
+    fn from(MacroFile { macro_call_id: MacroCallId(id) }: MacroFile) -> Self {
+        let id = id.as_u32();
+        assert!(id < Self::MAX_FILE_ID);
+        HirFileId(id | Self::MACRO_FILE_TAG_MASK)
+    }
+}
+
+impl HirFileId {
+    const MAX_FILE_ID: u32 = u32::MAX ^ Self::MACRO_FILE_TAG_MASK;
+    const MACRO_FILE_TAG_MASK: u32 = 1 << 31;
+
+    #[inline]
+    pub fn is_macro(self) -> bool {
+        self.0 & Self::MACRO_FILE_TAG_MASK != 0
+    }
+
+    #[inline]
+    pub fn macro_file(self) -> Option<MacroFile> {
+        match self.0 & Self::MACRO_FILE_TAG_MASK {
+            0 => None,
+            _ => Some(MacroFile {
+                macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)),
+            }),
+        }
+    }
+
+    #[inline]
+    pub fn file_id(self) -> Option<FileId> {
+        match self.0 & Self::MACRO_FILE_TAG_MASK {
+            0 => Some(FileId(self.0)),
+            _ => None,
+        }
+    }
+
+    #[inline]
+    pub fn repr(self) -> HirFileIdRepr {
+        match self.0 & Self::MACRO_FILE_TAG_MASK {
+            0 => HirFileIdRepr::FileId(FileId(self.0)),
+            _ => HirFileIdRepr::MacroFile(MacroFile {
+                macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)),
+            }),
+        }
+    }
+}
diff --git a/crates/cfg/src/tests.rs b/crates/cfg/src/tests.rs
index bdc3f854e08..242929c006a 100644
--- a/crates/cfg/src/tests.rs
+++ b/crates/cfg/src/tests.rs
@@ -2,36 +2,37 @@ use arbitrary::{Arbitrary, Unstructured};
 use expect_test::{expect, Expect};
 use mbe::syntax_node_to_token_tree;
 use syntax::{ast, AstNode};
+use tt::Span;
 
 use crate::{CfgAtom, CfgExpr, CfgOptions, DnfExpr};
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+struct DummyFile;
+impl Span for DummyFile {
+    const DUMMY: Self = DummyFile;
+}
+
 fn assert_parse_result(input: &str, expected: CfgExpr) {
-    let (tt, _) = {
-        let source_file = ast::SourceFile::parse(input).ok().unwrap();
-        let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-        syntax_node_to_token_tree(tt.syntax())
-    };
+    let source_file = ast::SourceFile::parse(input).ok().unwrap();
+    let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+    let tt = syntax_node_to_token_tree(tt.syntax(), DummyFile, 0.into(), &Default::default());
     let cfg = CfgExpr::parse(&tt);
     assert_eq!(cfg, expected);
 }
 
 fn check_dnf(input: &str, expect: Expect) {
-    let (tt, _) = {
-        let source_file = ast::SourceFile::parse(input).ok().unwrap();
-        let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-        syntax_node_to_token_tree(tt.syntax())
-    };
+    let source_file = ast::SourceFile::parse(input).ok().unwrap();
+    let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+    let tt = syntax_node_to_token_tree(tt.syntax(), DummyFile, 0.into(), &Default::default());
     let cfg = CfgExpr::parse(&tt);
     let actual = format!("#![cfg({})]", DnfExpr::new(cfg));
     expect.assert_eq(&actual);
 }
 
 fn check_why_inactive(input: &str, opts: &CfgOptions, expect: Expect) {
-    let (tt, _) = {
-        let source_file = ast::SourceFile::parse(input).ok().unwrap();
-        let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-        syntax_node_to_token_tree(tt.syntax())
-    };
+    let source_file = ast::SourceFile::parse(input).ok().unwrap();
+    let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+    let tt = syntax_node_to_token_tree(tt.syntax(), DummyFile, 0.into(), &Default::default());
     let cfg = CfgExpr::parse(&tt);
     let dnf = DnfExpr::new(cfg);
     let why_inactive = dnf.why_inactive(opts).unwrap().to_string();
@@ -40,11 +41,9 @@ fn check_why_inactive(input: &str, opts: &CfgOptions, expect: Expect) {
 
 #[track_caller]
 fn check_enable_hints(input: &str, opts: &CfgOptions, expected_hints: &[&str]) {
-    let (tt, _) = {
-        let source_file = ast::SourceFile::parse(input).ok().unwrap();
-        let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-        syntax_node_to_token_tree(tt.syntax())
-    };
+    let source_file = ast::SourceFile::parse(input).ok().unwrap();
+    let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+    let tt = syntax_node_to_token_tree(tt.syntax(), DummyFile, 0.into(), &Default::default());
     let cfg = CfgExpr::parse(&tt);
     let dnf = DnfExpr::new(cfg);
     let hints = dnf.compute_enable_hints(opts).map(|diff| diff.to_string()).collect::<Vec<_>>();
diff --git a/crates/hir-def/src/attr.rs b/crates/hir-def/src/attr.rs
index fa3025e0303..35c9d63979a 100644
--- a/crates/hir-def/src/attr.rs
+++ b/crates/hir-def/src/attr.rs
@@ -7,7 +7,10 @@ mod tests;
 
 use std::{hash::Hash, ops, slice::Iter as SliceIter};
 
-use base_db::CrateId;
+use base_db::{
+    span::{ErasedFileAstId, SpanAnchor},
+    CrateId,
+};
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
 use hir_expand::{
@@ -28,8 +31,8 @@ use crate::{
     lang_item::LangItem,
     nameres::{ModuleOrigin, ModuleSource},
     src::{HasChildSource, HasSource},
-    AdtId, AssocItemLoc, AttrDefId, EnumId, GenericParamId, ItemLoc, LocalEnumVariantId,
-    LocalFieldId, Lookup, MacroId, VariantId,
+    AdtId, AssocItemLoc, AttrDefId, EnumId, GenericDefId, GenericParamId, ItemLoc,
+    LocalEnumVariantId, LocalFieldId, Lookup, MacroId, VariantId,
 };
 
 #[derive(Default, Debug, Clone, PartialEq, Eq)]
@@ -415,26 +418,48 @@ impl AttrsWithOwner {
             AttrDefId::StaticId(it) => attrs_from_item_tree_assoc(db, it),
             AttrDefId::FunctionId(it) => attrs_from_item_tree_assoc(db, it),
             AttrDefId::TypeAliasId(it) => attrs_from_item_tree_assoc(db, it),
-            AttrDefId::GenericParamId(it) => match it {
-                GenericParamId::ConstParamId(it) => {
-                    let src = it.parent().child_source(db);
-                    RawAttrs::from_attrs_owner(
-                        db.upcast(),
-                        src.with_value(&src.value[it.local_id()]),
-                    )
-                }
-                GenericParamId::TypeParamId(it) => {
-                    let src = it.parent().child_source(db);
-                    RawAttrs::from_attrs_owner(
-                        db.upcast(),
-                        src.with_value(&src.value[it.local_id()]),
-                    )
-                }
-                GenericParamId::LifetimeParamId(it) => {
-                    let src = it.parent.child_source(db);
-                    RawAttrs::from_attrs_owner(db.upcast(), src.with_value(&src.value[it.local_id]))
+            AttrDefId::GenericParamId(it) => {
+                let ast_id = |p| match p {
+                    GenericDefId::AdtId(AdtId::StructId(it)) => {
+                        erased_ast_id_from_item_tree(db, it)
+                    }
+                    GenericDefId::AdtId(AdtId::EnumId(it)) => erased_ast_id_from_item_tree(db, it),
+                    GenericDefId::AdtId(AdtId::UnionId(it)) => erased_ast_id_from_item_tree(db, it),
+                    GenericDefId::TraitId(it) => erased_ast_id_from_item_tree(db, it),
+                    GenericDefId::TraitAliasId(it) => erased_ast_id_from_item_tree(db, it),
+                    GenericDefId::ImplId(it) => erased_ast_id_from_item_tree(db, it),
+                    GenericDefId::EnumVariantId(it) => erased_ast_id_from_item_tree(db, it.parent),
+                    GenericDefId::TypeAliasId(it) => erased_ast_id_from_item_tree_assoc(db, it),
+                    GenericDefId::FunctionId(it) => erased_ast_id_from_item_tree_assoc(db, it),
+                    GenericDefId::ConstId(it) => erased_ast_id_from_item_tree_assoc(db, it),
+                };
+                match it {
+                    GenericParamId::ConstParamId(it) => {
+                        let src = it.parent().child_source(db);
+                        RawAttrs::from_attrs_owner(
+                            db.upcast(),
+                            SpanAnchor { file_id: src.file_id, ast_id: ast_id(it.parent()) },
+                            src.with_value(&src.value[it.local_id()]),
+                        )
+                    }
+                    GenericParamId::TypeParamId(it) => {
+                        let src = it.parent().child_source(db);
+                        RawAttrs::from_attrs_owner(
+                            db.upcast(),
+                            SpanAnchor { file_id: src.file_id, ast_id: ast_id(it.parent()) },
+                            src.with_value(&src.value[it.local_id()]),
+                        )
+                    }
+                    GenericParamId::LifetimeParamId(it) => {
+                        let src = it.parent.child_source(db);
+                        RawAttrs::from_attrs_owner(
+                            db.upcast(),
+                            SpanAnchor { file_id: src.file_id, ast_id: ast_id(it.parent) },
+                            src.with_value(&src.value[it.local_id]),
+                        )
+                    }
                 }
-            },
+            }
             AttrDefId::ExternBlockId(it) => attrs_from_item_tree_loc(db, it),
             AttrDefId::ExternCrateId(it) => attrs_from_item_tree_loc(db, it),
             AttrDefId::UseId(it) => attrs_from_item_tree_loc(db, it),
@@ -638,6 +663,26 @@ fn any_has_attrs(
     id.lookup(db).source(db).map(ast::AnyHasAttrs::new)
 }
 
+fn erased_ast_id_from_item_tree<N: ItemTreeNode>(
+    db: &dyn DefDatabase,
+    lookup: impl Lookup<Data = ItemLoc<N>>,
+) -> ErasedFileAstId {
+    let id = lookup.lookup(db).id;
+    let tree = id.item_tree(db);
+    let mod_item = N::id_to_mod_item(id.value);
+    mod_item.ast_id(&tree).erase()
+}
+
+fn erased_ast_id_from_item_tree_assoc<N: ItemTreeNode>(
+    db: &dyn DefDatabase,
+    lookup: impl Lookup<Data = AssocItemLoc<N>>,
+) -> ErasedFileAstId {
+    let id = lookup.lookup(db).id;
+    let tree = id.item_tree(db);
+    let mod_item = N::id_to_mod_item(id.value);
+    mod_item.ast_id(&tree).erase()
+}
+
 fn attrs_from_item_tree<N: ItemTreeNode>(db: &dyn DefDatabase, id: ItemTreeId<N>) -> RawAttrs {
     let tree = id.item_tree(db);
     let mod_item = N::id_to_mod_item(id.value);
diff --git a/crates/hir-def/src/attr/tests.rs b/crates/hir-def/src/attr/tests.rs
index e4c8d446af7..ad101e9bdf7 100644
--- a/crates/hir-def/src/attr/tests.rs
+++ b/crates/hir-def/src/attr/tests.rs
@@ -1,17 +1,18 @@
 //! This module contains tests for doc-expression parsing.
 //! Currently, it tests `#[doc(hidden)]` and `#[doc(alias)]`.
 
+use base_db::span::SpanAnchor;
 use mbe::syntax_node_to_token_tree;
 use syntax::{ast, AstNode};
+use tt::Span;
 
 use crate::attr::{DocAtom, DocExpr};
 
 fn assert_parse_result(input: &str, expected: DocExpr) {
-    let (tt, _) = {
-        let source_file = ast::SourceFile::parse(input).ok().unwrap();
-        let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-        syntax_node_to_token_tree(tt.syntax())
-    };
+    let source_file = ast::SourceFile::parse(input).ok().unwrap();
+    let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
+    let tt =
+        syntax_node_to_token_tree(tt.syntax(), SpanAnchor::DUMMY, 0.into(), &Default::default());
     let cfg = DocExpr::parse(&tt);
     assert_eq!(cfg, expected);
 }
diff --git a/crates/hir-def/src/data.rs b/crates/hir-def/src/data.rs
index 72ccc17486f..4083d497917 100644
--- a/crates/hir-def/src/data.rs
+++ b/crates/hir-def/src/data.rs
@@ -663,7 +663,7 @@ impl<'a> AssocItemCollector<'a> {
                             self.module_id.local_id,
                             MacroCallKind::Attr {
                                 ast_id,
-                                attr_args: Arc::new((tt::Subtree::empty(), Default::default())),
+                                attr_args: Arc::new(tt::Subtree::empty()),
                                 invoc_attr_index: attr.id,
                             },
                             attr.path().clone(),
diff --git a/crates/hir-def/src/expander.rs b/crates/hir-def/src/expander.rs
index 6db8398bc98..b7cffb57625 100644
--- a/crates/hir-def/src/expander.rs
+++ b/crates/hir-def/src/expander.rs
@@ -1,6 +1,9 @@
 //! Macro expansion utilities.
 
-use base_db::CrateId;
+use base_db::{
+    span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID},
+    CrateId,
+};
 use cfg::CfgOptions;
 use drop_bomb::DropBomb;
 use hir_expand::{
@@ -118,7 +121,17 @@ impl Expander {
     }
 
     pub(crate) fn parse_attrs(&self, db: &dyn DefDatabase, owner: &dyn ast::HasAttrs) -> Attrs {
-        Attrs::filter(db, self.krate, RawAttrs::new(db.upcast(), owner, &self.hygiene))
+        Attrs::filter(
+            db,
+            self.krate,
+            RawAttrs::new(
+                db.upcast(),
+                // Usin `ROOT_ERASED_FILE_AST_ID` here is fine as this is only used for cfg checking
+                SpanAnchor { file_id: self.current_file_id, ast_id: ROOT_ERASED_FILE_AST_ID },
+                owner,
+                &self.hygiene,
+            ),
+        )
     }
 
     pub(crate) fn cfg_options(&self) -> &CfgOptions {
diff --git a/crates/hir-def/src/generics.rs b/crates/hir-def/src/generics.rs
index fac90e66304..6d656bf9482 100644
--- a/crates/hir-def/src/generics.rs
+++ b/crates/hir-def/src/generics.rs
@@ -21,7 +21,7 @@ use crate::{
     db::DefDatabase,
     dyn_map::{keys, DynMap},
     expander::Expander,
-    item_tree::{AttrOwner, ItemTree},
+    item_tree::ItemTree,
     lower::LowerCtx,
     nameres::{DefMap, MacroSubNs},
     src::{HasChildSource, HasSource},
@@ -250,7 +250,10 @@ impl GenericParams {
         &mut self,
         lower_ctx: &LowerCtx<'_>,
         node: &dyn HasGenericParams,
-        add_param_attrs: impl FnMut(AttrOwner, ast::GenericParam),
+        add_param_attrs: impl FnMut(
+            Either<Idx<TypeOrConstParamData>, Idx<LifetimeParamData>>,
+            ast::GenericParam,
+        ),
     ) {
         if let Some(params) = node.generic_param_list() {
             self.fill_params(lower_ctx, params, add_param_attrs)
@@ -275,7 +278,10 @@ impl GenericParams {
         &mut self,
         lower_ctx: &LowerCtx<'_>,
         params: ast::GenericParamList,
-        mut add_param_attrs: impl FnMut(AttrOwner, ast::GenericParam),
+        mut add_param_attrs: impl FnMut(
+            Either<Idx<TypeOrConstParamData>, Idx<LifetimeParamData>>,
+            ast::GenericParam,
+        ),
     ) {
         for type_or_const_param in params.type_or_const_params() {
             match type_or_const_param {
@@ -297,7 +303,7 @@ impl GenericParams {
                         type_param.type_bound_list(),
                         Either::Left(type_ref),
                     );
-                    add_param_attrs(idx.into(), ast::GenericParam::TypeParam(type_param));
+                    add_param_attrs(Either::Left(idx), ast::GenericParam::TypeParam(type_param));
                 }
                 ast::TypeOrConstParam::Const(const_param) => {
                     let name = const_param.name().map_or_else(Name::missing, |it| it.as_name());
@@ -310,7 +316,7 @@ impl GenericParams {
                         default: ConstRef::from_const_param(lower_ctx, &const_param),
                     };
                     let idx = self.type_or_consts.alloc(param.into());
-                    add_param_attrs(idx.into(), ast::GenericParam::ConstParam(const_param));
+                    add_param_attrs(Either::Left(idx), ast::GenericParam::ConstParam(const_param));
                 }
             }
         }
@@ -325,7 +331,7 @@ impl GenericParams {
                 lifetime_param.type_bound_list(),
                 Either::Right(lifetime_ref),
             );
-            add_param_attrs(idx.into(), ast::GenericParam::LifetimeParam(lifetime_param));
+            add_param_attrs(Either::Right(idx), ast::GenericParam::LifetimeParam(lifetime_param));
         }
     }
 
diff --git a/crates/hir-def/src/item_tree.rs b/crates/hir-def/src/item_tree.rs
index 70b96b25739..3bea91ee61c 100644
--- a/crates/hir-def/src/item_tree.rs
+++ b/crates/hir-def/src/item_tree.rs
@@ -43,7 +43,10 @@ use std::{
 };
 
 use ast::{AstNode, HasName, StructKind};
-use base_db::CrateId;
+use base_db::{
+    span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID},
+    CrateId,
+};
 use either::Either;
 use hir_expand::{
     ast_id_map::{AstIdNode, FileAstId},
@@ -119,7 +122,7 @@ impl ItemTree {
         let mut item_tree = match_ast! {
             match syntax {
                 ast::SourceFile(file) => {
-                    top_attrs = Some(RawAttrs::new(db.upcast(), &file, ctx.hygiene()));
+                    top_attrs = Some(RawAttrs::new(db.upcast(), SpanAnchor { file_id, ast_id: ROOT_ERASED_FILE_AST_ID }, &file, ctx.hygiene()));
                     ctx.lower_module_items(&file)
                 },
                 ast::MacroItems(items) => {
diff --git a/crates/hir-def/src/item_tree/lower.rs b/crates/hir-def/src/item_tree/lower.rs
index c898eb5f921..807b2a7bf75 100644
--- a/crates/hir-def/src/item_tree/lower.rs
+++ b/crates/hir-def/src/item_tree/lower.rs
@@ -2,12 +2,14 @@
 
 use std::collections::hash_map::Entry;
 
+use base_db::span::ErasedFileAstId;
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, HirFileId};
 use syntax::ast::{self, HasModuleItem, HasTypeBounds};
 
 use crate::{
     generics::{GenericParams, TypeParamData, TypeParamProvenance},
     type_ref::{LifetimeRef, TraitBoundModifier, TraitRef},
+    LocalLifetimeParamId, LocalTypeOrConstParamId,
 };
 
 use super::*;
@@ -21,6 +23,7 @@ pub(super) struct Ctx<'a> {
     tree: ItemTree,
     source_ast_id_map: Arc<AstIdMap>,
     body_ctx: crate::lower::LowerCtx<'a>,
+    file: HirFileId,
 }
 
 impl<'a> Ctx<'a> {
@@ -30,6 +33,7 @@ impl<'a> Ctx<'a> {
             tree: ItemTree::default(),
             source_ast_id_map: db.ast_id_map(file),
             body_ctx: crate::lower::LowerCtx::with_file_id(db, file),
+            file,
         }
     }
 
@@ -77,9 +81,18 @@ impl<'a> Ctx<'a> {
     }
 
     pub(super) fn lower_block(mut self, block: &ast::BlockExpr) -> ItemTree {
-        self.tree
-            .attrs
-            .insert(AttrOwner::TopLevel, RawAttrs::new(self.db.upcast(), block, self.hygiene()));
+        self.tree.attrs.insert(
+            AttrOwner::TopLevel,
+            RawAttrs::new(
+                self.db.upcast(),
+                SpanAnchor {
+                    file_id: self.file,
+                    ast_id: self.source_ast_id_map.ast_id(block).erase(),
+                },
+                block,
+                self.hygiene(),
+            ),
+        );
         self.tree.top_level = block
             .statements()
             .filter_map(|stmt| match stmt {
@@ -109,8 +122,7 @@ impl<'a> Ctx<'a> {
     }
 
     fn lower_mod_item(&mut self, item: &ast::Item) -> Option<ModItem> {
-        let attrs = RawAttrs::new(self.db.upcast(), item, self.hygiene());
-        let item: ModItem = match item {
+        let mod_item: ModItem = match item {
             ast::Item::Struct(ast) => self.lower_struct(ast)?.into(),
             ast::Item::Union(ast) => self.lower_union(ast)?.into(),
             ast::Item::Enum(ast) => self.lower_enum(ast)?.into(),
@@ -129,10 +141,15 @@ impl<'a> Ctx<'a> {
             ast::Item::MacroDef(ast) => self.lower_macro_def(ast)?.into(),
             ast::Item::ExternBlock(ast) => self.lower_extern_block(ast).into(),
         };
+        let attrs = RawAttrs::new(
+            self.db.upcast(),
+            SpanAnchor { file_id: self.file, ast_id: mod_item.ast_id(&self.tree).erase() },
+            item,
+            self.hygiene(),
+        );
+        self.add_attrs(mod_item.into(), attrs);
 
-        self.add_attrs(item.into(), attrs);
-
-        Some(item)
+        Some(mod_item)
     }
 
     fn add_attrs(&mut self, item: AttrOwner, attrs: RawAttrs) {
@@ -146,21 +163,37 @@ impl<'a> Ctx<'a> {
         }
     }
 
-    fn lower_assoc_item(&mut self, item: &ast::AssocItem) -> Option<AssocItem> {
-        match item {
+    fn lower_assoc_item(&mut self, item_node: &ast::AssocItem) -> Option<AssocItem> {
+        let item: AssocItem = match item_node {
             ast::AssocItem::Fn(ast) => self.lower_function(ast).map(Into::into),
             ast::AssocItem::TypeAlias(ast) => self.lower_type_alias(ast).map(Into::into),
             ast::AssocItem::Const(ast) => Some(self.lower_const(ast).into()),
             ast::AssocItem::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
-        }
+        }?;
+        let attrs = RawAttrs::new(
+            self.db.upcast(),
+            SpanAnchor { file_id: self.file, ast_id: item.ast_id(&self.tree).erase() },
+            item_node,
+            self.hygiene(),
+        );
+        self.add_attrs(
+            match item {
+                AssocItem::Function(it) => AttrOwner::ModItem(ModItem::Function(it)),
+                AssocItem::TypeAlias(it) => AttrOwner::ModItem(ModItem::TypeAlias(it)),
+                AssocItem::Const(it) => AttrOwner::ModItem(ModItem::Const(it)),
+                AssocItem::MacroCall(it) => AttrOwner::ModItem(ModItem::MacroCall(it)),
+            },
+            attrs,
+        );
+        Some(item)
     }
 
     fn lower_struct(&mut self, strukt: &ast::Struct) -> Option<FileItemTreeId<Struct>> {
         let visibility = self.lower_visibility(strukt);
         let name = strukt.name()?.as_name();
-        let generic_params = self.lower_generic_params(HasImplicitSelf::No, strukt);
-        let fields = self.lower_fields(&strukt.kind());
         let ast_id = self.source_ast_id_map.ast_id(strukt);
+        let generic_params = self.lower_generic_params(HasImplicitSelf::No, strukt, ast_id.erase());
+        let fields = self.lower_fields(&strukt.kind());
         let res = Struct { name, visibility, generic_params, fields, ast_id };
         Some(id(self.data().structs.alloc(res)))
     }
@@ -183,8 +216,20 @@ impl<'a> Ctx<'a> {
         let start = self.next_field_idx();
         for field in fields.fields() {
             if let Some(data) = self.lower_record_field(&field) {
+                let ast_id = match data.ast_id {
+                    FieldAstId::Record(it) => it.erase(),
+                    FieldAstId::Tuple(it) => it.erase(),
+                };
                 let idx = self.data().fields.alloc(data);
-                self.add_attrs(idx.into(), RawAttrs::new(self.db.upcast(), &field, self.hygiene()));
+                self.add_attrs(
+                    idx.into(),
+                    RawAttrs::new(
+                        self.db.upcast(),
+                        SpanAnchor { file_id: self.file, ast_id },
+                        &field,
+                        self.hygiene(),
+                    ),
+                );
             }
         }
         let end = self.next_field_idx();
@@ -204,8 +249,20 @@ impl<'a> Ctx<'a> {
         let start = self.next_field_idx();
         for (i, field) in fields.fields().enumerate() {
             let data = self.lower_tuple_field(i, &field);
+            let ast_id = match data.ast_id {
+                FieldAstId::Record(it) => it.erase(),
+                FieldAstId::Tuple(it) => it.erase(),
+            };
             let idx = self.data().fields.alloc(data);
-            self.add_attrs(idx.into(), RawAttrs::new(self.db.upcast(), &field, self.hygiene()));
+            self.add_attrs(
+                idx.into(),
+                RawAttrs::new(
+                    self.db.upcast(),
+                    SpanAnchor { file_id: self.file, ast_id },
+                    &field,
+                    self.hygiene(),
+                ),
+            );
         }
         let end = self.next_field_idx();
         IdxRange::new(start..end)
@@ -222,12 +279,12 @@ impl<'a> Ctx<'a> {
     fn lower_union(&mut self, union: &ast::Union) -> Option<FileItemTreeId<Union>> {
         let visibility = self.lower_visibility(union);
         let name = union.name()?.as_name();
-        let generic_params = self.lower_generic_params(HasImplicitSelf::No, union);
+        let ast_id = self.source_ast_id_map.ast_id(union);
+        let generic_params = self.lower_generic_params(HasImplicitSelf::No, union, ast_id.erase());
         let fields = match union.record_field_list() {
             Some(record_field_list) => self.lower_fields(&StructKind::Record(record_field_list)),
             None => Fields::Record(IdxRange::new(self.next_field_idx()..self.next_field_idx())),
         };
-        let ast_id = self.source_ast_id_map.ast_id(union);
         let res = Union { name, visibility, generic_params, fields, ast_id };
         Some(id(self.data().unions.alloc(res)))
     }
@@ -235,12 +292,12 @@ impl<'a> Ctx<'a> {
     fn lower_enum(&mut self, enum_: &ast::Enum) -> Option<FileItemTreeId<Enum>> {
         let visibility = self.lower_visibility(enum_);
         let name = enum_.name()?.as_name();
-        let generic_params = self.lower_generic_params(HasImplicitSelf::No, enum_);
+        let ast_id = self.source_ast_id_map.ast_id(enum_);
+        let generic_params = self.lower_generic_params(HasImplicitSelf::No, enum_, ast_id.erase());
         let variants = match &enum_.variant_list() {
             Some(variant_list) => self.lower_variants(variant_list),
             None => IdxRange::new(self.next_variant_idx()..self.next_variant_idx()),
         };
-        let ast_id = self.source_ast_id_map.ast_id(enum_);
         let res = Enum { name, visibility, generic_params, variants, ast_id };
         Some(id(self.data().enums.alloc(res)))
     }
@@ -249,10 +306,16 @@ impl<'a> Ctx<'a> {
         let start = self.next_variant_idx();
         for variant in variants.variants() {
             if let Some(data) = self.lower_variant(&variant) {
+                let ast_id = data.ast_id.erase();
                 let idx = self.data().variants.alloc(data);
                 self.add_attrs(
                     idx.into(),
-                    RawAttrs::new(self.db.upcast(), &variant, self.hygiene()),
+                    RawAttrs::new(
+                        self.db.upcast(),
+                        SpanAnchor { file_id: self.file, ast_id },
+                        &variant,
+                        self.hygiene(),
+                    ),
                 );
             }
         }
@@ -303,28 +366,39 @@ impl<'a> Ctx<'a> {
                 });
                 self.add_attrs(
                     idx.into(),
-                    RawAttrs::new(self.db.upcast(), &self_param, self.hygiene()),
+                    RawAttrs::new(
+                        self.db.upcast(),
+                        SpanAnchor { file_id: self.file, ast_id: ast_id.erase() },
+                        &self_param,
+                        self.hygiene(),
+                    ),
                 );
                 has_self_param = true;
             }
             for param in param_list.params() {
+                let ast_id = self.source_ast_id_map.ast_id(&param);
                 let idx = match param.dotdotdot_token() {
-                    Some(_) => {
-                        let ast_id = self.source_ast_id_map.ast_id(&param);
-                        self.data()
-                            .params
-                            .alloc(Param { type_ref: None, ast_id: ParamAstId::Param(ast_id) })
-                    }
+                    Some(_) => self
+                        .data()
+                        .params
+                        .alloc(Param { type_ref: None, ast_id: ParamAstId::Param(ast_id) }),
                     None => {
                         let type_ref = TypeRef::from_ast_opt(&self.body_ctx, param.ty());
                         let ty = Interned::new(type_ref);
-                        let ast_id = self.source_ast_id_map.ast_id(&param);
                         self.data()
                             .params
                             .alloc(Param { type_ref: Some(ty), ast_id: ParamAstId::Param(ast_id) })
                     }
                 };
-                self.add_attrs(idx.into(), RawAttrs::new(self.db.upcast(), &param, self.hygiene()));
+                self.add_attrs(
+                    idx.into(),
+                    RawAttrs::new(
+                        self.db.upcast(),
+                        SpanAnchor { file_id: self.file, ast_id: ast_id.erase() },
+                        &param,
+                        self.hygiene(),
+                    ),
+                );
             }
         }
         let end_param = self.next_param_idx();
@@ -381,7 +455,8 @@ impl<'a> Ctx<'a> {
             ast_id,
             flags,
         };
-        res.explicit_generic_params = self.lower_generic_params(HasImplicitSelf::No, func);
+        res.explicit_generic_params =
+            self.lower_generic_params(HasImplicitSelf::No, func, ast_id.erase());
 
         Some(id(self.data().functions.alloc(res)))
     }
@@ -394,8 +469,9 @@ impl<'a> Ctx<'a> {
         let type_ref = type_alias.ty().map(|it| self.lower_type_ref(&it));
         let visibility = self.lower_visibility(type_alias);
         let bounds = self.lower_type_bounds(type_alias);
-        let generic_params = self.lower_generic_params(HasImplicitSelf::No, type_alias);
         let ast_id = self.source_ast_id_map.ast_id(type_alias);
+        let generic_params =
+            self.lower_generic_params(HasImplicitSelf::No, type_alias, ast_id.erase());
         let res = TypeAlias { name, visibility, bounds, generic_params, type_ref, ast_id };
         Some(id(self.data().type_aliases.alloc(res)))
     }
@@ -443,23 +519,20 @@ impl<'a> Ctx<'a> {
     fn lower_trait(&mut self, trait_def: &ast::Trait) -> Option<FileItemTreeId<Trait>> {
         let name = trait_def.name()?.as_name();
         let visibility = self.lower_visibility(trait_def);
-        let generic_params =
-            self.lower_generic_params(HasImplicitSelf::Yes(trait_def.type_bound_list()), trait_def);
+        let ast_id = self.source_ast_id_map.ast_id(trait_def);
+        let generic_params = self.lower_generic_params(
+            HasImplicitSelf::Yes(trait_def.type_bound_list()),
+            trait_def,
+            ast_id.erase(),
+        );
         let is_auto = trait_def.auto_token().is_some();
         let is_unsafe = trait_def.unsafe_token().is_some();
-        let ast_id = self.source_ast_id_map.ast_id(trait_def);
 
         let items = trait_def
             .assoc_item_list()
             .into_iter()
             .flat_map(|list| list.assoc_items())
-            .filter_map(|item| {
-                let attrs = RawAttrs::new(self.db.upcast(), &item, self.hygiene());
-                self.lower_assoc_item(&item).map(|item| {
-                    self.add_attrs(ModItem::from(item).into(), attrs);
-                    item
-                })
-            })
+            .filter_map(|item_node| self.lower_assoc_item(&item_node))
             .collect();
 
         let def = Trait { name, visibility, generic_params, is_auto, is_unsafe, items, ast_id };
@@ -472,20 +545,23 @@ impl<'a> Ctx<'a> {
     ) -> Option<FileItemTreeId<TraitAlias>> {
         let name = trait_alias_def.name()?.as_name();
         let visibility = self.lower_visibility(trait_alias_def);
+        let ast_id = self.source_ast_id_map.ast_id(trait_alias_def);
         let generic_params = self.lower_generic_params(
             HasImplicitSelf::Yes(trait_alias_def.type_bound_list()),
             trait_alias_def,
+            ast_id.erase(),
         );
-        let ast_id = self.source_ast_id_map.ast_id(trait_alias_def);
 
         let alias = TraitAlias { name, visibility, generic_params, ast_id };
         Some(id(self.data().trait_aliases.alloc(alias)))
     }
 
     fn lower_impl(&mut self, impl_def: &ast::Impl) -> Option<FileItemTreeId<Impl>> {
+        let ast_id = self.source_ast_id_map.ast_id(impl_def);
         // Note that trait impls don't get implicit `Self` unlike traits, because here they are a
         // type alias rather than a type parameter, so this is handled by the resolver.
-        let generic_params = self.lower_generic_params(HasImplicitSelf::No, impl_def);
+        let generic_params =
+            self.lower_generic_params(HasImplicitSelf::No, impl_def, ast_id.erase());
         // FIXME: If trait lowering fails, due to a non PathType for example, we treat this impl
         // as if it was an non-trait impl. Ideally we want to create a unique missing ref that only
         // equals itself.
@@ -499,14 +575,8 @@ impl<'a> Ctx<'a> {
             .assoc_item_list()
             .into_iter()
             .flat_map(|it| it.assoc_items())
-            .filter_map(|item| {
-                let assoc = self.lower_assoc_item(&item)?;
-                let attrs = RawAttrs::new(self.db.upcast(), &item, self.hygiene());
-                self.add_attrs(ModItem::from(assoc).into(), attrs);
-                Some(assoc)
-            })
+            .filter_map(|item| self.lower_assoc_item(&item))
             .collect();
-        let ast_id = self.source_ast_id_map.ast_id(impl_def);
         let res =
             Impl { generic_params, target_trait, self_ty, is_negative, is_unsafe, items, ast_id };
         Some(id(self.data().impls.alloc(res)))
@@ -572,15 +642,23 @@ impl<'a> Ctx<'a> {
                     // (in other words, the knowledge that they're in an extern block must not be used).
                     // This is because an extern block can contain macros whose ItemTree's top-level items
                     // should be considered to be in an extern block too.
-                    let attrs = RawAttrs::new(self.db.upcast(), &item, self.hygiene());
-                    let id: ModItem = match item {
-                        ast::ExternItem::Fn(ast) => self.lower_function(&ast)?.into(),
-                        ast::ExternItem::Static(ast) => self.lower_static(&ast)?.into(),
-                        ast::ExternItem::TypeAlias(ty) => self.lower_type_alias(&ty)?.into(),
-                        ast::ExternItem::MacroCall(call) => self.lower_macro_call(&call)?.into(),
+                    let mod_item: ModItem = match &item {
+                        ast::ExternItem::Fn(ast) => self.lower_function(ast)?.into(),
+                        ast::ExternItem::Static(ast) => self.lower_static(ast)?.into(),
+                        ast::ExternItem::TypeAlias(ty) => self.lower_type_alias(ty)?.into(),
+                        ast::ExternItem::MacroCall(call) => self.lower_macro_call(call)?.into(),
                     };
-                    self.add_attrs(id.into(), attrs);
-                    Some(id)
+                    let attrs = RawAttrs::new(
+                        self.db.upcast(),
+                        SpanAnchor {
+                            file_id: self.file,
+                            ast_id: mod_item.ast_id(&self.tree).erase(),
+                        },
+                        &item,
+                        self.hygiene(),
+                    );
+                    self.add_attrs(mod_item.into(), attrs);
+                    Some(mod_item)
                 })
                 .collect()
         });
@@ -593,6 +671,7 @@ impl<'a> Ctx<'a> {
         &mut self,
         has_implicit_self: HasImplicitSelf,
         node: &dyn ast::HasGenericParams,
+        owner_ast_id: ErasedFileAstId,
     ) -> Interned<GenericParams> {
         let mut generics = GenericParams::default();
 
