Auto merge of #17520 - Veykril:slim-proc-macro-api, r=Veykril

internal: Cleanup proc-macro-srv some more

53 files changed, 351 insertions, 348 deletions

diff --git a/src/tools/rust-analyzer/Cargo.lock b/src/tools/rust-analyzer/Cargo.lock
index 790bccea196..56deb1b7a19 100644
--- a/src/tools/rust-analyzer/Cargo.lock
+++ b/src/tools/rust-analyzer/Cargo.lock
@@ -1337,7 +1337,6 @@ dependencies = [
  "stdx",
  "text-size",
  "tracing",
- "triomphe",
  "tt",
 ]
 
diff --git a/src/tools/rust-analyzer/crates/base-db/src/lib.rs b/src/tools/rust-analyzer/crates/base-db/src/lib.rs
index f5165ea8a7b..96fbbc317d4 100644
--- a/src/tools/rust-analyzer/crates/base-db/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/base-db/src/lib.rs
@@ -1,7 +1,5 @@
 //! base_db defines basic database traits. The concrete DB is defined by ide.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod change;
 mod input;
 
diff --git a/src/tools/rust-analyzer/crates/cfg/src/lib.rs b/src/tools/rust-analyzer/crates/cfg/src/lib.rs
index 9a365889e6a..8b30286a0a8 100644
--- a/src/tools/rust-analyzer/crates/cfg/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/cfg/src/lib.rs
@@ -1,7 +1,5 @@
 //! cfg defines conditional compiling options, `cfg` attribute parser and evaluator
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod cfg_expr;
 mod dnf;
 #[cfg(test)]
diff --git a/src/tools/rust-analyzer/crates/flycheck/src/lib.rs b/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
index 4584400e66f..a257633516c 100644
--- a/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/flycheck/src/lib.rs
@@ -6,8 +6,6 @@
 // addition to `cargo check`. Either split it into 3 crates (one for test, one for check
 // and one common utilities) or change its name and docs to reflect the current state.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{fmt, io, process::Command, time::Duration};
 
 use crossbeam_channel::{never, select, unbounded, Receiver, Sender};
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/lib.rs b/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
index 3fa98efbb5e..211cdd35fd7 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/lib.rs
@@ -7,7 +7,6 @@
 //! Note that `hir_def` is a work in progress, so not all of the above is
 //! actually true.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 #[cfg(feature = "in-rust-tree")]
diff --git a/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs b/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
index a7150cf3087..e7c34e51e85 100644
--- a/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-expand/src/lib.rs
@@ -4,7 +4,6 @@
 //! tree originates not from the text of some `FileId`, but from some macro
 //! expansion.
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
-#![warn(rust_2018_idioms, unused_lifetimes)]
 
 pub mod attrs;
 pub mod builtin_attr_macro;
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
index 07c0cf920f7..bd650869bb3 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
@@ -1,6 +1,6 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
-#![warn(rust_2018_idioms, unused_lifetimes)]
+
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 #[cfg(feature = "in-rust-tree")]
diff --git a/src/tools/rust-analyzer/crates/hir/src/lib.rs b/src/tools/rust-analyzer/crates/hir/src/lib.rs
index eea25ac18ae..a9ae8d56490 100644
--- a/src/tools/rust-analyzer/crates/hir/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/lib.rs
@@ -17,7 +17,6 @@
 //! from the ide with completions, hovers, etc. It is a (soft, internal) boundary:
 //! <https://www.tedinski.com/2018/02/06/system-boundaries.html>.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![recursion_limit = "512"]
 
diff --git a/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs b/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
index abebdec1d18..685d230dc6f 100644
--- a/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-assists/src/lib.rs
@@ -58,8 +58,6 @@
 //! See also this post:
 //! <https://rust-analyzer.github.io/blog/2020/09/28/how-to-make-a-light-bulb.html>
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod assist_config;
 mod assist_context;
 #[cfg(test)]
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
index 8323b8f9331..7150fe3f017 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
@@ -1,7 +1,5 @@
 //! `completions` crate provides utilities for generating completions of user input.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod completions;
 mod config;
 mod context;
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
index 357209ceb0b..8fac5baa57b 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
@@ -2,8 +2,6 @@
 //!
 //! It is mainly a `HirDatabase` for semantic analysis, plus a `SymbolsDatabase`, for fuzzy search.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod apply_change;
 
 pub mod active_parameter;
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
index f176c30c4a3..2bf3f5f0ceb 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
@@ -23,8 +23,6 @@
 //! There are also a couple of ad-hoc diagnostics implemented directly here, we
 //! don't yet have a great pattern for how to do them properly.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod handlers {
     pub(crate) mod break_outside_of_loop;
     pub(crate) mod expected_function;
diff --git a/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs b/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
index b5bf510aeed..407433ed192 100644
--- a/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
@@ -3,8 +3,6 @@
 //! Allows searching the AST for code that matches one or more patterns and then replacing that code
 //! based on a template.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 // Feature: Structural Search and Replace
 //
 // Search and replace with named wildcards that will match any expression, type, path, pattern or item.
diff --git a/src/tools/rust-analyzer/crates/ide/src/lib.rs b/src/tools/rust-analyzer/crates/ide/src/lib.rs
index a2ac62341df..28ae0dce987 100644
--- a/src/tools/rust-analyzer/crates/ide/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/lib.rs
@@ -8,7 +8,7 @@
 //! in this crate.
 
 // For proving that RootDatabase is RefUnwindSafe.
-#![warn(rust_2018_idioms, unused_lifetimes)]
+
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![recursion_limit = "128"]
 
diff --git a/src/tools/rust-analyzer/crates/limit/src/lib.rs b/src/tools/rust-analyzer/crates/limit/src/lib.rs
index 27471db6a34..c1caeed2f87 100644
--- a/src/tools/rust-analyzer/crates/limit/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/limit/src/lib.rs
@@ -1,7 +1,5 @@
 //! limit defines a struct to enforce limits.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 #[cfg(feature = "tracking")]
 use std::sync::atomic::AtomicUsize;
 
diff --git a/src/tools/rust-analyzer/crates/mbe/src/lib.rs b/src/tools/rust-analyzer/crates/mbe/src/lib.rs
index 5f0598dfe07..b2fd91f6ced 100644
--- a/src/tools/rust-analyzer/crates/mbe/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/mbe/src/lib.rs
@@ -6,8 +6,6 @@
 //! The tests for this functionality live in another crate:
 //! `hir_def::macro_expansion_tests::mbe`.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod expander;
 mod parser;
 mod syntax_bridge;
diff --git a/src/tools/rust-analyzer/crates/parser/src/lib.rs b/src/tools/rust-analyzer/crates/parser/src/lib.rs
index c2f9ea47728..738ed239a7c 100644
--- a/src/tools/rust-analyzer/crates/parser/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/lib.rs
@@ -17,7 +17,6 @@
 //!
 //! [`Parser`]: crate::parser::Parser
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(rustdoc::private_intra_doc_links)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
diff --git a/src/tools/rust-analyzer/crates/paths/src/lib.rs b/src/tools/rust-analyzer/crates/paths/src/lib.rs
index 33c3f83db50..885f071889e 100644
--- a/src/tools/rust-analyzer/crates/paths/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/paths/src/lib.rs
@@ -1,8 +1,6 @@
 //! Thin wrappers around `std::path`/`camino::path`, distinguishing between absolute and
 //! relative paths.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{
     borrow::Borrow,
     ffi::OsStr,
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
index 11fd076a6f6..7f633d91ecc 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
@@ -15,7 +15,6 @@ doctest = false
 serde.workspace = true
 serde_json = { workspace = true, features = ["unbounded_depth"] }
 tracing.workspace = true
-triomphe.workspace = true
 rustc-hash.workspace = true
 indexmap.workspace = true
 
