Use triomphe Arc

94 files changed, 337 insertions, 263 deletions

diff --git a/Cargo.lock b/Cargo.lock
index e0d5878d7fa..f0fe95327f3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -94,6 +94,7 @@ dependencies = [
  "stdx",
  "syntax",
  "test-utils",
+ "triomphe",
  "tt",
  "vfs",
 ]
@@ -498,6 +499,7 @@ dependencies = [
  "smallvec",
  "stdx",
  "syntax",
+ "triomphe",
  "tt",
 ]
 
@@ -534,6 +536,7 @@ dependencies = [
  "syntax",
  "test-utils",
  "tracing",
+ "triomphe",
  "tt",
 ]
 
@@ -558,6 +561,7 @@ dependencies = [
  "stdx",
  "syntax",
  "tracing",
+ "triomphe",
  "tt",
 ]
 
@@ -595,6 +599,7 @@ dependencies = [
  "tracing",
  "tracing-subscriber",
  "tracing-tree",
+ "triomphe",
  "typed-arena",
 ]
 
@@ -656,6 +661,7 @@ dependencies = [
  "text-edit",
  "toolchain",
  "tracing",
+ "triomphe",
  "url",
 ]
 
@@ -724,6 +730,7 @@ dependencies = [
  "test-utils",
  "text-edit",
  "tracing",
+ "triomphe",
  "xshell",
 ]
 
@@ -761,6 +768,7 @@ dependencies = [
  "syntax",
  "test-utils",
  "text-edit",
+ "triomphe",
 ]
 
 [[package]]
@@ -820,6 +828,7 @@ dependencies = [
  "hashbrown",
  "once_cell",
  "rustc-hash",
+ "triomphe",
 ]
 
 [[package]]
@@ -1234,6 +1243,7 @@ dependencies = [
  "snap",
  "stdx",
  "tracing",
+ "triomphe",
  "tt",
 ]
 
@@ -1315,6 +1325,7 @@ dependencies = [
  "stdx",
  "toolchain",
  "tracing",
+ "triomphe",
 ]
 
 [[package]]
@@ -1484,6 +1495,7 @@ dependencies = [
  "tracing-log",
  "tracing-subscriber",
  "tracing-tree",
+ "triomphe",
  "tt",
  "vfs",
  "vfs-notify",
@@ -1730,6 +1742,7 @@ dependencies = [
  "stdx",
  "test-utils",
  "text-edit",
+ "triomphe",
  "ungrammar",
 ]
 
@@ -1940,6 +1953,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "triomphe"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1ee9bd9239c339d714d657fac840c6d2a4f9c45f4f9ec7b0975113458be78db"
+
+[[package]]
 name = "tt"
 version = "0.0.0"
 dependencies = [
diff --git a/Cargo.toml b/Cargo.toml
index 985a1844c73..ef8d8c0eef4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -81,3 +81,4 @@ smol_str = "0.2.0"
 # the following crates are pinned to prevent us from pulling in syn 2 until all our dependencies have moved
 serde = { version = "=1.0.156", features = ["derive"] }
 serde_json = "1.0.94"
+triomphe = { version = "0.1.8", default-features = false, features = ["std"] }
diff --git a/crates/base-db/Cargo.toml b/crates/base-db/Cargo.toml
index c2d021c2238..6001772c86e 100644
--- a/crates/base-db/Cargo.toml
+++ b/crates/base-db/Cargo.toml
@@ -15,6 +15,8 @@ doctest = false
 salsa = "0.17.0-pre.2"
 rustc-hash = "1.1.0"
 
+triomphe.workspace = true
+
 la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
 
 # local deps
diff --git a/crates/base-db/src/change.rs b/crates/base-db/src/change.rs
index f1973a20714..2b33457b6d5 100644
--- a/crates/base-db/src/change.rs
+++ b/crates/base-db/src/change.rs
@@ -1,9 +1,10 @@
 //! Defines a unit of change that can applied to the database to get the next
 //! state. Changes are transactional.
 