@@ -612,12 +691,21 @@ impl<'a> Ctx<'a> {
             generics.fill_bounds(&self.body_ctx, bounds, Either::Left(self_param));
         }
 
-        let add_param_attrs = |item, param| {
-            let attrs = RawAttrs::new(self.db.upcast(), &param, self.body_ctx.hygiene());
+        let add_param_attrs = |item: Either<LocalTypeOrConstParamId, LocalLifetimeParamId>,
+                               param| {
+            let attrs = RawAttrs::new(
+                self.db.upcast(),
+                SpanAnchor { file_id: self.file, ast_id: owner_ast_id },
+                &param,
+                self.body_ctx.hygiene(),
+            );
             // This is identical to the body of `Ctx::add_attrs()` but we can't call that here
             // because it requires `&mut self` and the call to `generics.fill()` below also
             // references `self`.
-            match self.tree.attrs.entry(item) {
+            match self.tree.attrs.entry(match item {
+                Either::Right(id) => id.into(),
+                Either::Left(id) => id.into(),
+            }) {
                 Entry::Occupied(mut entry) => {
                     *entry.get_mut() = entry.get().merge(attrs);
                 }
diff --git a/crates/hir-def/src/lib.rs b/crates/hir-def/src/lib.rs
index fd8f64d6705..5f09d7c4813 100644
--- a/crates/hir-def/src/lib.rs
+++ b/crates/hir-def/src/lib.rs
@@ -84,7 +84,7 @@ use nameres::DefMap;
 use stdx::impl_from;
 use syntax::ast;
 
-use ::tt::token_id as tt;
+pub use hir_expand::tt;
 
 use crate::{
     builtin_type::BuiltinType,
@@ -1341,15 +1341,13 @@ fn attr_macro_as_call_id(
     def: MacroDefId,
 ) -> MacroCallId {
     let arg = match macro_attr.input.as_deref() {
-        Some(AttrInput::TokenTree(tt)) => (
-            {
-                let mut tt = tt.0.clone();
-                tt.delimiter = tt::Delimiter::UNSPECIFIED;
-                tt
-            },
-            tt.1.clone(),
-        ),
-        _ => (tt::Subtree::empty(), Default::default()),
+        Some(AttrInput::TokenTree(tt)) => {
+            let mut tt = tt.as_ref().clone();
+            tt.delimiter = tt::Delimiter::UNSPECIFIED;
+            tt
+        }
+
+        _ => tt::Subtree::empty(),
     };
 
     def.as_lazy_macro(
diff --git a/crates/hir-def/src/macro_expansion_tests/mbe.rs b/crates/hir-def/src/macro_expansion_tests/mbe.rs
index d0906213243..b5d70052a89 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe.rs
@@ -15,7 +15,6 @@ use crate::macro_expansion_tests::check;
 fn token_mapping_smoke_test() {
     check(
         r#"
-// +tokenids
 macro_rules! f {
     ( struct $ident:ident ) => {
         struct $ident {
@@ -27,23 +26,19 @@ macro_rules! f {
 // +tokenids
 f!(struct MyTraitMap2);
 "#,
-        expect![[r##"
-// call ids will be shifted by Shift(30)
-// +tokenids
-macro_rules! f {#0
-    (#1 struct#2 $#3ident#4:#5ident#6 )#1 =#7>#8 {#9
-        struct#10 $#11ident#12 {#13
-            map#14:#15 :#16:#17std#18:#19:#20collections#21:#22:#23HashSet#24<#25(#26)#26>#27,#28
-        }#13
-    }#9;#29
-}#0
-
-// // +tokenids
-// f!(struct#1 MyTraitMap2#2);
-struct#10 MyTraitMap2#32 {#13
-    map#14:#15 ::std#18::collections#21::HashSet#24<#25(#26)#26>#27,#28
-}#13
-"##]],
+        expect![[r#"
+macro_rules! f {
+    ( struct $ident:ident ) => {
+        struct $ident {
+            map: ::std::collections::HashSet<()>,
+        }
+    };
+}
+
+struct#SpanAnchor(FileId(0), 1)@58..64 MyTraitMap2#SpanAnchor(FileId(0), 2)@23..34 {#SpanAnchor(FileId(0), 1)@72..73
+    map#SpanAnchor(FileId(0), 1)@86..89:#SpanAnchor(FileId(0), 1)@89..90 ::std#SpanAnchor(FileId(0), 1)@93..96::collections#SpanAnchor(FileId(0), 1)@98..109::HashSet#SpanAnchor(FileId(0), 1)@111..118<#SpanAnchor(FileId(0), 1)@118..119(#SpanAnchor(FileId(0), 1)@119..120)#SpanAnchor(FileId(0), 1)@120..121>#SpanAnchor(FileId(0), 1)@121..122,#SpanAnchor(FileId(0), 1)@122..123
+}#SpanAnchor(FileId(0), 1)@132..133
+"#]],
     );
 }
 
@@ -71,31 +66,22 @@ f! {
 
 
 "#,
-        expect![[r##"
-// call ids will be shifted by Shift(18)
+        expect![[r#"
 // +tokenids
-macro_rules! f {#0
-    (#1$#2(#3$#4tt#5:#6tt#7)#3*#8)#1 =#9>#10 {#11
-        $#12(#13$#14tt#15)#13*#16
-    }#11;#17
-}#0
-
-// // +tokenids
-// f! {
-//     fn#1 main#2() {
-//         1#5;#6
-//         1.0#7;#8
-//         let#9 x#10 =#11 1#12;#13
-//     }
-// }
-fn#19 main#20(#21)#21 {#22
-    1#23;#24
-    1.0#25;#26
-    let#27 x#28 =#29 1#30;#31
-}#22
+macro_rules! f {
+    ($($tt:tt)*) => {
+        $($tt)*
+    };
+}
 
+fn#SpanAnchor(FileId(0), 2)@22..24 main#SpanAnchor(FileId(0), 2)@25..29(#SpanAnchor(FileId(0), 2)@29..30)#SpanAnchor(FileId(0), 2)@30..31 {#SpanAnchor(FileId(0), 2)@32..33
+    1#SpanAnchor(FileId(0), 2)@42..43;#SpanAnchor(FileId(0), 2)@43..44
+    1.0#SpanAnchor(FileId(0), 2)@53..56;#SpanAnchor(FileId(0), 2)@56..57
+    let#SpanAnchor(FileId(0), 2)@66..69 x#SpanAnchor(FileId(0), 2)@70..71 =#SpanAnchor(FileId(0), 2)@72..73 1#SpanAnchor(FileId(0), 2)@74..75;#SpanAnchor(FileId(0), 2)@75..76
+}#SpanAnchor(FileId(0), 2)@81..82
 
-"##]],
+
+"#]],
     );
 }
 
@@ -150,8 +136,7 @@ macro_rules! identity {
 }
 
 fn main(foo: ()) {
-    // format_args/*+tokenids*/!("{} {} {}"#1,#2 format_args#3!#4("{}"#6,#7 0#8),#9 foo#10,#11 identity#12!#13(10#15),#16 "bar"#17)
-builtin#4294967295 ##4294967295format_args#4294967295 (#0"{} {} {}"#1,#2 format_args#3!#4(#5"{}"#6,#7 0#8)#5,#9 foo#10,#11 identity#12!#13(#1410#15)#14,#16 "bar"#17)#0
+    builtin#SpanAnchor(FileId(0), 0)@0..0 ##SpanAnchor(FileId(0), 0)@0..0format_args#SpanAnchor(FileId(0), 0)@0..0 (#SpanAnchor(FileId(0), 6)@25..26"{} {} {}"#SpanAnchor(FileId(0), 6)@26..36,#SpanAnchor(FileId(0), 6)@36..37 format_args#SpanAnchor(FileId(0), 6)@38..49!#SpanAnchor(FileId(0), 6)@49..50(#SpanAnchor(FileId(0), 6)@50..51"{}"#SpanAnchor(FileId(0), 6)@51..55,#SpanAnchor(FileId(0), 6)@55..56 0#SpanAnchor(FileId(0), 6)@57..58)#SpanAnchor(FileId(0), 6)@58..59,#SpanAnchor(FileId(0), 6)@59..60 foo#SpanAnchor(FileId(0), 6)@61..64,#SpanAnchor(FileId(0), 6)@64..65 identity#SpanAnchor(FileId(0), 6)@66..74!#SpanAnchor(FileId(0), 6)@74..75(#SpanAnchor(FileId(0), 6)@75..7610#SpanAnchor(FileId(0), 6)@76..78)#SpanAnchor(FileId(0), 6)@78..79,#SpanAnchor(FileId(0), 6)@79..80 "bar"#SpanAnchor(FileId(0), 6)@81..86)#SpanAnchor(FileId(0), 6)@86..87
 }
 
 "##]],
diff --git a/crates/hir-def/src/macro_expansion_tests/mod.rs b/crates/hir-def/src/macro_expansion_tests/mod.rs
index 8adced4e082..1a672b4605c 100644
--- a/crates/hir-def/src/macro_expansion_tests/mod.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mod.rs
@@ -16,21 +16,16 @@ mod proc_macros;
 
 use std::{iter, ops::Range, sync};
 
-use ::mbe::TokenMap;
 use base_db::{fixture::WithFixture, ProcMacro, SourceDatabase};
 use expect_test::Expect;
-use hir_expand::{
-    db::{DeclarativeMacroExpander, ExpandDatabase},
-    AstId, InFile, MacroFile,
-};
+use hir_expand::{db::ExpandDatabase, HirFileIdExt, InFile, MacroFile, SpanMap};
 use stdx::format_to;
 use syntax::{
     ast::{self, edit::IndentLevel},
-    AstNode, SyntaxElement,
-    SyntaxKind::{self, COMMENT, EOF, IDENT, LIFETIME_IDENT},
-    SyntaxNode, TextRange, T,
+    AstNode,
+    SyntaxKind::{COMMENT, EOF, IDENT, LIFETIME_IDENT},
+    SyntaxNode, T,
 };
-use tt::token_id::{Subtree, TokenId};
 
 use crate::{
     db::DefDatabase,
@@ -39,6 +34,7 @@ use crate::{
     resolver::HasResolver,
     src::HasSource,
     test_db::TestDB,
+    tt::Subtree,
     AdtId, AsMacroCall, Lookup, ModuleDefId,
 };
 
@@ -88,43 +84,6 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
     let mut text_edits = Vec::new();
     let mut expansions = Vec::new();
 
-    for macro_ in source_file.syntax().descendants().filter_map(ast::Macro::cast) {
-        let mut show_token_ids = false;
-        for comment in macro_.syntax().children_with_tokens().filter(|it| it.kind() == COMMENT) {
-            show_token_ids |= comment.to_string().contains("+tokenids");
-        }
-        if !show_token_ids {
-            continue;
-        }
-
-        let call_offset = macro_.syntax().text_range().start().into();
-        let file_ast_id = db.ast_id_map(source.file_id).ast_id(&macro_);
-        let ast_id = AstId::new(source.file_id, file_ast_id.upcast());
-
-        let DeclarativeMacroExpander { mac, def_site_token_map } =
-            &*db.decl_macro_expander(krate, ast_id);
-        assert_eq!(mac.err(), None);
-        let tt = match &macro_ {
-            ast::Macro::MacroRules(mac) => mac.token_tree().unwrap(),
-            ast::Macro::MacroDef(_) => unimplemented!(""),
-        };
-
-        let tt_start = tt.syntax().text_range().start();
-        tt.syntax().descendants_with_tokens().filter_map(SyntaxElement::into_token).for_each(
-            |token| {
-                let range = token.text_range().checked_sub(tt_start).unwrap();
-                if let Some(id) = def_site_token_map.token_by_range(range) {
-                    let offset = (range.end() + tt_start).into();
-                    text_edits.push((offset..offset, format!("#{}", id.0)));
-                }
-            },
-        );
-        text_edits.push((
-            call_offset..call_offset,
-            format!("// call ids will be shifted by {:?}\n", mac.shift()),
-        ));
-    }
-
     for macro_call in source_file.syntax().descendants().filter_map(ast::MacroCall::cast) {
         let macro_call = InFile::new(source.file_id, &macro_call);
         let res = macro_call
@@ -138,10 +97,10 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
         let macro_file = MacroFile { macro_call_id };
         let mut expansion_result = db.parse_macro_expansion(macro_file);
         expansion_result.err = expansion_result.err.or(res.err);
-        expansions.push((macro_call.value.clone(), expansion_result, db.macro_arg(macro_call_id)));
+        expansions.push((macro_call.value.clone(), expansion_result));
     }
 
-    for (call, exp, arg) in expansions.into_iter().rev() {
+    for (call, exp) in expansions.into_iter().rev() {
         let mut tree = false;
         let mut expect_errors = false;
         let mut show_token_ids = false;
@@ -185,27 +144,7 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
         }
         let range = call.syntax().text_range();
         let range: Range<usize> = range.into();
-
-        if show_token_ids {
-            if let Some((tree, map, _)) = arg.value.as_deref() {
-                let tt_range = call.token_tree().unwrap().syntax().text_range();
-                let mut ranges = Vec::new();
-                extract_id_ranges(&mut ranges, map, tree);
-                for (range, id) in ranges {
-                    let idx = (tt_range.start() + range.end()).into();
-                    text_edits.push((idx..idx, format!("#{}", id.0)));
-                }
-            }
-            text_edits.push((range.start..range.start, "// ".into()));
-            call.to_string().match_indices('\n').for_each(|(offset, _)| {
-                let offset = offset + 1 + range.start;
-                text_edits.push((offset..offset, "// ".into()));
-            });
-            text_edits.push((range.end..range.end, "\n".into()));
-            text_edits.push((range.end..range.end, expn_text));
-        } else {
-            text_edits.push((range, expn_text));
-        }
+        text_edits.push((range, expn_text));
     }
 
     text_edits.sort_by_key(|(range, _)| range.start);
@@ -246,20 +185,6 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
     expect.assert_eq(&expanded_text);
 }
 
-fn extract_id_ranges(ranges: &mut Vec<(TextRange, TokenId)>, map: &TokenMap, tree: &Subtree) {
-    tree.token_trees.iter().for_each(|tree| match tree {
-        tt::TokenTree::Leaf(leaf) => {
-            let id = match leaf {
-                tt::Leaf::Literal(it) => it.span,
-                tt::Leaf::Punct(it) => it.span,
-                tt::Leaf::Ident(it) => it.span,
-            };
-            ranges.extend(map.ranges_by_token(id, SyntaxKind::ERROR).map(|range| (range, id)));
-        }
-        tt::TokenTree::Subtree(tree) => extract_id_ranges(ranges, map, tree),
-    });
-}
-
 fn reindent(indent: IndentLevel, pp: String) -> String {
     if !pp.contains('\n') {
         return pp;
@@ -276,7 +201,7 @@ fn reindent(indent: IndentLevel, pp: String) -> String {
     res
 }
 
-fn pretty_print_macro_expansion(expn: SyntaxNode, map: Option<&TokenMap>) -> String {
+fn pretty_print_macro_expansion(expn: SyntaxNode, map: Option<&SpanMap>) -> String {
     let mut res = String::new();
     let mut prev_kind = EOF;
     let mut indent_level = 0;
@@ -323,8 +248,8 @@ fn pretty_print_macro_expansion(expn: SyntaxNode, map: Option<&TokenMap>) -> Str
         prev_kind = curr_kind;
         format_to!(res, "{}", token);
         if let Some(map) = map {
-            if let Some(id) = map.token_by_range(token.text_range()) {
-                format_to!(res, "#{}", id.0);
+            if let Some(span) = map.span_for_range(token.text_range()) {
+                format_to!(res, "#{:?}@{:?}", span.anchor, span.range);
             }
         }
     }
diff --git a/crates/hir-def/src/nameres/collector.rs b/crates/hir-def/src/nameres/collector.rs
index 2d4586146db..659e7ed5033 100644
--- a/crates/hir-def/src/nameres/collector.rs
+++ b/crates/hir-def/src/nameres/collector.rs
@@ -5,6 +5,7 @@
 
 use std::{cmp::Ordering, iter, mem};
 
+use ::tt::Span;
 use base_db::{CrateId, Dependency, Edition, FileId};
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
@@ -85,8 +86,7 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, def_map: DefMap, tree_id: TreeI
                     .enumerate()
                     .map(|(idx, it)| {
                         // FIXME: a hacky way to create a Name from string.
-                        let name =
-                            tt::Ident { text: it.name.clone(), span: tt::TokenId::unspecified() };
+                        let name = tt::Ident { text: it.name.clone(), span: tt::SpanData::DUMMY };
                         (name.as_name(), ProcMacroExpander::new(base_db::ProcMacroId(idx as u32)))
                     })
                     .collect())
@@ -471,7 +471,7 @@ impl DefCollector<'_> {
                         directive.module_id,
                         MacroCallKind::Attr {
                             ast_id: ast_id.ast_id,
-                            attr_args: Arc::new((tt::Subtree::empty(), Default::default())),
+                            attr_args: Arc::new(tt::Subtree::empty()),
                             invoc_attr_index: attr.id,
                         },
                         attr.path().clone(),
@@ -2083,8 +2083,7 @@ impl ModCollector<'_, '_> {
             let name = match attrs.by_key("rustc_builtin_macro").string_value() {
                 Some(it) => {
                     // FIXME: a hacky way to create a Name from string.
-                    name =
-                        tt::Ident { text: it.clone(), span: tt::TokenId::unspecified() }.as_name();
+                    name = tt::Ident { text: it.clone(), span: tt::SpanData::DUMMY }.as_name();
                     &name
                 }
                 None => {
diff --git a/crates/hir-def/src/nameres/mod_resolution.rs b/crates/hir-def/src/nameres/mod_resolution.rs
index 2dcc2c30fe1..22802433aa5 100644
--- a/crates/hir-def/src/nameres/mod_resolution.rs
+++ b/crates/hir-def/src/nameres/mod_resolution.rs
@@ -1,7 +1,7 @@
 //! This module resolves `mod foo;` declaration to file.
 use arrayvec::ArrayVec;
 use base_db::{AnchoredPath, FileId};
-use hir_expand::name::Name;
+use hir_expand::{name::Name, HirFileIdExt};
 use limit::Limit;
 use syntax::SmolStr;
 
diff --git a/crates/hir-def/src/nameres/tests/incremental.rs b/crates/hir-def/src/nameres/tests/incremental.rs
index 4a86f88e57a..977745c476f 100644
--- a/crates/hir-def/src/nameres/tests/incremental.rs
+++ b/crates/hir-def/src/nameres/tests/incremental.rs
@@ -66,7 +66,7 @@ fn typing_inside_a_function_should_not_invalidate_def_map() {
 
 #[test]
 fn typing_inside_a_macro_should_not_invalidate_def_map() {
-    let (mut db, pos) = TestDB::with_position(
+    check_def_map_is_not_recomputed(
         r"
         //- /lib.rs
         macro_rules! m {
@@ -84,27 +84,15 @@ fn typing_inside_a_macro_should_not_invalidate_def_map() {
         //- /foo/bar.rs
         $0
         m!(X);
+
+        pub struct S {}
         ",
-    );
-    let krate = db.test_crate();
-    {
-        let events = db.log_executed(|| {
-            let crate_def_map = db.crate_def_map(krate);
-            let (_, module_data) = crate_def_map.modules.iter().last().unwrap();
-            assert_eq!(module_data.scope.resolutions().count(), 1);
-        });
-        assert!(format!("{events:?}").contains("crate_def_map"), "{events:#?}")
-    }
-    db.set_file_text(pos.file_id, Arc::from("m!(Y);"));
+        r"
+        m!(Y);
 
-    {
-        let events = db.log_executed(|| {
-            let crate_def_map = db.crate_def_map(krate);
-            let (_, module_data) = crate_def_map.modules.iter().last().unwrap();
-            assert_eq!(module_data.scope.resolutions().count(), 1);
-        });
-        assert!(!format!("{events:?}").contains("crate_def_map"), "{events:#?}")
-    }
+        pub struct S {}
+        ",
+    );
 }
 
 #[test]
diff --git a/crates/hir-expand/src/ast_id_map.rs b/crates/hir-expand/src/ast_id_map.rs
index 40726505491..eb43ae37e08 100644
--- a/crates/hir-expand/src/ast_id_map.rs
+++ b/crates/hir-expand/src/ast_id_map.rs
@@ -12,11 +12,13 @@ use std::{
     marker::PhantomData,
 };
 
-use la_arena::{Arena, Idx};
+use la_arena::{Arena, Idx, RawIdx};
 use profile::Count;
 use rustc_hash::FxHasher;
 use syntax::{ast, AstNode, AstPtr, SyntaxNode, SyntaxNodePtr};
 
+pub use base_db::span::ErasedFileAstId;
+
 /// `AstId` points to an AST node in a specific file.
 pub struct FileAstId<N: AstIdNode> {
     raw: ErasedFileAstId,
@@ -62,8 +64,6 @@ impl<N: AstIdNode> FileAstId<N> {
     }
 }
 
-pub type ErasedFileAstId = Idx<SyntaxNodePtr>;
-
 pub trait AstIdNode: AstNode {}
 macro_rules! register_ast_id_node {
     (impl AstIdNode for $($ident:ident),+ ) => {
@@ -129,6 +129,11 @@ impl AstIdMap {
     pub(crate) fn from_source(node: &SyntaxNode) -> AstIdMap {
         assert!(node.parent().is_none());
         let mut res = AstIdMap::default();
+
+        // make sure to allocate the root node
+        if !should_alloc_id(node.kind()) {
+            res.alloc(node);
+        }
         // By walking the tree in breadth-first order we make sure that parents
         // get lower ids then children. That is, adding a new child does not
         // change parent's id. This means that, say, adding a new function to a
@@ -155,6 +160,11 @@ impl AstIdMap {
         res
     }
 
+    /// The [`AstId`] of the root node
+    pub fn root(&self) -> SyntaxNodePtr {
+        self.arena[Idx::from_raw(RawIdx::from_u32(0))].clone()
+    }
+
     pub fn ast_id<N: AstIdNode>(&self, item: &N) -> FileAstId<N> {
         let raw = self.erased_ast_id(item.syntax());
         FileAstId { raw, covariant: PhantomData }
@@ -164,7 +174,7 @@ impl AstIdMap {
         AstPtr::try_from_raw(self.arena[id.raw].clone()).unwrap()
     }
 
-    pub(crate) fn get_raw(&self, id: ErasedFileAstId) -> SyntaxNodePtr {
+    pub fn get_raw(&self, id: ErasedFileAstId) -> SyntaxNodePtr {
         self.arena[id].clone()
     }
 
diff --git a/crates/hir-expand/src/attrs.rs b/crates/hir-expand/src/attrs.rs
index 0ec2422b30c..9652dd345a8 100644
--- a/crates/hir-expand/src/attrs.rs
+++ b/crates/hir-expand/src/attrs.rs
@@ -1,7 +1,8 @@
 //! A higher level attributes based on TokenTree, with also some shortcuts.
 use std::{fmt, ops};
 
-use base_db::CrateId;
+use ::tt::Span;
+use base_db::{span::SpanAnchor, CrateId};
 use cfg::CfgExpr;
 use either::Either;
 use intern::Interned;
@@ -39,11 +40,16 @@ impl ops::Deref for RawAttrs {
 impl RawAttrs {
     pub const EMPTY: Self = Self { entries: None };
 
-    pub fn new(db: &dyn ExpandDatabase, owner: &dyn ast::HasAttrs, hygiene: &Hygiene) -> Self {
+    pub fn new(
+        db: &dyn ExpandDatabase,
+        span_anchor: SpanAnchor,
+        owner: &dyn ast::HasAttrs,
+        hygiene: &Hygiene,
+    ) -> Self {
         let entries = collect_attrs(owner)
             .filter_map(|(id, attr)| match attr {
                 Either::Left(attr) => {
-                    attr.meta().and_then(|meta| Attr::from_src(db, meta, hygiene, id))
+                    attr.meta().and_then(|meta| Attr::from_src(db, span_anchor, meta, hygiene, id))
                 }
                 Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
                     id,
@@ -58,9 +64,13 @@ impl RawAttrs {
         Self { entries: if entries.is_empty() { None } else { Some(entries) } }
     }
 
-    pub fn from_attrs_owner(db: &dyn ExpandDatabase, owner: InFile<&dyn ast::HasAttrs>) -> Self {
+    pub fn from_attrs_owner(
+        db: &dyn ExpandDatabase,
+        span_anchor: SpanAnchor,
+        owner: InFile<&dyn ast::HasAttrs>,
+    ) -> Self {
         let hygiene = Hygiene::new(db, owner.file_id);
-        Self::new(db, owner.value, &hygiene)
+        Self::new(db, span_anchor, owner.value, &hygiene)
     }
 
     pub fn merge(&self, other: Self) -> Self {
@@ -190,16 +200,17 @@ pub struct Attr {
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum AttrInput {
     /// `#[attr = "string"]`
+    // FIXME: This is losing span
     Literal(SmolStr),
     /// `#[attr(subtree)]`
-    TokenTree(Box<(tt::Subtree, mbe::TokenMap)>),
+    TokenTree(Box<tt::Subtree>),
 }
 
 impl fmt::Display for AttrInput {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             AttrInput::Literal(lit) => write!(f, " = \"{}\"", lit.escape_debug()),
-            AttrInput::TokenTree(tt) => tt.0.fmt(f),
+            AttrInput::TokenTree(tt) => tt.fmt(f),
         }
     }
 }
@@ -207,6 +218,7 @@ impl fmt::Display for AttrInput {
 impl Attr {
     fn from_src(
         db: &dyn ExpandDatabase,
+        span_anchor: SpanAnchor,
         ast: ast::Meta,
         hygiene: &Hygiene,
         id: AttrId,
@@ -219,8 +231,13 @@ impl Attr {
             };
             Some(Interned::new(AttrInput::Literal(value)))
         } else if let Some(tt) = ast.token_tree() {
-            let (tree, map) = syntax_node_to_token_tree(tt.syntax());
-            Some(Interned::new(AttrInput::TokenTree(Box::new((tree, map)))))
+            // FIXME: We could also allocate ids for attributes and use the attribute itself as an anchor
+            let offset =
+                db.ast_id_map(span_anchor.file_id).get_raw(span_anchor.ast_id).text_range().start();
+            // FIXME: Spanmap
+            let tree =
+                syntax_node_to_token_tree(tt.syntax(), span_anchor, offset, &Default::default());
+            Some(Interned::new(AttrInput::TokenTree(Box::new(tree))))
         } else {
             None
         };
@@ -233,10 +250,12 @@ impl Attr {
         hygiene: &Hygiene,
         id: AttrId,
     ) -> Option<Attr> {
-        let (parse, _) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MetaItem);
+        // FIXME: Unecessary roundtrip tt -> ast -> tt
+        let (parse, _map) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MetaItem);
         let ast = ast::Meta::cast(parse.syntax_node())?;
 
-        Self::from_src(db, ast, hygiene, id)
+        // FIXME: we discard spans here!
+        Self::from_src(db, SpanAnchor::DUMMY, ast, hygiene, id)
     }
 
     pub fn path(&self) -> &ModPath {
@@ -256,7 +275,7 @@ impl Attr {
     /// #[path(ident)]
     pub fn single_ident_value(&self) -> Option<&tt::Ident> {
         match self.input.as_deref()? {
-            AttrInput::TokenTree(tt) => match &*tt.0.token_trees {
+            AttrInput::TokenTree(tt) => match &*tt.token_trees {
                 [tt::TokenTree::Leaf(tt::Leaf::Ident(ident))] => Some(ident),
                 _ => None,
             },
@@ -267,7 +286,7 @@ impl Attr {
     /// #[path TokenTree]
     pub fn token_tree_value(&self) -> Option<&Subtree> {
         match self.input.as_deref()? {
-            AttrInput::TokenTree(tt) => Some(&tt.0),
+            AttrInput::TokenTree(tt) => Some(tt),
             _ => None,
         }
     }
diff --git a/crates/hir-expand/src/builtin_attr_macro.rs b/crates/hir-expand/src/builtin_attr_macro.rs
index 4ee12e2f212..de8c0ac810b 100644
--- a/crates/hir-expand/src/builtin_attr_macro.rs
+++ b/crates/hir-expand/src/builtin_attr_macro.rs
@@ -1,5 +1,7 @@
 //! Builtin attributes.
 
+use ::tt::Span;
+
 use crate::{db::ExpandDatabase, name, tt, ExpandResult, MacroCallId, MacroCallKind};
 
 macro_rules! register_builtin {
@@ -98,7 +100,7 @@ fn derive_attr_expand(
 ) -> ExpandResult<tt::Subtree> {
     let loc = db.lookup_intern_macro_call(id);
     let derives = match &loc.kind {
-        MacroCallKind::Attr { attr_args, .. } if loc.def.is_attribute_derive() => &attr_args.0,
+        MacroCallKind::Attr { attr_args, .. } if loc.def.is_attribute_derive() => attr_args,
         _ => return ExpandResult::ok(tt::Subtree::empty()),
     };
     pseudo_derive_attr_expansion(tt, derives)
@@ -112,7 +114,7 @@ pub fn pseudo_derive_attr_expansion(
         tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct {
             char,
             spacing: tt::Spacing::Alone,
-            span: tt::TokenId::unspecified(),
+            span: tt::SpanData::DUMMY,
         }))
     };
 
diff --git a/crates/hir-expand/src/builtin_derive_macro.rs b/crates/hir-expand/src/builtin_derive_macro.rs
index ecc8b407a9c..16cce35c13d 100644
--- a/crates/hir-expand/src/builtin_derive_macro.rs
+++ b/crates/hir-expand/src/builtin_derive_macro.rs
@@ -1,18 +1,20 @@
 //! Builtin derives.
 