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/json.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/json.rs
new file mode 100644
index 00000000000..ec89f6a9e65
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/json.rs
@@ -0,0 +1,35 @@
+//! Protocol functions for json.
+use std::io::{self, BufRead, Write};
+
+pub fn read_json<'a>(
+    inp: &mut impl BufRead,
+    buf: &'a mut String,
+) -> io::Result<Option<&'a String>> {
+    loop {
+        buf.clear();
+
+        inp.read_line(buf)?;
+        buf.pop(); // Remove trailing '\n'
+
+        if buf.is_empty() {
+            return Ok(None);
+        }
+
+        // Some ill behaved macro try to use stdout for debugging
+        // We ignore it here
+        if !buf.starts_with('{') {
+            tracing::error!("proc-macro tried to print : {}", buf);
+            continue;
+        }
+
+        return Ok(Some(buf));
+    }
+}
+
+pub fn write_json(out: &mut impl Write, msg: &str) -> io::Result<()> {
+    tracing::debug!("> {}", msg);
+    out.write_all(msg.as_bytes())?;
+    out.write_all(b"\n")?;
+    out.flush()?;
+    Ok(())
+}
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
index 0de76689ab0..4c65dd5969c 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
@@ -5,27 +5,23 @@
 //! is used to provide basic infrastructure for communication between two
 //! processes: Client (RA itself), Server (the external program)
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
+pub mod json;
 pub mod msg;
 mod process;
 
 use base_db::Env;
-use indexmap::IndexSet;
 use paths::{AbsPath, AbsPathBuf};
-use rustc_hash::FxHashMap;
 use span::Span;
-use std::{
-    fmt, io,
-    sync::{Arc, Mutex},
-};
+use std::{fmt, io, sync::Arc};
+use tt::SmolStr;
 
 use serde::{Deserialize, Serialize};
 
 use crate::{
     msg::{
         deserialize_span_data_index_map, flat::serialize_span_data_index_map, ExpandMacro,
-        ExpnGlobals, FlatTree, PanicMessage, HAS_GLOBAL_SPANS, RUST_ANALYZER_SPAN_SUPPORT,
+        ExpnGlobals, FlatTree, PanicMessage, SpanDataIndexMap, HAS_GLOBAL_SPANS,
+        RUST_ANALYZER_SPAN_SUPPORT,
     },
     process::ProcMacroProcessSrv,
 };
@@ -48,9 +44,7 @@ pub struct ProcMacroServer {
     ///
     /// That means that concurrent salsa requests may block each other when expanding proc macros,
     /// which is unfortunate, but simple and good enough for the time being.
-    ///
-    /// Therefore, we just wrap the `ProcMacroProcessSrv` in a mutex here.
-    process: Arc<Mutex<ProcMacroProcessSrv>>,
+    process: Arc<ProcMacroProcessSrv>,
     path: AbsPathBuf,
 }
 
@@ -70,9 +64,9 @@ impl MacroDylib {
 /// we share a single expander process for all macros.
 #[derive(Debug, Clone)]
 pub struct ProcMacro {
-    process: Arc<Mutex<ProcMacroProcessSrv>>,
-    dylib_path: AbsPathBuf,
-    name: String,
+    process: Arc<ProcMacroProcessSrv>,
+    dylib_path: Arc<AbsPathBuf>,
+    name: SmolStr,
     kind: ProcMacroKind,
 }
 
@@ -81,7 +75,7 @@ impl PartialEq for ProcMacro {
     fn eq(&self, other: &Self) -> bool {
         self.name == other.name
             && self.kind == other.kind
-            && self.dylib_path == other.dylib_path
+            && Arc::ptr_eq(&self.dylib_path, &other.dylib_path)
             && Arc::ptr_eq(&self.process, &other.process)
     }
 }
@@ -89,7 +83,6 @@ impl PartialEq for ProcMacro {
 #[derive(Clone, Debug)]
 pub struct ServerError {
     pub message: String,
-    // io::Error isn't Clone for some reason
     pub io: Option<Arc<io::Error>>,
 }
 
@@ -104,21 +97,15 @@ impl fmt::Display for ServerError {
     }
 }
 
-pub struct MacroPanic {
-    pub message: String,
-}
-
 impl ProcMacroServer {
     /// Spawns an external process as the proc macro server and returns a client connected to it.
     pub fn spawn(
         process_path: &AbsPath,
-        env: &FxHashMap<String, String>,
+        env: impl IntoIterator<Item = (impl AsRef<std::ffi::OsStr>, impl AsRef<std::ffi::OsStr>)>
+            + Clone,
     ) -> io::Result<ProcMacroServer> {
         let process = ProcMacroProcessSrv::run(process_path, env)?;
-        Ok(ProcMacroServer {
-            process: Arc::new(Mutex::new(process)),
-            path: process_path.to_owned(),
-        })
+        Ok(ProcMacroServer { process: Arc::new(process), path: process_path.to_owned() })
     }
 
     pub fn path(&self) -> &AbsPath {
@@ -127,17 +114,17 @@ impl ProcMacroServer {
 
     pub fn load_dylib(&self, dylib: MacroDylib) -> Result<Vec<ProcMacro>, ServerError> {
         let _p = tracing::info_span!("ProcMacroServer::load_dylib").entered();
-        let macros =
-            self.process.lock().unwrap_or_else(|e| e.into_inner()).find_proc_macros(&dylib.path)?;
+        let macros = self.process.find_proc_macros(&dylib.path)?;
 
+        let dylib_path = Arc::new(dylib.path);
         match macros {
             Ok(macros) => Ok(macros
                 .into_iter()
                 .map(|(name, kind)| ProcMacro {
                     process: self.process.clone(),
-                    name,
+                    name: name.into(),
                     kind,
-                    dylib_path: dylib.path.clone(),
+                    dylib_path: dylib_path.clone(),
                 })
                 .collect()),
             Err(message) => Err(ServerError { message, io: None }),
@@ -163,38 +150,37 @@ impl ProcMacro {
         call_site: Span,
         mixed_site: Span,
     ) -> Result<Result<tt::Subtree<Span>, PanicMessage>, ServerError> {
-        let version = self.process.lock().unwrap_or_else(|e| e.into_inner()).version();
+        let version = self.process.version();
         let current_dir = env.get("CARGO_MANIFEST_DIR");
 
-        let mut span_data_table = IndexSet::default();
+        let mut span_data_table = SpanDataIndexMap::default();
         let def_site = span_data_table.insert_full(def_site).0;
         let call_site = span_data_table.insert_full(call_site).0;
         let mixed_site = span_data_table.insert_full(mixed_site).0;
         let task = ExpandMacro {
-            macro_body: FlatTree::new(subtree, version, &mut span_data_table),
-            macro_name: self.name.to_string(),
-            attributes: attr.map(|subtree| FlatTree::new(subtree, version, &mut span_data_table)),
+            data: msg::ExpandMacroData {
+                macro_body: FlatTree::new(subtree, version, &mut span_data_table),
+                macro_name: self.name.to_string(),
+                attributes: attr
+                    .map(|subtree| FlatTree::new(subtree, version, &mut span_data_table)),
+                has_global_spans: ExpnGlobals {
+                    serialize: version >= HAS_GLOBAL_SPANS,
+                    def_site,
+                    call_site,
+                    mixed_site,
+                },
+                span_data_table: if version >= RUST_ANALYZER_SPAN_SUPPORT {
+                    serialize_span_data_index_map(&span_data_table)
+                } else {
+                    Vec::new()
+                },
+            },
             lib: self.dylib_path.to_path_buf().into(),
             env: env.into(),
             current_dir,
-            has_global_spans: ExpnGlobals {
-                serialize: version >= HAS_GLOBAL_SPANS,
-                def_site,
-                call_site,
-                mixed_site,
-            },
-            span_data_table: if version >= RUST_ANALYZER_SPAN_SUPPORT {
-                serialize_span_data_index_map(&span_data_table)
-            } else {
-                Vec::new()
-            },
         };
 