-use std::{fmt, sync::Arc};
+use std::fmt;
 
 use salsa::Durability;
+use triomphe::Arc;
 use vfs::FileId;
 
 use crate::{CrateGraph, ProcMacros, SourceDatabaseExt, SourceRoot, SourceRootId};
diff --git a/crates/base-db/src/fixture.rs b/crates/base-db/src/fixture.rs
index 1936eabdd9f..e89d3ae4bb3 100644
--- a/crates/base-db/src/fixture.rs
+++ b/crates/base-db/src/fixture.rs
@@ -1,5 +1,5 @@
 //! A set of high-level utility fixture methods to use in tests.
-use std::{mem, str::FromStr, sync::Arc};
+use std::{mem, str::FromStr, sync};
 
 use cfg::CfgOptions;
 use rustc_hash::FxHashMap;
@@ -7,6 +7,7 @@ use test_utils::{
     extract_range_or_offset, Fixture, FixtureWithProjectMeta, RangeOrOffset, CURSOR_MARKER,
     ESCAPED_CURSOR_MARKER,
 };
+use triomphe::Arc;
 use tt::token_id::{Leaf, Subtree, TokenTree};
 use vfs::{file_set::FileSet, VfsPath};
 
@@ -334,7 +335,7 @@ pub fn identity(_attr: TokenStream, item: TokenStream) -> TokenStream {
             ProcMacro {
                 name: "identity".into(),
                 kind: crate::ProcMacroKind::Attr,
-                expander: Arc::new(IdentityProcMacroExpander),
+                expander: sync::Arc::new(IdentityProcMacroExpander),
             },
         ),
         (
@@ -348,7 +349,7 @@ pub fn derive_identity(item: TokenStream) -> TokenStream {
             ProcMacro {
                 name: "DeriveIdentity".into(),
                 kind: crate::ProcMacroKind::CustomDerive,
-                expander: Arc::new(IdentityProcMacroExpander),
+                expander: sync::Arc::new(IdentityProcMacroExpander),
             },
         ),
         (
@@ -362,7 +363,7 @@ pub fn input_replace(attr: TokenStream, _item: TokenStream) -> TokenStream {
             ProcMacro {
                 name: "input_replace".into(),
                 kind: crate::ProcMacroKind::Attr,
-                expander: Arc::new(AttributeInputReplaceProcMacroExpander),
+                expander: sync::Arc::new(AttributeInputReplaceProcMacroExpander),
             },
         ),
         (
@@ -376,7 +377,7 @@ pub fn mirror(input: TokenStream) -> TokenStream {
             ProcMacro {
                 name: "mirror".into(),
                 kind: crate::ProcMacroKind::FuncLike,
-                expander: Arc::new(MirrorProcMacroExpander),
+                expander: sync::Arc::new(MirrorProcMacroExpander),
             },
         ),
         (
@@ -390,7 +391,7 @@ pub fn shorten(input: TokenStream) -> TokenStream {
             ProcMacro {
                 name: "shorten".into(),
                 kind: crate::ProcMacroKind::FuncLike,
-                expander: Arc::new(ShortenProcMacroExpander),
+                expander: sync::Arc::new(ShortenProcMacroExpander),
             },
         ),
     ]
diff --git a/crates/base-db/src/input.rs b/crates/base-db/src/input.rs
index e6d265df675..e8d521b42f8 100644
--- a/crates/base-db/src/input.rs
+++ b/crates/base-db/src/input.rs
@@ -6,12 +6,13 @@
 //! actual IO. See `vfs` and `project_model` in the `rust-analyzer` crate for how
 //! actual IO is done and lowered to input.
 
-use std::{fmt, mem, ops, panic::RefUnwindSafe, str::FromStr, sync::Arc};
+use std::{fmt, mem, ops, panic::RefUnwindSafe, str::FromStr, sync};
 
 use cfg::CfgOptions;
 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};
 
@@ -263,7 +264,7 @@ pub type TargetLayoutLoadResult = Result<Arc<str>, Arc<str>>;
 pub struct ProcMacro {
     pub name: SmolStr,
     pub kind: ProcMacroKind,
-    pub expander: Arc<dyn ProcMacroExpander>,
+    pub expander: sync::Arc<dyn ProcMacroExpander>,
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
diff --git a/crates/base-db/src/lib.rs b/crates/base-db/src/lib.rs
index b65cf7341f3..af204e44e6e 100644
--- a/crates/base-db/src/lib.rs
+++ b/crates/base-db/src/lib.rs
@@ -6,10 +6,11 @@ mod input;
 mod change;
 pub mod fixture;
 