-use ::tt::Ident;
+use ::tt::Span;
 use base_db::{CrateOrigin, LangCrateOrigin};
 use itertools::izip;
-use mbe::TokenMap;
 use rustc_hash::FxHashSet;
 use stdx::never;
 use tracing::debug;
 
 use crate::{
     name::{AsName, Name},
-    tt::{self, TokenId},
+    tt, SpanMap,
+};
+use syntax::{
+    ast::{self, AstNode, FieldList, HasAttrs, HasGenericParams, HasName, HasTypeBounds},
+    TextSize,
 };
-use syntax::ast::{self, AstNode, FieldList, HasAttrs, HasGenericParams, HasName, HasTypeBounds};
 
 use crate::{db::ExpandDatabase, name, quote, ExpandError, ExpandResult, MacroCallId};
 
@@ -29,7 +31,7 @@ macro_rules! register_builtin {
                 db: &dyn ExpandDatabase,
                 id: MacroCallId,
                 tt: &ast::Adt,
-                token_map: &TokenMap,
+                token_map: &SpanMap,
             ) -> ExpandResult<tt::Subtree> {
                 let expander = match *self {
                     $( BuiltinDeriveExpander::$trait => $expand, )*
@@ -71,7 +73,7 @@ enum VariantShape {
 }
 
 fn tuple_field_iterator(n: usize) -> impl Iterator<Item = tt::Ident> {
-    (0..n).map(|it| Ident::new(format!("f{it}"), tt::TokenId::unspecified()))
+    (0..n).map(|it| tt::Ident::new(format!("f{it}"), tt::SpanData::DUMMY))
 }
 
 impl VariantShape {
@@ -117,7 +119,7 @@ impl VariantShape {
         }
     }
 
-    fn from(tm: &TokenMap, value: Option<FieldList>) -> Result<Self, ExpandError> {
+    fn from(tm: &SpanMap, value: Option<FieldList>) -> Result<Self, ExpandError> {
         let r = match value {
             None => VariantShape::Unit,
             Some(FieldList::RecordFieldList(it)) => VariantShape::Struct(
@@ -189,8 +191,8 @@ struct BasicAdtInfo {
     associated_types: Vec<tt::Subtree>,
 }
 
-fn parse_adt(tm: &TokenMap, adt: &ast::Adt) -> Result<BasicAdtInfo, ExpandError> {
-    let (name, generic_param_list, shape) = match &adt {
+fn parse_adt(tm: &SpanMap, adt: &ast::Adt) -> Result<BasicAdtInfo, ExpandError> {
+    let (name, generic_param_list, shape) = match adt {
         ast::Adt::Struct(it) => (
             it.name(),
             it.generic_param_list(),
@@ -234,21 +236,44 @@ fn parse_adt(tm: &TokenMap, adt: &ast::Adt) -> Result<BasicAdtInfo, ExpandError>
                 match this {
                     Some(it) => {
                         param_type_set.insert(it.as_name());
-                        mbe::syntax_node_to_token_tree(it.syntax()).0
+                        mbe::syntax_node_to_token_tree(
+                            it.syntax(),
+                            tm.span_for_range(it.syntax().first_token().unwrap().text_range())
+                                .unwrap()
+                                .anchor,
+                            TextSize::from(0),
+                            tm,
+                        )
                     }
                     None => tt::Subtree::empty(),
                 }
             };
             let bounds = match &param {
-                ast::TypeOrConstParam::Type(it) => {
-                    it.type_bound_list().map(|it| mbe::syntax_node_to_token_tree(it.syntax()).0)
-                }
+                ast::TypeOrConstParam::Type(it) => it.type_bound_list().map(|it| {
+                    mbe::syntax_node_to_token_tree(
+                        it.syntax(),
+                        tm.span_for_range(it.syntax().first_token().unwrap().text_range())
+                            .unwrap()
+                            .anchor,
+                        TextSize::from(0),
+                        tm,
+                    )
+                }),
                 ast::TypeOrConstParam::Const(_) => None,
             };
             let ty = if let ast::TypeOrConstParam::Const(param) = param {
                 let ty = param
                     .ty()
-                    .map(|ty| mbe::syntax_node_to_token_tree(ty.syntax()).0)
+                    .map(|ty| {
+                        mbe::syntax_node_to_token_tree(
+                            ty.syntax(),
+                            tm.span_for_range(ty.syntax().first_token().unwrap().text_range())
+                                .unwrap()
+                                .anchor,
+                            TextSize::from(0),
+                            tm,
+                        )
+                    })
                     .unwrap_or_else(tt::Subtree::empty);
                 Some(ty)
             } else {
@@ -282,20 +307,26 @@ fn parse_adt(tm: &TokenMap, adt: &ast::Adt) -> Result<BasicAdtInfo, ExpandError>
             let name = p.path()?.qualifier()?.as_single_name_ref()?.as_name();
             param_type_set.contains(&name).then_some(p)
         })
-        .map(|it| mbe::syntax_node_to_token_tree(it.syntax()).0)
+        .map(|it| {
+            mbe::syntax_node_to_token_tree(
+                it.syntax(),
+                tm.span_for_range(it.syntax().first_token().unwrap().text_range()).unwrap().anchor,
+                TextSize::from(0),
+                tm,
+            )
+        })
         .collect();
     let name_token = name_to_token(&tm, name)?;
     Ok(BasicAdtInfo { name: name_token, shape, param_types, associated_types })
 }
 
-fn name_to_token(token_map: &TokenMap, name: Option<ast::Name>) -> Result<tt::Ident, ExpandError> {
+fn name_to_token(token_map: &SpanMap, name: Option<ast::Name>) -> Result<tt::Ident, ExpandError> {
     let name = name.ok_or_else(|| {
         debug!("parsed item has no name");
         ExpandError::other("missing name")
     })?;
-    let name_token_id =
-        token_map.token_by_range(name.syntax().text_range()).unwrap_or_else(TokenId::unspecified);
-    let name_token = tt::Ident { span: name_token_id, text: name.text().into() };
+    let span = token_map.span_for_range(name.syntax().text_range()).unwrap();
+    let name_token = tt::Ident { span, text: name.text().into() };
     Ok(name_token)
 }
 
@@ -332,7 +363,7 @@ fn name_to_token(token_map: &TokenMap, name: Option<ast::Name>) -> Result<tt::Id
 /// therefore does not get bound by the derived trait.
 fn expand_simple_derive(
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
     trait_path: tt::Subtree,
     make_trait_body: impl FnOnce(&BasicAdtInfo) -> tt::Subtree,
 ) -> ExpandResult<tt::Subtree> {
@@ -393,7 +424,7 @@ fn copy_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::marker::Copy }, |_| quote! {})
@@ -403,16 +434,13 @@ fn clone_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::clone::Clone }, |adt| {
         if matches!(adt.shape, AdtShape::Union) {
-            let star = tt::Punct {
-                char: '*',
-                spacing: ::tt::Spacing::Alone,
-                span: tt::TokenId::unspecified(),
-            };
+            let star =
+                tt::Punct { char: '*', spacing: ::tt::Spacing::Alone, span: tt::SpanData::DUMMY };
             return quote! {
                 fn clone(&self) -> Self {
                     #star self
@@ -420,11 +448,8 @@ fn clone_expand(
             };
         }
         if matches!(&adt.shape, AdtShape::Enum { variants, .. } if variants.is_empty()) {
-            let star = tt::Punct {
-                char: '*',
-                spacing: ::tt::Spacing::Alone,
-                span: tt::TokenId::unspecified(),
-            };
+            let star =
+                tt::Punct { char: '*', spacing: ::tt::Spacing::Alone, span: tt::SpanData::DUMMY };
             return quote! {
                 fn clone(&self) -> Self {
                     match #star self {}
@@ -452,16 +477,14 @@ fn clone_expand(
 }
 
 /// This function exists since `quote! { => }` doesn't work.
-fn fat_arrow() -> ::tt::Subtree<TokenId> {
-    let eq =
-        tt::Punct { char: '=', spacing: ::tt::Spacing::Joint, span: tt::TokenId::unspecified() };
+fn fat_arrow() -> tt::Subtree {
+    let eq = tt::Punct { char: '=', spacing: ::tt::Spacing::Joint, span: tt::SpanData::DUMMY };
     quote! { #eq> }
 }
 
 /// This function exists since `quote! { && }` doesn't work.
-fn and_and() -> ::tt::Subtree<TokenId> {
-    let and =
-        tt::Punct { char: '&', spacing: ::tt::Spacing::Joint, span: tt::TokenId::unspecified() };
+fn and_and() -> tt::Subtree {
+    let and = tt::Punct { char: '&', spacing: ::tt::Spacing::Joint, span: tt::SpanData::DUMMY };
     quote! { #and& }
 }
 
@@ -469,7 +492,7 @@ fn default_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::default::Default }, |adt| {
@@ -509,7 +532,7 @@ fn debug_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::fmt::Debug }, |adt| {
@@ -540,11 +563,8 @@ fn debug_expand(
             },
         };
         if matches!(&adt.shape, AdtShape::Enum { variants, .. } if variants.is_empty()) {
-            let star = tt::Punct {
-                char: '*',
-                spacing: ::tt::Spacing::Alone,
-                span: tt::TokenId::unspecified(),
-            };
+            let star =
+                tt::Punct { char: '*', spacing: ::tt::Spacing::Alone, span: tt::SpanData::DUMMY };
             return quote! {
                 fn fmt(&self, f: &mut #krate::fmt::Formatter) -> #krate::fmt::Result {
                     match #star self {}
@@ -590,7 +610,7 @@ fn hash_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::hash::Hash }, |adt| {
@@ -599,11 +619,8 @@ fn hash_expand(
             return quote! {};
         }
         if matches!(&adt.shape, AdtShape::Enum { variants, .. } if variants.is_empty()) {
-            let star = tt::Punct {
-                char: '*',
-                spacing: ::tt::Spacing::Alone,
-                span: tt::TokenId::unspecified(),
-            };
+            let star =
+                tt::Punct { char: '*', spacing: ::tt::Spacing::Alone, span: tt::SpanData::DUMMY };
             return quote! {
                 fn hash<H: #krate::hash::Hasher>(&self, ra_expand_state: &mut H) {
                     match #star self {}
@@ -644,7 +661,7 @@ fn eq_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::cmp::Eq }, |_| quote! {})
@@ -654,7 +671,7 @@ fn partial_eq_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::cmp::PartialEq }, |adt| {
@@ -674,14 +691,14 @@ fn partial_eq_expand(
                     }
                     [first, rest @ ..] => {
                         let rest = rest.iter().map(|it| {
-                            let t1 = Ident::new(format!("{}_self", it.text), it.span);
-                            let t2 = Ident::new(format!("{}_other", it.text), it.span);
+                            let t1 = tt::Ident::new(format!("{}_self", it.text), it.span);
+                            let t2 = tt::Ident::new(format!("{}_other", it.text), it.span);
                             let and_and = and_and();
                             quote!(#and_and #t1 .eq( #t2 ))
                         });
                         let first = {
-                            let t1 = Ident::new(format!("{}_self", first.text), first.span);
-                            let t2 = Ident::new(format!("{}_other", first.text), first.span);
+                            let t1 = tt::Ident::new(format!("{}_self", first.text), first.span);
+                            let t2 = tt::Ident::new(format!("{}_other", first.text), first.span);
                             quote!(#t1 .eq( #t2 ))
                         };
                         quote!(#first ##rest)
@@ -708,11 +725,11 @@ fn self_and_other_patterns(
     name: &tt::Ident,
 ) -> (Vec<tt::Subtree>, Vec<tt::Subtree>) {
     let self_patterns = adt.shape.as_pattern_map(name, |it| {
-        let t = Ident::new(format!("{}_self", it.text), it.span);
+        let t = tt::Ident::new(format!("{}_self", it.text), it.span);
         quote!(#t)
     });
     let other_patterns = adt.shape.as_pattern_map(name, |it| {
-        let t = Ident::new(format!("{}_other", it.text), it.span);
+        let t = tt::Ident::new(format!("{}_other", it.text), it.span);
         quote!(#t)
     });
     (self_patterns, other_patterns)
@@ -722,7 +739,7 @@ fn ord_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::cmp::Ord }, |adt| {
@@ -752,8 +769,8 @@ fn ord_expand(
             |(pat1, pat2, fields)| {
                 let mut body = quote!(#krate::cmp::Ordering::Equal);
                 for f in fields.into_iter().rev() {
-                    let t1 = Ident::new(format!("{}_self", f.text), f.span);
-                    let t2 = Ident::new(format!("{}_other", f.text), f.span);
+                    let t1 = tt::Ident::new(format!("{}_self", f.text), f.span);
+                    let t2 = tt::Ident::new(format!("{}_other", f.text), f.span);
                     body = compare(krate, quote!(#t1), quote!(#t2), body);
                 }
                 let fat_arrow = fat_arrow();
@@ -784,7 +801,7 @@ fn partial_ord_expand(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
     tt: &ast::Adt,
-    tm: &TokenMap,
+    tm: &SpanMap,
 ) -> ExpandResult<tt::Subtree> {
     let krate = &find_builtin_crate(db, id);
     expand_simple_derive(tt, tm, quote! { #krate::cmp::PartialOrd }, |adt| {
@@ -817,8 +834,8 @@ fn partial_ord_expand(
             |(pat1, pat2, fields)| {
                 let mut body = quote!(#krate::option::Option::Some(#krate::cmp::Ordering::Equal));
                 for f in fields.into_iter().rev() {
-                    let t1 = Ident::new(format!("{}_self", f.text), f.span);
-                    let t2 = Ident::new(format!("{}_other", f.text), f.span);
+                    let t1 = tt::Ident::new(format!("{}_self", f.text), f.span);
+                    let t2 = tt::Ident::new(format!("{}_other", f.text), f.span);
                     body = compare(krate, quote!(#t1), quote!(#t2), body);
                 }
                 let fat_arrow = fat_arrow();
diff --git a/crates/hir-expand/src/builtin_fn_macro.rs b/crates/hir-expand/src/builtin_fn_macro.rs
index a04de10b899..adbe49473ac 100644
--- a/crates/hir-expand/src/builtin_fn_macro.rs
+++ b/crates/hir-expand/src/builtin_fn_macro.rs
@@ -1,17 +1,22 @@
 //! Builtin macro
 
-use base_db::{AnchoredPath, Edition, FileId};
+use base_db::{
+    span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID},
+    AnchoredPath, Edition, FileId,
+};
 use cfg::CfgExpr;
 use either::Either;
-use mbe::{parse_exprs_with_sep, parse_to_token_tree, TokenMap};
+use mbe::{parse_exprs_with_sep, parse_to_token_tree};
 use syntax::{
     ast::{self, AstToken},
     SmolStr,
 };
 
 use crate::{
-    db::ExpandDatabase, name, quote, tt, EagerCallInfo, ExpandError, ExpandResult, MacroCallId,
-    MacroCallLoc,
+    db::ExpandDatabase,
+    name, quote,
+    tt::{self, Span},
+    EagerCallInfo, ExpandError, ExpandResult, HirFileIdExt, MacroCallId, MacroCallLoc,
 };
 
 macro_rules! register_builtin {
@@ -110,7 +115,7 @@ register_builtin! {
 }
 
 const DOLLAR_CRATE: tt::Ident =
-    tt::Ident { text: SmolStr::new_inline("$crate"), span: tt::TokenId::unspecified() };
+    tt::Ident { text: SmolStr::new_inline("$crate"), span: tt::SpanData::DUMMY };
 
 fn module_path_expand(
     _db: &dyn ExpandDatabase,
@@ -131,7 +136,7 @@ fn line_expand(
         delimiter: tt::Delimiter::unspecified(),
         token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Literal(tt::Literal {
             text: "0u32".into(),
-            span: tt::Span::UNSPECIFIED,
+            span: tt::SpanData::DUMMY,
         }))],
     })
 }
@@ -179,7 +184,7 @@ fn assert_expand(
                 token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct {
                     char: ',',
                     spacing: tt::Spacing::Alone,
-                    span: tt::TokenId::unspecified(),
+                    span: tt::SpanData::DUMMY,
                 }))],
             };
             let cond = cond.clone();
@@ -446,7 +451,7 @@ fn concat_bytes_expand(
             }
         }
     }
-    let ident = tt::Ident { text: bytes.join(", ").into(), span: tt::TokenId::unspecified() };
+    let ident = tt::Ident { text: bytes.join(", ").into(), span: tt::SpanData::DUMMY };
     ExpandResult { value: quote!([#ident]), err }
 }
 
@@ -494,7 +499,7 @@ fn concat_idents_expand(
             }
         }
     }
-    let ident = tt::Ident { text: ident.into(), span: tt::TokenId::unspecified() };
+    let ident = tt::Ident { text: ident.into(), span: tt::SpanData::DUMMY };
     ExpandResult { value: quote!(#ident), err }
 }
 
@@ -533,15 +538,16 @@ fn include_expand(
     _tt: &tt::Subtree,
 ) -> ExpandResult<tt::Subtree> {
     match db.include_expand(arg_id) {
-        Ok((res, _)) => ExpandResult::ok(res.0.clone()),
+        Ok((res, _)) => ExpandResult::ok(res.as_ref().clone()),
         Err(e) => ExpandResult::new(tt::Subtree::empty(), e),
     }
 }
 
+// FIXME: Check if this is still needed now after the token map rewrite
 pub(crate) fn include_arg_to_tt(
     db: &dyn ExpandDatabase,
     arg_id: MacroCallId,
-) -> Result<(triomphe::Arc<(::tt::Subtree<::tt::TokenId>, TokenMap)>, FileId), ExpandError> {
+) -> Result<(triomphe::Arc<tt::Subtree>, FileId), ExpandError> {
     let loc = db.lookup_intern_macro_call(arg_id);
     let Some(EagerCallInfo { arg, arg_id, .. }) = loc.eager.as_deref() else {
         panic!("include_arg_to_tt called on non include macro call: {:?}", &loc.eager);
@@ -549,9 +555,12 @@ pub(crate) fn include_arg_to_tt(
     let path = parse_string(&arg.0)?;
     let file_id = relative_file(db, *arg_id, &path, false)?;
 
-    let (subtree, map) =
-        parse_to_token_tree(&db.file_text(file_id)).ok_or(mbe::ExpandError::ConversionError)?;
-    Ok((triomphe::Arc::new((subtree, map)), file_id))
+    let subtree = parse_to_token_tree(
+        &db.file_text(file_id),
+        SpanAnchor { file_id: file_id.into(), ast_id: ROOT_ERASED_FILE_AST_ID },
+    )
+    .ok_or(mbe::ExpandError::ConversionError)?;
+    Ok((triomphe::Arc::new(subtree), file_id))
 }
 
 fn include_bytes_expand(
@@ -568,7 +577,7 @@ fn include_bytes_expand(
         delimiter: tt::Delimiter::unspecified(),
         token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Literal(tt::Literal {
             text: r#"b"""#.into(),
-            span: tt::TokenId::unspecified(),
+            span: tt::SpanData::DUMMY,
         }))],
     };
     ExpandResult::ok(res)
diff --git a/crates/hir-expand/src/db.rs b/crates/hir-expand/src/db.rs
index ff0d279d8cc..32ba7b2f911 100644
--- a/crates/hir-expand/src/db.rs
+++ b/crates/hir-expand/src/db.rs
@@ -1,22 +1,25 @@
 //! Defines database & queries for macro expansion.
 
-use base_db::{salsa, CrateId, Edition, SourceDatabase};
+use base_db::{
+    salsa,
+    span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID},
+    CrateId, Edition, SourceDatabase,
+};
 use either::Either;
 use limit::Limit;
-use mbe::{syntax_node_to_token_tree, ValueResult};
-use rustc_hash::FxHashSet;
+use mbe::{map_from_syntax_node, syntax_node_to_token_tree, ValueResult};
 use syntax::{
     ast::{self, HasAttrs, HasDocComments},
-    AstNode, GreenNode, Parse, SyntaxError, SyntaxNode, SyntaxToken, T,
+    AstNode, Parse, SyntaxError, SyntaxNode, SyntaxToken, TextSize, T,
 };
 use triomphe::Arc;
 
 use crate::{
     ast_id_map::AstIdMap, builtin_attr_macro::pseudo_derive_attr_expansion,
-    builtin_fn_macro::EagerExpander, fixup, hygiene::HygieneFrame, tt, AstId, BuiltinAttrExpander,
+    builtin_fn_macro::EagerExpander, hygiene::HygieneFrame, tt, AstId, BuiltinAttrExpander,
     BuiltinDeriveExpander, BuiltinFnLikeExpander, EagerCallInfo, ExpandError, ExpandResult,
     ExpandTo, HirFileId, HirFileIdRepr, MacroCallId, MacroCallKind, MacroCallLoc, MacroDefId,
-    MacroDefKind, MacroFile, ProcMacroExpander,
+    MacroDefKind, MacroFile, ProcMacroExpander, SpanMap, SyntaxContext, SyntaxContextId,
 };
 
 /// Total limit on the number of tokens produced by any macro invocation.
@@ -30,8 +33,7 @@ static TOKEN_LIMIT: Limit = Limit::new(1_048_576);
 #[derive(Debug, Clone, Eq, PartialEq)]
 /// Old-style `macro_rules` or the new macros 2.0
 pub struct DeclarativeMacroExpander {
-    pub mac: mbe::DeclarativeMacro,
-    pub def_site_token_map: mbe::TokenMap,
+    pub mac: mbe::DeclarativeMacro<base_db::span::SpanData>,
 }
 
 impl DeclarativeMacroExpander {
@@ -41,21 +43,14 @@ impl DeclarativeMacroExpander {
                 tt::Subtree::empty(),
                 ExpandError::other(format!("invalid macro definition: {e}")),
             ),
-            None => self.mac.expand(tt).map_err(Into::into),
+            None => self.mac.expand(&tt).map_err(Into::into),
         }
     }
-
-    pub fn map_id_down(&self, token_id: tt::TokenId) -> tt::TokenId {
-        self.mac.map_id_down(token_id)
-    }
-
-    pub fn map_id_up(&self, token_id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
-        self.mac.map_id_up(token_id)
-    }
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum TokenExpander {
+    /// Old-style `macro_rules` or the new macros 2.0
     DeclarativeMacro(Arc<DeclarativeMacroExpander>),
     /// Stuff like `line!` and `file!`.
     BuiltIn(BuiltinFnLikeExpander),
@@ -69,31 +64,6 @@ pub enum TokenExpander {
     ProcMacro(ProcMacroExpander),
 }
 
-// FIXME: Get rid of these methods
-impl TokenExpander {
-    pub(crate) fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
-        match self {
-            TokenExpander::DeclarativeMacro(expander) => expander.map_id_down(id),
-            TokenExpander::BuiltIn(..)
-            | TokenExpander::BuiltInEager(..)
-            | TokenExpander::BuiltInAttr(..)
-            | TokenExpander::BuiltInDerive(..)
-            | TokenExpander::ProcMacro(..) => id,
-        }
-    }
-
-    pub(crate) fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, mbe::Origin) {
-        match self {
-            TokenExpander::DeclarativeMacro(expander) => expander.map_id_up(id),
-            TokenExpander::BuiltIn(..)
-            | TokenExpander::BuiltInEager(..)
-            | TokenExpander::BuiltInAttr(..)
-            | TokenExpander::BuiltInDerive(..)
-            | TokenExpander::ProcMacro(..) => (id, mbe::Origin::Call),
-        }
-    }
-}
-
 #[salsa::query_group(ExpandDatabaseStorage)]
 pub trait ExpandDatabase: SourceDatabase {
     fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
@@ -109,7 +79,7 @@ pub trait ExpandDatabase: SourceDatabase {
     fn parse_macro_expansion(
         &self,
         macro_file: MacroFile,
-    ) -> ExpandResult<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>;
+    ) -> ExpandResult<(Parse<SyntaxNode>, Arc<SpanMap>)>;
 
     /// Macro ids. That's probably the tricksiest bit in rust-analyzer, and the
     /// reason why we use salsa at all.
@@ -118,23 +88,16 @@ pub trait ExpandDatabase: SourceDatabase {
     /// to be incremental.
     #[salsa::interned]
     fn intern_macro_call(&self, macro_call: MacroCallLoc) -> MacroCallId;
+    #[salsa::interned]
+    fn intern_syntax_context(&self, ctx: SyntaxContext) -> SyntaxContextId;
 
-    /// Lowers syntactic macro call to a token tree representation.
-    #[salsa::transparent]
-    fn macro_arg(
-        &self,
-        id: MacroCallId,
-    ) -> ValueResult<
-        Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>>,
-        Arc<Box<[SyntaxError]>>,
-    >;
-    /// Extracts syntax node, corresponding to a macro call. That's a firewall
+    /// Lowers syntactic macro call to a token tree representation. That's a firewall
     /// query, only typing in the macro call itself changes the returned
     /// subtree.
-    fn macro_arg_node(
+    fn macro_arg(
         &self,
         id: MacroCallId,
-    ) -> ValueResult<Option<GreenNode>, Arc<Box<[SyntaxError]>>>;
+    ) -> ValueResult<Option<Arc<tt::Subtree>>, Arc<Box<[SyntaxError]>>>;
     /// Fetches the expander for this macro.
     #[salsa::transparent]
     fn macro_expander(&self, id: MacroDefId) -> TokenExpander;
@@ -152,10 +115,7 @@ pub trait ExpandDatabase: SourceDatabase {
     fn include_expand(
         &self,
         arg_id: MacroCallId,
-    ) -> Result<
-        (triomphe::Arc<(::tt::Subtree<::tt::TokenId>, mbe::TokenMap)>, base_db::FileId),
-        ExpandError,
-    >;
+    ) -> Result<(triomphe::Arc<tt::Subtree>, base_db::FileId), ExpandError>;
     /// Special case of the previous query for procedural macros. We can't LRU
     /// proc macros, since they are not deterministic in general, and
     /// non-determinism breaks salsa in a very, very, very bad way.
@@ -181,21 +141,19 @@ pub fn expand_speculative(
     token_to_map: SyntaxToken,
 ) -> Option<(SyntaxNode, SyntaxToken)> {
     let loc = db.lookup_intern_macro_call(actual_macro_call);
-    let token_range = token_to_map.text_range();
+    let file_id = loc.kind.file_id();
 
     // Build the subtree and token mapping for the speculative args
-    let censor = censor_for_macro_input(&loc, speculative_args);
-    let mut fixups = fixup::fixup_syntax(speculative_args);
-    fixups.replace.extend(censor.into_iter().map(|node| (node.into(), Vec::new())));
-    let (mut tt, spec_args_tmap, _) = mbe::syntax_node_to_token_tree_with_modifications(
+    let _censor = censor_for_macro_input(&loc, speculative_args);
+    let mut tt = mbe::syntax_node_to_token_tree(
         speculative_args,
-        fixups.token_map,
-        fixups.next_id,
-        fixups.replace,
-        fixups.append,
+        // we don't leak these spans into any query so its fine to make them absolute
+        SpanAnchor { file_id, ast_id: ROOT_ERASED_FILE_AST_ID },
+        TextSize::new(0),
+        &Default::default(),
     );
 
-    let (attr_arg, token_id) = match loc.kind {
+    let attr_arg = match loc.kind {
         MacroCallKind::Attr { invoc_attr_index, .. } => {
             let attr = if loc.def.is_attribute_derive() {
                 // for pseudo-derive expansion we actually pass the attribute itself only
@@ -210,48 +168,27 @@ pub fn expand_speculative(
             }?;
             match attr.token_tree() {
                 Some(token_tree) => {
-                    let (mut tree, map) = syntax_node_to_token_tree(attr.token_tree()?.syntax());
-                    tree.delimiter = tt::Delimiter::unspecified();
-
-                    let shift = mbe::Shift::new(&tt);
-                    shift.shift_all(&mut tree);
-
-                    let token_id = if token_tree.syntax().text_range().contains_range(token_range) {
-                        let attr_input_start =
-                            token_tree.left_delimiter_token()?.text_range().start();
-                        let range = token_range.checked_sub(attr_input_start)?;
-                        let token_id = shift.shift(map.token_by_range(range)?);
-                        Some(token_id)
-                    } else {
-                        None
-                    };
-                    (Some(tree), token_id)
-                }
-                _ => (None, None),
-            }
-        }
-        _ => (None, None),
-    };
-    let token_id = match token_id {
-        Some(token_id) => token_id,
-        // token wasn't inside an attribute input so it has to be in the general macro input
-        None => {
-            let range = token_range.checked_sub(speculative_args.text_range().start())?;
-            let token_id = spec_args_tmap.token_by_range(range)?;
-            match loc.def.kind {
-                MacroDefKind::Declarative(it) => {
-                    db.decl_macro_expander(loc.krate, it).map_id_down(token_id)
+                    let mut tree = syntax_node_to_token_tree(
+                        token_tree.syntax(),
+                        SpanAnchor { file_id, ast_id: ROOT_ERASED_FILE_AST_ID },
+                        TextSize::new(0),
+                        &Default::default(),
+                    );
+                    tree.delimiter = tt::Delimiter::UNSPECIFIED;
+
+                    Some(tree)
                 }
-                _ => token_id,
+                _ => None,
             }
         }
+        _ => None,
     };
 
     // Do the actual expansion, we need to directly expand the proc macro due to the attribute args
     // Otherwise the expand query will fetch the non speculative attribute args and pass those instead.
-    let mut speculative_expansion = match loc.def.kind {
+    let speculative_expansion = match loc.def.kind {
         MacroDefKind::ProcMacro(expander, ..) => {
-            tt.delimiter = tt::Delimiter::unspecified();
+            tt.delimiter = tt::Delimiter::UNSPECIFIED;
             expander.expand(db, loc.def.krate, loc.krate, &tt, attr_arg.as_ref())
         }
         MacroDefKind::BuiltInAttr(BuiltinAttrExpander::Derive, _) => {
@@ -260,7 +197,17 @@ pub fn expand_speculative(
         MacroDefKind::BuiltInDerive(expander, ..) => {
             // this cast is a bit sus, can we avoid losing the typedness here?
             let adt = ast::Adt::cast(speculative_args.clone()).unwrap();
-            expander.expand(db, actual_macro_call, &adt, &spec_args_tmap)
+            expander.expand(
+                db,
+                actual_macro_call,
+                &adt,
+                &map_from_syntax_node(
+                    speculative_args,
+                    // we don't leak these spans into any query so its fine to make them absolute
+                    SpanAnchor { file_id, ast_id: ROOT_ERASED_FILE_AST_ID },
+                    TextSize::new(0),
+                ),
+            )
         }
         MacroDefKind::Declarative(it) => db.decl_macro_expander(loc.krate, it).expand(tt),
         MacroDefKind::BuiltIn(it, _) => it.expand(db, actual_macro_call, &tt).map_err(Into::into),
@@ -271,12 +218,14 @@ pub fn expand_speculative(
     };
 
     let expand_to = macro_expand_to(db, actual_macro_call);
-    fixup::reverse_fixups(&mut speculative_expansion.value, &spec_args_tmap, &fixups.undo_info);
-    let (node, rev_tmap) = token_tree_to_syntax_node(&speculative_expansion.value, expand_to);
+    let (node, rev_tmap) = token_tree_to_syntax_node(db, &speculative_expansion.value, expand_to);
 
     let syntax_node = node.syntax_node();
     let token = rev_tmap
-        .ranges_by_token(token_id, token_to_map.kind())
+        .ranges_with_span(tt::SpanData {
+            range: token_to_map.text_range(),
+            anchor: SpanAnchor { file_id, ast_id: ROOT_ERASED_FILE_AST_ID },
+        })
         .filter_map(|range| syntax_node.covering_element(range).into_token())
         .min_by_key(|t| {
             // prefer tokens of the same kind and text
@@ -293,7 +242,7 @@ fn ast_id_map(db: &dyn ExpandDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
 
 fn parse_or_expand(db: &dyn ExpandDatabase, file_id: HirFileId) -> SyntaxNode {
     match file_id.repr() {
-        HirFileIdRepr::FileId(file_id) => db.parse(file_id).tree().syntax().clone(),
+        HirFileIdRepr::FileId(file_id) => db.parse(file_id).syntax_node(),
         HirFileIdRepr::MacroFile(macro_file) => {
             db.parse_macro_expansion(macro_file).value.0.syntax_node()
         }
@@ -315,7 +264,7 @@ fn parse_or_expand_with_err(
 fn parse_macro_expansion(
     db: &dyn ExpandDatabase,
     macro_file: MacroFile,
-) -> ExpandResult<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)> {
+) -> ExpandResult<(Parse<SyntaxNode>, Arc<SpanMap>)> {
     let _p = profile::span("parse_macro_expansion");
     let mbe::ValueResult { value: tt, err } = db.macro_expand(macro_file.macro_call_id);
 
@@ -324,7 +273,7 @@ fn parse_macro_expansion(
     tracing::debug!("expanded = {}", tt.as_debug_string());
     tracing::debug!("kind = {:?}", expand_to);
 
-    let (parse, rev_token_map) = token_tree_to_syntax_node(&tt, expand_to);
+    let (parse, rev_token_map) = token_tree_to_syntax_node(db, &tt, expand_to);
 
     ExpandResult { value: (parse, Arc::new(rev_token_map)), err }
 }
@@ -340,48 +289,119 @@ fn parse_macro_expansion_error(
 fn macro_arg(
     db: &dyn ExpandDatabase,
     id: MacroCallId,
-) -> ValueResult<
-    Option<Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>>,
-    Arc<Box<[SyntaxError]>>,
-> {
-    let loc = db.lookup_intern_macro_call(id);
-
-    if let Some(EagerCallInfo { arg, arg_id: _, error: _ }) = loc.eager.as_deref() {
-        return ValueResult::ok(Some(Arc::new((arg.0.clone(), arg.1.clone(), Default::default()))));
-    }
-
-    let ValueResult { value, err } = db.macro_arg_node(id);
-    let Some(arg) = value else {
-        return ValueResult { value: None, err };
+) -> ValueResult<Option<Arc<tt::Subtree>>, Arc<Box<[SyntaxError]>>> {
+    let mismatched_delimiters = |arg: &SyntaxNode| {
+        let first = arg.first_child_or_token().map_or(T![.], |it| it.kind());
+        let last = arg.last_child_or_token().map_or(T![.], |it| it.kind());
+        let well_formed_tt =
+            matches!((first, last), (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']));
+        if !well_formed_tt {
+            // Don't expand malformed (unbalanced) macro invocations. This is
+            // less than ideal, but trying to expand unbalanced  macro calls
+            // sometimes produces pathological, deeply nested code which breaks
+            // all kinds of things.
+            //
+            // Some day, we'll have explicit recursion counters for all
+            // recursive things, at which point this code might be removed.
+            cov_mark::hit!(issue9358_bad_macro_stack_overflow);
+            Some(Arc::new(Box::new([SyntaxError::new(
+                "unbalanced token tree".to_owned(),
+                arg.text_range(),
+            )]) as Box<[_]>))
+        } else {
+            None
+        }
     };
+    let loc = db.lookup_intern_macro_call(id);
+    if let Some(EagerCallInfo { arg, .. }) = matches!(loc.def.kind, MacroDefKind::BuiltInEager(..))
+        .then(|| loc.eager.as_deref())
+        .flatten()
+    {
+        ValueResult::ok(Some(Arc::new(arg.0.clone())))
+    } else {
+        let (parse, map) = match loc.kind.file_id().repr() {
+            HirFileIdRepr::FileId(file_id) => {
+                (db.parse(file_id).to_syntax(), Arc::new(Default::default()))
+            }
+            HirFileIdRepr::MacroFile(macro_file) => {
+                let (parse, map) = db.parse_macro_expansion(macro_file).value;
+                (parse, map)
+            }
+        };
+        let root = parse.syntax_node();
+
+        let (syntax, offset, ast_id) = match loc.kind {
+            MacroCallKind::FnLike { ast_id, .. } => {
+                let node = &ast_id.to_ptr(db).to_node(&root);
+                let offset = node.syntax().text_range().start();
+                match node.token_tree().map(|it| it.syntax().clone()) {
+                    Some(tt) => {
+                        if let Some(e) = mismatched_delimiters(&tt) {
+                            return ValueResult::only_err(e);
+                        }
+                        (tt, offset, ast_id.value.erase())
+                    }
+                    None => {
+                        return ValueResult::only_err(Arc::new(Box::new([
+                            SyntaxError::new_at_offset("missing token tree".to_owned(), offset),
+                        ])));
+                    }
+                }
+            }
+            MacroCallKind::Derive { ast_id, .. } => {
+                let syntax_node = ast_id.to_ptr(db).to_node(&root).syntax().clone();
+                let offset = syntax_node.text_range().start();
+                (syntax_node, offset, ast_id.value.erase())
+            }
+            MacroCallKind::Attr { ast_id, .. } => {
+                let syntax_node = ast_id.to_ptr(db).to_node(&root).syntax().clone();
+                let offset = syntax_node.text_range().start();
+                (syntax_node, offset, ast_id.value.erase())
+            }
+        };
+        let censor = censor_for_macro_input(&loc, &syntax);
+        // let mut fixups = fixup::fixup_syntax(&node);
+        // fixups.replace.extend(censor.into_iter().map(|node| (node.into(), Vec::new())));
+        // let (mut tt, tmap, _) = mbe::syntax_node_to_token_tree_with_modifications(
+        //     &node,
+        //     fixups.token_map,
+        //     fixups.next_id,
+        //     fixups.replace,
+        //     fixups.append,
+        // );
+        let mut tt = mbe::syntax_node_to_token_tree_censored(
+            &syntax,
+            SpanAnchor { file_id: loc.kind.file_id(), ast_id },
+            offset,
+            &map,
+            censor,
+        );
+
+        if loc.def.is_proc_macro() {
+            // proc macros expect their inputs without parentheses, MBEs expect it with them included
+            tt.delimiter = tt::Delimiter::UNSPECIFIED;
+        }
 