-        let response = self
-            .process
-            .lock()
-            .unwrap_or_else(|e| e.into_inner())
-            .send_task(msg::Request::ExpandMacro(Box::new(task)))?;
+        let response = self.process.send_task(msg::Request::ExpandMacro(Box::new(task)))?;
 
         match response {
             msg::Response::ExpandMacro(it) => {
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
index ad0e1f187b6..fa3ba9bbfcd 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg.rs
@@ -72,6 +72,16 @@ pub struct PanicMessage(pub String);
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct ExpandMacro {
+    pub lib: Utf8PathBuf,
+    /// Environment variables to set during macro expansion.
+    pub env: Vec<(String, String)>,
+    pub current_dir: Option<String>,
+    #[serde(flatten)]
+    pub data: ExpandMacroData,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct ExpandMacroData {
     /// Argument of macro call.
     ///
     /// In custom derive this will be a struct or enum; in attribute-like macro - underlying
@@ -86,13 +96,6 @@ pub struct ExpandMacro {
 
     /// Possible attributes for the attribute-like macros.
     pub attributes: Option<FlatTree>,
-
-    pub lib: Utf8PathBuf,
-
-    /// Environment variables to set during macro expansion.
-    pub env: Vec<(String, String)>,
-
-    pub current_dir: Option<String>,
     /// marker for serde skip stuff
     #[serde(skip_serializing_if = "ExpnGlobals::skip_serializing_if")]
     #[serde(default)]
@@ -119,8 +122,12 @@ impl ExpnGlobals {
 }
 
 pub trait Message: Serialize + DeserializeOwned {
-    fn read(inp: &mut impl BufRead, buf: &mut String) -> io::Result<Option<Self>> {
-        Ok(match read_json(inp, buf)? {
+    fn read<R: BufRead>(
+        from_proto: ProtocolRead<R>,
+        inp: &mut R,
+        buf: &mut String,
+    ) -> io::Result<Option<Self>> {
+        Ok(match from_proto(inp, buf)? {
             None => None,
             Some(text) => {
                 let mut deserializer = serde_json::Deserializer::from_str(text);
@@ -131,44 +138,20 @@ pub trait Message: Serialize + DeserializeOwned {
             }
         })
     }
-    fn write(self, out: &mut impl Write) -> io::Result<()> {
+    fn write<W: Write>(self, to_proto: ProtocolWrite<W>, out: &mut W) -> io::Result<()> {
         let text = serde_json::to_string(&self)?;
-        write_json(out, &text)
+        to_proto(out, &text)
     }
 }
 
 impl Message for Request {}
 impl Message for Response {}
 
-fn read_json<'a>(inp: &mut impl BufRead, buf: &'a mut String) -> io::Result<Option<&'a String>> {
-    loop {
-        buf.clear();
-
-        inp.read_line(buf)?;
-        buf.pop(); // Remove trailing '\n'
-
-        if buf.is_empty() {
-            return Ok(None);
-        }
-
-        // Some ill behaved macro try to use stdout for debugging
-        // We ignore it here
-        if !buf.starts_with('{') {
-            tracing::error!("proc-macro tried to print : {}", buf);
-            continue;
-        }
-
-        return Ok(Some(buf));
-    }
-}
-
-fn write_json(out: &mut impl Write, msg: &str) -> io::Result<()> {
-    tracing::debug!("> {}", msg);
-    out.write_all(msg.as_bytes())?;
-    out.write_all(b"\n")?;
-    out.flush()?;
-    Ok(())
-}
+#[allow(type_alias_bounds)]
+type ProtocolRead<R: BufRead> =
+    for<'i, 'buf> fn(inp: &'i mut R, buf: &'buf mut String) -> io::Result<Option<&'buf String>>;
+#[allow(type_alias_bounds)]
+type ProtocolWrite<W: Write> = for<'o, 'msg> fn(out: &'o mut W, msg: &'msg str) -> io::Result<()>;
 
 #[cfg(test)]
 mod tests {
@@ -268,25 +251,30 @@ mod tests {
         let tt = fixture_token_tree();
         let mut span_data_table = Default::default();
         let task = ExpandMacro {
-            macro_body: FlatTree::new(&tt, CURRENT_API_VERSION, &mut span_data_table),
-            macro_name: Default::default(),
-            attributes: None,
+            data: ExpandMacroData {
+                macro_body: FlatTree::new(&tt, CURRENT_API_VERSION, &mut span_data_table),
+                macro_name: Default::default(),
+                attributes: None,
+                has_global_spans: ExpnGlobals {
+                    serialize: true,
+                    def_site: 0,
+                    call_site: 0,
+                    mixed_site: 0,
+                },
+                span_data_table: Vec::new(),
+            },
             lib: Utf8PathBuf::from_path_buf(std::env::current_dir().unwrap()).unwrap(),
             env: Default::default(),
             current_dir: Default::default(),
-            has_global_spans: ExpnGlobals {
-                serialize: true,
-                def_site: 0,
-                call_site: 0,
-                mixed_site: 0,
-            },
-            span_data_table: Vec::new(),
         };
 
         let json = serde_json::to_string(&task).unwrap();
         // println!("{}", json);
         let back: ExpandMacro = serde_json::from_str(&json).unwrap();
 
-        assert_eq!(tt, back.macro_body.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table));
+        assert_eq!(
+            tt,
+            back.data.macro_body.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table)
+        );
     }
 }
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
index 99cdbd930e1..11fd7596f2b 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/msg/flat.rs
@@ -37,7 +37,6 @@
 
 use std::collections::VecDeque;
 
-use indexmap::IndexSet;
 use la_arena::RawIdx;
 use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
@@ -46,7 +45,8 @@ use text_size::TextRange;
 
 use crate::msg::ENCODE_CLOSE_SPAN_VERSION;
 
-pub type SpanDataIndexMap = IndexSet<Span>;
+pub type SpanDataIndexMap =
+    indexmap::IndexSet<Span, std::hash::BuildHasherDefault<rustc_hash::FxHasher>>;
 
 pub fn serialize_span_data_index_map(map: &SpanDataIndexMap) -> Vec<u32> {
     map.iter()
@@ -328,7 +328,7 @@ impl InternableSpan for TokenId {
     }
 }
 impl InternableSpan for Span {
-    type Table = IndexSet<Span>;
+    type Table = SpanDataIndexMap;
     fn token_id_of(table: &mut Self::Table, span: Self) -> TokenId {
         TokenId(table.insert_full(span).0 as u32)
     }
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/process.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/process.rs
index 718a96dc80f..2b1a791827a 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/process.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/process.rs
@@ -3,43 +3,48 @@
 use std::{
     io::{self, BufRead, BufReader, Read, Write},
     process::{Child, ChildStdin, ChildStdout, Command, Stdio},
-    sync::Arc,
+    sync::{Arc, Mutex},
 };
 
 use paths::AbsPath;
-use rustc_hash::FxHashMap;
 use stdx::JodChild;
 
 use crate::{
+    json::{read_json, write_json},
     msg::{Message, Request, Response, SpanMode, CURRENT_API_VERSION, RUST_ANALYZER_SPAN_SUPPORT},
     ProcMacroKind, ServerError,
 };
 