-use std::{panic, sync::Arc};
+use std::panic;
 
 use rustc_hash::FxHashSet;
 use syntax::{ast, Parse, SourceFile, TextRange, TextSize};
+use triomphe::Arc;
 
 pub use crate::{
     change::Change,
diff --git a/crates/hir-def/Cargo.toml b/crates/hir-def/Cargo.toml
index f4414a3e221..83c7051646e 100644
--- a/crates/hir-def/Cargo.toml
+++ b/crates/hir-def/Cargo.toml
@@ -29,6 +29,7 @@ once_cell = "1.17.0"
 rustc-hash = "1.1.0"
 smallvec.workspace = true
 tracing = "0.1.35"
+triomphe.workspace = true
 
 rustc_abi = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_abi", default-features = false }
 rustc_index = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_index", default-features = false }
diff --git a/crates/hir-def/src/attr.rs b/crates/hir-def/src/attr.rs
index 1ebbe160b07..f93d8d5c78e 100644
--- a/crates/hir-def/src/attr.rs
+++ b/crates/hir-def/src/attr.rs
@@ -5,7 +5,7 @@ pub mod builtin;
 #[cfg(test)]
 mod tests;
 
-use std::{hash::Hash, ops, sync::Arc};
+use std::{hash::Hash, ops};
 
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
@@ -21,6 +21,7 @@ use syntax::{
     ast::{self, HasAttrs, IsString},
     AstPtr, AstToken, SmolStr, TextRange, TextSize,
 };
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
diff --git a/crates/hir-def/src/body.rs b/crates/hir-def/src/body.rs
index 0c0e8ac8204..c2a27cd82ba 100644
--- a/crates/hir-def/src/body.rs
+++ b/crates/hir-def/src/body.rs
@@ -6,7 +6,7 @@ mod tests;
 pub mod scope;
 mod pretty;
 
-use std::{ops::Index, sync::Arc};
+use std::ops::Index;
 
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
@@ -16,6 +16,7 @@ use la_arena::{Arena, ArenaMap};
 use profile::Count;
 use rustc_hash::FxHashMap;
 use syntax::{ast, AstPtr, SyntaxNodePtr};
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
diff --git a/crates/hir-def/src/body/lower.rs b/crates/hir-def/src/body/lower.rs
index 611031eb8c4..0ecad857a44 100644
--- a/crates/hir-def/src/body/lower.rs
+++ b/crates/hir-def/src/body/lower.rs
@@ -1,7 +1,7 @@
 //! Transforms `ast::Expr` into an equivalent `hir_def::expr::Expr`
 //! representation.
 
-use std::{mem, sync::Arc};
+use std::mem;
 
 use base_db::CrateId;
 use either::Either;
@@ -22,6 +22,7 @@ use syntax::{
     },
     AstNode, AstPtr, SyntaxNodePtr,
 };
+use triomphe::Arc;
 
 use crate::{
     body::{Body, BodyDiagnostic, BodySourceMap, ExprPtr, LabelPtr, PatPtr},
diff --git a/crates/hir-def/src/body/scope.rs b/crates/hir-def/src/body/scope.rs
index 1143f666eea..0340bd18c2a 100644
--- a/crates/hir-def/src/body/scope.rs
+++ b/crates/hir-def/src/body/scope.rs
@@ -1,9 +1,8 @@
 //! Name resolution for expressions.
-use std::sync::Arc;
-
 use hir_expand::name::Name;
 use la_arena::{Arena, Idx, IdxRange, RawIdx};
 use rustc_hash::FxHashMap;
+use triomphe::Arc;
 
 use crate::{
     body::Body,
diff --git a/crates/hir-def/src/data.rs b/crates/hir-def/src/data.rs
index 7c6c089d65b..de67f0b23cf 100644
--- a/crates/hir-def/src/data.rs
+++ b/crates/hir-def/src/data.rs
@@ -2,14 +2,13 @@
 
 pub mod adt;
 
-use std::sync::Arc;
-
 use hir_expand::{
     name::Name, AstId, ExpandResult, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefKind,
 };
 use intern::Interned;
 use smallvec::SmallVec;
 use syntax::{ast, Parse};
+use triomphe::Arc;
 
 use crate::{
     attr::Attrs,
diff --git a/crates/hir-def/src/data/adt.rs b/crates/hir-def/src/data/adt.rs
index 4eefd66d477..6db5abccc92 100644
--- a/crates/hir-def/src/data/adt.rs
+++ b/crates/hir-def/src/data/adt.rs
@@ -1,7 +1,5 @@
 //! Defines hir-level representation of structs, enums and unions
 