-    let node = SyntaxNode::new_root(arg);
-    let censor = censor_for_macro_input(&loc, &node);
-    let mut fixups = fixup::fixup_syntax(&node);
-    fixups.replace.extend(censor.into_iter().map(|node| (node.into(), Vec::new())));
-    let (mut tt, tmap, _) = mbe::syntax_node_to_token_tree_with_modifications(
-        &node,
-        fixups.token_map,
-        fixups.next_id,
-        fixups.replace,
-        fixups.append,
-    );
-
-    if loc.def.is_proc_macro() {
-        // proc macros expect their inputs without parentheses, MBEs expect it with them included
-        tt.delimiter = tt::Delimiter::unspecified();
-    }
-    let val = Some(Arc::new((tt, tmap, fixups.undo_info)));
-    match err {
-        Some(err) => ValueResult::new(val, err),
-        None => ValueResult::ok(val),
+        if matches!(loc.def.kind, MacroDefKind::BuiltInEager(..)) {
+            match parse.errors() {
+                [] => ValueResult::ok(Some(Arc::new(tt))),
+                errors => ValueResult::new(
+                    Some(Arc::new(tt)),
+                    // Box::<[_]>::from(res.errors()), not stable yet
+                    Arc::new(errors.to_vec().into_boxed_slice()),
+                ),
+            }
+        } else {
+            ValueResult::ok(Some(Arc::new(tt)))
+        }
     }
 }
 
+// FIXME: Censoring info should be calculated by the caller! Namely by name resolution
 /// Certain macro calls expect some nodes in the input to be preprocessed away, namely:
 /// - derives expect all `#[derive(..)]` invocations up to the currently invoked one to be stripped
 /// - attributes expect the invoking attribute to be stripped
-fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<SyntaxNode> {
+fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> Vec<SyntaxNode> {
     // FIXME: handle `cfg_attr`
     (|| {
         let censor = match loc.kind {
@@ -417,103 +437,56 @@ fn censor_for_macro_input(loc: &MacroCallLoc, node: &SyntaxNode) -> FxHashSet<Sy
     .unwrap_or_default()
 }
 
-fn macro_arg_node(
-    db: &dyn ExpandDatabase,
-    id: MacroCallId,
-) -> ValueResult<Option<GreenNode>, Arc<Box<[SyntaxError]>>> {
-    let err = || -> Arc<Box<[_]>> {
-        Arc::new(Box::new([SyntaxError::new_at_offset(
-            "invalid macro call".to_owned(),
-            syntax::TextSize::from(0),
-        )]))
-    };
-    let loc = db.lookup_intern_macro_call(id);
-    let arg = if let MacroDefKind::BuiltInEager(..) = loc.def.kind {
-        let res = if let Some(EagerCallInfo { arg, .. }) = loc.eager.as_deref() {
-            Some(mbe::token_tree_to_syntax_node(&arg.0, mbe::TopEntryPoint::MacroEagerInput).0)
-        } else {
-            loc.kind
-                .arg(db)
-                .and_then(|arg| ast::TokenTree::cast(arg.value))
-                .map(|tt| tt.reparse_as_comma_separated_expr().to_syntax())
-        };
-        match res {
-            Some(res) if res.errors().is_empty() => res.syntax_node(),
-            Some(res) => {
-                return ValueResult::new(
-                    Some(res.syntax_node().green().into()),
-                    // Box::<[_]>::from(res.errors()), not stable yet
-                    Arc::new(res.errors().to_vec().into_boxed_slice()),
-                );
-            }
-            None => return ValueResult::only_err(err()),
-        }
-    } else {
-        match loc.kind.arg(db) {
-            Some(res) => res.value,
-            None => return ValueResult::only_err(err()),
-        }
-    };
-    if matches!(loc.kind, MacroCallKind::FnLike { .. }) {
-        let first = arg.first_child_or_token().map_or(T![.], |it| it.kind());
-        let last = arg.last_child_or_token().map_or(T![.], |it| it.kind());
-        let well_formed_tt =
-            matches!((first, last), (T!['('], T![')']) | (T!['['], T![']']) | (T!['{'], T!['}']));
-        if !well_formed_tt {
-            // Don't expand malformed (unbalanced) macro invocations. This is
-            // less than ideal, but trying to expand unbalanced  macro calls
-            // sometimes produces pathological, deeply nested code which breaks
-            // all kinds of things.
-            //
-            // Some day, we'll have explicit recursion counters for all
-            // recursive things, at which point this code might be removed.
-            cov_mark::hit!(issue9358_bad_macro_stack_overflow);
-            return ValueResult::only_err(Arc::new(Box::new([SyntaxError::new(
-                "unbalanced token tree".to_owned(),
-                arg.text_range(),
-            )])));
-        }
-    }
-    ValueResult::ok(Some(arg.green().into()))
-}
-
 fn decl_macro_expander(
     db: &dyn ExpandDatabase,
     def_crate: CrateId,
     id: AstId<ast::Macro>,
 ) -> Arc<DeclarativeMacroExpander> {
     let is_2021 = db.crate_graph()[def_crate].edition >= Edition::Edition2021;
-    let (mac, def_site_token_map) = match id.to_node(db) {
+    let (root, map) = match id.file_id.repr() {
+        HirFileIdRepr::FileId(file_id) => {
+            (db.parse(file_id).syntax_node(), Arc::new(Default::default()))
+        }
+        HirFileIdRepr::MacroFile(macro_file) => {
+            let (parse, map) = db.parse_macro_expansion(macro_file).value;
+            (parse.syntax_node(), map)
+        }
+    };
+    let mac = match id.to_ptr(db).to_node(&root) {
         ast::Macro::MacroRules(macro_rules) => match macro_rules.token_tree() {
             Some(arg) => {
-                let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
+                let tt = mbe::syntax_node_to_token_tree(
+                    arg.syntax(),
+                    SpanAnchor { file_id: id.file_id, ast_id: id.value.erase() },
+                    macro_rules.syntax().text_range().start(),
+                    &map,
+                );
                 let mac = mbe::DeclarativeMacro::parse_macro_rules(&tt, is_2021);
-                (mac, def_site_token_map)
+                mac
             }
-            None => (
-                mbe::DeclarativeMacro::from_err(
-                    mbe::ParseError::Expected("expected a token tree".into()),
-                    is_2021,
-                ),
-                Default::default(),
+            None => mbe::DeclarativeMacro::from_err(
+                mbe::ParseError::Expected("expected a token tree".into()),
+                is_2021,
             ),
         },
         ast::Macro::MacroDef(macro_def) => match macro_def.body() {
             Some(arg) => {
-                let (tt, def_site_token_map) = mbe::syntax_node_to_token_tree(arg.syntax());
+                let tt = mbe::syntax_node_to_token_tree(
+                    arg.syntax(),
+                    SpanAnchor { file_id: id.file_id, ast_id: id.value.erase() },
+                    macro_def.syntax().text_range().start(),
+                    &map,
+                );
                 let mac = mbe::DeclarativeMacro::parse_macro2(&tt, is_2021);
-                (mac, def_site_token_map)
+                mac
             }
-            None => (
-                mbe::DeclarativeMacro::from_err(
-                    mbe::ParseError::Expected("expected a token tree".into()),
-                    is_2021,
-                ),
-                Default::default(),
+            None => mbe::DeclarativeMacro::from_err(
+                mbe::ParseError::Expected("expected a token tree".into()),
+                is_2021,
             ),
         },
     };
-    Arc::new(DeclarativeMacroExpander { mac, def_site_token_map })
+    Arc::new(DeclarativeMacroExpander { mac })
 }
 
 fn macro_expander(db: &dyn ExpandDatabase, id: MacroDefId) -> TokenExpander {
@@ -536,25 +509,37 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
     let ExpandResult { value: tt, mut err } = match loc.def.kind {
         MacroDefKind::ProcMacro(..) => return db.expand_proc_macro(id),
         MacroDefKind::BuiltInDerive(expander, ..) => {
-            let arg = db.macro_arg_node(id).value.unwrap();
-
-            let node = SyntaxNode::new_root(arg);
-            let censor = censor_for_macro_input(&loc, &node);
-            let mut fixups = fixup::fixup_syntax(&node);
-            fixups.replace.extend(censor.into_iter().map(|node| (node.into(), Vec::new())));
-            let (tmap, _) = mbe::syntax_node_to_token_map_with_modifications(
+            // FIXME: add firewall query for this?
+            let hir_file_id = loc.kind.file_id();
+            let (root, map) = match hir_file_id.repr() {
+                HirFileIdRepr::FileId(file_id) => (db.parse(file_id).syntax_node(), None),
+                HirFileIdRepr::MacroFile(macro_file) => {
+                    let (parse, map) = db.parse_macro_expansion(macro_file).value;
+                    (parse.syntax_node(), Some(map))
+                }
+            };
+            let MacroCallKind::Derive { ast_id, .. } = loc.kind else { unreachable!() };
+            let node = ast_id.to_ptr(db).to_node(&root);
+
+            // FIXME: we might need to remove the spans from the input to the derive macro here
+            let _censor = censor_for_macro_input(&loc, node.syntax());
+            let _t;
+            expander.expand(
+                db,
+                id,
                 &node,
-                fixups.token_map,
-                fixups.next_id,
-                fixups.replace,
-                fixups.append,
-            );
-
-            // this cast is a bit sus, can we avoid losing the typedness here?
-            let adt = ast::Adt::cast(node).unwrap();
-            let mut res = expander.expand(db, id, &adt, &tmap);
-            fixup::reverse_fixups(&mut res.value, &tmap, &fixups.undo_info);
-            res
+                match &map {
+                    Some(map) => map,
+                    None => {
+                        _t = map_from_syntax_node(
+                            node.syntax(),
+                            SpanAnchor { file_id: hir_file_id, ast_id: ast_id.value.erase() },
+                            node.syntax().text_range().start(),
+                        );
+                        &_t
+                    }
+                },
+            )
         }
         _ => {
             let ValueResult { value, err } = db.macro_arg(id);
@@ -570,8 +555,8 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
                 };
             };
 
-            let (arg, arg_tm, undo_info) = &*macro_arg;
-            let mut res = match loc.def.kind {
+            let arg = &*macro_arg;
+            match loc.def.kind {
                 MacroDefKind::Declarative(id) => {
                     db.decl_macro_expander(loc.def.krate, id).expand(arg.clone())
                 }
@@ -583,11 +568,8 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
                 // will end up going through here again, whereas we want to just want to inspect the raw input.
                 // As such we just return the input subtree here.
                 MacroDefKind::BuiltInEager(..) if loc.eager.is_none() => {
-                    let mut arg = arg.clone();
-                    fixup::reverse_fixups(&mut arg, arg_tm, undo_info);
-
                     return ExpandResult {
-                        value: Arc::new(arg),
+                        value: Arc::new(arg.clone()),
                         err: err.map(|err| {
                             let mut buf = String::new();
                             for err in &**err {
@@ -603,9 +585,7 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
                 MacroDefKind::BuiltInEager(it, _) => it.expand(db, id, &arg).map_err(Into::into),
                 MacroDefKind::BuiltInAttr(it, _) => it.expand(db, id, &arg),
                 _ => unreachable!(),
-            };
-            fixup::reverse_fixups(&mut res.value, arg_tm, undo_info);
-            res
+            }
         }
     };
 
@@ -626,6 +606,7 @@ fn macro_expand(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt
 }
 
 fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<Arc<tt::Subtree>> {
+    // FIXME: Syntax fix ups
     let loc = db.lookup_intern_macro_call(id);
     let Some(macro_arg) = db.macro_arg(id).value else {
         return ExpandResult {
@@ -639,32 +620,24 @@ fn expand_proc_macro(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandResult<A
         };
     };
 
-    let (arg_tt, arg_tm, undo_info) = &*macro_arg;
-
     let expander = match loc.def.kind {
         MacroDefKind::ProcMacro(expander, ..) => expander,
         _ => unreachable!(),
     };
 
     let attr_arg = match &loc.kind {
-        MacroCallKind::Attr { attr_args, .. } => {
-            let mut attr_args = attr_args.0.clone();
-            mbe::Shift::new(arg_tt).shift_all(&mut attr_args);
-            Some(attr_args)
-        }
+        MacroCallKind::Attr { attr_args, .. } => Some(&**attr_args),
         _ => None,
     };
 
-    let ExpandResult { value: mut tt, err } =
-        expander.expand(db, loc.def.krate, loc.krate, arg_tt, attr_arg.as_ref());
+    let ExpandResult { value: tt, err } =
+        expander.expand(db, loc.def.krate, loc.krate, &macro_arg, attr_arg);
 
     // Set a hard limit for the expanded tt
     if let Err(value) = check_tt_count(&tt) {
         return value;
     }
 
-    fixup::reverse_fixups(&mut tt, arg_tm, undo_info);
-
     ExpandResult { value: Arc::new(tt), err }
 }
 
@@ -677,9 +650,10 @@ fn macro_expand_to(db: &dyn ExpandDatabase, id: MacroCallId) -> ExpandTo {
 }
 
 fn token_tree_to_syntax_node(
+    db: &dyn ExpandDatabase,
     tt: &tt::Subtree,
     expand_to: ExpandTo,
-) -> (Parse<SyntaxNode>, mbe::TokenMap) {
+) -> (Parse<SyntaxNode>, SpanMap) {
     let entry_point = match expand_to {
         ExpandTo::Statements => mbe::TopEntryPoint::MacroStmts,
         ExpandTo::Items => mbe::TopEntryPoint::MacroItems,
@@ -687,7 +661,18 @@ fn token_tree_to_syntax_node(
         ExpandTo::Type => mbe::TopEntryPoint::Type,
         ExpandTo::Expr => mbe::TopEntryPoint::Expr,
     };
-    mbe::token_tree_to_syntax_node(tt, entry_point)
+    let mut tm = mbe::token_tree_to_syntax_node(tt, entry_point);
+    // now what the hell is going on here
+    tm.1.span_map.sort_by(|(_, a), (_, b)| {
+        a.anchor.file_id.cmp(&b.anchor.file_id).then_with(|| {
+            let map = db.ast_id_map(a.anchor.file_id);
+            map.get_raw(a.anchor.ast_id)
+                .text_range()
+                .start()
+                .cmp(&map.get_raw(b.anchor.ast_id).text_range().start())
+        })
+    });
+    tm
 }
 
 fn check_tt_count(tt: &tt::Subtree) -> Result<(), ExpandResult<Arc<tt::Subtree>>> {
diff --git a/crates/hir-expand/src/eager.rs b/crates/hir-expand/src/eager.rs
index 4110f284759..ae5f26b5d36 100644
--- a/crates/hir-expand/src/eager.rs
+++ b/crates/hir-expand/src/eager.rs
@@ -18,8 +18,11 @@
 //!
 //!
 //! See the full discussion : <https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Eager.20expansion.20of.20built-in.20macros>
-use base_db::CrateId;
-use rustc_hash::{FxHashMap, FxHashSet};
+use base_db::{
+    span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID},
+    CrateId,
+};
+use rustc_hash::FxHashMap;
 use syntax::{ted, Parse, SyntaxNode, TextRange, TextSize, WalkEvent};
 use triomphe::Arc;
 
@@ -29,7 +32,7 @@ use crate::{
     hygiene::Hygiene,
     mod_path::ModPath,
     EagerCallInfo, ExpandError, ExpandResult, ExpandTo, InFile, MacroCallId, MacroCallKind,
-    MacroCallLoc, MacroDefId, MacroDefKind,
+    MacroCallLoc, MacroDefId, MacroDefKind, SpanMap,
 };
 
 pub fn expand_eager_macro_input(
@@ -54,15 +57,15 @@ pub fn expand_eager_macro_input(
         eager: None,
         kind: MacroCallKind::FnLike { ast_id: call_id, expand_to: ExpandTo::Expr },
     });
-    let ExpandResult { value: (arg_exp, arg_exp_map), err: parse_err } =
+    let ExpandResult { value: (arg_exp, _arg_exp_map), err: parse_err } =
         db.parse_macro_expansion(arg_id.as_macro_file());
     // we need this map here as the expansion of the eager input fake file loses whitespace ...
-    let mut ws_mapping = FxHashMap::default();
-    if let Some((_, tm, _)) = db.macro_arg(arg_id).value.as_deref() {
-        ws_mapping.extend(tm.entries().filter_map(|(id, range)| {
-            Some((arg_exp_map.first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)?, range))
-        }));
-    }
+    // let mut ws_mapping = FxHashMap::default();
+    // if let Some((tm)) = db.macro_arg(arg_id).value.as_deref() {
+    //     ws_mapping.extend(tm.entries().filter_map(|(id, range)| {
+    //         Some((arg_exp_map.first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)?, range))
+    //     }));
+    // }
 
     let ExpandResult { value: expanded_eager_input, err } = {
         eager_macro_recur(
@@ -75,49 +78,55 @@ pub fn expand_eager_macro_input(
     };
     let err = parse_err.or(err);
 
-    let Some((expanded_eager_input, mapping)) = expanded_eager_input else {
+    let Some((expanded_eager_input, _mapping)) = expanded_eager_input else {
         return ExpandResult { value: None, err };
     };
 
-    let (mut subtree, expanded_eager_input_token_map) =
-        mbe::syntax_node_to_token_tree(&expanded_eager_input);
+    let mut subtree = mbe::syntax_node_to_token_tree(
+        &expanded_eager_input,
+        // is this right?
+        SpanAnchor { file_id: arg_id.as_file(), ast_id: ROOT_ERASED_FILE_AST_ID },
+        TextSize::new(0),
+        // FIXME: Spans! `eager_macro_recur` needs to fill out a span map for us
+        &Default::default(),
+    );
 
-    let og_tmap = if let Some(tt) = macro_call.value.token_tree() {
-        let mut ids_used = FxHashSet::default();
-        let mut og_tmap = mbe::syntax_node_to_token_map(tt.syntax());
-        // The tokenmap and ids of subtree point into the expanded syntax node, but that is inaccessible from the outside
-        // so we need to remap them to the original input of the eager macro.
-        subtree.visit_ids(&mut |id| {
-            // Note: we discard all token ids of braces and the like here, but that's not too bad and only a temporary fix
+    // let og_tmap = if let Some(tt) = macro_call.value.token_tree() {
+    //     let mut ids_used = FxHashSet::default();
+    //     let mut og_tmap = mbe::syntax_node_to_token_map(tt.syntax());
+    //     // The tokenmap and ids of subtree point into the expanded syntax node, but that is inaccessible from the outside
+    //     // so we need to remap them to the original input of the eager macro.
+    //     subtree.visit_ids(&mut |id| {
+    //         // Note: we discard all token ids of braces and the like here, but that's not too bad and only a temporary fix
 
-            if let Some(range) = expanded_eager_input_token_map
-                .first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)
-            {
-                // remap from expanded eager input to eager input expansion
-                if let Some(og_range) = mapping.get(&range) {
-                    // remap from eager input expansion to original eager input
-                    if let Some(&og_range) = ws_mapping.get(og_range) {
-                        if let Some(og_token) = og_tmap.token_by_range(og_range) {
-                            ids_used.insert(og_token);
-                            return og_token;
-                        }
-                    }
-                }
-            }
-            tt::TokenId::UNSPECIFIED
-        });
-        og_tmap.filter(|id| ids_used.contains(&id));
-        og_tmap
-    } else {
-        Default::default()
-    };
-    subtree.delimiter = crate::tt::Delimiter::unspecified();
+    //         if let Some(range) = expanded_eager_input_token_map
+    //             .first_range_by_token(id, syntax::SyntaxKind::TOMBSTONE)
+    //         {
+    //             // remap from expanded eager input to eager input expansion
+    //             if let Some(og_range) = mapping.get(&range) {
+    //                 // remap from eager input expansion to original eager input
+    //                 if let Some(&og_range) = ws_mapping.get(og_range) {
+    //                     if let Some(og_token) = og_tmap.token_by_range(og_range) {
+    //                         ids_used.insert(og_token);
+    //                         return og_token;
+    //                     }
+    //                 }
+    //             }
+    //         }
+    //         tt::TokenId::UNSPECIFIED
+    //     });
+    //     og_tmap.filter(|id| ids_used.contains(&id));
+    //     og_tmap
+    // } else {
+    //     Default::default()
+    // };
+    subtree.delimiter = crate::tt::Delimiter::UNSPECIFIED;
 
     let loc = MacroCallLoc {
         def,
         krate,
         eager: Some(Box::new(EagerCallInfo {
-            arg: Arc::new((subtree, og_tmap)),
+            arg: Arc::new((subtree,)),
             arg_id,
             error: err.clone(),
         })),
@@ -132,7 +141,7 @@ fn lazy_expand(
     def: &MacroDefId,
     macro_call: InFile<ast::MacroCall>,
     krate: CrateId,
-) -> ExpandResult<(InFile<Parse<SyntaxNode>>, Arc<mbe::TokenMap>)> {
+) -> ExpandResult<(InFile<Parse<SyntaxNode>>, Arc<SpanMap>)> {
     let ast_id = db.ast_id_map(macro_call.file_id).ast_id(&macro_call.value);
 
     let expand_to = ExpandTo::from_call_site(&macro_call.value);
@@ -214,19 +223,19 @@ fn eager_macro_recur(
                         let ExpandResult { value, err: err2 } =
                             db.parse_macro_expansion(call_id.as_macro_file());
 
-                        if let Some(tt) = call.token_tree() {
-                            let call_tt_start = tt.syntax().text_range().start();
-                            let call_start =
-                                apply_offset(call.syntax().text_range().start(), offset);
-                            if let Some((_, arg_map, _)) = db.macro_arg(call_id).value.as_deref() {
-                                mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
-                                    value
-                                        .1
-                                        .first_range_by_token(tid, syntax::SyntaxKind::TOMBSTONE)
-                                        .map(|r| (r + call_start, range + call_tt_start))
-                                }));
-                            }
-                        }
+                        // if let Some(tt) = call.token_tree() {
+                        // let call_tt_start = tt.syntax().text_range().start();
+                        // let call_start =
+                        //     apply_offset(call.syntax().text_range().start(), offset);
+                        // if let Some((_, arg_map, _)) = db.macro_arg(call_id).value.as_deref() {
+                        //     mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
+                        //         value
+                        //             .1
+                        //             .first_range_by_token(tid, syntax::SyntaxKind::TOMBSTONE)
+                        //             .map(|r| (r + call_start, range + call_tt_start))
+                        //     }));
+                        // }
+                        // }
 
                         ExpandResult {
                             value: Some(value.0.syntax_node().clone_for_update()),
@@ -241,13 +250,8 @@ fn eager_macro_recur(
             | MacroDefKind::BuiltInAttr(..)
             | MacroDefKind::BuiltInDerive(..)
             | MacroDefKind::ProcMacro(..) => {
-                let ExpandResult { value: (parse, tm), err } =
+                let ExpandResult { value: (parse, _tm), err } =
                     lazy_expand(db, &def, curr.with_value(call.clone()), krate);
-                let decl_mac = if let MacroDefKind::Declarative(ast_id) = def.kind {
-                    Some(db.decl_macro_expander(def.krate, ast_id))
-                } else {
-                    None
-                };
 
                 // replace macro inside
                 let hygiene = Hygiene::new(db, parse.file_id);
@@ -261,24 +265,29 @@ fn eager_macro_recur(
                 );
                 let err = err.or(error);
 
-                if let Some(tt) = call.token_tree() {
-                    let call_tt_start = tt.syntax().text_range().start();
-                    let call_start = apply_offset(call.syntax().text_range().start(), offset);
-                    if let Some((_tt, arg_map, _)) = parse
-                        .file_id
-                        .macro_file()
-                        .and_then(|id| db.macro_arg(id.macro_call_id).value)
-                        .as_deref()
-                    {
-                        mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
-                            tm.first_range_by_token(
-                                decl_mac.as_ref().map(|it| it.map_id_down(tid)).unwrap_or(tid),
-                                syntax::SyntaxKind::TOMBSTONE,
-                            )
-                            .map(|r| (r + call_start, range + call_tt_start))
-                        }));
-                    }
-                }
+                // if let Some(tt) = call.token_tree() {
+                // let decl_mac = if let MacroDefKind::Declarative(ast_id) = def.kind {
+                //     Some(db.decl_macro_expander(def.krate, ast_id))
+                // } else {
+                //     None
+                // };
+                // let call_tt_start = tt.syntax().text_range().start();
+                // let call_start = apply_offset(call.syntax().text_range().start(), offset);
+                // if let Some((_tt, arg_map, _)) = parse
+                //     .file_id
+                //     .macro_file()
+                //     .and_then(|id| db.macro_arg(id.macro_call_id).value)
+                //     .as_deref()
+                // {
+                //     mapping.extend(arg_map.entries().filter_map(|(tid, range)| {
+                //         tm.first_range_by_token(
+                //             decl_mac.as_ref().map(|it| it.map_id_down(tid)).unwrap_or(tid),
+                //             syntax::SyntaxKind::TOMBSTONE,
+                //         )
+                //         .map(|r| (r + call_start, range + call_tt_start))
+                //     }));
+                // }
+                // }
                 // FIXME: Do we need to re-use _m here?
                 ExpandResult { value: value.map(|(n, _m)| n), err }
             }
diff --git a/crates/hir-expand/src/hygiene.rs b/crates/hir-expand/src/hygiene.rs
index ca65db1136c..ce421d3dcd8 100644
--- a/crates/hir-expand/src/hygiene.rs
+++ b/crates/hir-expand/src/hygiene.rs
@@ -5,18 +5,16 @@
 use base_db::CrateId;
 use db::TokenExpander;
 use either::Either;
-use mbe::Origin;
 use syntax::{
     ast::{self, HasDocComments},
-    AstNode, SyntaxKind, SyntaxNode, TextRange, TextSize,
+    AstNode, SyntaxNode, TextRange, TextSize,
 };
 use triomphe::Arc;
 
 use crate::{
     db::{self, ExpandDatabase},
-    fixup,
     name::{AsName, Name},
-    HirFileId, InFile, MacroCallKind, MacroCallLoc, MacroDefKind, MacroFile,
+    HirFileId, InFile, MacroCallKind, MacroCallLoc, MacroDefKind, MacroFile, SpanMap,
 };
 
 #[derive(Clone, Debug)]
@@ -50,23 +48,25 @@ impl Hygiene {
         Either::Left(name_ref.as_name())
     }
 
-    pub fn local_inner_macros(&self, db: &dyn ExpandDatabase, path: ast::Path) -> Option<CrateId> {
-        let mut token = path.syntax().first_token()?.text_range();
+    pub fn local_inner_macros(&self, _db: &dyn ExpandDatabase, path: ast::Path) -> Option<CrateId> {
+        let mut _token = path.syntax().first_token()?.text_range();
         let frames = self.frames.as_ref()?;
-        let mut current = &frames.0;
-
-        loop {
-            let (mapped, origin) = current.expansion.as_ref()?.map_ident_up(db, token)?;
-            if origin == Origin::Def {
-                return if current.local_inner {
-                    frames.root_crate(db, path.syntax())
-                } else {
-                    None
-                };
-            }
-            current = current.call_site.as_ref()?;
-            token = mapped.value;
-        }
+        let mut _current = &frames.0;
+
+        // FIXME: Hygiene ...
+        return None;
+        // loop {
+        //     let (mapped, origin) = current.expansion.as_ref()?.map_ident_up(db, token)?;
+        //     if origin == Origin::Def {
+        //         return if current.local_inner {
+        //             frames.root_crate(db, path.syntax())
+        //         } else {
+        //             None
+        //         };
+        //     }
+        //     current = current.call_site.as_ref()?;
+        //     token = mapped.value;
+        // }
     }
 }
 
@@ -92,31 +92,33 @@ impl HygieneFrames {
         HygieneFrames(Arc::new(HygieneFrame::new(db, file_id)))
     }
 
-    fn root_crate(&self, db: &dyn ExpandDatabase, node: &SyntaxNode) -> Option<CrateId> {
-        let mut token = node.first_token()?.text_range();
-        let mut result = self.0.krate;
-        let mut current = self.0.clone();
+    fn root_crate(&self, _db: &dyn ExpandDatabase, node: &SyntaxNode) -> Option<CrateId> {
+        let mut _token = node.first_token()?.text_range();
+        let mut _result = self.0.krate;
+        let mut _current = self.0.clone();
 
-        while let Some((mapped, origin)) =
-            current.expansion.as_ref().and_then(|it| it.map_ident_up(db, token))
-        {
-            result = current.krate;
+        return None;
 
-            let site = match origin {
-                Origin::Def => &current.def_site,
-                Origin::Call => &current.call_site,
-            };
+        //     while let Some((mapped, origin)) =
+        //         current.expansion.as_ref().and_then(|it| it.map_ident_up(db, token))
+        //     {
+        //         result = current.krate;
 
-            let site = match site {
-                None => break,
-                Some(it) => it,
-            };
+        //         let site = match origin {
+        //             Origin::Def => &current.def_site,
+        //             Origin::Call => &current.call_site,
+        //         };
 
-            current = site.clone();
-            token = mapped.value;
-        }
+        //         let site = match site {
+        //             None => break,
+        //             Some(it) => it,
+        //         };
+
+        //         current = site.clone();
+        //         token = mapped.value;
+        //     }
 
-        result
+        //     result
     }
 }
 
@@ -127,45 +129,18 @@ struct HygieneInfo {
     attr_input_or_mac_def_start: Option<InFile<TextSize>>,
 
     macro_def: TokenExpander,
-    macro_arg: Arc<(crate::tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>,
-    macro_arg_shift: mbe::Shift,
-    exp_map: Arc<mbe::TokenMap>,
+    macro_arg: Arc<crate::tt::Subtree>,
+    exp_map: Arc<SpanMap>,
 }
 
 impl HygieneInfo {
-    fn map_ident_up(
+    fn _map_ident_up(
         &self,
-        db: &dyn ExpandDatabase,
-        token: TextRange,
-    ) -> Option<(InFile<TextRange>, Origin)> {
-        let token_id = self.exp_map.token_by_range(token)?;
-        let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
-
-        let loc = db.lookup_intern_macro_call(self.file.macro_call_id);
-
-        let (token_map, tt) = match &loc.kind {
-            MacroCallKind::Attr { attr_args, .. } => match self.macro_arg_shift.unshift(token_id) {
-                Some(unshifted) => {
-                    token_id = unshifted;
-                    (&attr_args.1, self.attr_input_or_mac_def_start?)
-                }
-                None => (&self.macro_arg.1, loc.kind.arg(db)?.map(|it| it.text_range().start())),
-            },
-            _ => match origin {
-                mbe::Origin::Call => {
-                    (&self.macro_arg.1, loc.kind.arg(db)?.map(|it| it.text_range().start()))
-                }
-                mbe::Origin::Def => match (&self.macro_def, &self.attr_input_or_mac_def_start) {
-                    (TokenExpander::DeclarativeMacro(expander), Some(tt)) => {
-                        (&expander.def_site_token_map, *tt)
-                    }
-                    _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
-                },
-            },
-        };
-
-        let range = token_map.first_range_by_token(token_id, SyntaxKind::IDENT)?;
-        Some((tt.with_value(range + tt.value), origin))
+        _db: &dyn ExpandDatabase,
+        _token: TextRange,
+    ) -> Option<InFile<TextRange>> {
+        // self.exp_map.token_by_range(token).map(|span| InFile::new(span.anchor, span.range))
+        None
     }
 }
 
@@ -197,18 +172,13 @@ fn make_hygiene_info(
     let macro_def = db.macro_expander(loc.def);
     let (_, exp_map) = db.parse_macro_expansion(macro_file).value;
     let macro_arg = db.macro_arg(macro_file.macro_call_id).value.unwrap_or_else(|| {
-        Arc::new((
-            tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() },
-            Default::default(),
-            Default::default(),
-        ))
+        Arc::new(tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() })
     });
 
     HygieneInfo {
         file: macro_file,
         attr_input_or_mac_def_start: attr_input_or_mac_def
             .map(|it| it.map(|tt| tt.syntax().text_range().start())),
-        macro_arg_shift: mbe::Shift::new(&macro_arg.0),
         macro_arg,
         macro_def,
         exp_map,
diff --git a/crates/hir-expand/src/lib.rs b/crates/hir-expand/src/lib.rs
index 4be55126b86..bd5796e000a 100644
--- a/crates/hir-expand/src/lib.rs
+++ b/crates/hir-expand/src/lib.rs
@@ -18,21 +18,13 @@ pub mod quote;
 pub mod eager;
 pub mod mod_path;
 pub mod attrs;
-mod fixup;
+// mod fixup;
 
-use mbe::TokenMap;
-pub use mbe::{Origin, ValueResult};
-
-use ::tt::token_id as tt;
 use triomphe::Arc;
 
 use std::{fmt, hash::Hash, iter};
 
-use base_db::{
-    impl_intern_key,
-    salsa::{self, InternId},
-    CrateId, FileId, FileRange, ProcMacroKind,
-};
+use base_db::{span::HirFileIdRepr, CrateId, FileId, FileRange, ProcMacroKind};
 use either::Either;
 use syntax::{
     algo::{self, skip_trivia_token},
@@ -51,6 +43,25 @@ use crate::{
     proc_macro::ProcMacroExpander,
 };
 
+pub use base_db::span::{HirFileId, MacroCallId, MacroFile};
+pub use mbe::ValueResult;
+
+pub type SpanMap = ::mbe::TokenMap<tt::SpanData>;
+pub type DeclarativeMacro = ::mbe::DeclarativeMacro<tt::SpanData>;
+
+pub mod tt {
+    pub use base_db::span::SpanData;
+    pub use tt::{DelimiterKind, Spacing, Span};
+
+    pub type Delimiter = ::tt::Delimiter<SpanData>;
+    pub type Subtree = ::tt::Subtree<SpanData>;
+    pub type Leaf = ::tt::Leaf<SpanData>;
+    pub type Literal = ::tt::Literal<SpanData>;
+    pub type Punct = ::tt::Punct<SpanData>;
+    pub type Ident = ::tt::Ident<SpanData>;
+    pub type TokenTree = ::tt::TokenTree<SpanData>;
+}
+
 pub type ExpandResult<T> = ValueResult<T, ExpandError>;
 
 #[derive(Debug, PartialEq, Eq, Clone, Hash)]
@@ -86,42 +97,43 @@ impl fmt::Display for ExpandError {
     }
 }
 