 #[derive(Debug)]
 pub(crate) struct ProcMacroProcessSrv {
+    /// The state of the proc-macro server process, the protocol is currently strictly sequential
+    /// hence the lock on the state.
+    state: Mutex<ProcessSrvState>,
+    version: u32,
+    mode: SpanMode,
+}
+
+#[derive(Debug)]
+struct ProcessSrvState {
     process: Process,
     stdin: ChildStdin,
     stdout: BufReader<ChildStdout>,
     /// Populated when the server exits.
     server_exited: Option<ServerError>,
-    version: u32,
-    mode: SpanMode,
 }
 
 impl ProcMacroProcessSrv {
     pub(crate) fn run(
         process_path: &AbsPath,
-        env: &FxHashMap<String, String>,
+        env: impl IntoIterator<Item = (impl AsRef<std::ffi::OsStr>, impl AsRef<std::ffi::OsStr>)>
+            + Clone,
     ) -> io::Result<ProcMacroProcessSrv> {
         let create_srv = |null_stderr| {
-            let mut process = Process::run(process_path, env, null_stderr)?;
+            let mut process = Process::run(process_path, env.clone(), null_stderr)?;
             let (stdin, stdout) = process.stdio().expect("couldn't access child stdio");
 
             io::Result::Ok(ProcMacroProcessSrv {
-                process,
-                stdin,
-                stdout,
-                server_exited: None,
+                state: Mutex::new(ProcessSrvState { process, stdin, stdout, server_exited: None }),
                 version: 0,
                 mode: SpanMode::Id,
             })
@@ -76,7 +81,7 @@ impl ProcMacroProcessSrv {
         self.version
     }
 
-    pub(crate) fn version_check(&mut self) -> Result<u32, ServerError> {
+    fn version_check(&self) -> Result<u32, ServerError> {
         let request = Request::ApiVersionCheck {};
         let response = self.send_task(request)?;
 
@@ -86,7 +91,7 @@ impl ProcMacroProcessSrv {
         }
     }
 
-    fn enable_rust_analyzer_spans(&mut self) -> Result<SpanMode, ServerError> {
+    fn enable_rust_analyzer_spans(&self) -> Result<SpanMode, ServerError> {
         let request = Request::SetConfig(crate::msg::ServerConfig {
             span_mode: crate::msg::SpanMode::RustAnalyzer,
         });
@@ -99,7 +104,7 @@ impl ProcMacroProcessSrv {
     }
 
     pub(crate) fn find_proc_macros(
-        &mut self,
+        &self,
         dylib_path: &AbsPath,
     ) -> Result<Result<Vec<(String, ProcMacroKind)>, String>, ServerError> {
         let request = Request::ListMacros { dylib_path: dylib_path.to_path_buf().into() };
@@ -112,20 +117,21 @@ impl ProcMacroProcessSrv {
         }
     }
 
-    pub(crate) fn send_task(&mut self, req: Request) -> Result<Response, ServerError> {
-        if let Some(server_error) = &self.server_exited {
+    pub(crate) fn send_task(&self, req: Request) -> Result<Response, ServerError> {
+        let state = &mut *self.state.lock().unwrap();
+        if let Some(server_error) = &state.server_exited {
             return Err(server_error.clone());
         }
 
         let mut buf = String::new();
-        send_request(&mut self.stdin, &mut self.stdout, req, &mut buf).map_err(|e| {
+        send_request(&mut state.stdin, &mut state.stdout, req, &mut buf).map_err(|e| {
             if e.io.as_ref().map(|it| it.kind()) == Some(io::ErrorKind::BrokenPipe) {
-                match self.process.child.try_wait() {
+                match state.process.child.try_wait() {
                     Ok(None) => e,
                     Ok(Some(status)) => {
                         let mut msg = String::new();
                         if !status.success() {
-                            if let Some(stderr) = self.process.child.stderr.as_mut() {
+                            if let Some(stderr) = state.process.child.stderr.as_mut() {
                                 _ = stderr.read_to_string(&mut msg);
                             }
                         }
@@ -133,7 +139,7 @@ impl ProcMacroProcessSrv {
                             message: format!("server exited with {status}: {msg}"),
                             io: None,
                         };
-                        self.server_exited = Some(server_error.clone());
+                        state.server_exited = Some(server_error.clone());
                         server_error
                     }
                     Err(_) => e,
@@ -153,7 +159,7 @@ struct Process {
 impl Process {
     fn run(
         path: &AbsPath,
-        env: &FxHashMap<String, String>,
+        env: impl IntoIterator<Item = (impl AsRef<std::ffi::OsStr>, impl AsRef<std::ffi::OsStr>)>,
         null_stderr: bool,
     ) -> io::Result<Process> {
         let child = JodChild(mk_child(path, env, null_stderr)?);
@@ -171,7 +177,7 @@ impl Process {
 
 fn mk_child(
     path: &AbsPath,
-    env: &FxHashMap<String, String>,
+    env: impl IntoIterator<Item = (impl AsRef<std::ffi::OsStr>, impl AsRef<std::ffi::OsStr>)>,
     null_stderr: bool,
 ) -> io::Result<Child> {
     let mut cmd = Command::new(path);
@@ -196,11 +202,11 @@ fn send_request(
     req: Request,
     buf: &mut String,
 ) -> Result<Response, ServerError> {
-    req.write(&mut writer).map_err(|err| ServerError {
+    req.write(write_json, &mut writer).map_err(|err| ServerError {
         message: "failed to write request".into(),
         io: Some(Arc::new(err)),
     })?;
-    let res = Response::read(&mut reader, buf).map_err(|err| ServerError {
+    let res = Response::read(read_json, &mut reader, buf).map_err(|err| ServerError {
         message: "failed to read response".into(),
         io: Some(Arc::new(err)),
     })?;
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv-cli/src/main.rs b/src/tools/rust-analyzer/crates/proc-macro-srv-cli/src/main.rs
index df0ae3171f5..174f9c52462 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv-cli/src/main.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv-cli/src/main.rs
@@ -6,6 +6,8 @@
 #[cfg(feature = "in-rust-tree")]
 extern crate rustc_driver as _;
 
+use proc_macro_api::json::{read_json, write_json};
+
 use std::io;
 
 fn main() -> std::io::Result<()> {
@@ -26,19 +28,49 @@ fn main() -> std::io::Result<()> {
 
 #[cfg(not(any(feature = "sysroot-abi", rust_analyzer)))]
 fn run() -> io::Result<()> {
-    eprintln!("proc-macro-srv-cli requires the `sysroot-abi` feature to be enabled");
-    std::process::exit(70);
+    let err = "proc-macro-srv-cli needs to be compiled with the `sysroot-abi` feature to function";
+    eprintln!("{err}");
+    use proc_macro_api::msg::{self, Message};
+
+    let read_request =
+        |buf: &mut String| msg::Request::read(read_json, &mut io::stdin().lock(), buf);
+
+    let write_response = |msg: msg::Response| msg.write(write_json, &mut io::stdout().lock());
+
+    let mut buf = String::new();
+
+    while let Some(req) = read_request(&mut buf)? {
+        let res = match req {
+            msg::Request::ListMacros { .. } => msg::Response::ListMacros(Err(err.to_owned())),
+            msg::Request::ExpandMacro(_) => {
+                msg::Response::ExpandMacro(Err(msg::PanicMessage(err.to_owned())))
+            }
+            msg::Request::ApiVersionCheck {} => {
+                msg::Response::ApiVersionCheck(proc_macro_api::msg::CURRENT_API_VERSION)
+            }
+            msg::Request::SetConfig(_) => {
+                msg::Response::SetConfig(proc_macro_api::msg::ServerConfig {
+                    span_mode: msg::SpanMode::Id,
+                })
+            }
+        };
+        write_response(res)?
+    }
+    Ok(())
 }
 
 #[cfg(any(feature = "sysroot-abi", rust_analyzer))]
 fn run() -> io::Result<()> {
     use proc_macro_api::msg::{self, Message};
+    use proc_macro_srv::EnvSnapshot;
 
-    let read_request = |buf: &mut String| msg::Request::read(&mut io::stdin().lock(), buf);
+    let read_request =
+        |buf: &mut String| msg::Request::read(read_json, &mut io::stdin().lock(), buf);
 
-    let write_response = |msg: msg::Response| msg.write(&mut io::stdout().lock());
+    let write_response = |msg: msg::Response| msg.write(write_json, &mut io::stdout().lock());
 
-    let mut srv = proc_macro_srv::ProcMacroSrv::default();
+    let env = EnvSnapshot::new();
+    let mut srv = proc_macro_srv::ProcMacroSrv::new(&env);
     let mut buf = String::new();
 
     while let Some(req) = read_request(&mut buf)? {
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/build.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/build.rs
index 874d1c6cd38..9a17cfc9f36 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/build.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/build.rs
@@ -1,27 +1,15 @@
 //! Determine rustc version `proc-macro-srv` (and thus the sysroot ABI) is
 //! build with and make it accessible at runtime for ABI selection.
 