-use std::sync::Arc;
-
 use base_db::CrateId;
 use bitflags::bitflags;
 use cfg::CfgOptions;
@@ -15,6 +13,7 @@ use intern::Interned;
 use la_arena::{Arena, ArenaMap};
 use rustc_abi::{Align, Integer, IntegerType, ReprFlags, ReprOptions};
 use syntax::ast::{self, HasName, HasVisibility};
+use triomphe::Arc;
 
 use crate::{
     builtin_type::{BuiltinInt, BuiltinUint},
diff --git a/crates/hir-def/src/db.rs b/crates/hir-def/src/db.rs
index cc87b03eef7..98db5edccc6 100644
--- a/crates/hir-def/src/db.rs
+++ b/crates/hir-def/src/db.rs
@@ -1,12 +1,11 @@
 //! Defines database & queries for name resolution.
-use std::sync::Arc;
-
 use base_db::{salsa, CrateId, SourceDatabase, Upcast};
 use either::Either;
 use hir_expand::{db::ExpandDatabase, HirFileId};
 use intern::Interned;
 use la_arena::ArenaMap;
 use syntax::{ast, AstPtr};
+use triomphe::Arc;
 
 use crate::{
     attr::{Attrs, AttrsWithOwner},
diff --git a/crates/hir-def/src/generics.rs b/crates/hir-def/src/generics.rs
index c7668577585..c79c1709630 100644
--- a/crates/hir-def/src/generics.rs
+++ b/crates/hir-def/src/generics.rs
@@ -3,8 +3,6 @@
 //! generic parameters. See also the `Generics` type and the `generics_of` query
 //! in rustc.
 
-use std::sync::Arc;
-
 use base_db::FileId;
 use either::Either;
 use hir_expand::{
@@ -16,6 +14,7 @@ use la_arena::{Arena, ArenaMap, Idx};
 use once_cell::unsync::Lazy;
 use stdx::impl_from;
 use syntax::ast::{self, HasGenericParams, HasName, HasTypeBounds};
+use triomphe::Arc;
 
 use crate::{
     child_by_source::ChildBySource,
diff --git a/crates/hir-def/src/import_map.rs b/crates/hir-def/src/import_map.rs
index 0480e6a51d3..4ea807e7d58 100644
--- a/crates/hir-def/src/import_map.rs
+++ b/crates/hir-def/src/import_map.rs
@@ -1,6 +1,6 @@
 //! A map of all publicly exported items in a crate.
 
-use std::{fmt, hash::BuildHasherDefault, sync::Arc};
+use std::{fmt, hash::BuildHasherDefault};
 
 use base_db::CrateId;
 use fst::{self, Streamer};
@@ -8,6 +8,7 @@ use hir_expand::name::Name;
 use indexmap::{map::Entry, IndexMap};
 use itertools::Itertools;
 use rustc_hash::{FxHashSet, FxHasher};
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase, item_scope::ItemInNs, visibility::Visibility, AssocItemId, ModuleDefId,
diff --git a/crates/hir-def/src/item_tree.rs b/crates/hir-def/src/item_tree.rs
index 7f2e88e4275..c332cc28c3c 100644
--- a/crates/hir-def/src/item_tree.rs
+++ b/crates/hir-def/src/item_tree.rs
@@ -40,7 +40,6 @@ use std::{
     hash::{Hash, Hasher},
     marker::PhantomData,
     ops::Index,
-    sync::Arc,
 };
 
 use ast::{AstNode, HasName, StructKind};
@@ -60,6 +59,7 @@ use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
 use stdx::never;
 use syntax::{ast, match_ast, SyntaxKind};
+use triomphe::Arc;
 
 use crate::{
     attr::Attrs,
diff --git a/crates/hir-def/src/item_tree/lower.rs b/crates/hir-def/src/item_tree/lower.rs
index 457a519872c..46633667ed3 100644
--- a/crates/hir-def/src/item_tree/lower.rs
+++ b/crates/hir-def/src/item_tree/lower.rs
@@ -1,6 +1,6 @@
 //! AST -> `ItemTree` lowering code.
 
-use std::{collections::hash_map::Entry, sync::Arc};
+use std::collections::hash_map::Entry;
 
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, HirFileId};
 use syntax::ast::{self, HasModuleItem, HasTypeBounds};
diff --git a/crates/hir-def/src/lang_item.rs b/crates/hir-def/src/lang_item.rs
index 818054188be..253e2daeddf 100644
--- a/crates/hir-def/src/lang_item.rs
+++ b/crates/hir-def/src/lang_item.rs
@@ -2,10 +2,9 @@
 //!
 //! This attribute to tell the compiler about semi built-in std library
 //! features, such as Fn family of traits.
-use std::sync::Arc;
-
 use rustc_hash::FxHashMap;
 use syntax::SmolStr;
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase, path::Path, AdtId, AssocItemId, AttrDefId, CrateId, EnumId, EnumVariantId,
diff --git a/crates/hir-def/src/lib.rs b/crates/hir-def/src/lib.rs
index 8e69a64e7e9..66388552322 100644
--- a/crates/hir-def/src/lib.rs
+++ b/crates/hir-def/src/lib.rs
@@ -49,6 +49,7 @@ pub mod find_path;
 pub mod import_map;
 
 pub use rustc_abi as layout;
+use triomphe::Arc;
 