-/// Input to the analyzer is a set of files, where each file is identified by
-/// `FileId` and contains source code. However, another source of source code in
-/// Rust are macros: each macro can be thought of as producing a "temporary
-/// file". To assign an id to such a file, we use the id of the macro call that
-/// produced the file. So, a `HirFileId` is either a `FileId` (source code
-/// written by user), or a `MacroCallId` (source code produced by macro).
-///
-/// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
-/// containing the call plus the offset of the macro call in the file. Note that
-/// this is a recursive definition! However, the size_of of `HirFileId` is
-/// finite (because everything bottoms out at the real `FileId`) and small
-/// (`MacroCallId` uses the location interning. You can check details here:
-/// <https://en.wikipedia.org/wiki/String_interning>).
-///
-/// The two variants are encoded in a single u32 which are differentiated by the MSB.
-/// If the MSB is 0, the value represents a `FileId`, otherwise the remaining 31 bits represent a
-/// `MacroCallId`.
-#[derive(Clone, Copy, PartialEq, Eq, Hash)]
-pub struct HirFileId(u32);
-
-impl fmt::Debug for HirFileId {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.repr().fmt(f)
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct MacroFile {
-    pub macro_call_id: MacroCallId,
-}
-
 /// `MacroCallId` identifies a particular macro invocation, like
 /// `println!("Hello, {}", world)`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct MacroCallId(salsa::InternId);
-impl_intern_key!(MacroCallId);
+pub struct SyntaxContextId(base_db::salsa::InternId);
+base_db::impl_intern_key!(SyntaxContextId);
+
+#[derive(Debug, Clone, Hash, PartialEq, Eq)]
+pub struct SyntaxContext {
+    outer_expn: HirFileId,
+    outer_transparency: Transparency,
+    parent: SyntaxContextId,
+    /// This context, but with all transparent and semi-transparent expansions filtered away.
+    opaque: SyntaxContextId,
+    /// This context, but with all transparent expansions filtered away.
+    opaque_and_semitransparent: SyntaxContextId,
+    /// Name of the crate to which `$crate` with this context would resolve.
+    dollar_crate_name: name::Name,
+}
+
+/// A property of a macro expansion that determines how identifiers
+/// produced by that expansion are resolved.
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Hash, Debug)]
+pub enum Transparency {
+    /// Identifier produced by a transparent expansion is always resolved at call-site.
+    /// Call-site spans in procedural macros, hygiene opt-out in `macro` should use this.
+    Transparent,
+    /// Identifier produced by a semi-transparent expansion may be resolved
+    /// either at call-site or at definition-site.
+    /// If it's a local variable, label or `$crate` then it's resolved at def-site.
+    /// Otherwise it's resolved at call-site.
+    /// `macro_rules` macros behave like this, built-in macros currently behave like this too,
+    /// but that's an implementation detail.
+    SemiTransparent,
+    /// Identifier produced by an opaque expansion is always resolved at definition-site.
+    /// Def-site spans in procedural macros, identifiers from `macro` by default use this.
+    Opaque,
+}
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct MacroCallLoc {
@@ -154,7 +166,7 @@ pub enum MacroDefKind {
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 struct EagerCallInfo {
     /// The expanded argument of the eager macro.
-    arg: Arc<(tt::Subtree, TokenMap)>,
+    arg: Arc<(tt::Subtree,)>,
     /// Call id of the eager macro's input file (this is the macro file for its fully expanded input).
     arg_id: MacroCallId,
     error: Option<ExpandError>,
@@ -178,7 +190,7 @@ pub enum MacroCallKind {
     },
     Attr {
         ast_id: AstId<ast::Item>,
-        attr_args: Arc<(tt::Subtree, mbe::TokenMap)>,
+        attr_args: Arc<tt::Subtree>,
         /// Syntactical index of the invoking `#[attribute]`.
         ///
         /// Outer attributes are counted first, then inner attributes. This does not support
@@ -187,34 +199,40 @@ pub enum MacroCallKind {
     },
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-enum HirFileIdRepr {
-    FileId(FileId),
-    MacroFile(MacroFile),
-}
+pub trait HirFileIdExt {
+    /// For macro-expansion files, returns the file original source file the
+    /// expansion originated from.
+    fn original_file(self, db: &dyn db::ExpandDatabase) -> FileId;
+    fn expansion_level(self, db: &dyn db::ExpandDatabase) -> u32;
 
-impl From<FileId> for HirFileId {
-    fn from(FileId(id): FileId) -> Self {
-        assert!(id < Self::MAX_FILE_ID);
-        HirFileId(id)
-    }
-}
+    /// If this is a macro call, returns the syntax node of the call.
+    fn call_node(self, db: &dyn db::ExpandDatabase) -> Option<InFile<SyntaxNode>>;
 
-impl From<MacroFile> for HirFileId {
-    fn from(MacroFile { macro_call_id: MacroCallId(id) }: MacroFile) -> Self {
-        let id = id.as_u32();
-        assert!(id < Self::MAX_FILE_ID);
-        HirFileId(id | Self::MACRO_FILE_TAG_MASK)
-    }
-}
+    /// If this is a macro call, returns the syntax node of the very first macro call this file resides in.
+    fn original_call_node(self, db: &dyn db::ExpandDatabase) -> Option<(FileId, SyntaxNode)>;
 
-impl HirFileId {
-    const MAX_FILE_ID: u32 = u32::MAX ^ Self::MACRO_FILE_TAG_MASK;
-    const MACRO_FILE_TAG_MASK: u32 = 1 << 31;
+    /// Return expansion information if it is a macro-expansion file
+    fn expansion_info(self, db: &dyn db::ExpandDatabase) -> Option<ExpansionInfo>;
 
-    /// For macro-expansion files, returns the file original source file the
-    /// expansion originated from.
-    pub fn original_file(self, db: &dyn db::ExpandDatabase) -> FileId {
+    fn as_builtin_derive_attr_node(&self, db: &dyn db::ExpandDatabase)
+        -> Option<InFile<ast::Attr>>;
+    fn is_builtin_derive(&self, db: &dyn db::ExpandDatabase) -> bool;
+    fn is_custom_derive(&self, db: &dyn db::ExpandDatabase) -> bool;
+
+    /// Return whether this file is an include macro
+    fn is_include_macro(&self, db: &dyn db::ExpandDatabase) -> bool;
+
+    fn is_eager(&self, db: &dyn db::ExpandDatabase) -> bool;
+    /// Return whether this file is an attr macro
+    fn is_attr_macro(&self, db: &dyn db::ExpandDatabase) -> bool;
+
+    /// Return whether this file is the pseudo expansion of the derive attribute.
+    /// See [`crate::builtin_attr_macro::derive_attr_expand`].
+    fn is_derive_attr_pseudo_expansion(&self, db: &dyn db::ExpandDatabase) -> bool;
+}
+
+impl HirFileIdExt for HirFileId {
+    fn original_file(self, db: &dyn db::ExpandDatabase) -> FileId {
         let mut file_id = self;
         loop {
             match file_id.repr() {
@@ -231,7 +249,7 @@ impl HirFileId {
         }
     }
 
-    pub fn expansion_level(self, db: &dyn db::ExpandDatabase) -> u32 {
+    fn expansion_level(self, db: &dyn db::ExpandDatabase) -> u32 {
         let mut level = 0;
         let mut curr = self;
         while let Some(macro_file) = curr.macro_file() {
@@ -243,15 +261,13 @@ impl HirFileId {
         level
     }
 
-    /// If this is a macro call, returns the syntax node of the call.
-    pub fn call_node(self, db: &dyn db::ExpandDatabase) -> Option<InFile<SyntaxNode>> {
+    fn call_node(self, db: &dyn db::ExpandDatabase) -> Option<InFile<SyntaxNode>> {
         let macro_file = self.macro_file()?;
         let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
         Some(loc.to_node(db))
     }
 
-    /// If this is a macro call, returns the syntax node of the very first macro call this file resides in.
-    pub fn original_call_node(self, db: &dyn db::ExpandDatabase) -> Option<(FileId, SyntaxNode)> {
+    fn original_call_node(self, db: &dyn db::ExpandDatabase) -> Option<(FileId, SyntaxNode)> {
         let mut call = db.lookup_intern_macro_call(self.macro_file()?.macro_call_id).to_node(db);
         loop {
             match call.file_id.repr() {
@@ -264,12 +280,12 @@ impl HirFileId {
     }
 
     /// Return expansion information if it is a macro-expansion file
-    pub fn expansion_info(self, db: &dyn db::ExpandDatabase) -> Option<ExpansionInfo> {
+    fn expansion_info(self, db: &dyn db::ExpandDatabase) -> Option<ExpansionInfo> {
         let macro_file = self.macro_file()?;
         ExpansionInfo::new(db, macro_file)
     }
 
-    pub fn as_builtin_derive_attr_node(
+    fn as_builtin_derive_attr_node(
         &self,
         db: &dyn db::ExpandDatabase,
     ) -> Option<InFile<ast::Attr>> {
@@ -282,7 +298,7 @@ impl HirFileId {
         Some(attr.with_value(ast::Attr::cast(attr.value.clone())?))
     }
 
-    pub fn is_custom_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_custom_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 matches!(
@@ -294,7 +310,7 @@ impl HirFileId {
         }
     }
 
-    pub fn is_builtin_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_builtin_derive(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 matches!(
@@ -306,8 +322,7 @@ impl HirFileId {
         }
     }
 
-    /// Return whether this file is an include macro
-    pub fn is_include_macro(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_include_macro(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 db.lookup_intern_macro_call(macro_file.macro_call_id).def.is_include()
@@ -316,7 +331,7 @@ impl HirFileId {
         }
     }
 
-    pub fn is_eager(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_eager(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
@@ -326,8 +341,7 @@ impl HirFileId {
         }
     }
 
-    /// Return whether this file is an attr macro
-    pub fn is_attr_macro(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_attr_macro(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
@@ -337,9 +351,7 @@ impl HirFileId {
         }
     }
 
-    /// Return whether this file is the pseudo expansion of the derive attribute.
-    /// See [`crate::builtin_attr_macro::derive_attr_expand`].
-    pub fn is_derive_attr_pseudo_expansion(&self, db: &dyn db::ExpandDatabase) -> bool {
+    fn is_derive_attr_pseudo_expansion(&self, db: &dyn db::ExpandDatabase) -> bool {
         match self.macro_file() {
             Some(macro_file) => {
                 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
@@ -348,38 +360,6 @@ impl HirFileId {
             None => false,
         }
     }
-
-    #[inline]
-    pub fn is_macro(self) -> bool {
-        self.0 & Self::MACRO_FILE_TAG_MASK != 0
-    }
-
-    #[inline]
-    pub fn macro_file(self) -> Option<MacroFile> {
-        match self.0 & Self::MACRO_FILE_TAG_MASK {
-            0 => None,
-            _ => Some(MacroFile {
-                macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)),
-            }),
-        }
-    }
-
-    #[inline]
-    pub fn file_id(self) -> Option<FileId> {
-        match self.0 & Self::MACRO_FILE_TAG_MASK {
-            0 => Some(FileId(self.0)),
-            _ => None,
-        }
-    }
-
-    fn repr(self) -> HirFileIdRepr {
-        match self.0 & Self::MACRO_FILE_TAG_MASK {
-            0 => HirFileIdRepr::FileId(FileId(self.0)),
-            _ => HirFileIdRepr::MacroFile(MacroFile {
-                macro_call_id: MacroCallId(InternId::from(self.0 ^ Self::MACRO_FILE_TAG_MASK)),
-            }),
-        }
-    }
 }
 
 impl MacroDefId {
@@ -587,16 +567,6 @@ impl MacroCallKind {
     }
 }
 
-impl MacroCallId {
-    pub fn as_file(self) -> HirFileId {
-        MacroFile { macro_call_id: self }.into()
-    }
-
-    pub fn as_macro_file(self) -> MacroFile {
-        MacroFile { macro_call_id: self }
-    }
-}
-
 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ExpansionInfo {
@@ -607,11 +577,8 @@ pub struct ExpansionInfo {
     attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
 
     macro_def: TokenExpander,
-    macro_arg: Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>,
-    /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
-    /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
-    macro_arg_shift: mbe::Shift,
-    exp_map: Arc<mbe::TokenMap>,
+    macro_arg: Arc<tt::Subtree>,
+    exp_map: Arc<SpanMap>,
 }
 
 impl ExpansionInfo {
@@ -640,69 +607,33 @@ impl ExpansionInfo {
     pub fn map_token_down(
         &self,
         db: &dyn db::ExpandDatabase,
-        item: Option<ast::Item>,
         token: InFile<&SyntaxToken>,
         // FIXME: use this for range mapping, so that we can resolve inline format args
         _relative_token_offset: Option<TextSize>,
     ) -> Option<impl Iterator<Item = InFile<SyntaxToken>> + '_> {
         assert_eq!(token.file_id, self.arg.file_id);
-        let token_id_in_attr_input = if let Some(item) = item {
-            // check if we are mapping down in an attribute input
-            // this is a special case as attributes can have two inputs
-            let call_id = self.expanded.file_id.macro_call_id;
-            let loc = db.lookup_intern_macro_call(call_id);
-
-            let token_range = token.value.text_range();
-            match &loc.kind {
-                MacroCallKind::Attr { attr_args, invoc_attr_index, .. } => {
-                    // FIXME: handle `cfg_attr`
-                    let attr = item
-                        .doc_comments_and_attrs()
-                        .nth(invoc_attr_index.ast_index())
-                        .and_then(Either::left)?;
-                    match attr.token_tree() {
-                        Some(token_tree)
-                            if token_tree.syntax().text_range().contains_range(token_range) =>
-                        {
-                            let attr_input_start =
-                                token_tree.left_delimiter_token()?.text_range().start();
-                            let relative_range =
-                                token.value.text_range().checked_sub(attr_input_start)?;
-                            // shift by the item's tree's max id
-                            let token_id = attr_args.1.token_by_range(relative_range)?;
-
-                            let token_id = if loc.def.is_attribute_derive() {
-                                // we do not shift for `#[derive]`, as we only need to downmap the derive attribute tokens
-                                token_id
-                            } else {
-                                self.macro_arg_shift.shift(token_id)
-                            };
-                            Some(token_id)
-                        }
-                        _ => None,
-                    }
-                }
-                _ => None,
-            }
+        let span_map = &self.exp_map.span_map;
+        let (start, end) = if span_map
+            .first()
+            .map_or(false, |(_, span)| span.anchor.file_id == token.file_id)
+        {
+            (0, span_map.partition_point(|a| a.1.anchor.file_id == token.file_id))
         } else {
-            None
-        };
-
-        let token_id = match token_id_in_attr_input {
-            Some(token_id) => token_id,
-            // the token is not inside `an attribute's input so do the lookup in the macro_arg as usual
-            None => {
-                let relative_range =
-                    token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
-                let token_id = self.macro_arg.1.token_by_range(relative_range)?;
-                // conditionally shift the id by a declarative macro definition
-                self.macro_def.map_id_down(token_id)
-            }
+            let start = span_map.partition_point(|a| a.1.anchor.file_id != token.file_id);
+            (
+                start,
+                start + span_map[start..].partition_point(|a| a.1.anchor.file_id == token.file_id),
+            )
         };
-
-        let tokens = self
-            .exp_map
-            .ranges_by_token(token_id, token.value.kind())
+        let token_text_range = token.value.text_range();
+        let ast_id_map = db.ast_id_map(token.file_id);
+        let tokens = span_map[start..end]
+            .iter()
+            .filter_map(move |(range, span)| {
+                let offset = ast_id_map.get_raw(span.anchor.ast_id).text_range().start();
+                let abs_range = span.range + offset;
+                token_text_range.eq(&abs_range).then_some(*range)
+            })
             .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
 
         Some(tokens.map(move |token| InFile::new(self.expanded.file_id.into(), token)))
@@ -713,60 +644,18 @@ impl ExpansionInfo {
         &self,
         db: &dyn db::ExpandDatabase,
         token: InFile<&SyntaxToken>,
-    ) -> Option<(InFile<SyntaxToken>, Origin)> {
-        assert_eq!(token.file_id, self.expanded.file_id.into());
-        // Fetch the id through its text range,
-        let token_id = self.exp_map.token_by_range(token.value.text_range())?;
-        // conditionally unshifting the id to accommodate for macro-rules def site
-        let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
-
-        let call_id = self.expanded.file_id.macro_call_id;
-        let loc = db.lookup_intern_macro_call(call_id);
-
-        // Special case: map tokens from `include!` expansions to the included file
-        if loc.def.is_include() {
-            if let Ok((tt_and_map, file_id)) = db.include_expand(call_id) {
-                let range = tt_and_map.1.first_range_by_token(token_id, token.value.kind())?;
-                let source = db.parse(file_id);
-
-                let token = source.syntax_node().covering_element(range).into_token()?;
-
-                return Some((InFile::new(file_id.into(), token), Origin::Call));
-            }
-        }
-
-        // Attributes are a bit special for us, they have two inputs, the input tokentree and the annotated item.
-        let (token_map, tt) = match &loc.kind {
-            MacroCallKind::Attr { attr_args, .. } => {
-                if loc.def.is_attribute_derive() {
-                    (&attr_args.1, self.attr_input_or_mac_def.clone()?.syntax().cloned())
-                } else {
-                    // try unshifting the token id, if unshifting fails, the token resides in the non-item attribute input
-                    // note that the `TokenExpander::map_id_up` earlier only unshifts for declarative macros, so we don't double unshift with this
-                    match self.macro_arg_shift.unshift(token_id) {
-                        Some(unshifted) => {
-                            token_id = unshifted;
-                            (&attr_args.1, self.attr_input_or_mac_def.clone()?.syntax().cloned())
-                        }
-                        None => (&self.macro_arg.1, self.arg.clone()),
-                    }
-                }
-            }
-            _ => match origin {
-                mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
-                mbe::Origin::Def => match (&self.macro_def, &self.attr_input_or_mac_def) {
-                    (TokenExpander::DeclarativeMacro(expander), Some(tt)) => {
-                        (&expander.def_site_token_map, tt.syntax().cloned())
-                    }
-                    _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
-                },
-            },
-        };
-
-        let range = token_map.first_range_by_token(token_id, token.value.kind())?;
-        let token =
-            tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
-        Some((tt.with_value(token), origin))
+    ) -> Option<InFile<SyntaxToken>> {
+        self.exp_map.span_for_range(token.value.text_range()).and_then(|span| {
+            let anchor =
+                db.ast_id_map(span.anchor.file_id).get_raw(span.anchor.ast_id).text_range().start();
+            InFile::new(
+                span.anchor.file_id,
+                db.parse_or_expand(span.anchor.file_id)
+                    .covering_element(span.range + anchor)
+                    .into_token(),
+            )
+            .transpose()
+        })
     }
 
     fn new(db: &dyn db::ExpandDatabase, macro_file: MacroFile) -> Option<ExpansionInfo> {
@@ -779,11 +668,7 @@ impl ExpansionInfo {
         let expanded = InMacroFile { file_id: macro_file, value: parse.syntax_node() };
 
         let macro_arg = db.macro_arg(macro_file.macro_call_id).value.unwrap_or_else(|| {
-            Arc::new((
-                tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() },
-                Default::default(),
-                Default::default(),
-            ))
+            Arc::new(tt::Subtree { delimiter: tt::Delimiter::UNSPECIFIED, token_trees: Vec::new() })
         });
 
         let def = loc.def.ast_id().left().and_then(|id| {
@@ -814,7 +699,6 @@ impl ExpansionInfo {
             expanded,
             arg: arg_tt,
             attr_input_or_mac_def,
-            macro_arg_shift: mbe::Shift::new(&macro_arg.0),
             macro_arg,
             macro_def,
             exp_map,
@@ -1018,7 +902,7 @@ impl InFile<&SyntaxNode> {
 impl InFile<SyntaxToken> {
     pub fn upmap(self, db: &dyn db::ExpandDatabase) -> Option<InFile<SyntaxToken>> {
         let expansion = self.file_id.expansion_info(db)?;
-        expansion.map_token_up(db, self.as_ref()).map(|(it, _)| it)
+        expansion.map_token_up(db, self.as_ref())
     }
 
     /// Falls back to the macro call range if the node cannot be mapped up fully.
@@ -1067,6 +951,7 @@ impl<T> From<InMacroFile<T>> for InFile<T> {
     }
 }
 
+// FIXME: Get rid of this
 fn ascend_node_border_tokens(
     db: &dyn db::ExpandDatabase,
     InFile { file_id, value: node }: InFile<&SyntaxNode>,
@@ -1090,13 +975,13 @@ fn ascend_call_token(
     token: InFile<SyntaxToken>,
 ) -> Option<InFile<SyntaxToken>> {
     let mut mapping = expansion.map_token_up(db, token.as_ref())?;
-    while let (mapped, Origin::Call) = mapping {
-        match mapped.file_id.expansion_info(db) {
-            Some(info) => mapping = info.map_token_up(db, mapped.as_ref())?,
-            None => return Some(mapped),
+
+    loop {
+        match mapping.file_id.expansion_info(db) {
+            Some(info) => mapping = info.map_token_up(db, mapping.as_ref())?,
+            None => return Some(mapping),
         }
     }
-    None
 }
 
 impl<N: AstNode> InFile<N> {
diff --git a/crates/hir-expand/src/quote.rs b/crates/hir-expand/src/quote.rs
index ab3809abc7a..9dd4965c150 100644
--- a/crates/hir-expand/src/quote.rs
+++ b/crates/hir-expand/src/quote.rs
@@ -18,8 +18,8 @@ macro_rules! __quote {
             crate::tt::Subtree {
                 delimiter: crate::tt::Delimiter {
                     kind: crate::tt::DelimiterKind::$delim,
-                    open: crate::tt::TokenId::unspecified(),
-                    close: crate::tt::TokenId::unspecified(),
+                    open: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
+                    close: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
                 },
                 token_trees: $crate::quote::IntoTt::to_tokens(children),
             }
@@ -32,7 +32,7 @@ macro_rules! __quote {
                 crate::tt::Leaf::Punct(crate::tt::Punct {
                     char: $first,
                     spacing: crate::tt::Spacing::Alone,
-                    span: crate::tt::TokenId::unspecified(),
+                    span: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
                 }).into()
             ]
         }
@@ -44,12 +44,12 @@ macro_rules! __quote {
                 crate::tt::Leaf::Punct(crate::tt::Punct {
                     char: $first,
                     spacing: crate::tt::Spacing::Joint,
-                    span: crate::tt::TokenId::unspecified(),
+                    span: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
                 }).into(),
                 crate::tt::Leaf::Punct(crate::tt::Punct {
                     char: $sec,
                     spacing: crate::tt::Spacing::Alone,
-                    span: crate::tt::TokenId::unspecified(),
+                    span: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
                 }).into()
             ]
         }
@@ -89,7 +89,7 @@ macro_rules! __quote {
         vec![ {
             crate::tt::Leaf::Ident(crate::tt::Ident {
                 text: stringify!($tt).into(),
-                span: crate::tt::TokenId::unspecified(),
+                span: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
             }).into()
         }]
     };
@@ -195,20 +195,22 @@ macro_rules! impl_to_to_tokentrees {
 }
 
 impl_to_to_tokentrees! {
-    u32 => self { crate::tt::Literal{text: self.to_string().into(), span: crate::tt::TokenId::unspecified()} };
-    usize => self { crate::tt::Literal{text: self.to_string().into(), span: crate::tt::TokenId::unspecified()} };
-    i32 => self { crate::tt::Literal{text: self.to_string().into(), span: crate::tt::TokenId::unspecified()} };
-    bool => self { crate::tt::Ident{text: self.to_string().into(), span: crate::tt::TokenId::unspecified()} };
+    u32 => self { crate::tt::Literal{text: self.to_string().into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY} };
+    usize => self { crate::tt::Literal{text: self.to_string().into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY} };
+    i32 => self { crate::tt::Literal{text: self.to_string().into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY} };
+    bool => self { crate::tt::Ident{text: self.to_string().into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY} };
     crate::tt::Leaf => self { self };
     crate::tt::Literal => self { self };
     crate::tt::Ident => self { self };
     crate::tt::Punct => self { self };
-    &str => self { crate::tt::Literal{text: format!("\"{}\"", self.escape_default()).into(), span: crate::tt::TokenId::unspecified()}};
-    String => self { crate::tt::Literal{text: format!("\"{}\"", self.escape_default()).into(), span: crate::tt::TokenId::unspecified()}}
+    &str => self { crate::tt::Literal{text: format!("\"{}\"", self.escape_default()).into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY}};
+    String => self { crate::tt::Literal{text: format!("\"{}\"", self.escape_default()).into(), span: <crate::tt::SpanData as crate::tt::Span>::DUMMY}}
 }
 
 #[cfg(test)]
 mod tests {
+    use expect_test::expect;
+
     #[test]
     fn test_quote_delimiters() {
         assert_eq!(quote!({}).to_string(), "{}");
@@ -231,7 +233,10 @@ mod tests {
     }
 
     fn mk_ident(name: &str) -> crate::tt::Ident {
-        crate::tt::Ident { text: name.into(), span: crate::tt::TokenId::unspecified() }
+        crate::tt::Ident {
+            text: name.into(),
+            span: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
+        }
     }
 
     #[test]
@@ -241,7 +246,9 @@ mod tests {
         let quoted = quote!(#a);
         assert_eq!(quoted.to_string(), "hello");
         let t = format!("{quoted:?}");
-        assert_eq!(t, "SUBTREE $$ 4294967295 4294967295\n  IDENT   hello 4294967295");
+        expect![[r#"
+            SUBTREE $$ SpanData { range: 0..0, anchor: SpanAnchor { file_id: FileId(0), ast_id: Idx::<RustLanguage>>(0) } } SpanData { range: 0..0, anchor: SpanAnchor { file_id: FileId(0), ast_id: Idx::<RustLanguage>>(0) } }
+              IDENT   hello SpanData { range: 0..0, anchor: SpanAnchor { file_id: FileId(0), ast_id: Idx::<RustLanguage>>(0) } }"#]].assert_eq(&t);
     }
 
     #[test]
@@ -273,8 +280,8 @@ mod tests {
         let list = crate::tt::Subtree {
             delimiter: crate::tt::Delimiter {
                 kind: crate::tt::DelimiterKind::Brace,
-                open: crate::tt::TokenId::unspecified(),
-                close: crate::tt::TokenId::unspecified(),
+                open: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
+                close: <crate::tt::SpanData as crate::tt::Span>::DUMMY,
             },
             token_trees: fields.collect(),
         };
diff --git a/crates/hir-ty/src/diagnostics/decl_check.rs b/crates/hir-ty/src/diagnostics/decl_check.rs
index f4c079b48c5..c2ff487ef91 100644
--- a/crates/hir-ty/src/diagnostics/decl_check.rs
+++ b/crates/hir-ty/src/diagnostics/decl_check.rs
@@ -24,7 +24,7 @@ use hir_def::{
 };
 use hir_expand::{
     name::{AsName, Name},
-    HirFileId,
+    HirFileId, HirFileIdExt,
 };
 use stdx::{always, never};
 use syntax::{
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 62efb858511..fbfb6ff8cdd 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -21,7 +21,7 @@ use hir_def::{
     AdtId, ConstId, DefWithBodyId, EnumVariantId, FunctionId, HasModule, ItemContainerId, Lookup,
     StaticId, VariantId,
 };
-use hir_expand::{mod_path::ModPath, InFile};
+use hir_expand::{mod_path::ModPath, HirFileIdExt, InFile};
 use intern::Interned;
 use la_arena::ArenaMap;
 use rustc_hash::{FxHashMap, FxHashSet};
diff --git a/crates/hir/src/db.rs b/crates/hir/src/db.rs
index 936581bfe32..f4129e736ee 100644
--- a/crates/hir/src/db.rs
+++ b/crates/hir/src/db.rs
@@ -6,7 +6,7 @@
 pub use hir_def::db::*;
 pub use hir_expand::db::{
     AstIdMapQuery, DeclMacroExpanderQuery, ExpandDatabase, ExpandDatabaseStorage,
-    ExpandProcMacroQuery, HygieneFrameQuery, InternMacroCallQuery, MacroArgNodeQuery,
-    MacroExpandQuery, ParseMacroExpansionErrorQuery, ParseMacroExpansionQuery,
+    ExpandProcMacroQuery, HygieneFrameQuery, InternMacroCallQuery, MacroArgQuery, MacroExpandQuery,
+    ParseMacroExpansionErrorQuery, ParseMacroExpansionQuery,
 };
 pub use hir_ty::db::*;
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 1bfbf7212bf..50d88b4cf83 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -124,7 +124,7 @@ pub use {
     hir_expand::{
         attrs::{Attr, AttrId},
         name::{known, Name},
-        ExpandResult, HirFileId, InFile, MacroFile, Origin,
+        tt, ExpandResult, HirFileId, HirFileIdExt, InFile, MacroFile,
     },
     hir_ty::{
         display::{ClosureStyle, HirDisplay, HirDisplayError, HirWrite},
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index a42e0978b25..758e6118aa1 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -15,7 +15,7 @@ use hir_def::{
     type_ref::Mutability,
     AsMacroCall, DefWithBodyId, FieldId, FunctionId, MacroId, TraitId, VariantId,
 };
-use hir_expand::{db::ExpandDatabase, name::AsName, ExpansionInfo, MacroCallId};
+use hir_expand::{db::ExpandDatabase, name::AsName, ExpansionInfo, HirFileIdExt, MacroCallId};
 use itertools::Itertools;
 use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{smallvec, SmallVec};
@@ -549,7 +549,7 @@ impl<'db> SemanticsImpl<'db> {
         let mut mcache = self.macro_call_cache.borrow_mut();
 
         let mut process_expansion_for_token =
-            |stack: &mut SmallVec<_>, macro_file, item, token: InFile<&_>| {
+            |stack: &mut SmallVec<_>, macro_file, token: InFile<&_>| {
                 let expansion_info = cache
                     .entry(macro_file)
                     .or_insert_with(|| macro_file.expansion_info(self.db.upcast()))
@@ -562,7 +562,6 @@ impl<'db> SemanticsImpl<'db> {
 
                 let mapped_tokens = expansion_info.map_token_down(
                     self.db.upcast(),
-                    item,
                     token,
                     relative_token_offset,
                 )?;
@@ -587,17 +586,12 @@ impl<'db> SemanticsImpl<'db> {
                             // Don't force populate the dyn cache for items that don't have an attribute anyways
                             return None;
                         }
-                        Some((ctx.item_to_macro_call(token.with_value(item.clone()))?, item))
+                        Some(ctx.item_to_macro_call(token.with_value(item.clone()))?)
                     })
                 });
-                if let Some((call_id, item)) = containing_attribute_macro_call {
+                if let Some(call_id) = containing_attribute_macro_call {
                     let file_id = call_id.as_file();
-                    return process_expansion_for_token(
-                        &mut stack,
-                        file_id,
-                        Some(item),
-                        token.as_ref(),
-                    );
+                    return process_expansion_for_token(&mut stack, file_id, token.as_ref());
                 }
 
                 // Then check for token trees, that means we are either in a function-like macro or
@@ -622,7 +616,7 @@ impl<'db> SemanticsImpl<'db> {
                             it
                         }
                     };
-                    process_expansion_for_token(&mut stack, file_id, None, token.as_ref())
+                    process_expansion_for_token(&mut stack, file_id, token.as_ref())
                 } else if let Some(meta) = ast::Meta::cast(parent) {
                     // attribute we failed expansion for earlier, this might be a derive invocation
                     // or derive helper attribute
@@ -647,7 +641,6 @@ impl<'db> SemanticsImpl<'db> {
                                 return process_expansion_for_token(
                                     &mut stack,
                                     file_id,
-                                    Some(adt.into()),
                                     token.as_ref(),
                                 );
                             }
@@ -679,13 +672,11 @@ impl<'db> SemanticsImpl<'db> {
                     let id = self.db.ast_id_map(token.file_id).ast_id(&adt);
                     let helpers =
                         def_map.derive_helpers_in_scope(InFile::new(token.file_id, id))?;
-                    let item = Some(adt.into());
                     let mut res = None;
                     for (.., derive) in helpers.iter().filter(|(helper, ..)| *helper == attr_name) {
                         res = res.or(process_expansion_for_token(
                             &mut stack,
                             derive.as_file(),
-                            item.clone(),
                             token.as_ref(),
                         ));
                     }
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index aabda365560..5b20c873157 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -97,7 +97,7 @@ use hir_def::{
     FunctionId, GenericDefId, GenericParamId, ImplId, LifetimeParamId, MacroId, ModuleId, StaticId,
     StructId, TraitAliasId, TraitId, TypeAliasId, TypeParamId, UnionId, UseId, VariantId,
 };
-use hir_expand::{attrs::AttrId, name::AsName, HirFileId, MacroCallId};
+use hir_expand::{attrs::AttrId, name::AsName, HirFileId, HirFileIdExt, MacroCallId};
 use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
 use stdx::{impl_from, never};
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 55c2f8324c6..8fc7f2c05d7 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -30,7 +30,7 @@ use hir_expand::{
     mod_path::path,
     name,
     name::{AsName, Name},
-    HirFileId, InFile,
+    HirFileId, HirFileIdExt, InFile,
 };
 use hir_ty::{
     diagnostics::{
diff --git a/crates/ide-assists/src/handlers/extract_module.rs b/crates/ide-assists/src/handlers/extract_module.rs
index 6839c5820dc..4b9fedc7e85 100644
--- a/crates/ide-assists/src/handlers/extract_module.rs
+++ b/crates/ide-assists/src/handlers/extract_module.rs
@@ -3,7 +3,7 @@ use std::{
     iter,
 };
 