-use std::{env, fs::File, io::Write, path::PathBuf, process::Command};
+use std::{env, process::Command};
 
 fn main() {
-    println!("cargo:rustc-check-cfg=cfg(rust_analyzer)");
-
-    let mut path = PathBuf::from(env::var_os("OUT_DIR").unwrap());
-    path.push("rustc_version.rs");
-    let mut f = File::create(&path).unwrap();
+    println!("cargo::rustc-check-cfg=cfg(rust_analyzer)");
 
     let rustc = env::var("RUSTC").expect("proc-macro-srv's build script expects RUSTC to be set");
     let output = Command::new(rustc).arg("--version").output().expect("rustc --version must run");
     let version_string = std::str::from_utf8(&output.stdout[..])
         .expect("rustc --version output must be UTF-8")
         .trim();
-
-    write!(
-        f,
-        "
-    #[allow(dead_code)]
-    pub(crate) const RUSTC_VERSION_STRING: &str = {version_string:?};
-    "
-    )
-    .unwrap();
+    println!("cargo::rustc-env=RUSTC_VERSION={}", version_string);
 }
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/build.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/build.rs
index 6a0ae362d88..ff2f5d18639 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/build.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/build.rs
@@ -8,7 +8,7 @@
 //! 1.58) and future ABIs (stage1, nightly)
 
 use std::{
-    env, fs,
+    env,
     path::{Path, PathBuf},
     process::Command,
 };
@@ -30,8 +30,7 @@ fn main() {
 
     if !has_features {
         println!("proc-macro-test testing only works on nightly toolchains");
-        let info_path = out_dir.join("proc_macro_test_location.txt");
-        fs::File::create(info_path).unwrap();
+        println!("cargo::rustc-env=PROC_MACRO_TEST_LOCATION=\"\"");
         return;
     }
 
@@ -121,6 +120,5 @@ fn main() {
     // This file is under `target_dir` and is already under `OUT_DIR`.
     let artifact_path = artifact_path.expect("no dylib for proc-macro-test-impl found");
 
-    let info_path = out_dir.join("proc_macro_test_location.txt");
-    fs::write(info_path, artifact_path.to_str().unwrap()).unwrap();
+    println!("cargo::rustc-env=PROC_MACRO_TEST_LOCATION={}", artifact_path.display());
 }
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/imp/src/lib.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/imp/src/lib.rs
index 5f8530d08c4..a1707364f3c 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/imp/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/imp/src/lib.rs
@@ -1,6 +1,6 @@
 //! Exports a few trivial procedural macros for testing.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
+
 #![feature(proc_macro_span, proc_macro_def_site)]
 #![allow(clippy::all)]
 
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/src/lib.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/src/lib.rs
index 739c6ec6f44..6464adb2ca7 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/proc-macro-test/src/lib.rs
@@ -1,6 +1,3 @@
 //! Exports a few trivial procedural macros for testing.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
-pub static PROC_MACRO_TEST_LOCATION: &str =
-    include_str!(concat!(env!("OUT_DIR"), "/proc_macro_test_location.txt"));
+pub static PROC_MACRO_TEST_LOCATION: &str = env!("PROC_MACRO_TEST_LOCATION");
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/dylib.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/dylib.rs
index 474f00a574f..78ae4574c40 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/dylib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/dylib.rs
@@ -2,13 +2,13 @@
 
 mod version;
 
+use proc_macro::bridge;
 use std::{fmt, fs::File, io};
 
 use libloading::Library;
 use memmap2::Mmap;
 use object::Object;
 use paths::{AbsPath, Utf8Path, Utf8PathBuf};
-use proc_macro::bridge;
 use proc_macro_api::ProcMacroKind;
 
 use crate::ProcMacroSrvSpan;
@@ -133,24 +133,33 @@ impl ProcMacroLibraryLibloading {
     }
 }
 
-pub struct Expander {
+pub(crate) struct Expander {
     inner: ProcMacroLibraryLibloading,
+    path: Utf8PathBuf,
+}
+
+impl Drop for Expander {
+    fn drop(&mut self) {
+        #[cfg(windows)]
+        std::fs::remove_file(&self.path).ok();
+        _ = self.path;
+    }
 }
 
 impl Expander {
-    pub fn new(lib: &Utf8Path) -> Result<Expander, LoadProcMacroDylibError> {
+    pub(crate) fn new(lib: &Utf8Path) -> Result<Expander, LoadProcMacroDylibError> {
         // Some libraries for dynamic loading require canonicalized path even when it is
         // already absolute
         let lib = lib.canonicalize_utf8()?;
 
-        let lib = ensure_file_with_lock_free_access(&lib)?;
+        let path = ensure_file_with_lock_free_access(&lib)?;
 
-        let library = ProcMacroLibraryLibloading::open(lib.as_ref())?;
+        let library = ProcMacroLibraryLibloading::open(path.as_ref())?;
 
-        Ok(Expander { inner: library })
+        Ok(Expander { inner: library, path })
     }
 
-    pub fn expand<S: ProcMacroSrvSpan>(
+    pub(crate) fn expand<S: ProcMacroSrvSpan>(
         &self,
         macro_name: &str,
         macro_body: tt::Subtree<S>,
@@ -169,7 +178,7 @@ impl Expander {
         result.map_err(|e| e.into_string().unwrap_or_default())
     }
 
-    pub fn list_macros(&self) -> Vec<(String, ProcMacroKind)> {
+    pub(crate) fn list_macros(&self) -> Vec<(String, ProcMacroKind)> {
         self.inner.proc_macros.list_macros()
     }
 }
@@ -198,7 +207,7 @@ fn ensure_file_with_lock_free_access(path: &Utf8Path) -> io::Result<Utf8PathBuf>
     unique_name.push_str(file_name);
 
     to.push(unique_name);
-    std::fs::copy(path, &to).unwrap();
+    std::fs::copy(path, &to)?;
     Ok(to)
 }
 
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/lib.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/lib.rs
index 2472c1e3119..34851ee0bee 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/lib.rs
@@ -13,7 +13,6 @@
 #![cfg(any(feature = "sysroot-abi", rust_analyzer))]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![feature(proc_macro_internals, proc_macro_diagnostic, proc_macro_span)]
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(unreachable_pub, internal_features)]
 
 extern crate proc_macro;
@@ -27,13 +26,15 @@ extern crate rustc_lexer;
 
 mod dylib;
 mod proc_macros;
-mod server;
+mod server_impl;
 
 use std::{
     collections::{hash_map::Entry, HashMap},
     env,
     ffi::OsString,
-    fs, thread,
+    fs,
+    path::{Path, PathBuf},
+    thread,
     time::SystemTime,
 };
 
@@ -47,46 +48,25 @@ use proc_macro_api::{
 };
 use span::Span;
 
-use crate::server::TokenStream;
+use crate::server_impl::TokenStream;
 
-// see `build.rs`
-include!(concat!(env!("OUT_DIR"), "/rustc_version.rs"));
+pub const RUSTC_VERSION_STRING: &str = env!("RUSTC_VERSION");
 