 #[cfg(test)]
 mod test_db;
@@ -56,10 +57,7 @@ mod test_db;
 mod macro_expansion_tests;
 mod pretty;
 
-use std::{
-    hash::{Hash, Hasher},
-    sync::Arc,
-};
+use std::hash::{Hash, Hasher};
 
 use base_db::{impl_intern_key, salsa, CrateId, ProcMacroKind};
 use hir_expand::{
diff --git a/crates/hir-def/src/lower.rs b/crates/hir-def/src/lower.rs
index 1991d547f5d..af623fd0e5d 100644
--- a/crates/hir-def/src/lower.rs
+++ b/crates/hir-def/src/lower.rs
@@ -1,9 +1,8 @@
 //! Context for lowering paths.
-use std::sync::Arc;
-
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, AstId, HirFileId, InFile};
 use once_cell::unsync::OnceCell;
 use syntax::ast;
+use triomphe::Arc;
 
 use crate::{db::DefDatabase, path::Path};
 
diff --git a/crates/hir-def/src/macro_expansion_tests/mod.rs b/crates/hir-def/src/macro_expansion_tests/mod.rs
index 552d69ca2ea..c48c0c1aee5 100644
--- a/crates/hir-def/src/macro_expansion_tests/mod.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mod.rs
@@ -14,7 +14,7 @@ mod builtin_fn_macro;
 mod builtin_derive_macro;
 mod proc_macros;
 
-use std::{iter, ops::Range, sync::Arc};
+use std::{iter, ops::Range, sync};
 
 use ::mbe::TokenMap;
 use base_db::{fixture::WithFixture, ProcMacro, SourceDatabase};
@@ -50,7 +50,7 @@ pub fn identity_when_valid(_attr: TokenStream, item: TokenStream) -> TokenStream
         ProcMacro {
             name: "identity_when_valid".into(),
             kind: base_db::ProcMacroKind::Attr,
-            expander: Arc::new(IdentityWhenValidProcMacroExpander),
+            expander: sync::Arc::new(IdentityWhenValidProcMacroExpander),
         },
     )];
     let db = TestDB::with_files_extra_proc_macros(ra_fixture, extra_proc_macros);
diff --git a/crates/hir-def/src/nameres.rs b/crates/hir-def/src/nameres.rs
index 655004dcfe2..803342fdab5 100644
--- a/crates/hir-def/src/nameres.rs
+++ b/crates/hir-def/src/nameres.rs
@@ -57,7 +57,7 @@ mod path_resolution;
 #[cfg(test)]
 mod tests;
 
-use std::{cmp::Ord, ops::Deref, sync::Arc};
+use std::{cmp::Ord, ops::Deref};
 
 use base_db::{CrateId, Edition, FileId};
 use hir_expand::{name::Name, InFile, MacroCallId, MacroDefId};
@@ -67,6 +67,7 @@ use profile::Count;
 use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::format_to;
 use syntax::{ast, SmolStr};
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
diff --git a/crates/hir-def/src/nameres/collector.rs b/crates/hir-def/src/nameres/collector.rs
index 05d49ee814b..3ec33f663a3 100644
--- a/crates/hir-def/src/nameres/collector.rs
+++ b/crates/hir-def/src/nameres/collector.rs
@@ -26,6 +26,7 @@ use limit::Limit;
 use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::always;
 use syntax::{ast, SmolStr};
+use triomphe::Arc;
 
 use crate::{
     attr::Attrs,
@@ -476,10 +477,7 @@ impl DefCollector<'_> {
                         directive.module_id,
                         MacroCallKind::Attr {
                             ast_id: ast_id.ast_id,
-                            attr_args: std::sync::Arc::new((
-                                tt::Subtree::empty(),
-                                Default::default(),
-                            )),
+                            attr_args: Arc::new((tt::Subtree::empty(), Default::default())),
                             invoc_attr_index: attr.id,
                         },
                         attr.path().clone(),
diff --git a/crates/hir-def/src/nameres/tests.rs b/crates/hir-def/src/nameres/tests.rs
index 8a27c60df5c..dd7c3c36306 100644
--- a/crates/hir-def/src/nameres/tests.rs
+++ b/crates/hir-def/src/nameres/tests.rs
@@ -4,10 +4,9 @@ mod macros;
 mod mod_resolution;
 mod primitives;
 