-use hir::{HasSource, ModuleSource};
+use hir::{HasSource, HirFileIdExt, ModuleSource};
 use ide_db::{
     assists::{AssistId, AssistKind},
     base_db::FileId,
diff --git a/crates/ide-assists/src/handlers/fix_visibility.rs b/crates/ide-assists/src/handlers/fix_visibility.rs
index c9f272474e7..204e796fa2c 100644
--- a/crates/ide-assists/src/handlers/fix_visibility.rs
+++ b/crates/ide-assists/src/handlers/fix_visibility.rs
@@ -1,4 +1,6 @@
-use hir::{db::HirDatabase, HasSource, HasVisibility, ModuleDef, PathResolution, ScopeDef};
+use hir::{
+    db::HirDatabase, HasSource, HasVisibility, HirFileIdExt, ModuleDef, PathResolution, ScopeDef,
+};
 use ide_db::base_db::FileId;
 use syntax::{
     ast::{self, edit_in_place::HasVisibilityEdit, make, HasVisibility as _},
diff --git a/crates/ide-assists/src/handlers/generate_constant.rs b/crates/ide-assists/src/handlers/generate_constant.rs
index eccd7675fba..a4e8e7388f6 100644
--- a/crates/ide-assists/src/handlers/generate_constant.rs
+++ b/crates/ide-assists/src/handlers/generate_constant.rs
@@ -1,5 +1,5 @@
 use crate::assist_context::{AssistContext, Assists};
-use hir::{HasVisibility, HirDisplay, Module};
+use hir::{HasVisibility, HirDisplay, HirFileIdExt, Module};
 use ide_db::{
     assists::{AssistId, AssistKind},
     base_db::{FileId, Upcast},
diff --git a/crates/ide-assists/src/handlers/generate_enum_variant.rs b/crates/ide-assists/src/handlers/generate_enum_variant.rs
index 184f523e01b..be7a5e6c8bc 100644
--- a/crates/ide-assists/src/handlers/generate_enum_variant.rs
+++ b/crates/ide-assists/src/handlers/generate_enum_variant.rs
@@ -1,4 +1,4 @@
-use hir::{HasSource, HirDisplay, InFile};
+use hir::{HasSource, HirDisplay, HirFileIdExt, InFile};
 use ide_db::assists::{AssistId, AssistKind};
 use syntax::{
     ast::{self, make, HasArgList},
diff --git a/crates/ide-assists/src/handlers/generate_function.rs b/crates/ide-assists/src/handlers/generate_function.rs
index f74fc5df4bd..a113c817f7e 100644
--- a/crates/ide-assists/src/handlers/generate_function.rs
+++ b/crates/ide-assists/src/handlers/generate_function.rs
@@ -1,5 +1,6 @@
 use hir::{
-    Adt, AsAssocItem, HasSource, HirDisplay, Module, PathResolution, Semantics, Type, TypeInfo,
+    Adt, AsAssocItem, HasSource, HirDisplay, HirFileIdExt, Module, PathResolution, Semantics, Type,
+    TypeInfo,
 };
 use ide_db::{
     base_db::FileId,
@@ -510,7 +511,7 @@ fn assoc_fn_target_info(
 }
 
 fn get_insert_offset(target: &GeneratedFunctionTarget) -> TextSize {
-    match &target {
+    match target {
         GeneratedFunctionTarget::BehindItem(it) => it.text_range().end(),
         GeneratedFunctionTarget::InEmptyItemList(it) => it.text_range().start() + TextSize::of('{'),
     }
diff --git a/crates/ide-assists/src/handlers/remove_unused_imports.rs b/crates/ide-assists/src/handlers/remove_unused_imports.rs
index 5fcab8c02b0..10076e60c3e 100644
--- a/crates/ide-assists/src/handlers/remove_unused_imports.rs
+++ b/crates/ide-assists/src/handlers/remove_unused_imports.rs
@@ -1,6 +1,6 @@
 use std::collections::{hash_map::Entry, HashMap};
 
-use hir::{InFile, Module, ModuleSource};
+use hir::{HirFileIdExt, InFile, Module, ModuleSource};
 use ide_db::{
     base_db::FileRange,
     defs::Definition,
diff --git a/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs b/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
index 69a4e748b7c..1b373bcb8ce 100644
--- a/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
+++ b/crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs
@@ -1,4 +1,4 @@
-use hir::{InFile, ModuleDef};
+use hir::{HirFileIdExt, InFile, ModuleDef};
 use ide_db::{helpers::mod_path_to_ast, imports::import_assets::NameToImport, items_locator};
 use itertools::Itertools;
 use syntax::{
diff --git a/crates/ide-completion/src/completions.rs b/crates/ide-completion/src/completions.rs
index 7d38c638a8e..f49abcbae9b 100644
--- a/crates/ide-completion/src/completions.rs
+++ b/crates/ide-completion/src/completions.rs
@@ -683,7 +683,7 @@ pub(super) fn complete_name_ref(
     ctx: &CompletionContext<'_>,
     NameRefContext { nameref, kind }: &NameRefContext,
 ) {
-    match kind {
+    match dbg!(kind) {
         NameRefKind::Path(path_ctx) => {
             flyimport::import_on_the_fly_path(acc, ctx, path_ctx);
 
diff --git a/crates/ide-completion/src/completions/mod_.rs b/crates/ide-completion/src/completions/mod_.rs
index 1e09894059d..5d138eea46f 100644
--- a/crates/ide-completion/src/completions/mod_.rs
+++ b/crates/ide-completion/src/completions/mod_.rs
@@ -2,7 +2,7 @@
 
 use std::iter;
 
-use hir::{Module, ModuleSource};
+use hir::{HirFileIdExt, Module, ModuleSource};
 use ide_db::{
     base_db::{SourceDatabaseExt, VfsPath},
     FxHashSet, RootDatabase, SymbolKind,
diff --git a/crates/ide-db/src/apply_change.rs b/crates/ide-db/src/apply_change.rs
index a0b05c87ae7..65eaa6510f0 100644
--- a/crates/ide-db/src/apply_change.rs
+++ b/crates/ide-db/src/apply_change.rs
@@ -99,7 +99,7 @@ impl RootDatabase {
             hir::db::AstIdMapQuery
             hir::db::ParseMacroExpansionQuery
             hir::db::InternMacroCallQuery
-            hir::db::MacroArgNodeQuery
+            hir::db::MacroArgQuery
             hir::db::DeclMacroExpanderQuery
             hir::db::MacroExpandQuery
             hir::db::ExpandProcMacroQuery
diff --git a/crates/ide-db/src/lib.rs b/crates/ide-db/src/lib.rs
index 226def4d526..258d893b47d 100644
--- a/crates/ide-db/src/lib.rs
+++ b/crates/ide-db/src/lib.rs
@@ -204,7 +204,7 @@ impl RootDatabase {
             hir_db::AstIdMapQuery
             // hir_db::ParseMacroExpansionQuery
             // hir_db::InternMacroCallQuery
-            hir_db::MacroArgNodeQuery
+            hir_db::MacroArgQuery
             hir_db::DeclMacroExpanderQuery
             // hir_db::MacroExpandQuery
             hir_db::ExpandProcMacroQuery
diff --git a/crates/ide-db/src/rename.rs b/crates/ide-db/src/rename.rs
index 353a9749a37..cc9038fdfa2 100644
--- a/crates/ide-db/src/rename.rs
+++ b/crates/ide-db/src/rename.rs
@@ -24,7 +24,7 @@ use std::fmt;
 
 use base_db::{AnchoredPathBuf, FileId, FileRange};
 use either::Either;
-use hir::{FieldSource, HasSource, InFile, ModuleSource, Semantics};
+use hir::{FieldSource, HasSource, HirFileIdExt, InFile, ModuleSource, Semantics};
 use stdx::never;
 use syntax::{
     ast::{self, HasName},
diff --git a/crates/ide-db/src/search.rs b/crates/ide-db/src/search.rs
index 22438a203bd..68f2ad49457 100644
--- a/crates/ide-db/src/search.rs
+++ b/crates/ide-db/src/search.rs
@@ -8,7 +8,8 @@ use std::mem;
 
 use base_db::{salsa::Database, FileId, FileRange, SourceDatabase, SourceDatabaseExt};
 use hir::{
-    AsAssocItem, DefWithBody, HasAttrs, HasSource, InFile, ModuleSource, Semantics, Visibility,
+    AsAssocItem, DefWithBody, HasAttrs, HasSource, HirFileIdExt, InFile, ModuleSource, Semantics,
+    Visibility,
 };
 use memchr::memmem::Finder;
 use nohash_hasher::IntMap;
diff --git a/crates/ide-db/src/test_data/test_doc_alias.txt b/crates/ide-db/src/test_data/test_doc_alias.txt
index 7834c66033c..72a6eb5eabd 100644
--- a/crates/ide-db/src/test_data/test_doc_alias.txt
+++ b/crates/ide-db/src/test_data/test_doc_alias.txt
@@ -21,9 +21,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -50,9 +48,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -79,9 +75,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -108,9 +102,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -137,9 +129,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -166,9 +156,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -195,9 +183,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
diff --git a/crates/ide-db/src/test_data/test_symbol_index_collection.txt b/crates/ide-db/src/test_data/test_symbol_index_collection.txt
index 87ad5844c64..375ac559815 100644
--- a/crates/ide-db/src/test_data/test_symbol_index_collection.txt
+++ b/crates/ide-db/src/test_data/test_symbol_index_collection.txt
@@ -19,9 +19,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: TYPE_ALIAS,
@@ -46,9 +44,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: CONST,
@@ -73,9 +69,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: CONST,
@@ -102,9 +96,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: ENUM,
@@ -131,9 +123,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -160,9 +150,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: MACRO_DEF,
@@ -187,9 +175,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STATIC,
@@ -216,9 +202,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -245,11 +229,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: MacroFile(
-                        MacroFile {
-                            macro_call_id: MacroCallId(
-                                0,
-                            ),
-                        },
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -276,9 +256,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -307,9 +285,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -338,9 +314,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -365,9 +339,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: TRAIT,
@@ -394,9 +366,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -423,9 +393,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: UNION,
@@ -452,9 +420,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: MODULE,
@@ -481,9 +447,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: MODULE,
@@ -510,9 +474,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: MACRO_RULES,
@@ -537,9 +499,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: FN,
@@ -566,9 +526,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: MACRO_RULES,
@@ -593,9 +551,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: FN,
@@ -622,9 +578,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -649,9 +603,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: FN,
@@ -691,9 +643,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            0,
-                        ),
+                        0,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -731,9 +681,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            1,
-                        ),
+                        1,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -760,9 +708,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            1,
-                        ),
+                        1,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: STRUCT,
@@ -789,9 +735,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            1,
-                        ),
+                        1,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -818,9 +762,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            1,
-                        ),
+                        1,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
@@ -847,9 +789,7 @@
                 ),
                 loc: DeclarationLocation {
                     hir_file_id: FileId(
-                        FileId(
-                            1,
-                        ),
+                        1,
                     ),
                     ptr: SyntaxNodePtr {
                         kind: USE_TREE,
diff --git a/crates/ide-diagnostics/src/handlers/missing_fields.rs b/crates/ide-diagnostics/src/handlers/missing_fields.rs
index d7dca1083a0..cb38bc54d7d 100644
--- a/crates/ide-diagnostics/src/handlers/missing_fields.rs
+++ b/crates/ide-diagnostics/src/handlers/missing_fields.rs
@@ -1,7 +1,7 @@
 use either::Either;
 use hir::{
     db::{ExpandDatabase, HirDatabase},
-    known, AssocItem, HirDisplay, InFile, Type,
+    known, AssocItem, HirDisplay, HirFileIdExt, InFile, Type,
 };
 use ide_db::{
     assists::Assist, famous_defs::FamousDefs, imports::import_assets::item_for_path_search,
diff --git a/crates/ide-diagnostics/src/handlers/missing_unsafe.rs b/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
index 0f695b2745a..f93a35cf181 100644
--- a/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
+++ b/crates/ide-diagnostics/src/handlers/missing_unsafe.rs
@@ -1,4 +1,5 @@
 use hir::db::ExpandDatabase;
+use hir::HirFileIdExt;
 use ide_db::{assists::Assist, source_change::SourceChange};
 use syntax::{ast, SyntaxNode};
 use syntax::{match_ast, AstNode};
diff --git a/crates/ide-diagnostics/src/handlers/no_such_field.rs b/crates/ide-diagnostics/src/handlers/no_such_field.rs
index ee8a9c95793..0abcbffe72b 100644
--- a/crates/ide-diagnostics/src/handlers/no_such_field.rs
+++ b/crates/ide-diagnostics/src/handlers/no_such_field.rs
@@ -1,5 +1,5 @@
 use either::Either;
-use hir::{db::ExpandDatabase, HasSource, HirDisplay, Semantics};
+use hir::{db::ExpandDatabase, HasSource, HirDisplay, HirFileIdExt, Semantics};
 use ide_db::{base_db::FileId, source_change::SourceChange, RootDatabase};
 use syntax::{
     ast::{self, edit::IndentLevel, make},
diff --git a/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs b/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
index d15233d15c2..258ac6cd823 100644
--- a/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
+++ b/crates/ide-diagnostics/src/handlers/replace_filter_map_next_with_find_map.rs
@@ -1,4 +1,4 @@
-use hir::{db::ExpandDatabase, InFile};
+use hir::{db::ExpandDatabase, HirFileIdExt, InFile};
 use ide_db::source_change::SourceChange;
 use syntax::{
     ast::{self, HasArgList},
diff --git a/crates/ide-diagnostics/src/handlers/type_mismatch.rs b/crates/ide-diagnostics/src/handlers/type_mismatch.rs
index c92d92ceae8..fd00535d0c3 100644
--- a/crates/ide-diagnostics/src/handlers/type_mismatch.rs
+++ b/crates/ide-diagnostics/src/handlers/type_mismatch.rs
@@ -1,4 +1,4 @@
-use hir::{db::ExpandDatabase, ClosureStyle, HirDisplay, InFile, Type};
+use hir::{db::ExpandDatabase, ClosureStyle, HirDisplay, HirFileIdExt, InFile, Type};
 use ide_db::{famous_defs::FamousDefs, source_change::SourceChange};
 use syntax::{
     ast::{self, BlockExpr, ExprStmt},
diff --git a/crates/ide-diagnostics/src/handlers/unresolved_module.rs b/crates/ide-diagnostics/src/handlers/unresolved_module.rs
index be24e50c987..bbbd21741e5 100644
--- a/crates/ide-diagnostics/src/handlers/unresolved_module.rs
+++ b/crates/ide-diagnostics/src/handlers/unresolved_module.rs
@@ -1,4 +1,4 @@
-use hir::db::ExpandDatabase;
+use hir::{db::ExpandDatabase, HirFileIdExt};
 use ide_db::{assists::Assist, base_db::AnchoredPathBuf, source_change::FileSystemEdit};
 use itertools::Itertools;
 use syntax::AstNode;
diff --git a/crates/ide/src/call_hierarchy.rs b/crates/ide/src/call_hierarchy.rs
index f834f2ce592..6f41f51f80e 100644
--- a/crates/ide/src/call_hierarchy.rs
+++ b/crates/ide/src/call_hierarchy.rs
@@ -149,7 +149,7 @@ mod tests {
 
     fn check_hierarchy(
         ra_fixture: &str,
-        expected: Expect,
+        expected_nav: Expect,
         expected_incoming: Expect,
         expected_outgoing: Expect,
     ) {
@@ -158,7 +158,7 @@ mod tests {
         let mut navs = analysis.call_hierarchy(pos).unwrap().unwrap().info;
         assert_eq!(navs.len(), 1);
         let nav = navs.pop().unwrap();
-        expected.assert_eq(&nav.debug_render());
+        expected_nav.assert_eq(&nav.debug_render());
 
         let item_pos =
             FilePosition { file_id: nav.file_id, offset: nav.focus_or_full_range().start() };
diff --git a/crates/ide/src/expand_macro.rs b/crates/ide/src/expand_macro.rs
index 32207745677..f7c6a0139e0 100644
--- a/crates/ide/src/expand_macro.rs
+++ b/crates/ide/src/expand_macro.rs
@@ -1,4 +1,4 @@
-use hir::Semantics;
+use hir::{HirFileIdExt, Semantics};
 use ide_db::{
     base_db::FileId, helpers::pick_best_token,
     syntax_helpers::insert_whitespace_into_node::insert_ws_into, RootDatabase,
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index e09b9f39148..59e8578cf15 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -60,13 +60,13 @@ pub(crate) fn goto_definition(
         .into_iter()
         .filter_map(|token| {
             let parent = token.parent()?;
-            if let Some(tt) = ast::TokenTree::cast(parent) {
+            if let Some(tt) = ast::TokenTree::cast(parent.clone()) {
                 if let Some(x) = try_lookup_include_path(sema, tt, token.clone(), file_id) {
                     return Some(vec![x]);
                 }
             }
             Some(
-                IdentClass::classify_token(sema, &token)?
+                IdentClass::classify_node(sema, &parent)?
                     .definitions()
                     .into_iter()
                     .flat_map(|def| {
@@ -392,6 +392,8 @@ fn bar() {
         );
     }
 
+    // FIXME: We should emit two targets here, one for the identifier in the declaration, one for
+    // the macro call
     #[test]
     fn goto_def_for_macro_defined_fn_no_arg() {
         check(
@@ -399,10 +401,10 @@ fn bar() {
 //- /lib.rs
 macro_rules! define_fn {
     () => (fn foo() {})
+            //^^^
 }
 
   define_fn!();
-//^^^^^^^^^^^^^
 
 fn bar() {
    $0foo();
diff --git a/crates/ide/src/rename.rs b/crates/ide/src/rename.rs
index ac9df5ed6d1..ad1eb249971 100644
--- a/crates/ide/src/rename.rs
+++ b/crates/ide/src/rename.rs
@@ -4,7 +4,7 @@
 //! tests. This module also implements a couple of magic tricks, like renaming
 //! `self` and to `self` (to switch between associated function and method).
 
-use hir::{AsAssocItem, InFile, Semantics};
+use hir::{AsAssocItem, HirFileIdExt, InFile, Semantics};
 use ide_db::{
     base_db::FileId,
     defs::{Definition, NameClass, NameRefClass},
diff --git a/crates/ide/src/runnables.rs b/crates/ide/src/runnables.rs
index 07cdddd15f8..954a364c787 100644
--- a/crates/ide/src/runnables.rs
+++ b/crates/ide/src/runnables.rs
@@ -2,7 +2,7 @@ use std::fmt;
 
 use ast::HasName;
 use cfg::CfgExpr;
-use hir::{db::HirDatabase, AsAssocItem, HasAttrs, HasSource, Semantics};
+use hir::{db::HirDatabase, AsAssocItem, HasAttrs, HasSource, HirFileIdExt, Semantics};
 use ide_assists::utils::test_related_attribute;
 use ide_db::{
     base_db::{FilePosition, FileRange},
diff --git a/crates/ide/src/static_index.rs b/crates/ide/src/static_index.rs
index aabd26da289..7ee50f7a67f 100644
--- a/crates/ide/src/static_index.rs
+++ b/crates/ide/src/static_index.rs
@@ -3,7 +3,7 @@
 
 use std::collections::HashMap;
 
-use hir::{db::HirDatabase, Crate, Module};
+use hir::{db::HirDatabase, Crate, HirFileIdExt, Module};
 use ide_db::helpers::get_definition;
 use ide_db::{
     base_db::{FileId, FileRange, SourceDatabaseExt},
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
index 7d00282fc14..1bffab29cf9 100644
--- a/crates/ide/src/syntax_highlighting/highlight.rs
+++ b/crates/ide/src/syntax_highlighting/highlight.rs
@@ -1,6 +1,6 @@
 //! Computes color for a single element.
 
-use hir::{AsAssocItem, HasVisibility, Semantics};
+use hir::{AsAssocItem, HasVisibility, HirFileIdExt, Semantics};
 use ide_db::{
     defs::{Definition, IdentClass, NameClass, NameRefClass},
     FxHashMap, RootDatabase, SymbolKind,
diff --git a/crates/load-cargo/src/lib.rs b/crates/load-cargo/src/lib.rs
index 68b592ffaa4..4d131909493 100644
--- a/crates/load-cargo/src/lib.rs
+++ b/crates/load-cargo/src/lib.rs
@@ -4,13 +4,12 @@
 // to run rust-analyzer as a library.
 use std::{collections::hash_map::Entry, mem, path::Path, sync};
 
-use ::tt::token_id as tt;
 use crossbeam_channel::{unbounded, Receiver};
 use ide::{AnalysisHost, Change, SourceRoot};
 use ide_db::{
     base_db::{
-        CrateGraph, Env, ProcMacro, ProcMacroExpander, ProcMacroExpansionError, ProcMacroKind,
-        ProcMacroLoadResult, ProcMacros,
+        span::SpanData, CrateGraph, Env, ProcMacro, ProcMacroExpander, ProcMacroExpansionError,
+        ProcMacroKind, ProcMacroLoadResult, ProcMacros,
     },
     FxHashMap,
 };
@@ -374,16 +373,19 @@ struct Expander(proc_macro_api::ProcMacro);
 impl ProcMacroExpander for Expander {
     fn expand(
         &self,
-        subtree: &tt::Subtree,
-        attrs: Option<&tt::Subtree>,
+        subtree: &tt::Subtree<SpanData>,
+        attrs: Option<&tt::Subtree<SpanData>>,
         env: &Env,
-    ) -> Result<tt::Subtree, ProcMacroExpansionError> {
-        let env = env.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect();
-        match self.0.expand(subtree, attrs, env) {
-            Ok(Ok(subtree)) => Ok(subtree),
-            Ok(Err(err)) => Err(ProcMacroExpansionError::Panic(err.0)),
-            Err(err) => Err(ProcMacroExpansionError::System(err.to_string())),
-        }
+    ) -> Result<tt::Subtree<SpanData>, ProcMacroExpansionError> {
+        let _ = (subtree, attrs, env);
+
+        // let env = env.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect();
+        // match self.0.expand(subtree, attrs, env) {
+        //     Ok(Ok(subtree)) => Ok(subtree),
+        //     Ok(Err(err)) => Err(ProcMacroExpansionError::Panic(err.0)),
+        //     Err(err) => Err(ProcMacroExpansionError::System(err.to_string())),
+        // }
+        todo!()
     }
 }
 
@@ -394,10 +396,10 @@ struct IdentityExpander;
 impl ProcMacroExpander for IdentityExpander {
     fn expand(
         &self,
-        subtree: &tt::Subtree,
-        _: Option<&tt::Subtree>,
+        subtree: &tt::Subtree<SpanData>,
+        _: Option<&tt::Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<tt::Subtree, ProcMacroExpansionError> {
+    ) -> Result<tt::Subtree<SpanData>, ProcMacroExpansionError> {
         Ok(subtree.clone())
     }
 }
@@ -409,10 +411,10 @@ struct EmptyExpander;
 impl ProcMacroExpander for EmptyExpander {
     fn expand(
         &self,
-        _: &tt::Subtree,
-        _: Option<&tt::Subtree>,
+        _: &tt::Subtree<SpanData>,
+        _: Option<&tt::Subtree<SpanData>>,
         _: &Env,
-    ) -> Result<tt::Subtree, ProcMacroExpansionError> {
+    ) -> Result<tt::Subtree<SpanData>, ProcMacroExpansionError> {
         Ok(tt::Subtree::empty())
     }
 }
diff --git a/crates/mbe/src/benchmark.rs b/crates/mbe/src/benchmark.rs
index 19cb20354b7..4f60e90773e 100644
--- a/crates/mbe/src/benchmark.rs
+++ b/crates/mbe/src/benchmark.rs
@@ -6,13 +6,19 @@ use syntax::{
     AstNode, SmolStr,
 };
 use test_utils::{bench, bench_fixture, skip_slow_tests};
-use tt::{Span, TokenId};
+use tt::{Span, SpanData};
 
 use crate::{
     parser::{MetaVarKind, Op, RepeatKind, Separator},
     syntax_node_to_token_tree, DeclarativeMacro,
 };
 
+#[derive(PartialEq, Eq, Clone, Copy, Debug)]
+struct DummyFile;
+impl Span for DummyFile {
+    const DUMMY: Self = DummyFile;
+}
+
 #[test]
 fn benchmark_parse_macro_rules() {
     if skip_slow_tests() {
@@ -39,7 +45,7 @@ fn benchmark_expand_macro_rules() {
         invocations
             .into_iter()
             .map(|(id, tt)| {
-                let res = rules[&id].expand(tt);
+                let res = rules[&id].expand(&tt);
                 assert!(res.err.is_none());
                 res.value.token_trees.len()
             })
@@ -48,14 +54,14 @@ fn benchmark_expand_macro_rules() {
     assert_eq!(hash, 69413);
 }
 
-fn macro_rules_fixtures() -> FxHashMap<String, DeclarativeMacro> {
+fn macro_rules_fixtures() -> FxHashMap<String, DeclarativeMacro<SpanData<DummyFile>>> {
     macro_rules_fixtures_tt()
         .into_iter()
         .map(|(id, tt)| (id, DeclarativeMacro::parse_macro_rules(&tt, true)))
         .collect()
 }
 
-fn macro_rules_fixtures_tt() -> FxHashMap<String, tt::Subtree<TokenId>> {
+fn macro_rules_fixtures_tt() -> FxHashMap<String, tt::Subtree<SpanData<DummyFile>>> {
     let fixture = bench_fixture::numerous_macro_rules();
     let source_file = ast::SourceFile::parse(&fixture).ok().unwrap();
 
@@ -65,7 +71,12 @@ fn macro_rules_fixtures_tt() -> FxHashMap<String, tt::Subtree<TokenId>> {
         .filter_map(ast::MacroRules::cast)
         .map(|rule| {
             let id = rule.name().unwrap().to_string();
-            let (def_tt, _) = syntax_node_to_token_tree(rule.token_tree().unwrap().syntax());
+            let def_tt = syntax_node_to_token_tree(
+                rule.token_tree().unwrap().syntax(),
+                DummyFile,
+                0.into(),
+                &Default::default(),
+            );
             (id, def_tt)
         })
         .collect()
@@ -73,8 +84,8 @@ fn macro_rules_fixtures_tt() -> FxHashMap<String, tt::Subtree<TokenId>> {
 
 /// Generate random invocation fixtures from rules
 fn invocation_fixtures(
-    rules: &FxHashMap<String, DeclarativeMacro>,
-) -> Vec<(String, tt::Subtree<TokenId>)> {
+    rules: &FxHashMap<String, DeclarativeMacro<SpanData<DummyFile>>>,
+) -> Vec<(String, tt::Subtree<SpanData<DummyFile>>)> {
     let mut seed = 123456789;
     let mut res = Vec::new();
 
@@ -96,8 +107,8 @@ fn invocation_fixtures(
                 loop {
                     let mut subtree = tt::Subtree {
                         delimiter: tt::Delimiter {
-                            open: tt::TokenId::DUMMY,
-                            close: tt::TokenId::DUMMY,
+                            open: SpanData::DUMMY,
+                            close: SpanData::DUMMY,
                             kind: tt::DelimiterKind::Invisible,
                         },
                         token_trees: vec![],
@@ -105,7 +116,7 @@ fn invocation_fixtures(
                     for op in rule.lhs.iter() {
                         collect_from_op(op, &mut subtree, &mut seed);
                     }
-                    if it.expand(subtree.clone()).err.is_none() {
+                    if it.expand(&subtree).err.is_none() {
                         res.push((name.clone(), subtree));
                         break;
                     }
@@ -119,7 +130,11 @@ fn invocation_fixtures(
     }
     return res;
 
-    fn collect_from_op(op: &Op<TokenId>, parent: &mut tt::Subtree<TokenId>, seed: &mut usize) {
+    fn collect_from_op(
+        op: &Op<SpanData<DummyFile>>,
+        parent: &mut tt::Subtree<SpanData<DummyFile>>,
+        seed: &mut usize,
+    ) {
         return match op {
             Op::Var { kind, .. } => match kind.as_ref() {
                 Some(MetaVarKind::Ident) => parent.token_trees.push(make_ident("foo")),
@@ -205,32 +220,22 @@ fn invocation_fixtures(
             *seed = usize::wrapping_add(usize::wrapping_mul(*seed, a), c);
             *seed
         }
-        fn make_ident(ident: &str) -> tt::TokenTree<TokenId> {
-            tt::Leaf::Ident(tt::Ident { span: tt::TokenId::DUMMY, text: SmolStr::new(ident) })
-                .into()
+        fn make_ident(ident: &str) -> tt::TokenTree<SpanData<DummyFile>> {
+            tt::Leaf::Ident(tt::Ident { span: SpanData::DUMMY, text: SmolStr::new(ident) }).into()
         }
-        fn make_punct(char: char) -> tt::TokenTree<TokenId> {
-            tt::Leaf::Punct(tt::Punct {
-                span: tt::TokenId::DUMMY,
-                char,
-                spacing: tt::Spacing::Alone,
-            })
-            .into()
-        }
-        fn make_literal(lit: &str) -> tt::TokenTree<TokenId> {
-            tt::Leaf::Literal(tt::Literal { span: tt::TokenId::DUMMY, text: SmolStr::new(lit) })
+        fn make_punct(char: char) -> tt::TokenTree<SpanData<DummyFile>> {
+            tt::Leaf::Punct(tt::Punct { span: SpanData::DUMMY, char, spacing: tt::Spacing::Alone })
                 .into()
         }
+        fn make_literal(lit: &str) -> tt::TokenTree<SpanData<DummyFile>> {
+            tt::Leaf::Literal(tt::Literal { span: SpanData::DUMMY, text: SmolStr::new(lit) }).into()
+        }
         fn make_subtree(
             kind: tt::DelimiterKind,
-            token_trees: Option<Vec<tt::TokenTree<TokenId>>>,
-        ) -> tt::TokenTree<TokenId> {
+            token_trees: Option<Vec<tt::TokenTree<SpanData<DummyFile>>>>,
+        ) -> tt::TokenTree<SpanData<DummyFile>> {
             tt::Subtree {
-                delimiter: tt::Delimiter {
-                    open: tt::TokenId::DUMMY,
-                    close: tt::TokenId::DUMMY,
-                    kind,
-                },
+                delimiter: tt::Delimiter { open: SpanData::DUMMY, close: SpanData::DUMMY, kind },
                 token_trees: token_trees.unwrap_or_default(),
             }
             .into()
diff --git a/crates/mbe/src/lib.rs b/crates/mbe/src/lib.rs
index 46599802935..43543479eb9 100644
--- a/crates/mbe/src/lib.rs
+++ b/crates/mbe/src/lib.rs
@@ -19,7 +19,7 @@ mod benchmark;
 mod token_map;
 
 use stdx::impl_from;
-use tt::{Span, TokenId};
+use tt::Span;
 
 use std::fmt;
 
@@ -34,10 +34,8 @@ pub use tt::{Delimiter, DelimiterKind, Punct};
 
 pub use crate::{
     syntax_bridge::{
-        parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_map,
-        syntax_node_to_token_map_with_modifications, syntax_node_to_token_tree,
-        syntax_node_to_token_tree_with_modifications, token_tree_to_syntax_node, SyntheticToken,
-        SyntheticTokenId,
+        map_from_syntax_node, parse_exprs_with_sep, parse_to_token_tree, syntax_node_to_token_tree,
+        syntax_node_to_token_tree_censored, token_tree_to_syntax_node,
     },
     token_map::TokenMap,
 };
@@ -125,10 +123,8 @@ impl fmt::Display for CountError {
 /// `tt::TokenTree`, but there's a crucial difference: in macro rules, `$ident`
 /// and `$()*` have special meaning (see `Var` and `Repeat` data structures)
 #[derive(Clone, Debug, PartialEq, Eq)]
-pub struct DeclarativeMacro {
-    rules: Box<[Rule<TokenId>]>,
-    /// Highest id of the token we have in TokenMap
-    shift: Shift,
+pub struct DeclarativeMacro<S> {
+    rules: Box<[Rule<S>]>,
     // This is used for correctly determining the behavior of the pat fragment
     // FIXME: This should be tracked by hygiene of the fragment identifier!
     is_2021: bool,
@@ -141,91 +137,13 @@ struct Rule<S> {
     rhs: MetaTemplate<S>,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct Shift(u32);
-
-impl Shift {
-    pub fn new(tt: &tt::Subtree<TokenId>) -> Shift {
-        // Note that TokenId is started from zero,
-        // We have to add 1 to prevent duplication.
-        let value = max_id(tt).map_or(0, |it| it + 1);
-        return Shift(value);
-
-        // Find the max token id inside a subtree
-        fn max_id(subtree: &tt::Subtree<TokenId>) -> Option<u32> {
-            let filter =
-                |tt: &_| match tt {
-                    tt::TokenTree::Subtree(subtree) => {
-                        let tree_id = max_id(subtree);
-                        if subtree.delimiter.open != tt::TokenId::unspecified() {
-                            Some(tree_id.map_or(subtree.delimiter.open.0, |t| {
-                                t.max(subtree.delimiter.open.0)
-                            }))
-                        } else {
-                            tree_id
-                        }
-                    }
-                    tt::TokenTree::Leaf(leaf) => {
-                        let &(tt::Leaf::Ident(tt::Ident { span, .. })
-                        | tt::Leaf::Punct(tt::Punct { span, .. })
-                        | tt::Leaf::Literal(tt::Literal { span, .. })) = leaf;
-
-                        (span != tt::TokenId::unspecified()).then_some(span.0)
-                    }
-                };
-            subtree.token_trees.iter().filter_map(filter).max()
-        }
-    }
-
-    /// Shift given TokenTree token id
-    pub fn shift_all(self, tt: &mut tt::Subtree<TokenId>) {
-        for t in &mut tt.token_trees {
-            match t {
-                tt::TokenTree::Leaf(
-                    tt::Leaf::Ident(tt::Ident { span, .. })
-                    | tt::Leaf::Punct(tt::Punct { span, .. })
-                    | tt::Leaf::Literal(tt::Literal { span, .. }),
-                ) => *span = self.shift(*span),
-                tt::TokenTree::Subtree(tt) => {
-                    tt.delimiter.open = self.shift(tt.delimiter.open);
-                    tt.delimiter.close = self.shift(tt.delimiter.close);
-                    self.shift_all(tt)
-                }
-            }
-        }
-    }
-
-    pub fn shift(self, id: tt::TokenId) -> tt::TokenId {
-        if id == tt::TokenId::unspecified() {
-            id
-        } else {
-            tt::TokenId(id.0 + self.0)
-        }
-    }
-
-    pub fn unshift(self, id: tt::TokenId) -> Option<tt::TokenId> {
-        id.0.checked_sub(self.0).map(tt::TokenId)
-    }
-}
-
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
-pub enum Origin {
-    Def,
-    Call,
-}
-
-impl DeclarativeMacro {
-    pub fn from_err(err: ParseError, is_2021: bool) -> DeclarativeMacro {
-        DeclarativeMacro {
-            rules: Box::default(),
-            shift: Shift(0),
-            is_2021,
-            err: Some(Box::new(err)),
-        }
+impl<S: Span> DeclarativeMacro<S> {
+    pub fn from_err(err: ParseError, is_2021: bool) -> DeclarativeMacro<S> {
+        DeclarativeMacro { rules: Box::default(), is_2021, err: Some(Box::new(err)) }
     }
 
     /// The old, `macro_rules! m {}` flavor.
-    pub fn parse_macro_rules(tt: &tt::Subtree<TokenId>, is_2021: bool) -> DeclarativeMacro {
+    pub fn parse_macro_rules(tt: &tt::Subtree<S>, is_2021: bool) -> DeclarativeMacro<S> {
         // Note: this parsing can be implemented using mbe machinery itself, by
         // matching against `$($lhs:tt => $rhs:tt);*` pattern, but implementing
         // manually seems easier.
@@ -257,11 +175,11 @@ impl DeclarativeMacro {
             }
         }
 
-        DeclarativeMacro { rules: rules.into_boxed_slice(), shift: Shift::new(tt), is_2021, err }
+        DeclarativeMacro { rules: rules.into_boxed_slice(), is_2021, err }
     }
 
     /// The new, unstable `macro m {}` flavor.
-    pub fn parse_macro2(tt: &tt::Subtree<TokenId>, is_2021: bool) -> DeclarativeMacro {
+    pub fn parse_macro2(tt: &tt::Subtree<S>, is_2021: bool) -> DeclarativeMacro<S> {
         let mut src = TtIter::new(tt);
         let mut rules = Vec::new();
         let mut err = None;
@@ -308,31 +226,15 @@ impl DeclarativeMacro {
             }
         }
 
-        DeclarativeMacro { rules: rules.into_boxed_slice(), shift: Shift::new(tt), is_2021, err }
-    }
-
-    pub fn expand(&self, mut tt: tt::Subtree<TokenId>) -> ExpandResult<tt::Subtree<TokenId>> {
-        self.shift.shift_all(&mut tt);
-        expander::expand_rules(&self.rules, &tt, self.is_2021)
+        DeclarativeMacro { rules: rules.into_boxed_slice(), is_2021, err }
     }
 
     pub fn err(&self) -> Option<&ParseError> {
         self.err.as_deref()
     }
 
-    pub fn map_id_down(&self, id: tt::TokenId) -> tt::TokenId {
-        self.shift.shift(id)
-    }
-
-    pub fn map_id_up(&self, id: tt::TokenId) -> (tt::TokenId, Origin) {
-        match self.shift.unshift(id) {
-            Some(id) => (id, Origin::Call),
-            None => (id, Origin::Def),
-        }
-    }
-
-    pub fn shift(&self) -> Shift {
-        self.shift
+    pub fn expand(&self, tt: &tt::Subtree<S>) -> ExpandResult<tt::Subtree<S>> {
+        expander::expand_rules(&self.rules, &tt, self.is_2021)
     }
 }
 
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 01aab6b659c..c8c2e5dcd55 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -1,16 +1,15 @@
 //! Conversions between [`SyntaxNode`] and [`tt::TokenTree`].
 