-trait ProcMacroSrvSpan: Copy {
-    type Server: proc_macro::bridge::server::Server<TokenStream = TokenStream<Self>>;
-    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server;
+pub struct ProcMacroSrv<'env> {
+    expanders: HashMap<(Utf8PathBuf, SystemTime), dylib::Expander>,
+    span_mode: SpanMode,
+    env: &'env EnvSnapshot,
 }
 
-impl ProcMacroSrvSpan for TokenId {
-    type Server = server::token_id::TokenIdServer;
-
-    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server {
-        Self::Server { interner: &server::SYMBOL_INTERNER, call_site, def_site, mixed_site }
+impl<'env> ProcMacroSrv<'env> {
+    pub fn new(env: &'env EnvSnapshot) -> Self {
+        Self { expanders: Default::default(), span_mode: Default::default(), env }
     }
 }
-impl ProcMacroSrvSpan for Span {
-    type Server = server::rust_analyzer_span::RaSpanServer;
-    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server {
-        Self::Server {
-            interner: &server::SYMBOL_INTERNER,
-            call_site,
-            def_site,
-            mixed_site,
-            tracked_env_vars: Default::default(),
-            tracked_paths: Default::default(),
-        }
-    }
-}
-
-#[derive(Default)]
-pub struct ProcMacroSrv {
-    expanders: HashMap<(Utf8PathBuf, SystemTime), dylib::Expander>,
-    span_mode: SpanMode,
-}
 
 const EXPANDER_STACK_SIZE: usize = 8 * 1024 * 1024;
 
-impl ProcMacroSrv {
+impl<'env> ProcMacroSrv<'env> {
     pub fn set_span_mode(&mut self, span_mode: SpanMode) {
         self.span_mode = span_mode;
     }
@@ -97,52 +77,24 @@ impl ProcMacroSrv {
 
     pub fn expand(
         &mut self,
-        task: msg::ExpandMacro,
+        msg::ExpandMacro { lib, env, current_dir, data }: msg::ExpandMacro,
     ) -> Result<(msg::FlatTree, Vec<u32>), msg::PanicMessage> {
         let span_mode = self.span_mode;
-        let expander = self.expander(task.lib.as_ref()).map_err(|err| {
+        let snapped_env = self.env;
+        let expander = self.expander(lib.as_ref()).map_err(|err| {
             debug_assert!(false, "should list macros before asking to expand");
             msg::PanicMessage(format!("failed to load macro: {err}"))
         })?;
 
-        let prev_env = EnvSnapshot::new();
-        for (k, v) in &task.env {
-            env::set_var(k, v);
-        }
-        let prev_working_dir = match &task.current_dir {
-            Some(dir) => {
-                let prev_working_dir = std::env::current_dir().ok();
-                if let Err(err) = std::env::set_current_dir(dir) {
-                    eprintln!("Failed to set the current working dir to {dir}. Error: {err:?}")
-                }
-                prev_working_dir
-            }
-            None => None,
-        };
-
-        let ExpnGlobals { def_site, call_site, mixed_site, .. } = task.has_global_spans;
+        let prev_env = EnvChange::apply(snapped_env, env, current_dir.as_ref().map(<_>::as_ref));
 
         let result = match span_mode {
-            SpanMode::Id => {
-                expand_id(task, expander, def_site, call_site, mixed_site).map(|it| (it, vec![]))
-            }
-            SpanMode::RustAnalyzer => {
-                expand_ra_span(task, expander, def_site, call_site, mixed_site)
-            }
+            SpanMode::Id => expand_id(data, expander).map(|it| (it, vec![])),
+            SpanMode::RustAnalyzer => expand_ra_span(data, expander),
         };
 
         prev_env.rollback();
 
-        if let Some(dir) = prev_working_dir {
-            if let Err(err) = std::env::set_current_dir(&dir) {
-                eprintln!(
-                    "Failed to set the current working dir to {}. Error: {:?}",
-                    dir.display(),
-                    err
-                )
-            }
-        }
-
         result.map_err(msg::PanicMessage)
     }
 
@@ -169,33 +121,55 @@ impl ProcMacroSrv {
     }
 }
 
+trait ProcMacroSrvSpan: Copy {
+    type Server: proc_macro::bridge::server::Server<TokenStream = TokenStream<Self>>;
+    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server;
+}
+
+impl ProcMacroSrvSpan for TokenId {
+    type Server = server_impl::token_id::TokenIdServer;
+
+    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server {
+        Self::Server { interner: &server_impl::SYMBOL_INTERNER, call_site, def_site, mixed_site }
+    }
+}
+impl ProcMacroSrvSpan for Span {
+    type Server = server_impl::rust_analyzer_span::RaSpanServer;
+    fn make_server(call_site: Self, def_site: Self, mixed_site: Self) -> Self::Server {
+        Self::Server {
+            interner: &server_impl::SYMBOL_INTERNER,
+            call_site,
+            def_site,
+            mixed_site,
+            tracked_env_vars: Default::default(),
+            tracked_paths: Default::default(),
+        }
+    }
+}
+
 fn expand_id(
-    task: msg::ExpandMacro,
+    msg::ExpandMacroData {
+        macro_body,
+        macro_name,
+        attributes,
+        has_global_spans: ExpnGlobals { serialize: _, def_site, call_site, mixed_site },
+        span_data_table: _,
+    }: msg::ExpandMacroData,
     expander: &dylib::Expander,
-    def_site: usize,
-    call_site: usize,
-    mixed_site: usize,
 ) -> Result<msg::FlatTree, String> {
     let def_site = TokenId(def_site as u32);
     let call_site = TokenId(call_site as u32);
     let mixed_site = TokenId(mixed_site as u32);
 
-    let macro_body = task.macro_body.to_subtree_unresolved(CURRENT_API_VERSION);
-    let attributes = task.attributes.map(|it| it.to_subtree_unresolved(CURRENT_API_VERSION));
+    let macro_body = macro_body.to_subtree_unresolved(CURRENT_API_VERSION);
+    let attributes = attributes.map(|it| it.to_subtree_unresolved(CURRENT_API_VERSION));
     let result = thread::scope(|s| {
         let thread = thread::Builder::new()
             .stack_size(EXPANDER_STACK_SIZE)
-            .name(task.macro_name.clone())
+            .name(macro_name.clone())
             .spawn_scoped(s, || {
                 expander
-                    .expand(
-                        &task.macro_name,
-                        macro_body,
-                        attributes,
-                        def_site,
-                        call_site,
-                        mixed_site,
-                    )
+                    .expand(&macro_name, macro_body, attributes, def_site, call_site, mixed_site)
                     .map(|it| msg::FlatTree::new_raw(&it, CURRENT_API_VERSION))
             });
         let res = match thread {
@@ -212,35 +186,31 @@ fn expand_id(
 }
 
 fn expand_ra_span(
-    task: msg::ExpandMacro,
+    msg::ExpandMacroData {
+        macro_body,
+        macro_name,
+        attributes,
+        has_global_spans: ExpnGlobals { serialize: _, def_site, call_site, mixed_site },
+        span_data_table,
+    }: msg::ExpandMacroData,
     expander: &dylib::Expander,
-    def_site: usize,
-    call_site: usize,
-    mixed_site: usize,
 ) -> Result<(msg::FlatTree, Vec<u32>), String> {
-    let mut span_data_table = deserialize_span_data_index_map(&task.span_data_table);
+    let mut span_data_table = deserialize_span_data_index_map(&span_data_table);
 
     let def_site = span_data_table[def_site];
     let call_site = span_data_table[call_site];
     let mixed_site = span_data_table[mixed_site];
 