-use std::sync::Arc;
-
 use base_db::{fixture::WithFixture, SourceDatabase};
 use expect_test::{expect, Expect};
+use triomphe::Arc;
 
 use crate::{db::DefDatabase, test_db::TestDB};
 
diff --git a/crates/hir-def/src/nameres/tests/incremental.rs b/crates/hir-def/src/nameres/tests/incremental.rs
index 50751ab9c89..4931c36bbca 100644
--- a/crates/hir-def/src/nameres/tests/incremental.rs
+++ b/crates/hir-def/src/nameres/tests/incremental.rs
@@ -1,6 +1,5 @@
-use std::sync::Arc;
-
 use base_db::SourceDatabaseExt;
+use triomphe::Arc;
 
 use crate::{db::DefDatabase, AdtId, ModuleDefId};
 
diff --git a/crates/hir-def/src/resolver.rs b/crates/hir-def/src/resolver.rs
index 12499faeb62..45ec454b9eb 100644
--- a/crates/hir-def/src/resolver.rs
+++ b/crates/hir-def/src/resolver.rs
@@ -1,5 +1,5 @@
 //! Name resolution façade.
-use std::{fmt, hash::BuildHasherDefault, sync::Arc};
+use std::{fmt, hash::BuildHasherDefault};
 
 use base_db::CrateId;
 use hir_expand::name::{name, Name};
@@ -7,6 +7,7 @@ use indexmap::IndexMap;
 use intern::Interned;
 use rustc_hash::FxHashSet;
 use smallvec::{smallvec, SmallVec};
+use triomphe::Arc;
 
 use crate::{
     body::scope::{ExprScopes, ScopeId},
diff --git a/crates/hir-def/src/test_db.rs b/crates/hir-def/src/test_db.rs
index 6bfcd90970d..d4b40313642 100644
--- a/crates/hir-def/src/test_db.rs
+++ b/crates/hir-def/src/test_db.rs
@@ -1,9 +1,6 @@
 //! Database used for testing `hir_def`.
 
-use std::{
-    fmt, panic,
-    sync::{Arc, Mutex},
-};
+use std::{fmt, panic, sync::Mutex};
 
 use base_db::{
     salsa::{self, Durability},
@@ -13,6 +10,7 @@ use base_db::{
 use hir_expand::{db::ExpandDatabase, InFile};
 use rustc_hash::FxHashSet;
 use syntax::{algo, ast, AstNode};
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
diff --git a/crates/hir-def/src/visibility.rs b/crates/hir-def/src/visibility.rs
index ab76ed43d3a..30f48de61f2 100644
--- a/crates/hir-def/src/visibility.rs
+++ b/crates/hir-def/src/visibility.rs
@@ -1,10 +1,11 @@
 //! Defines hir-level representation of visibility (e.g. `pub` and `pub(crate)`).
 
-use std::{iter, sync::Arc};
+use std::iter;
 
 use hir_expand::{hygiene::Hygiene, InFile};
 use la_arena::ArenaMap;
 use syntax::ast;
+use triomphe::Arc;
 
 use crate::{
     db::DefDatabase,
diff --git a/crates/hir-expand/Cargo.toml b/crates/hir-expand/Cargo.toml
index 5c684be03cf..40d8659f25b 100644
--- a/crates/hir-expand/Cargo.toml
+++ b/crates/hir-expand/Cargo.toml
@@ -22,6 +22,7 @@ hashbrown = { version = "0.12.1", features = [
     "inline-more",
 ], default-features = false }
 smallvec.workspace = true
+triomphe.workspace = true
 
 # local deps
 stdx.workspace = true
diff --git a/crates/hir-expand/src/attrs.rs b/crates/hir-expand/src/attrs.rs
index 17360090db1..3ff18e982e1 100644
--- a/crates/hir-expand/src/attrs.rs
+++ b/crates/hir-expand/src/attrs.rs
@@ -1,5 +1,5 @@
 //! A higher level attributes based on TokenTree, with also some shortcuts.
-use std::{fmt, ops, sync::Arc};
+use std::{fmt, ops};
 
 use base_db::CrateId;
 use cfg::CfgExpr;
@@ -8,6 +8,7 @@ use intern::Interned;
 use mbe::{syntax_node_to_token_tree, DelimiterKind, Punct};
 use smallvec::{smallvec, SmallVec};
 use syntax::{ast, match_ast, AstNode, SmolStr, SyntaxNode};
+use triomphe::Arc;
 
 use crate::{
     db::ExpandDatabase,
@@ -50,7 +51,9 @@ impl RawAttrs {
                     path: Interned::new(ModPath::from(crate::name!(doc))),
                 }),
             })
-            .collect::<Arc<_>>();
+            .collect::<Vec<_>>();
+        // FIXME: use `Arc::from_iter` when it becomes available
+        let entries: Arc<[Attr]> = Arc::from(entries);
 