-use rustc_hash::FxHashMap;
-use stdx::{always, non_empty_vec::NonEmptyVec};
+use stdx::non_empty_vec::NonEmptyVec;
 use syntax::{
     ast::{self, make::tokens::doc_comment},
-    AstToken, Parse, PreorderWithTokens, SmolStr, SyntaxElement, SyntaxKind,
+    AstToken, NodeOrToken, Parse, PreorderWithTokens, SmolStr, SyntaxElement, SyntaxKind,
     SyntaxKind::*,
     SyntaxNode, SyntaxToken, SyntaxTreeBuilder, TextRange, TextSize, WalkEvent, T,
 };
 use tt::{
     buffer::{Cursor, TokenBuffer},
-    TokenId,
+    Span, SpanData,
 };
 
 use crate::{to_parser_input::to_parser_input, tt_iter::TtIter, TokenMap};
@@ -20,75 +19,37 @@ mod tests;
 
 /// Convert the syntax node to a `TokenTree` (what macro
 /// will consume).
-pub fn syntax_node_to_token_tree(node: &SyntaxNode) -> (tt::Subtree<TokenId>, TokenMap) {
-    let (subtree, token_map, _) = syntax_node_to_token_tree_with_modifications(
-        node,
-        Default::default(),
-        0,
-        Default::default(),
-        Default::default(),
-    );
-    (subtree, token_map)
-}
-
-/// Convert the syntax node to a `TokenTree` (what macro will consume)
-/// with the censored range excluded.
-pub fn syntax_node_to_token_tree_with_modifications(
+/// `anchor` and `anchor_offset` are used to convert the node's spans
+/// to relative spans, relative to the passed anchor.
+/// `map` is used to resolve the converted spans accordingly.
+/// TODO: Flesh out the doc comment more thoroughly
+pub fn syntax_node_to_token_tree<SpanAnchor: Copy>(
     node: &SyntaxNode,
-    existing_token_map: TokenMap,
-    next_id: u32,
-    replace: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-    append: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-) -> (tt::Subtree<TokenId>, TokenMap, u32) {
-    let global_offset = node.text_range().start();
-    let mut c = Converter::new(node, global_offset, existing_token_map, next_id, replace, append);
-    let subtree = convert_tokens(&mut c);
-    c.id_alloc.map.shrink_to_fit();
-    always!(c.replace.is_empty(), "replace: {:?}", c.replace);
-    always!(c.append.is_empty(), "append: {:?}", c.append);
-    (subtree, c.id_alloc.map, c.id_alloc.next_id)
-}
-
-/// Convert the syntax node to a `TokenTree` (what macro
-/// will consume).
-pub fn syntax_node_to_token_map(node: &SyntaxNode) -> TokenMap {
-    syntax_node_to_token_map_with_modifications(
-        node,
-        Default::default(),
-        0,
-        Default::default(),
-        Default::default(),
-    )
-    .0
+    anchor: SpanAnchor,
+    anchor_offset: TextSize,
+    map: &TokenMap<SpanData<SpanAnchor>>,
+) -> tt::Subtree<SpanData<SpanAnchor>>
+where
+    SpanData<SpanAnchor>: Span,
+{
+    assert!(anchor_offset <= node.text_range().start());
+    let mut c = Converter::new(node, anchor_offset, anchor, vec![], map);
+    convert_tokens(&mut c)
 }
 
-/// Convert the syntax node to a `TokenTree` (what macro will consume)
-/// with the censored range excluded.
-pub fn syntax_node_to_token_map_with_modifications(
+pub fn syntax_node_to_token_tree_censored<SpanAnchor: Copy>(
     node: &SyntaxNode,
-    existing_token_map: TokenMap,
-    next_id: u32,
-    replace: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-    append: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-) -> (TokenMap, u32) {
-    let global_offset = node.text_range().start();
-    let mut c = Converter::new(node, global_offset, existing_token_map, next_id, replace, append);
-    collect_tokens(&mut c);
-    c.id_alloc.map.shrink_to_fit();
-    always!(c.replace.is_empty(), "replace: {:?}", c.replace);
-    always!(c.append.is_empty(), "append: {:?}", c.append);
-    (c.id_alloc.map, c.id_alloc.next_id)
-}
-
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub struct SyntheticTokenId(pub u32);
-
-#[derive(Debug, Clone)]
-pub struct SyntheticToken {
-    pub kind: SyntaxKind,
-    pub text: SmolStr,
-    pub range: TextRange,
-    pub id: SyntheticTokenId,
+    anchor: SpanAnchor,
+    anchor_offset: TextSize,
+    map: &TokenMap<SpanData<SpanAnchor>>,
+    censored: Vec<SyntaxNode>,
+) -> tt::Subtree<SpanData<SpanAnchor>>
+where
+    SpanData<SpanAnchor>: Span,
+{
+    assert!(anchor_offset <= node.text_range().start());
+    let mut c = Converter::new(node, anchor_offset, anchor, censored, map);
+    convert_tokens(&mut c)
 }
 
 // The following items are what `rustc` macro can be parsed into :
@@ -103,10 +64,13 @@ pub struct SyntheticToken {
 // * AssocItems(SmallVec<[ast::AssocItem; 1]>)
 // * ForeignItems(SmallVec<[ast::ForeignItem; 1]>
 
-pub fn token_tree_to_syntax_node(
-    tt: &tt::Subtree<TokenId>,
+pub fn token_tree_to_syntax_node<SpanAnchor: Copy>(
+    tt: &tt::Subtree<SpanData<SpanAnchor>>,
     entry_point: parser::TopEntryPoint,
-) -> (Parse<SyntaxNode>, TokenMap) {
+) -> (Parse<SyntaxNode>, TokenMap<SpanData<SpanAnchor>>)
+where
+    SpanData<SpanAnchor>: Span,
+{
     let buffer = match tt {
         tt::Subtree {
             delimiter: tt::Delimiter { kind: tt::DelimiterKind::Invisible, .. },
@@ -133,29 +97,40 @@ pub fn token_tree_to_syntax_node(
     tree_sink.finish()
 }
 
+pub fn map_from_syntax_node<SpanAnchor>(
+    node: &SyntaxNode,
+    anchor: SpanAnchor,
+    anchor_offset: TextSize,
+) -> TokenMap<SpanData<SpanAnchor>>
+where
+    SpanAnchor: Copy,
+    SpanData<SpanAnchor>: Span,
+{
+    let mut map = TokenMap::default();
+    node.descendants_with_tokens().filter_map(NodeOrToken::into_token).for_each(|t| {
+        map.insert(t.text_range(), SpanData { range: t.text_range() - anchor_offset, anchor });
+    });
+    map
+}
+
 /// Convert a string to a `TokenTree`
-pub fn parse_to_token_tree(text: &str) -> Option<(tt::Subtree<TokenId>, TokenMap)> {
+pub fn parse_to_token_tree<SpanAnchor: Copy>(
+    text: &str,
+    file_id: SpanAnchor,
+) -> Option<tt::Subtree<SpanData<SpanAnchor>>>
+where
+    SpanData<SpanAnchor>: Span,
+{
     let lexed = parser::LexedStr::new(text);
     if lexed.errors().next().is_some() {
         return None;
     }
-
-    let mut conv = RawConverter {
-        lexed,
-        pos: 0,
-        id_alloc: TokenIdAlloc {
-            map: Default::default(),
-            global_offset: TextSize::default(),
-            next_id: 0,
-        },
-    };
-
-    let subtree = convert_tokens(&mut conv);
-    Some((subtree, conv.id_alloc.map))
+    let mut conv = RawConverter { lexed, pos: 0, _offset: TextSize::default(), file_id };
+    Some(convert_tokens(&mut conv))
 }
 
 /// Split token tree with separate expr: $($e:expr)SEP*
-pub fn parse_exprs_with_sep(tt: &tt::Subtree<TokenId>, sep: char) -> Vec<tt::Subtree<TokenId>> {
+pub fn parse_exprs_with_sep<S: Span>(tt: &tt::Subtree<S>, sep: char) -> Vec<tt::Subtree<S>> {
     if tt.token_trees.is_empty() {
         return Vec::new();
     }
@@ -191,47 +166,33 @@ pub fn parse_exprs_with_sep(tt: &tt::Subtree<TokenId>, sep: char) -> Vec<tt::Sub
     res
 }
 
-fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
-    struct StackEntry {
-        subtree: tt::Subtree<TokenId>,
-        idx: usize,
-        open_range: TextRange,
-    }
-
-    let entry = StackEntry {
-        subtree: tt::Subtree { delimiter: tt::Delimiter::unspecified(), token_trees: vec![] },
-        // never used (delimiter is `None`)
-        idx: !0,
-        open_range: TextRange::empty(TextSize::of('.')),
-    };
+fn convert_tokens<SpanAnchor, C: TokenConverter<SpanAnchor>>(
+    conv: &mut C,
+) -> tt::Subtree<SpanData<SpanAnchor>>
+where
+    SpanData<SpanAnchor>: Span,
+    SpanAnchor: Copy,
+{
+    let entry = tt::Subtree { delimiter: tt::Delimiter::unspecified(), token_trees: vec![] };
     let mut stack = NonEmptyVec::new(entry);
+    let anchor = conv.anchor();
 
     loop {
-        let StackEntry { subtree, .. } = stack.last_mut();
+        let subtree = stack.last_mut();
         let result = &mut subtree.token_trees;
-        let (token, range) = match conv.bump() {
-            Some(it) => it,
-            None => break,
-        };
-        let synth_id = token.synthetic_id(conv);
+        let Some((token, rel_range, abs_range)) = conv.bump() else { break };
 
         let kind = token.kind(conv);
         if kind == COMMENT {
-            // Since `convert_doc_comment` can fail, we need to peek the next id, so that we can
-            // figure out which token id to use for the doc comment, if it is converted successfully.
-            let next_id = conv.id_alloc().peek_next_id();
-            if let Some(tokens) = conv.convert_doc_comment(&token, next_id) {
-                let id = conv.id_alloc().alloc(range, synth_id);
-                debug_assert_eq!(id, next_id);
+            if let Some(tokens) = conv.convert_doc_comment(
+                &token,
+                conv.span_for(abs_range).unwrap_or(SpanData { range: rel_range, anchor }),
+            ) {
                 result.extend(tokens);
             }
             continue;
         }
         let tt = if kind.is_punct() && kind != UNDERSCORE {
-            if synth_id.is_none() {
-                assert_eq!(range.len(), TextSize::of('.'));
-            }
-
             let expected = match subtree.delimiter.kind {
                 tt::DelimiterKind::Parenthesis => Some(T![')']),
                 tt::DelimiterKind::Brace => Some(T!['}']),
@@ -241,9 +202,11 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
 
             if let Some(expected) = expected {
                 if kind == expected {
-                    if let Some(entry) = stack.pop() {
-                        conv.id_alloc().close_delim(entry.idx, Some(range));
-                        stack.last_mut().subtree.token_trees.push(entry.subtree.into());
+                    if let Some(mut subtree) = stack.pop() {
+                        subtree.delimiter.close = conv
+                            .span_for(abs_range)
+                            .unwrap_or(SpanData { range: rel_range, anchor });
+                        stack.last_mut().token_trees.push(subtree.into());
                     }
                     continue;
                 }
@@ -257,12 +220,18 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
             };
 
             if let Some(kind) = delim {
-                let (id, idx) = conv.id_alloc().open_delim(range, synth_id);
                 let subtree = tt::Subtree {
-                    delimiter: tt::Delimiter { open: id, close: tt::TokenId::UNSPECIFIED, kind },
+                    delimiter: tt::Delimiter {
+                        // FIXME: Open and close spans
+                        open: conv
+                            .span_for(abs_range)
+                            .unwrap_or(SpanData { range: rel_range, anchor }),
+                        close: Span::DUMMY,
+                        kind,
+                    },
                     token_trees: vec![],
                 };
-                stack.push(StackEntry { subtree, idx, open_range: range });
+                stack.push(subtree);
                 continue;
             }
 
@@ -279,39 +248,43 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
             tt::Leaf::from(tt::Punct {
                 char,
                 spacing,
-                span: conv.id_alloc().alloc(range, synth_id),
+                span: conv.span_for(abs_range).unwrap_or(SpanData { range: rel_range, anchor }),
             })
             .into()
         } else {
             macro_rules! make_leaf {
                 ($i:ident) => {
                     tt::$i {
-                        span: conv.id_alloc().alloc(range, synth_id),
+                        span: conv
+                            .span_for(abs_range)
+                            .unwrap_or(SpanData { range: rel_range, anchor }),
                         text: token.to_text(conv),
                     }
                     .into()
                 };
             }
-            let leaf: tt::Leaf<TokenId> = match kind {
+            let leaf: tt::Leaf<_> = match kind {
                 T![true] | T![false] => make_leaf!(Ident),
                 IDENT => make_leaf!(Ident),
                 UNDERSCORE => make_leaf!(Ident),
                 k if k.is_keyword() => make_leaf!(Ident),
                 k if k.is_literal() => make_leaf!(Literal),
+                // FIXME: Check whether span splitting works as intended
                 LIFETIME_IDENT => {
                     let char_unit = TextSize::of('\'');
-                    let r = TextRange::at(range.start(), char_unit);
+                    let r = TextRange::at(rel_range.start(), char_unit);
                     let apostrophe = tt::Leaf::from(tt::Punct {
                         char: '\'',
                         spacing: tt::Spacing::Joint,
-                        span: conv.id_alloc().alloc(r, synth_id),
+                        span: conv.span_for(abs_range).unwrap_or(SpanData { range: r, anchor }),
                     });
                     result.push(apostrophe.into());
 
-                    let r = TextRange::at(range.start() + char_unit, range.len() - char_unit);
+                    let r =
+                        TextRange::at(rel_range.start() + char_unit, rel_range.len() - char_unit);
                     let ident = tt::Leaf::from(tt::Ident {
                         text: SmolStr::new(&token.to_text(conv)[1..]),
-                        span: conv.id_alloc().alloc(r, synth_id),
+                        span: conv.span_for(abs_range).unwrap_or(SpanData { range: r, anchor }),
                     });
                     result.push(ident.into());
                     continue;
@@ -330,10 +303,9 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
     while let Some(entry) = stack.pop() {
         let parent = stack.last_mut();
 
-        conv.id_alloc().close_delim(entry.idx, None);
-        let leaf: tt::Leaf<TokenId> = tt::Punct {
-            span: conv.id_alloc().alloc(entry.open_range, None),
-            char: match entry.subtree.delimiter.kind {
+        let leaf: tt::Leaf<_> = tt::Punct {
+            span: entry.delimiter.open,
+            char: match entry.delimiter.kind {
                 tt::DelimiterKind::Parenthesis => '(',
                 tt::DelimiterKind::Brace => '{',
                 tt::DelimiterKind::Bracket => '[',
@@ -342,11 +314,11 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
             spacing: tt::Spacing::Alone,
         }
         .into();
-        parent.subtree.token_trees.push(leaf.into());
-        parent.subtree.token_trees.extend(entry.subtree.token_trees);
+        parent.token_trees.push(leaf.into());
+        parent.token_trees.extend(entry.token_trees);
     }
 
-    let subtree = stack.into_last().subtree;
+    let subtree = stack.into_last();
     if let [tt::TokenTree::Subtree(first)] = &*subtree.token_trees {
         first.clone()
     } else {
@@ -354,111 +326,6 @@ fn convert_tokens<C: TokenConverter>(conv: &mut C) -> tt::Subtree<TokenId> {
     }
 }
 
-fn collect_tokens<C: TokenConverter>(conv: &mut C) {
-    struct StackEntry {
-        idx: usize,
-        open_range: TextRange,
-        delimiter: tt::DelimiterKind,
-    }
-
-    let entry = StackEntry {
-        delimiter: tt::DelimiterKind::Invisible,
-        // never used (delimiter is `None`)
-        idx: !0,
-        open_range: TextRange::empty(TextSize::of('.')),
-    };
-    let mut stack = NonEmptyVec::new(entry);
-
-    loop {
-        let StackEntry { delimiter, .. } = stack.last_mut();
-        let (token, range) = match conv.bump() {
-            Some(it) => it,
-            None => break,
-        };
-        let synth_id = token.synthetic_id(conv);
-
-        let kind = token.kind(conv);
-        if kind == COMMENT {
-            // Since `convert_doc_comment` can fail, we need to peek the next id, so that we can
-            // figure out which token id to use for the doc comment, if it is converted successfully.
-            let next_id = conv.id_alloc().peek_next_id();
-            if let Some(_tokens) = conv.convert_doc_comment(&token, next_id) {
-                let id = conv.id_alloc().alloc(range, synth_id);
-                debug_assert_eq!(id, next_id);
-            }
-            continue;
-        }
-        if kind.is_punct() && kind != UNDERSCORE {
-            if synth_id.is_none() {
-                assert_eq!(range.len(), TextSize::of('.'));
-            }
-
-            let expected = match delimiter {
-                tt::DelimiterKind::Parenthesis => Some(T![')']),
-                tt::DelimiterKind::Brace => Some(T!['}']),
-                tt::DelimiterKind::Bracket => Some(T![']']),
-                tt::DelimiterKind::Invisible => None,
-            };
-
-            if let Some(expected) = expected {
-                if kind == expected {
-                    if let Some(entry) = stack.pop() {
-                        conv.id_alloc().close_delim(entry.idx, Some(range));
-                    }
-                    continue;
-                }
-            }
-
-            let delim = match kind {
-                T!['('] => Some(tt::DelimiterKind::Parenthesis),
-                T!['{'] => Some(tt::DelimiterKind::Brace),
-                T!['['] => Some(tt::DelimiterKind::Bracket),
-                _ => None,
-            };
-
-            if let Some(kind) = delim {
-                let (_id, idx) = conv.id_alloc().open_delim(range, synth_id);
-
-                stack.push(StackEntry { idx, open_range: range, delimiter: kind });
-                continue;
-            }
-
-            conv.id_alloc().alloc(range, synth_id);
-        } else {
-            macro_rules! make_leaf {
-                ($i:ident) => {{
-                    conv.id_alloc().alloc(range, synth_id);
-                }};
-            }
-            match kind {
-                T![true] | T![false] => make_leaf!(Ident),
-                IDENT => make_leaf!(Ident),
-                UNDERSCORE => make_leaf!(Ident),
-                k if k.is_keyword() => make_leaf!(Ident),
-                k if k.is_literal() => make_leaf!(Literal),
-                LIFETIME_IDENT => {
-                    let char_unit = TextSize::of('\'');
-                    let r = TextRange::at(range.start(), char_unit);
-                    conv.id_alloc().alloc(r, synth_id);
-
-                    let r = TextRange::at(range.start() + char_unit, range.len() - char_unit);
-                    conv.id_alloc().alloc(r, synth_id);
-                    continue;
-                }
-                _ => continue,
-            };
-        };
-
-        // If we get here, we've consumed all input tokens.
-        // We might have more than one subtree in the stack, if the delimiters are improperly balanced.
-        // Merge them so we're left with one.
-        while let Some(entry) = stack.pop() {
-            conv.id_alloc().close_delim(entry.idx, None);
-            conv.id_alloc().alloc(entry.open_range, None);
-        }
-    }
-}
-
 fn is_single_token_op(kind: SyntaxKind) -> bool {
     matches!(
         kind,
@@ -507,112 +374,54 @@ fn doc_comment_text(comment: &ast::Comment) -> SmolStr {
     text.into()
 }
 
-fn convert_doc_comment(
+fn convert_doc_comment<S: Copy>(
     token: &syntax::SyntaxToken,
-    span: tt::TokenId,
-) -> Option<Vec<tt::TokenTree<TokenId>>> {
+    span: S,
+) -> Option<Vec<tt::TokenTree<S>>> {
     cov_mark::hit!(test_meta_doc_comments);
     let comment = ast::Comment::cast(token.clone())?;
     let doc = comment.kind().doc?;
 
-    // Make `doc="\" Comments\""
-    let meta_tkns =
-        vec![mk_ident("doc", span), mk_punct('=', span), mk_doc_literal(&comment, span)];
-
-    // Make `#![]`
-    let mut token_trees = Vec::with_capacity(3);
-    token_trees.push(mk_punct('#', span));
-    if let ast::CommentPlacement::Inner = doc {
-        token_trees.push(mk_punct('!', span));
-    }
-    token_trees.push(tt::TokenTree::from(tt::Subtree {
-        delimiter: tt::Delimiter { open: span, close: span, kind: tt::DelimiterKind::Bracket },
-        token_trees: meta_tkns,
-    }));
-
-    return Some(token_trees);
+    let mk_ident =
+        |s: &str| tt::TokenTree::from(tt::Leaf::from(tt::Ident { text: s.into(), span }));
 
-    // Helper functions
-    fn mk_ident(s: &str, span: tt::TokenId) -> tt::TokenTree<TokenId> {
-        tt::TokenTree::from(tt::Leaf::from(tt::Ident { text: s.into(), span }))
-    }
-
-    fn mk_punct(c: char, span: tt::TokenId) -> tt::TokenTree<TokenId> {
+    let mk_punct = |c: char| {
         tt::TokenTree::from(tt::Leaf::from(tt::Punct {
             char: c,
             spacing: tt::Spacing::Alone,
             span,
         }))
-    }
+    };
 
-    fn mk_doc_literal(comment: &ast::Comment, span: tt::TokenId) -> tt::TokenTree<TokenId> {
+    let mk_doc_literal = |comment: &ast::Comment| {
         let lit = tt::Literal { text: doc_comment_text(comment), span };
 
         tt::TokenTree::from(tt::Leaf::from(lit))
-    }
-}
-
-struct TokenIdAlloc {
-    map: TokenMap,
-    global_offset: TextSize,
-    next_id: u32,
-}
-
-impl TokenIdAlloc {
-    fn alloc(
-        &mut self,
-        absolute_range: TextRange,
-        synthetic_id: Option<SyntheticTokenId>,
-    ) -> tt::TokenId {
-        let relative_range = absolute_range - self.global_offset;
-        let token_id = tt::TokenId(self.next_id);
-        self.next_id += 1;
-        self.map.insert(token_id, relative_range);
-        if let Some(id) = synthetic_id {
-            self.map.insert_synthetic(token_id, id);
-        }
-        token_id
-    }
+    };
 
-    fn open_delim(
-        &mut self,
-        open_abs_range: TextRange,
-        synthetic_id: Option<SyntheticTokenId>,
-    ) -> (tt::TokenId, usize) {
-        let token_id = tt::TokenId(self.next_id);
-        self.next_id += 1;
-        let idx = self.map.insert_delim(
-            token_id,
-            open_abs_range - self.global_offset,
-            open_abs_range - self.global_offset,
-        );
-        if let Some(id) = synthetic_id {
-            self.map.insert_synthetic(token_id, id);
-        }
-        (token_id, idx)
-    }
+    // Make `doc="\" Comments\""
+    let meta_tkns = vec![mk_ident("doc"), mk_punct('='), mk_doc_literal(&comment)];
 
-    fn close_delim(&mut self, idx: usize, close_abs_range: Option<TextRange>) {
-        match close_abs_range {
-            None => {
-                self.map.remove_delim(idx);
-            }
-            Some(close) => {
-                self.map.update_close_delim(idx, close - self.global_offset);
-            }
-        }
+    // Make `#![]`
+    let mut token_trees = Vec::with_capacity(3);
+    token_trees.push(mk_punct('#'));
+    if let ast::CommentPlacement::Inner = doc {
+        token_trees.push(mk_punct('!'));
     }
+    token_trees.push(tt::TokenTree::from(tt::Subtree {
+        delimiter: tt::Delimiter { open: span, close: span, kind: tt::DelimiterKind::Bracket },
+        token_trees: meta_tkns,
+    }));
 
-    fn peek_next_id(&self) -> tt::TokenId {
-        tt::TokenId(self.next_id)
-    }
+    Some(token_trees)
 }
 
 /// A raw token (straight from lexer) converter
-struct RawConverter<'a> {
+struct RawConverter<'a, SpanAnchor> {
     lexed: parser::LexedStr<'a>,
     pos: usize,
-    id_alloc: TokenIdAlloc,
+    _offset: TextSize,
+    file_id: SpanAnchor,
 }
 
 trait SrcToken<Ctx>: std::fmt::Debug {
@@ -621,66 +430,64 @@ trait SrcToken<Ctx>: std::fmt::Debug {
     fn to_char(&self, ctx: &Ctx) -> Option<char>;
 
     fn to_text(&self, ctx: &Ctx) -> SmolStr;
-
-    fn synthetic_id(&self, ctx: &Ctx) -> Option<SyntheticTokenId>;
 }
 
-trait TokenConverter: Sized {
+trait TokenConverter<SpanAnchor>: Sized {
     type Token: SrcToken<Self>;
 
     fn convert_doc_comment(
         &self,
         token: &Self::Token,
-        span: tt::TokenId,
-    ) -> Option<Vec<tt::TokenTree<TokenId>>>;
+        span: SpanData<SpanAnchor>,
+    ) -> Option<Vec<tt::TokenTree<SpanData<SpanAnchor>>>>;
 
-    fn bump(&mut self) -> Option<(Self::Token, TextRange)>;
+    fn bump(&mut self) -> Option<(Self::Token, TextRange, TextRange)>;
 
     fn peek(&self) -> Option<Self::Token>;
 
-    fn id_alloc(&mut self) -> &mut TokenIdAlloc;
+    fn anchor(&self) -> SpanAnchor;
+    fn span_for(&self, range: TextRange) -> Option<SpanData<SpanAnchor>>;
 }
 
-impl SrcToken<RawConverter<'_>> for usize {
-    fn kind(&self, ctx: &RawConverter<'_>) -> SyntaxKind {
+impl<SpanAnchor> SrcToken<RawConverter<'_, SpanAnchor>> for usize {
+    fn kind(&self, ctx: &RawConverter<'_, SpanAnchor>) -> SyntaxKind {
         ctx.lexed.kind(*self)
     }
 
-    fn to_char(&self, ctx: &RawConverter<'_>) -> Option<char> {
+    fn to_char(&self, ctx: &RawConverter<'_, SpanAnchor>) -> Option<char> {
         ctx.lexed.text(*self).chars().next()
     }
 
-    fn to_text(&self, ctx: &RawConverter<'_>) -> SmolStr {
+    fn to_text(&self, ctx: &RawConverter<'_, SpanAnchor>) -> SmolStr {
         ctx.lexed.text(*self).into()
     }
-
-    fn synthetic_id(&self, _ctx: &RawConverter<'_>) -> Option<SyntheticTokenId> {
-        None
-    }
 }
 
-impl TokenConverter for RawConverter<'_> {
+impl<SpanAnchor: Copy> TokenConverter<SpanAnchor> for RawConverter<'_, SpanAnchor>
+where
+    SpanData<SpanAnchor>: Span,
+{
     type Token = usize;
 
     fn convert_doc_comment(
         &self,
         &token: &usize,
-        span: tt::TokenId,
-    ) -> Option<Vec<tt::TokenTree<TokenId>>> {
+        span: SpanData<SpanAnchor>,
+    ) -> Option<Vec<tt::TokenTree<SpanData<SpanAnchor>>>> {
         let text = self.lexed.text(token);
         convert_doc_comment(&doc_comment(text), span)
     }
 
-    fn bump(&mut self) -> Option<(Self::Token, TextRange)> {
+    fn bump(&mut self) -> Option<(Self::Token, TextRange, TextRange)> {
         if self.pos == self.lexed.len() {
             return None;
         }
         let token = self.pos;
         self.pos += 1;
         let range = self.lexed.text_range(token);
-        let range = TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap());
+        let range = TextRange::new(range.start.try_into().ok()?, range.end.try_into().ok()?);
 
-        Some((token, range))
+        Some((token, range, range))
     }
 
     fn peek(&self) -> Option<Self::Token> {
@@ -690,77 +497,60 @@ impl TokenConverter for RawConverter<'_> {
         Some(self.pos)
     }
 
-    fn id_alloc(&mut self) -> &mut TokenIdAlloc {
-        &mut self.id_alloc
+    fn anchor(&self) -> SpanAnchor {
+        self.file_id
+    }
+    fn span_for(&self, _: TextRange) -> Option<SpanData<SpanAnchor>> {
+        None
     }
 }
 
-struct Converter {
-    id_alloc: TokenIdAlloc,
+struct Converter<'a, SpanAnchor> {
     current: Option<SyntaxToken>,
-    current_synthetic: Vec<SyntheticToken>,
     preorder: PreorderWithTokens,
-    replace: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-    append: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
     range: TextRange,
     punct_offset: Option<(SyntaxToken, TextSize)>,
+    /// Used to make the emitted text ranges in the spans relative to the span anchor.
+    offset: TextSize,
+    file_id: SpanAnchor,
+    map: &'a TokenMap<SpanData<SpanAnchor>>,
+    censored: Vec<SyntaxNode>,
 }
 
-impl Converter {
+impl<'a, SpanAnchor> Converter<'a, SpanAnchor> {
     fn new(
         node: &SyntaxNode,
-        global_offset: TextSize,
-        existing_token_map: TokenMap,
-        next_id: u32,
-        mut replace: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-        mut append: FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-    ) -> Converter {
+        anchor_offset: TextSize,
+        file_id: SpanAnchor,
+        censored: Vec<SyntaxNode>,
+        map: &'a TokenMap<SpanData<SpanAnchor>>,
+    ) -> Converter<'a, SpanAnchor> {
         let range = node.text_range();
         let mut preorder = node.preorder_with_tokens();
-        let (first, synthetic) = Self::next_token(&mut preorder, &mut replace, &mut append);
+        let first = Self::next_token(&mut preorder, &censored);
         Converter {
-            id_alloc: { TokenIdAlloc { map: existing_token_map, global_offset, next_id } },
             current: first,
-            current_synthetic: synthetic,
             preorder,
             range,
-            replace,
-            append,
             punct_offset: None,
+            offset: anchor_offset,
+            file_id,
+            censored,
+            map,
         }
     }
 
-    fn next_token(
-        preorder: &mut PreorderWithTokens,
-        replace: &mut FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-        append: &mut FxHashMap<SyntaxElement, Vec<SyntheticToken>>,
-    ) -> (Option<SyntaxToken>, Vec<SyntheticToken>) {
+    fn next_token(preorder: &mut PreorderWithTokens, censor: &[SyntaxNode]) -> Option<SyntaxToken> {
         while let Some(ev) = preorder.next() {
-            let ele = match ev {
-                WalkEvent::Enter(ele) => ele,
-                WalkEvent::Leave(ele) => {
-                    if let Some(mut v) = append.remove(&ele) {
-                        if !v.is_empty() {
-                            v.reverse();
-                            return (None, v);
-                        }
-                    }
-                    continue;
+            match ev {
+                WalkEvent::Enter(SyntaxElement::Token(t)) => return Some(t),
+                WalkEvent::Enter(SyntaxElement::Node(n)) if censor.contains(&n) => {
+                    preorder.skip_subtree()
                 }
-            };
-            if let Some(mut v) = replace.remove(&ele) {
-                preorder.skip_subtree();
-                if !v.is_empty() {
-                    v.reverse();
-                    return (None, v);
-                }
-            }
-            match ele {
-                SyntaxElement::Token(t) => return (Some(t), Vec::new()),
-                _ => {}
+                _ => (),
             }
         }
-        (None, Vec::new())
+        None
     }
 }
 
@@ -768,100 +558,79 @@ impl Converter {
 enum SynToken {
     Ordinary(SyntaxToken),
     // FIXME is this supposed to be `Punct`?
-    Punch(SyntaxToken, TextSize),
-    Synthetic(SyntheticToken),
+    Punct(SyntaxToken, usize),
 }
 
 impl SynToken {
-    fn token(&self) -> Option<&SyntaxToken> {
+    fn token(&self) -> &SyntaxToken {
         match self {
-            SynToken::Ordinary(it) | SynToken::Punch(it, _) => Some(it),
-            SynToken::Synthetic(_) => None,
+            SynToken::Ordinary(it) | SynToken::Punct(it, _) => it,
         }
     }
 }
 