-    let macro_body = task.macro_body.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table);
+    let macro_body = macro_body.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table);
     let attributes =
-        task.attributes.map(|it| it.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table));
+        attributes.map(|it| it.to_subtree_resolved(CURRENT_API_VERSION, &span_data_table));
     let result = thread::scope(|s| {
         let thread = thread::Builder::new()
             .stack_size(EXPANDER_STACK_SIZE)
-            .name(task.macro_name.clone())
+            .name(macro_name.clone())
             .spawn_scoped(s, || {
                 expander
-                    .expand(
-                        &task.macro_name,
-                        macro_body,
-                        attributes,
-                        def_site,
-                        call_site,
-                        mixed_site,
-                    )
+                    .expand(&macro_name, macro_body, attributes, def_site, call_site, mixed_site)
                     .map(|it| {
                         (
                             msg::FlatTree::new(&it, CURRENT_API_VERSION, &mut span_data_table),
@@ -271,31 +241,74 @@ impl PanicMessage {
     }
 }
 
-struct EnvSnapshot {
+pub struct EnvSnapshot {
     vars: HashMap<OsString, OsString>,
 }
 
 impl EnvSnapshot {
-    fn new() -> EnvSnapshot {
+    pub fn new() -> EnvSnapshot {
         EnvSnapshot { vars: env::vars_os().collect() }
     }
+}
+
+struct EnvChange<'snap> {
+    changed_vars: Vec<String>,
+    prev_working_dir: Option<PathBuf>,
+    snap: &'snap EnvSnapshot,
+}
+
+impl<'snap> EnvChange<'snap> {
+    fn apply(
+        snap: &'snap EnvSnapshot,
+        new_vars: Vec<(String, String)>,
+        current_dir: Option<&Path>,
+    ) -> EnvChange<'snap> {
+        let prev_working_dir = match current_dir {
+            Some(dir) => {
+                let prev_working_dir = std::env::current_dir().ok();
+                if let Err(err) = std::env::set_current_dir(dir) {
+                    eprintln!(
+                        "Failed to set the current working dir to {}. Error: {err:?}",
+                        dir.display()
+                    )
+                }
+                prev_working_dir
+            }
+            None => None,
+        };
+        EnvChange {
+            snap,
+            changed_vars: new_vars
+                .into_iter()
+                .map(|(k, v)| {
+                    env::set_var(&k, v);
+                    k
+                })
+                .collect(),
+            prev_working_dir,
+        }
+    }
 
     fn rollback(self) {}
 }
 
-impl Drop for EnvSnapshot {
+impl Drop for EnvChange<'_> {
     fn drop(&mut self) {
-        for (name, value) in env::vars_os() {
-            let old_value = self.vars.remove(&name);
-            if old_value != Some(value) {
-                match old_value {
-                    None => env::remove_var(name),
-                    Some(old_value) => env::set_var(name, old_value),
-                }
+        for name in self.changed_vars.drain(..) {
+            match self.snap.vars.get::<std::ffi::OsStr>(name.as_ref()) {
+                Some(prev_val) => env::set_var(name, prev_val),
+                None => env::remove_var(name),
             }
         }
-        for (name, old_value) in self.vars.drain() {
-            env::set_var(name, old_value)
+
+        if let Some(dir) = &self.prev_working_dir {
+            if let Err(err) = std::env::set_current_dir(&dir) {
+                eprintln!(
+                    "Failed to set the current working dir to {}. Error: {:?}",
+                    dir.display(),
+                    err
+                )
+            }
         }
     }
 }
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/proc_macros.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/proc_macros.rs
index b963a8a029f..d48c5b30dee 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/proc_macros.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/proc_macros.rs
@@ -1,9 +1,10 @@
 //! Proc macro ABI
 
-use libloading::Library;
 use proc_macro::bridge;
 use proc_macro_api::ProcMacroKind;
 
+use libloading::Library;
+
 use crate::{dylib::LoadProcMacroDylibError, ProcMacroSrvSpan};
 
 pub(crate) struct ProcMacros {
@@ -49,11 +50,12 @@ impl ProcMacros {
         call_site: S,
         mixed_site: S,
     ) -> Result<tt::Subtree<S>, crate::PanicMessage> {
-        let parsed_body = crate::server::TokenStream::with_subtree(macro_body);
+        let parsed_body = crate::server_impl::TokenStream::with_subtree(macro_body);
 
-        let parsed_attributes = attributes.map_or_else(crate::server::TokenStream::new, |attr| {
-            crate::server::TokenStream::with_subtree(attr)
-        });
+        let parsed_attributes = attributes
+            .map_or_else(crate::server_impl::TokenStream::new, |attr| {
+                crate::server_impl::TokenStream::with_subtree(attr)
+            });
 
         for proc_macro in &self.exported_macros {
             match proc_macro {
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl.rs
index e8b340a43d3..e8b340a43d3 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl.rs
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/rust_analyzer_span.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/rust_analyzer_span.rs
index 0350bde4122..bb174ba1b22 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/rust_analyzer_span.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/rust_analyzer_span.rs
@@ -14,7 +14,7 @@ use proc_macro::bridge::{self, server};
 use span::{Span, FIXUP_ERASED_FILE_AST_ID_MARKER};
 use tt::{TextRange, TextSize};
 
-use crate::server::{
+use crate::server_impl::{
     delim_to_external, delim_to_internal, literal_with_stringify_parts,
     token_stream::TokenStreamBuilder, Symbol, SymbolInternerRef, SYMBOL_INTERNER,
 };
@@ -29,7 +29,7 @@ mod tt {
     pub type Ident = ::tt::Ident<super::Span>;
 }
 
-type TokenStream = crate::server::TokenStream<Span>;
+type TokenStream = crate::server_impl::TokenStream<Span>;
 
 #[derive(Clone)]
 pub struct SourceFile;
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/symbol.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/symbol.rs
index 540d06457f2..540d06457f2 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/symbol.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/symbol.rs
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/token_id.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/token_id.rs
index ad7bd954cf1..12edacbe39d 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/token_id.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/token_id.rs
@@ -7,7 +7,7 @@ use std::{
 
 use proc_macro::bridge::{self, server};
 
-use crate::server::{
+use crate::server_impl::{
     delim_to_external, delim_to_internal, literal_with_stringify_parts,
     token_stream::TokenStreamBuilder, Symbol, SymbolInternerRef, SYMBOL_INTERNER,
 };
@@ -31,7 +31,7 @@ type Spacing = tt::Spacing;
 #[allow(unused)]
 type Literal = tt::Literal;
 type Span = tt::TokenId;
-type TokenStream = crate::server::TokenStream<Span>;
+type TokenStream = crate::server_impl::TokenStream<Span>;
 
 #[derive(Clone)]
 pub struct SourceFile;
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/token_stream.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/token_stream.rs
index b1a448427c6..b1a448427c6 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/server/token_stream.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/server_impl/token_stream.rs
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/tests/utils.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/tests/utils.rs
index 6050bc9e36e..03b1117a5bd 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-srv/src/tests/utils.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/tests/utils.rs
@@ -5,10 +5,10 @@ use proc_macro_api::msg::TokenId;
 use span::{ErasedFileAstId, FileId, Span, SpanAnchor, SyntaxContextId};
 use tt::TextRange;
 
-use crate::{dylib, proc_macro_test_dylib_path, ProcMacroSrv};
+use crate::{dylib, proc_macro_test_dylib_path, EnvSnapshot, ProcMacroSrv};
 