         Self { entries: if entries.is_empty() { None } else { Some(entries) } }
     }
@@ -68,7 +71,7 @@ impl RawAttrs {
             (Some(a), Some(b)) => {
                 let last_ast_index = a.last().map_or(0, |it| it.id.ast_index() + 1) as u32;
                 Self {
-                    entries: Some(
+                    entries: Some(Arc::from(
                         a.iter()
                             .cloned()
                             .chain(b.iter().map(|it| {
@@ -78,8 +81,9 @@ impl RawAttrs {
                                         << AttrId::AST_INDEX_BITS;
                                 it
                             }))
-                            .collect(),
-                    ),
+                            // FIXME: use `Arc::from_iter` when it becomes available
+                            .collect::<Vec<_>>(),
+                    )),
                 }
             }
         }
@@ -96,48 +100,51 @@ impl RawAttrs {
         }
 
         let crate_graph = db.crate_graph();
-        let new_attrs = self
-            .iter()
-            .flat_map(|attr| -> SmallVec<[_; 1]> {
-                let is_cfg_attr =
-                    attr.path.as_ident().map_or(false, |name| *name == crate::name![cfg_attr]);
-                if !is_cfg_attr {
-                    return smallvec![attr.clone()];
-                }
-
-                let subtree = match attr.token_tree_value() {
-                    Some(it) => it,
-                    _ => return smallvec![attr.clone()],
-                };
-
-                let (cfg, parts) = match parse_cfg_attr_input(subtree) {
-                    Some(it) => it,
-                    None => return smallvec![attr.clone()],
-                };
-                let index = attr.id;
-                let attrs =
-                    parts.enumerate().take(1 << AttrId::CFG_ATTR_BITS).filter_map(|(idx, attr)| {
-                        let tree = Subtree {
-                            delimiter: tt::Delimiter::unspecified(),
-                            token_trees: attr.to_vec(),
-                        };
-                        // FIXME hygiene
-                        let hygiene = Hygiene::new_unhygienic();
-                        Attr::from_tt(db, &tree, &hygiene, index.with_cfg_attr(idx))
-                    });
-
-                let cfg_options = &crate_graph[krate].cfg_options;
-                let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
-                let cfg = CfgExpr::parse(&cfg);
-                if cfg_options.check(&cfg) == Some(false) {
-                    smallvec![]
-                } else {
-                    cov_mark::hit!(cfg_attr_active);
-
-                    attrs.collect()
-                }
-            })
-            .collect();
+        let new_attrs = Arc::from(
+            self.iter()
+                .flat_map(|attr| -> SmallVec<[_; 1]> {
+                    let is_cfg_attr =
+                        attr.path.as_ident().map_or(false, |name| *name == crate::name![cfg_attr]);
+                    if !is_cfg_attr {
+                        return smallvec![attr.clone()];
+                    }
+
+                    let subtree = match attr.token_tree_value() {
+                        Some(it) => it,
+                        _ => return smallvec![attr.clone()],
+                    };
+
+                    let (cfg, parts) = match parse_cfg_attr_input(subtree) {
+                        Some(it) => it,
+                        None => return smallvec![attr.clone()],
+                    };
+                    let index = attr.id;
+                    let attrs = parts.enumerate().take(1 << AttrId::CFG_ATTR_BITS).filter_map(
+                        |(idx, attr)| {
+                            let tree = Subtree {
+                                delimiter: tt::Delimiter::unspecified(),
+                                token_trees: attr.to_vec(),
+                            };
+                            // FIXME hygiene
+                            let hygiene = Hygiene::new_unhygienic();
+                            Attr::from_tt(db, &tree, &hygiene, index.with_cfg_attr(idx))
+                        },
+                    );
+
+                    let cfg_options = &crate_graph[krate].cfg_options;
+                    let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
+                    let cfg = CfgExpr::parse(&cfg);
+                    if cfg_options.check(&cfg) == Some(false) {
+                        smallvec![]
+                    } else {
+                        cov_mark::hit!(cfg_attr_active);
+
+                        attrs.collect()
+                    }
+                })
+                // FIXME: use `Arc::from_iter` when it becomes available
+                .collect::<Vec<_>>(),
+        );
 
         RawAttrs { entries: Some(new_attrs) }
     }
diff --git a/crates/hir-expand/src/db.rs b/crates/hir-expand/src/db.rs
index 0f9e37c8338..965dfa824d8 100644
--- a/crates/hir-expand/src/db.rs
+++ b/crates/hir-expand/src/db.rs
@@ -1,7 +1,5 @@
 //! Defines database & queries for macro expansion.
 