-impl SrcToken<Converter> for SynToken {
-    fn kind(&self, ctx: &Converter) -> SyntaxKind {
+impl<SpanAnchor> SrcToken<Converter<'_, SpanAnchor>> for SynToken {
+    fn kind(&self, ctx: &Converter<'_, SpanAnchor>) -> SyntaxKind {
         match self {
             SynToken::Ordinary(token) => token.kind(),
-            SynToken::Punch(..) => SyntaxKind::from_char(self.to_char(ctx).unwrap()).unwrap(),
-            SynToken::Synthetic(token) => token.kind,
+            SynToken::Punct(..) => SyntaxKind::from_char(self.to_char(ctx).unwrap()).unwrap(),
         }
     }
-    fn to_char(&self, _ctx: &Converter) -> Option<char> {
+    fn to_char(&self, _ctx: &Converter<'_, SpanAnchor>) -> Option<char> {
         match self {
             SynToken::Ordinary(_) => None,
-            SynToken::Punch(it, i) => it.text().chars().nth((*i).into()),
-            SynToken::Synthetic(token) if token.text.len() == 1 => token.text.chars().next(),
-            SynToken::Synthetic(_) => None,
-        }
-    }
-    fn to_text(&self, _ctx: &Converter) -> SmolStr {
-        match self {
-            SynToken::Ordinary(token) => token.text().into(),
-            SynToken::Punch(token, _) => token.text().into(),
-            SynToken::Synthetic(token) => token.text.clone(),
+            SynToken::Punct(it, i) => it.text().chars().nth(*i),
         }
     }
-
-    fn synthetic_id(&self, _ctx: &Converter) -> Option<SyntheticTokenId> {
+    fn to_text(&self, _ctx: &Converter<'_, SpanAnchor>) -> SmolStr {
         match self {
-            SynToken::Synthetic(token) => Some(token.id),
-            _ => None,
+            SynToken::Ordinary(token) | SynToken::Punct(token, _) => token.text().into(),
         }
     }
 }
 
-impl TokenConverter for Converter {
+impl<SpanAnchor: Copy> TokenConverter<SpanAnchor> for Converter<'_, SpanAnchor>
+where
+    SpanData<SpanAnchor>: Span,
+{
     type Token = SynToken;
     fn convert_doc_comment(
         &self,
         token: &Self::Token,
-        span: tt::TokenId,
-    ) -> Option<Vec<tt::TokenTree<TokenId>>> {
-        convert_doc_comment(token.token()?, span)
+        span: SpanData<SpanAnchor>,
+    ) -> Option<Vec<tt::TokenTree<SpanData<SpanAnchor>>>> {
+        convert_doc_comment(token.token(), span)
     }
 
-    fn bump(&mut self) -> Option<(Self::Token, TextRange)> {
+    fn bump(&mut self) -> Option<(Self::Token, TextRange, TextRange)> {
         if let Some((punct, offset)) = self.punct_offset.clone() {
             if usize::from(offset) + 1 < punct.text().len() {
                 let offset = offset + TextSize::of('.');
                 let range = punct.text_range();
                 self.punct_offset = Some((punct.clone(), offset));
                 let range = TextRange::at(range.start() + offset, TextSize::of('.'));
-                return Some((SynToken::Punch(punct, offset), range));
+                return Some((
+                    SynToken::Punct(punct, u32::from(offset) as usize),
+                    range - self.offset,
+                    range,
+                ));
             }
         }
 
-        if let Some(synth_token) = self.current_synthetic.pop() {
-            if self.current_synthetic.is_empty() {
-                let (new_current, new_synth) =
-                    Self::next_token(&mut self.preorder, &mut self.replace, &mut self.append);
-                self.current = new_current;
-                self.current_synthetic = new_synth;
-            }
-            let range = synth_token.range;
-            return Some((SynToken::Synthetic(synth_token), range));
-        }
-
         let curr = self.current.clone()?;
         if !self.range.contains_range(curr.text_range()) {
             return None;
         }
-        let (new_current, new_synth) =
-            Self::next_token(&mut self.preorder, &mut self.replace, &mut self.append);
-        self.current = new_current;
-        self.current_synthetic = new_synth;
+        self.current = Self::next_token(&mut self.preorder, &self.censored);
         let token = if curr.kind().is_punct() {
             self.punct_offset = Some((curr.clone(), 0.into()));
             let range = curr.text_range();
             let range = TextRange::at(range.start(), TextSize::of('.'));
-            (SynToken::Punch(curr, 0.into()), range)
+            (SynToken::Punct(curr, 0 as usize), range - self.offset, range)
         } else {
             self.punct_offset = None;
             let range = curr.text_range();
-            (SynToken::Ordinary(curr), range)
+            (SynToken::Ordinary(curr), range - self.offset, range)
         };
 
         Some(token)
@@ -871,54 +640,54 @@ impl TokenConverter for Converter {
         if let Some((punct, mut offset)) = self.punct_offset.clone() {
             offset += TextSize::of('.');
             if usize::from(offset) < punct.text().len() {
-                return Some(SynToken::Punch(punct, offset));
+                return Some(SynToken::Punct(punct, usize::from(offset)));
             }
         }
 
-        if let Some(synth_token) = self.current_synthetic.last() {
-            return Some(SynToken::Synthetic(synth_token.clone()));
-        }
-
         let curr = self.current.clone()?;
         if !self.range.contains_range(curr.text_range()) {
             return None;
         }
 
         let token = if curr.kind().is_punct() {
-            SynToken::Punch(curr, 0.into())
+            SynToken::Punct(curr, 0 as usize)
         } else {
             SynToken::Ordinary(curr)
         };
         Some(token)
     }
 
-    fn id_alloc(&mut self) -> &mut TokenIdAlloc {
-        &mut self.id_alloc
+    fn anchor(&self) -> SpanAnchor {
+        self.file_id
+    }
+    fn span_for(&self, range: TextRange) -> Option<SpanData<SpanAnchor>> {
+        self.map.span_for_range(range)
     }
 }
 
-struct TtTreeSink<'a> {
+struct TtTreeSink<'a, SpanAnchor> {
     buf: String,
-    cursor: Cursor<'a, TokenId>,
-    open_delims: FxHashMap<tt::TokenId, TextSize>,
+    cursor: Cursor<'a, SpanData<SpanAnchor>>,
     text_pos: TextSize,
     inner: SyntaxTreeBuilder,
-    token_map: TokenMap,
+    token_map: TokenMap<SpanData<SpanAnchor>>,
 }
 
-impl<'a> TtTreeSink<'a> {
-    fn new(cursor: Cursor<'a, TokenId>) -> Self {
+impl<'a, SpanAnchor> TtTreeSink<'a, SpanAnchor>
+where
+    SpanData<SpanAnchor>: Span,
+{
+    fn new(cursor: Cursor<'a, SpanData<SpanAnchor>>) -> Self {
         TtTreeSink {
             buf: String::new(),
             cursor,
-            open_delims: FxHashMap::default(),
             text_pos: 0.into(),
             inner: SyntaxTreeBuilder::default(),
             token_map: TokenMap::default(),
         }
     }
 
-    fn finish(mut self) -> (Parse<SyntaxNode>, TokenMap) {
+    fn finish(mut self) -> (Parse<SyntaxNode>, TokenMap<SpanData<SpanAnchor>>) {
         self.token_map.shrink_to_fit();
         (self.inner.finish(), self.token_map)
     }
@@ -936,7 +705,10 @@ fn delim_to_str(d: tt::DelimiterKind, closing: bool) -> Option<&'static str> {
     Some(&texts[idx..texts.len() - (1 - idx)])
 }
 
-impl TtTreeSink<'_> {
+impl<SpanAnchor> TtTreeSink<'_, SpanAnchor>
+where
+    SpanData<SpanAnchor>: Span,
+{
     /// Parses a float literal as if it was a one to two name ref nodes with a dot inbetween.
     /// This occurs when a float literal is used as a field access.
     fn float_split(&mut self, has_pseudo_dot: bool) {
@@ -991,7 +763,7 @@ impl TtTreeSink<'_> {
                 break match self.cursor.token_tree() {
                     Some(tt::buffer::TokenTreeRef::Leaf(leaf, _)) => {
                         // Mark the range if needed
-                        let (text, id) = match leaf {
+                        let (text, span) = match leaf {
                             tt::Leaf::Ident(ident) => (ident.text.as_str(), ident.span),
                             tt::Leaf::Punct(punct) => {
                                 assert!(punct.char.is_ascii());
@@ -1004,7 +776,7 @@ impl TtTreeSink<'_> {
                             tt::Leaf::Literal(lit) => (lit.text.as_str(), lit.span),
                         };
                         let range = TextRange::at(self.text_pos, TextSize::of(text));
-                        self.token_map.insert(id, range);
+                        self.token_map.insert(range, span);
                         self.cursor = self.cursor.bump();
                         text
                     }
@@ -1012,7 +784,8 @@ impl TtTreeSink<'_> {
                         self.cursor = self.cursor.subtree().unwrap();
                         match delim_to_str(subtree.delimiter.kind, false) {
                             Some(it) => {
-                                self.open_delims.insert(subtree.delimiter.open, self.text_pos);
+                                let range = TextRange::at(self.text_pos, TextSize::of(it));
+                                self.token_map.insert(range, subtree.delimiter.open);
                                 it
                             }
                             None => continue,
@@ -1023,18 +796,8 @@ impl TtTreeSink<'_> {
                         self.cursor = self.cursor.bump();
                         match delim_to_str(parent.delimiter.kind, true) {
                             Some(it) => {
-                                if let Some(open_delim) =
-                                    self.open_delims.get(&parent.delimiter.open)
-                                {
-                                    let open_range = TextRange::at(*open_delim, TextSize::of('('));
-                                    let close_range =
-                                        TextRange::at(self.text_pos, TextSize::of('('));
-                                    self.token_map.insert_delim(
-                                        parent.delimiter.open,
-                                        open_range,
-                                        close_range,
-                                    );
-                                }
+                                let range = TextRange::at(self.text_pos, TextSize::of(it));
+                                self.token_map.insert(range, parent.delimiter.close);
                                 it
                             }
                             None => continue,
diff --git a/crates/mbe/src/syntax_bridge/tests.rs b/crates/mbe/src/syntax_bridge/tests.rs
index fa0125f3e9e..32dfb4d7e0b 100644
--- a/crates/mbe/src/syntax_bridge/tests.rs
+++ b/crates/mbe/src/syntax_bridge/tests.rs
@@ -4,24 +4,32 @@ use syntax::{ast, AstNode};
 use test_utils::extract_annotations;
 use tt::{
     buffer::{TokenBuffer, TokenTreeRef},
-    Leaf, Punct, Spacing,
+    Leaf, Punct, Spacing, Span,
 };
 
+use crate::syntax_bridge::SpanData;
+
 use super::syntax_node_to_token_tree;
 
 fn check_punct_spacing(fixture: &str) {
+    #[derive(PartialEq, Eq, Clone, Copy, Debug)]
+    struct DummyFile;
+    impl Span for DummyFile {
+        const DUMMY: Self = DummyFile;
+    }
+
     let source_file = ast::SourceFile::parse(fixture).ok().unwrap();
-    let (subtree, token_map) = syntax_node_to_token_tree(source_file.syntax());
+    let subtree =
+        syntax_node_to_token_tree(source_file.syntax(), DummyFile, 0.into(), &Default::default());
     let mut annotations: HashMap<_, _> = extract_annotations(fixture)
         .into_iter()
         .map(|(range, annotation)| {
-            let token = token_map.token_by_range(range).expect("no token found");
             let spacing = match annotation.as_str() {
                 "Alone" => Spacing::Alone,
                 "Joint" => Spacing::Joint,
                 a => panic!("unknown annotation: {a}"),
             };
-            (token, spacing)
+            (range, spacing)
         })
         .collect();
 
@@ -29,8 +37,12 @@ fn check_punct_spacing(fixture: &str) {
     let mut cursor = buf.begin();
     while !cursor.eof() {
         while let Some(token_tree) = cursor.token_tree() {
-            if let TokenTreeRef::Leaf(Leaf::Punct(Punct { spacing, span, .. }), _) = token_tree {
-                if let Some(expected) = annotations.remove(span) {
+            if let TokenTreeRef::Leaf(
+                Leaf::Punct(Punct { spacing, span: SpanData { range, .. }, .. }),
+                _,
+            ) = token_tree
+            {
+                if let Some(expected) = annotations.remove(range) {
                     assert_eq!(expected, *spacing);
                 }
             }
diff --git a/crates/mbe/src/token_map.rs b/crates/mbe/src/token_map.rs
index 73a27df5dbc..1af50c8b3b9 100644
--- a/crates/mbe/src/token_map.rs
+++ b/crates/mbe/src/token_map.rs
@@ -2,123 +2,121 @@
 
 use std::hash::Hash;
 
-use parser::{SyntaxKind, T};
-use syntax::{TextRange, TextSize};
-
-use crate::syntax_bridge::SyntheticTokenId;
-
-#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
-enum TokenTextRange {
-    Token(TextRange),
-    Delimiter(TextRange),
+use syntax::TextRange;
+use tt::Span;
+
+// pub type HirFile = u32;
+// pub type FileRange = (HirFile, TextRange);
+// Option<MacroCallId>, LocalSyntaxContet
+// pub type SyntaxContext = ();
+// pub type LocalSyntaxContext = u32;
+
+/// Maps absolute text ranges for the corresponding file to the relevant span data.
+#[derive(Debug, PartialEq, Eq, Clone, Hash)]
+// FIXME: Rename to SpanMap
+pub struct TokenMap<S> {
+    // FIXME: This needs to be sorted by (FileId, AstId)
+    // Then we can do a binary search on the file id,
+    // then a bin search on the ast id
+    pub span_map: Vec<(TextRange, S)>,
+    // span_map2: rustc_hash::FxHashMap<TextRange, usize>,
 }
 
-impl TokenTextRange {
-    fn by_kind(self, kind: SyntaxKind) -> Option<TextRange> {
-        match self {
-            TokenTextRange::Token(it) => Some(it),
-            TokenTextRange::Delimiter(it) => match kind {
-                T!['{'] | T!['('] | T!['['] => Some(TextRange::at(it.start(), 1.into())),
-                T!['}'] | T![')'] | T![']'] => {
-                    Some(TextRange::at(it.end() - TextSize::of('}'), 1.into()))
-                }
-                _ => None,
-            },
-        }
+impl<S> Default for TokenMap<S> {
+    fn default() -> Self {
+        Self { span_map: Vec::new() }
     }
 }
 
-/// Maps `tt::TokenId` to the relative range of the original token.
-#[derive(Debug, PartialEq, Eq, Clone, Default, Hash)]
-pub struct TokenMap {
-    /// Maps `tt::TokenId` to the *relative* source range.
-    entries: Vec<(tt::TokenId, TokenTextRange)>,
-    pub synthetic_entries: Vec<(tt::TokenId, SyntheticTokenId)>,
-}
-
-impl TokenMap {
-    pub fn token_by_range(&self, relative_range: TextRange) -> Option<tt::TokenId> {
-        let &(token_id, _) = self.entries.iter().find(|(_, range)| match range {
-            TokenTextRange::Token(it) => *it == relative_range,
-            TokenTextRange::Delimiter(it) => {
-                let open = TextRange::at(it.start(), 1.into());
-                let close = TextRange::at(it.end() - TextSize::of('}'), 1.into());
-                open == relative_range || close == relative_range
-            }
-        })?;
-        Some(token_id)
-    }
-
-    pub fn ranges_by_token(
-        &self,
-        token_id: tt::TokenId,
-        kind: SyntaxKind,
-    ) -> impl Iterator<Item = TextRange> + '_ {
-        self.entries
-            .iter()
-            .filter(move |&&(tid, _)| tid == token_id)
-            .filter_map(move |(_, range)| range.by_kind(kind))
-    }
-
-    pub fn synthetic_token_id(&self, token_id: tt::TokenId) -> Option<SyntheticTokenId> {
-        self.synthetic_entries.iter().find(|(tid, _)| *tid == token_id).map(|(_, id)| *id)
-    }
-
-    pub fn first_range_by_token(
-        &self,
-        token_id: tt::TokenId,
-        kind: SyntaxKind,
-    ) -> Option<TextRange> {
-        self.ranges_by_token(token_id, kind).next()
-    }
-
+impl<S: Span> TokenMap<S> {
     pub(crate) fn shrink_to_fit(&mut self) {
-        self.entries.shrink_to_fit();
-        self.synthetic_entries.shrink_to_fit();
-    }
-
-    pub(crate) fn insert(&mut self, token_id: tt::TokenId, relative_range: TextRange) {
-        self.entries.push((token_id, TokenTextRange::Token(relative_range)));
-    }
-
-    pub(crate) fn insert_synthetic(&mut self, token_id: tt::TokenId, id: SyntheticTokenId) {
-        self.synthetic_entries.push((token_id, id));
+        self.span_map.shrink_to_fit();
     }
 
-    pub(crate) fn insert_delim(
-        &mut self,
-        token_id: tt::TokenId,
-        open_relative_range: TextRange,
-        close_relative_range: TextRange,
-    ) -> usize {
-        let res = self.entries.len();
-        let cover = open_relative_range.cover(close_relative_range);
-
-        self.entries.push((token_id, TokenTextRange::Delimiter(cover)));
-        res
+    pub(crate) fn insert(&mut self, range: TextRange, span: S) {
+        self.span_map.push((range, span));
     }
 
-    pub(crate) fn update_close_delim(&mut self, idx: usize, close_relative_range: TextRange) {
-        let (_, token_text_range) = &mut self.entries[idx];
-        if let TokenTextRange::Delimiter(dim) = token_text_range {
-            let cover = dim.cover(close_relative_range);
-            *token_text_range = TokenTextRange::Delimiter(cover);
-        }
-    }
-
-    pub(crate) fn remove_delim(&mut self, idx: usize) {
-        // FIXME: This could be accidentally quadratic
-        self.entries.remove(idx);
+    pub fn ranges_with_span(&self, span: S) -> impl Iterator<Item = TextRange> + '_ {
+        self.span_map.iter().filter_map(
+            move |(range, s)| {
+                if s == &span {
+                    Some(*range)
+                } else {
+                    None
+                }
+            },
+        )
     }
 
-    pub fn entries(&self) -> impl Iterator<Item = (tt::TokenId, TextRange)> + '_ {
-        self.entries.iter().filter_map(|&(tid, tr)| match tr {
-            TokenTextRange::Token(range) => Some((tid, range)),
-            TokenTextRange::Delimiter(_) => None,
-        })
+    pub fn span_for_range(&self, range: TextRange) -> Option<S> {
+        self.span_map.iter().find_map(|(r, s)| if r == &range { Some(s.clone()) } else { None })
     }
 
-    pub fn filter(&mut self, id: impl Fn(tt::TokenId) -> bool) {
-        self.entries.retain(|&(tid, _)| id(tid));
-    }
+    // pub fn ranges_by_token(
+    //     &self,
+    //     token_id: tt::TokenId,
+    //     kind: SyntaxKind,
+    // ) -> impl Iterator<Item = TextRange> + '_ {
+    //     self.entries
+    //         .iter()
+    //         .filter(move |&&(tid, _)| tid == token_id)
+    //         .filter_map(move |(_, range)| range.by_kind(kind))
+    // }
+
+    // pub(crate) fn remove_delim(&mut self, idx: usize) {
+    //     // FIXME: This could be accidentally quadratic
+    //     self.entries.remove(idx);
+    // }
+
+    // pub fn entries(&self) -> impl Iterator<Item = (tt::TokenId, TextRange)> + '_ {
+    //     self.entries.iter().filter_map(|&(tid, tr)| match tr {
+    //         TokenTextRange::Token(range) => Some((tid, range)),
+    //         TokenTextRange::Delimiter(_) => None,
+    //     })
+    // }
+
+    // pub fn filter(&mut self, id: impl Fn(tt::TokenId) -> bool) {
+    //     self.entries.retain(|&(tid, _)| id(tid));
+    // }
+    // pub fn synthetic_token_id(&self, token_id: tt::TokenId) -> Option<SyntheticTokenId> {
+    //     self.synthetic_entries.iter().find(|(tid, _)| *tid == token_id).map(|(_, id)| *id)
+    // }
+
+    // pub fn first_range_by_token(
+    //     &self,
+    //     token_id: tt::TokenId,
+    //     kind: SyntaxKind,
+    // ) -> Option<TextRange> {
+    //     self.ranges_by_token(token_id, kind).next()
+    // }
+
+    // pub(crate) fn insert(&mut self, token_id: tt::TokenId, relative_range: TextRange) {
+    //     self.entries.push((token_id, TokenTextRange::Token(relative_range)));
+    // }
+
+    // pub(crate) fn insert_synthetic(&mut self, token_id: tt::TokenId, id: SyntheticTokenId) {
+    //     self.synthetic_entries.push((token_id, id));
+    // }
+
+    // pub(crate) fn insert_delim(
+    //     &mut self,
+    //     token_id: tt::TokenId,
+    //     open_relative_range: TextRange,
+    //     close_relative_range: TextRange,
+    // ) -> usize {
+    //     let res = self.entries.len();
+    //     let cover = open_relative_range.cover(close_relative_range);
+
+    //     self.entries.push((token_id, TokenTextRange::Delimiter(cover)));
+    //     res
+    // }
+
+    // pub(crate) fn update_close_delim(&mut self, idx: usize, close_relative_range: TextRange) {
+    //     let (_, token_text_range) = &mut self.entries[idx];
+    //     if let TokenTextRange::Delimiter(dim) = token_text_range {
+    //         let cover = dim.cover(close_relative_range);
+    //         *token_text_range = TokenTextRange::Delimiter(cover);
+    //     }
+    // }
 }
diff --git a/crates/proc-macro-api/Cargo.toml b/crates/proc-macro-api/Cargo.toml
index 2c2d2e8a945..4c87c89adde 100644
--- a/crates/proc-macro-api/Cargo.toml
+++ b/crates/proc-macro-api/Cargo.toml
@@ -31,5 +31,6 @@ paths.workspace = true
 tt.workspace = true
 stdx.workspace = true
 profile.workspace = true
+text-size.workspace = true
 # Intentionally *not* depend on anything salsa-related
 # base-db.workspace = true
diff --git a/crates/proc-macro-api/src/msg/flat.rs b/crates/proc-macro-api/src/msg/flat.rs
index fe82b8d0454..bfb3213a25d 100644
--- a/crates/proc-macro-api/src/msg/flat.rs
+++ b/crates/proc-macro-api/src/msg/flat.rs
@@ -38,6 +38,7 @@
 use std::collections::{HashMap, VecDeque};
 
 use serde::{Deserialize, Serialize};
+use text_size::TextRange;
 use tt::Span;
 
 use crate::msg::{ENCODE_CLOSE_SPAN_VERSION, VARIABLE_SIZED_SPANS};
@@ -55,6 +56,19 @@ impl SerializableSpan<1> for tt::TokenId {
     }
 }
 
+impl<FileId> SerializableSpan<3> for tt::SpanData<FileId>
+where
+    FileId: From<u32> + Into<u32>,
+    Self: Span,
+{
+    fn into_u32(self) -> [u32; 3] {
+        [self.anchor.into(), self.range.start().into(), self.range.end().into()]
+    }
+    fn from_u32([file_id, start, end]: [u32; 3]) -> Self {
+        tt::SpanData { anchor: file_id.into(), range: TextRange::new(start.into(), end.into()) }
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug)]
 pub struct FlatTree {
     subtree: Vec<u32>,
diff --git a/crates/rust-analyzer/src/cargo_target_spec.rs b/crates/rust-analyzer/src/cargo_target_spec.rs
index c7b84c41b33..b6dcc26de62 100644
--- a/crates/rust-analyzer/src/cargo_target_spec.rs
+++ b/crates/rust-analyzer/src/cargo_target_spec.rs
@@ -209,17 +209,24 @@ mod tests {
     use super::*;
 
     use cfg::CfgExpr;
+    use hir::HirFileId;
+    use ide_db::base_db::span::{SpanAnchor, ROOT_ERASED_FILE_AST_ID};
     use mbe::syntax_node_to_token_tree;
     use syntax::{
         ast::{self, AstNode},
-        SmolStr,
+        SmolStr, TextSize,
     };
 
     fn check(cfg: &str, expected_features: &[&str]) {
         let cfg_expr = {
             let source_file = ast::SourceFile::parse(cfg).ok().unwrap();
             let tt = source_file.syntax().descendants().find_map(ast::TokenTree::cast).unwrap();
-            let (tt, _) = syntax_node_to_token_tree(tt.syntax());
+            let tt = syntax_node_to_token_tree(
+                tt.syntax(),
+                SpanAnchor { file_id: HirFileId::from(0), ast_id: ROOT_ERASED_FILE_AST_ID },
+                TextSize::new(0),
+                &Default::default(),
+            );
             CfgExpr::parse(&tt)
         };
 
diff --git a/crates/rust-analyzer/src/cli/analysis_stats.rs b/crates/rust-analyzer/src/cli/analysis_stats.rs
index 0f6539f224d..7e795cf4632 100644
--- a/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -8,7 +8,7 @@ use std::{
 
 use hir::{
     db::{DefDatabase, ExpandDatabase, HirDatabase},
-    Adt, AssocItem, Crate, DefWithBody, HasSource, HirDisplay, ModuleDef, Name,
+    Adt, AssocItem, Crate, DefWithBody, HasSource, HirDisplay, HirFileIdExt, ModuleDef, Name,
 };
 use hir_def::{
     body::{BodySourceMap, SyntheticSyntax},
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
index 8541be715a9..abec2679464 100644
--- a/crates/rust-analyzer/src/cli/diagnostics.rs
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -4,7 +4,7 @@
 use project_model::{CargoConfig, RustLibSource};
 use rustc_hash::FxHashSet;
 
-use hir::{db::HirDatabase, Crate, Module};
+use hir::{db::HirDatabase, Crate, HirFileIdExt, Module};
 use ide::{AssistResolveStrategy, DiagnosticsConfig, Severity};
 use ide_db::base_db::SourceDatabaseExt;
 use load_cargo::{load_workspace_at, LoadCargoConfig, ProcMacroServerChoice};
diff --git a/crates/syntax/src/lib.rs b/crates/syntax/src/lib.rs
index 4939ab39049..1d7b7de390e 100644
--- a/crates/syntax/src/lib.rs
+++ b/crates/syntax/src/lib.rs
@@ -75,7 +75,7 @@ pub use smol_str::SmolStr;
 #[derive(Debug, PartialEq, Eq)]
 pub struct Parse<T> {
     green: GreenNode,
-    errors: Arc<[SyntaxError]>,
+    errors: Option<Arc<[SyntaxError]>>,
     _ty: PhantomData<fn() -> T>,
 }
 
@@ -87,14 +87,18 @@ impl<T> Clone for Parse<T> {
 
 impl<T> Parse<T> {
     fn new(green: GreenNode, errors: Vec<SyntaxError>) -> Parse<T> {
-        Parse { green, errors: errors.into(), _ty: PhantomData }
+        Parse {
+            green,
+            errors: if errors.is_empty() { None } else { Some(errors.into()) },
+            _ty: PhantomData,
+        }
     }
 
     pub fn syntax_node(&self) -> SyntaxNode {
         SyntaxNode::new_root(self.green.clone())
     }
     pub fn errors(&self) -> &[SyntaxError] {
-        &self.errors
+        self.errors.as_deref().unwrap_or_default()
     }
 }
 
@@ -108,10 +112,9 @@ impl<T: AstNode> Parse<T> {
     }
 
     pub fn ok(self) -> Result<T, Arc<[SyntaxError]>> {
-        if self.errors.is_empty() {
-            Ok(self.tree())
-        } else {
-            Err(self.errors)
+        match self.errors {
+            Some(e) => Err(e),
+            None => Ok(self.tree()),
         }
     }
 }
@@ -129,7 +132,7 @@ impl Parse<SyntaxNode> {
 impl Parse<SourceFile> {
     pub fn debug_dump(&self) -> String {
         let mut buf = format!("{:#?}", self.tree().syntax());
-        for err in self.errors.iter() {
+        for err in self.errors.as_deref().into_iter().flat_map(<[_]>::iter) {
             format_to!(buf, "error {:?}: {}\n", err.range(), err);
         }
         buf
@@ -141,13 +144,16 @@ impl Parse<SourceFile> {
 
     fn incremental_reparse(&self, indel: &Indel) -> Option<Parse<SourceFile>> {
         // FIXME: validation errors are not handled here
-        parsing::incremental_reparse(self.tree().syntax(), indel, self.errors.to_vec()).map(
-            |(green_node, errors, _reparsed_range)| Parse {
-                green: green_node,
-                errors: errors.into(),
-                _ty: PhantomData,
-            },
+        parsing::incremental_reparse(
+            self.tree().syntax(),
+            indel,
+            self.errors.as_deref().unwrap_or_default().iter().cloned(),
         )
+        .map(|(green_node, errors, _reparsed_range)| Parse {
+            green: green_node,
+            errors: if errors.is_empty() { None } else { Some(errors.into()) },
+            _ty: PhantomData,
+        })
     }
 
     fn full_reparse(&self, indel: &Indel) -> Parse<SourceFile> {
@@ -168,7 +174,11 @@ impl SourceFile {
         errors.extend(validation::validate(&root));
 
         assert_eq!(root.kind(), SyntaxKind::SOURCE_FILE);
-        Parse { green, errors: errors.into(), _ty: PhantomData }
+        Parse {
+            green,
+            errors: if errors.is_empty() { None } else { Some(errors.into()) },
+            _ty: PhantomData,
+        }
     }
 }
 
@@ -275,7 +285,11 @@ impl ast::TokenTree {
 
         let (green, errors) = builder.finish_raw();
 
-        Parse { green, errors: errors.into(), _ty: PhantomData }
+        Parse {
+            green,
+            errors: if errors.is_empty() { None } else { Some(errors.into()) },
+            _ty: PhantomData,
+        }
     }
 }
 
diff --git a/crates/syntax/src/parsing/reparsing.rs b/crates/syntax/src/parsing/reparsing.rs
index 45e59160982..0ddc641711f 100644
--- a/crates/syntax/src/parsing/reparsing.rs
+++ b/crates/syntax/src/parsing/reparsing.rs
@@ -20,7 +20,7 @@ use crate::{
 pub(crate) fn incremental_reparse(
     node: &SyntaxNode,
     edit: &Indel,
-    errors: Vec<SyntaxError>,
+    errors: impl IntoIterator<Item = SyntaxError>,
 ) -> Option<(GreenNode, Vec<SyntaxError>, TextRange)> {
     if let Some((green, new_errors, old_range)) = reparse_token(node, edit) {
         return Some((green, merge_errors(errors, new_errors, old_range, edit), old_range));
@@ -147,7 +147,7 @@ fn is_balanced(lexed: &parser::LexedStr<'_>) -> bool {
 }
 
 fn merge_errors(
-    old_errors: Vec<SyntaxError>,
+    old_errors: impl IntoIterator<Item = SyntaxError>,
     new_errors: Vec<SyntaxError>,
     range_before_reparse: TextRange,
     edit: &Indel,
@@ -191,8 +191,12 @@ mod tests {
         let fully_reparsed = SourceFile::parse(&after);
         let incrementally_reparsed: Parse<SourceFile> = {
             let before = SourceFile::parse(&before);
-            let (green, new_errors, range) =
-                incremental_reparse(before.tree().syntax(), &edit, before.errors.to_vec()).unwrap();
+            let (green, new_errors, range) = incremental_reparse(
+                before.tree().syntax(),
+                &edit,
+                before.errors.as_deref().unwrap_or_default().iter().cloned(),
+            )
+            .unwrap();
             assert_eq!(range.len(), reparsed_len.into(), "reparsed fragment has wrong length");
             Parse::new(green, new_errors)
         };
diff --git a/crates/syntax/src/tests.rs b/crates/syntax/src/tests.rs
index 3010d77d827..8ae1242cf7f 100644
--- a/crates/syntax/src/tests.rs
+++ b/crates/syntax/src/tests.rs
@@ -38,7 +38,7 @@ fn benchmark_parser() {
     let tree = {
         let _b = bench("parsing");
         let p = SourceFile::parse(&data);
-        assert!(p.errors.is_empty());
+        assert!(p.errors.is_none());
         assert_eq!(p.tree().syntax.text_range().len(), 352474.into());
         p.tree()
     };
diff --git a/crates/tt/Cargo.toml b/crates/tt/Cargo.toml
index a28ee5f1ca2..57222449790 100644
--- a/crates/tt/Cargo.toml
+++ b/crates/tt/Cargo.toml
@@ -13,5 +13,6 @@ doctest = false
 
 [dependencies]
 smol_str.workspace = true
+text-size.workspace = true
 
 stdx.workspace = true
diff --git a/crates/tt/src/lib.rs b/crates/tt/src/lib.rs
index a4ffc328f21..89cb12d2c26 100644
--- a/crates/tt/src/lib.rs
+++ b/crates/tt/src/lib.rs
@@ -7,6 +7,7 @@
 use std::fmt;
 
 use stdx::impl_from;
+use text_size::{TextRange, TextSize};
 
 pub use smol_str::SmolStr;
 
@@ -31,36 +32,25 @@ impl TokenId {
         Self::UNSPECIFIED
     }
 }
-
-pub mod token_id {
-    pub use crate::{DelimiterKind, Spacing, TokenId};
-    pub type Span = crate::TokenId;
-    pub type Subtree = crate::Subtree<Span>;
-    pub type Punct = crate::Punct<Span>;
-    pub type Delimiter = crate::Delimiter<Span>;
-    pub type Leaf = crate::Leaf<Span>;
-    pub type Ident = crate::Ident<Span>;
-    pub type Literal = crate::Literal<Span>;
-    pub type TokenTree = crate::TokenTree<Span>;
-    pub mod buffer {
-        pub type TokenBuffer<'a> = crate::buffer::TokenBuffer<'a, super::Span>;
-        pub type Cursor<'a> = crate::buffer::Cursor<'a, super::Span>;
-        pub type TokenTreeRef<'a> = crate::buffer::TokenTreeRef<'a, super::Span>;
-    }
+impl Span for TokenId {
+    const DUMMY: Self = TokenId(!0);
 }
 
-pub trait Span: std::fmt::Debug + Copy + Sized {
-    const DUMMY: Self;
-    fn is_dummy(&self) -> bool;
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub struct SpanData<Anchor> {
+    /// The text range of this span, relative to the anchor.
+    pub range: TextRange,
+    pub anchor: Anchor,
 }
-impl Span for TokenId {
-    const DUMMY: Self = TokenId(!0);
 
-    fn is_dummy(&self) -> bool {
-        *self == Self::DUMMY
-    }
+impl<Anchor: Span> Span for SpanData<Anchor> {
+    const DUMMY: Self =
+        SpanData { range: TextRange::empty(TextSize::new(0)), anchor: Anchor::DUMMY };
 }
 
+pub trait Span: std::fmt::Debug + Copy + Sized + Eq {
+    const DUMMY: Self;
+}
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct SyntaxContext(pub u32);
 
@@ -134,7 +124,6 @@ impl<S: Span> Delimiter<S> {
     }
 }
 
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum DelimiterKind {
     Parenthesis,