-fn parse_string(call_site: TokenId, src: &str) -> crate::server::TokenStream<TokenId> {
-    crate::server::TokenStream::with_subtree(
+fn parse_string(call_site: TokenId, src: &str) -> crate::server_impl::TokenStream<TokenId> {
+    crate::server_impl::TokenStream::with_subtree(
         mbe::parse_to_token_tree_static_span(call_site, src).unwrap(),
     )
 }
@@ -17,8 +17,8 @@ fn parse_string_spanned(
     anchor: SpanAnchor,
     call_site: SyntaxContextId,
     src: &str,
-) -> crate::server::TokenStream<Span> {
-    crate::server::TokenStream::with_subtree(
+) -> crate::server_impl::TokenStream<Span> {
+    crate::server_impl::TokenStream::with_subtree(
         mbe::parse_to_token_tree(anchor, call_site, src).unwrap(),
     )
 }
@@ -96,7 +96,8 @@ fn assert_expand_impl(
 
 pub(crate) fn list() -> Vec<String> {
     let dylib_path = proc_macro_test_dylib_path();
-    let mut srv = ProcMacroSrv::default();
+    let env = EnvSnapshot::new();
+    let mut srv = ProcMacroSrv::new(&env);
     let res = srv.list_macros(&dylib_path).unwrap();
     res.into_iter().map(|(name, kind)| format!("{name} [{kind:?}]")).collect()
 }
diff --git a/src/tools/rust-analyzer/crates/profile/src/lib.rs b/src/tools/rust-analyzer/crates/profile/src/lib.rs
index 2ccb1cd06ae..c1ae0d43d07 100644
--- a/src/tools/rust-analyzer/crates/profile/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/profile/src/lib.rs
@@ -1,7 +1,5 @@
 //! A collection of tools for profiling rust-analyzer.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 #[cfg(feature = "cpu_profiler")]
 mod google_cpu_profiler;
 mod memory_usage;
diff --git a/src/tools/rust-analyzer/crates/project-model/src/lib.rs b/src/tools/rust-analyzer/crates/project-model/src/lib.rs
index 35643dcc028..92bf6a08f87 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/lib.rs
@@ -15,8 +15,6 @@
 //!   procedural macros).
 //! * Lowering of concrete model to a [`base_db::CrateGraph`]
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod build_scripts;
 mod cargo_workspace;
 mod cfg;
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/bin/main.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/bin/main.rs
index 774784f37b0..1985093bc5c 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/bin/main.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/bin/main.rs
@@ -2,7 +2,6 @@
 //!
 //! Based on cli flags, either spawns an LSP server, or runs a batch analysis
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(clippy::print_stdout, clippy::print_stderr)]
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
index a398e98f093..a8e6657c24c 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
@@ -9,8 +9,6 @@
 //! The `cli` submodule implements some batch-processing analysis, primarily as
 //! a debugging aid.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 pub mod cli;
 
 mod caps;
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
index bd0f733ef39..7b9a10fdb8c 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/reload.rs
@@ -529,7 +529,7 @@ impl GlobalState {
                     None => ws.find_sysroot_proc_macro_srv()?,
                 };
 
-                let env = match &ws.kind {
+                let env: FxHashMap<_, _> = match &ws.kind {
                     ProjectWorkspaceKind::Cargo { cargo_config_extra_env, .. }
                     | ProjectWorkspaceKind::DetachedFile {
                         cargo: Some(_),
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
index f886df60e68..51b3076b463 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
@@ -8,7 +8,6 @@
 //! specific JSON shapes here -- there's little value in such tests, as we can't
 //! be sure without a real client anyway.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(clippy::disallowed_types)]
 
 mod ratoml;
diff --git a/src/tools/rust-analyzer/crates/sourcegen/src/lib.rs b/src/tools/rust-analyzer/crates/sourcegen/src/lib.rs
index 829b4d5b0ff..307c214c61d 100644
--- a/src/tools/rust-analyzer/crates/sourcegen/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/sourcegen/src/lib.rs
@@ -6,8 +6,6 @@
 //!
 //! This crate contains utilities to make this kind of source-gen easy.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{
     fmt, fs, mem,
     path::{Path, PathBuf},
diff --git a/src/tools/rust-analyzer/crates/stdx/src/lib.rs b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
index 54f10df42a8..76dbd42ff6b 100644
--- a/src/tools/rust-analyzer/crates/stdx/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
@@ -1,7 +1,5 @@
 //! Missing batteries for standard libraries.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::io as sio;
 use std::process::Command;
 use std::{cmp::Ordering, ops, time::Instant};
diff --git a/src/tools/rust-analyzer/crates/syntax/src/lib.rs b/src/tools/rust-analyzer/crates/syntax/src/lib.rs
index b5d816b0ce1..177f48b986a 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/lib.rs
@@ -20,7 +20,6 @@
 //! [Swift]: <https://github.com/apple/swift/blob/13d593df6f359d0cb2fc81cfaac273297c539455/lib/Syntax/README.md>
 
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
-#![warn(rust_2018_idioms, unused_lifetimes)]
 
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_lexer as rustc_lexer;
diff --git a/src/tools/rust-analyzer/crates/test-utils/src/lib.rs b/src/tools/rust-analyzer/crates/test-utils/src/lib.rs
index 53d4a28bc30..088817b8357 100644
--- a/src/tools/rust-analyzer/crates/test-utils/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/test-utils/src/lib.rs
@@ -6,7 +6,6 @@
 //! * Extracting markup (mainly, `$0` markers) out of fixture strings.
 //! * marks (see the eponymous module).
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
 #![allow(clippy::print_stderr)]
 
 mod assert_linear;
diff --git a/src/tools/rust-analyzer/crates/text-edit/src/lib.rs b/src/tools/rust-analyzer/crates/text-edit/src/lib.rs
index e2ff373c1ba..3efe0850d88 100644
--- a/src/tools/rust-analyzer/crates/text-edit/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/text-edit/src/lib.rs
@@ -4,8 +4,6 @@
 //! so `TextEdit` is the ultimate representation of the work done by
 //! rust-analyzer.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use itertools::Itertools;
 use std::cmp::max;
 pub use text_size::{TextRange, TextSize};
diff --git a/src/tools/rust-analyzer/crates/toolchain/src/lib.rs b/src/tools/rust-analyzer/crates/toolchain/src/lib.rs
index 2591ed16916..a0603e35a09 100644
--- a/src/tools/rust-analyzer/crates/toolchain/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/toolchain/src/lib.rs
@@ -1,7 +1,5 @@
 //! Discovery of `cargo` & `rustc` executables.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{env, iter, path::PathBuf};
 
 use camino::{Utf8Path, Utf8PathBuf};
diff --git a/src/tools/rust-analyzer/crates/tt/src/lib.rs b/src/tools/rust-analyzer/crates/tt/src/lib.rs
index b2a21b19132..369744d0e96 100644
--- a/src/tools/rust-analyzer/crates/tt/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/tt/src/lib.rs
@@ -2,8 +2,6 @@
 //! input and output) of macros. It closely mirrors `proc_macro` crate's
 //! `TokenTree`.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 pub mod buffer;
 pub mod iter;
 
diff --git a/src/tools/rust-analyzer/crates/vfs-notify/src/lib.rs b/src/tools/rust-analyzer/crates/vfs-notify/src/lib.rs
index 1dbccab370c..7e0f9af7af8 100644
--- a/src/tools/rust-analyzer/crates/vfs-notify/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/vfs-notify/src/lib.rs
@@ -7,8 +7,6 @@
 //! Hopefully, one day a reliable file watching/walking crate appears on
 //! crates.io, and we can reduce this to trivial glue code.
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 use std::{
     fs,
     path::{Component, Path},
diff --git a/src/tools/rust-analyzer/crates/vfs/src/lib.rs b/src/tools/rust-analyzer/crates/vfs/src/lib.rs
index 18c8699dd4d..b3aa6e2fe11 100644
--- a/src/tools/rust-analyzer/crates/vfs/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/vfs/src/lib.rs
@@ -38,8 +38,6 @@
 //! [`Handle`]: loader::Handle
 //! [`Entries`]: loader::Entry
 
-#![warn(rust_2018_idioms, unused_lifetimes)]
-
 mod anchored_path;
 pub mod file_set;
 pub mod loader;