-use std::sync::Arc;
-
 use base_db::{salsa, Edition, SourceDatabase};
 use either::Either;
 use limit::Limit;
@@ -11,6 +9,7 @@ use syntax::{
     ast::{self, HasAttrs, HasDocComments},
     AstNode, GreenNode, Parse, SyntaxError, SyntaxNode, SyntaxToken, T,
 };
+use triomphe::Arc;
 
 use crate::{
     ast_id_map::AstIdMap, builtin_attr_macro::pseudo_derive_attr_expansion,
diff --git a/crates/hir-expand/src/eager.rs b/crates/hir-expand/src/eager.rs
index d81bb647194..59a92ff0ab6 100644
--- a/crates/hir-expand/src/eager.rs
+++ b/crates/hir-expand/src/eager.rs
@@ -18,10 +18,9 @@
 //!
 //!
 //! See the full discussion : <https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Eager.20expansion.20of.20built-in.20macros>
-use std::sync::Arc;
-
 use base_db::CrateId;
 use syntax::{ted, Parse, SyntaxNode};
+use triomphe::Arc;
 
 use crate::{
     ast::{self, AstNode},
diff --git a/crates/hir-expand/src/hygiene.rs b/crates/hir-expand/src/hygiene.rs
index 9af38fed044..10f8fe9cec4 100644
--- a/crates/hir-expand/src/hygiene.rs
+++ b/crates/hir-expand/src/hygiene.rs
@@ -2,8 +2,6 @@
 //!
 //! Specifically, `ast` + `Hygiene` allows you to create a `Name`. Note that, at
 //! this moment, this is horribly incomplete and handles only `$crate`.
-use std::sync::Arc;
-
 use base_db::CrateId;
 use db::TokenExpander;
 use either::Either;
@@ -12,6 +10,7 @@ use syntax::{
     ast::{self, HasDocComments},
     AstNode, SyntaxKind, SyntaxNode, TextRange, TextSize,
 };
+use triomphe::Arc;
 
 use crate::{
     db::{self, ExpandDatabase},
diff --git a/crates/hir-expand/src/lib.rs b/crates/hir-expand/src/lib.rs
index ce0006d8422..c24887e15ff 100644
--- a/crates/hir-expand/src/lib.rs
+++ b/crates/hir-expand/src/lib.rs
@@ -24,8 +24,9 @@ use mbe::TokenMap;
 pub use mbe::{Origin, ValueResult};
 
 use ::tt::token_id as tt;
+use triomphe::Arc;
 
-use std::{fmt, hash::Hash, iter, sync::Arc};
+use std::{fmt, hash::Hash, iter};
 
 use base_db::{
     impl_intern_key,
diff --git a/crates/hir-ty/Cargo.toml b/crates/hir-ty/Cargo.toml
index 3ab7460e8cd..51d69d103ad 100644
--- a/crates/hir-ty/Cargo.toml
+++ b/crates/hir-ty/Cargo.toml
@@ -28,6 +28,7 @@ chalk-recursive = { version = "0.89.0", default-features = false }
 chalk-derive = "0.89.0"
 la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
 once_cell = "1.17.0"
+triomphe.workspace = true
 typed-arena = "2.0.1"
 rustc_index = { version = "0.0.20221221", package = "hkalbasi-rustc-ap-rustc_index", default-features = false }
 
diff --git a/crates/hir-ty/src/autoderef.rs b/crates/hir-ty/src/autoderef.rs
index 37ecdc23edc..f5b3f176b12 100644
--- a/crates/hir-ty/src/autoderef.rs
+++ b/crates/hir-ty/src/autoderef.rs
@@ -3,12 +3,11 @@
 //! reference to a type with the field `bar`. This is an approximation of the
 //! logic in rustc (which lives in rustc_hir_analysis/check/autoderef.rs).
 
-use std::sync::Arc;
-
 use chalk_ir::cast::Cast;
 use hir_def::lang_item::LangItem;
 use hir_expand::name::name;
 use limit::Limit;
+use triomphe::Arc;
 
 use crate::{
     db::HirDatabase, infer::unify::InferenceTable, Canonical, Goal, Interner, ProjectionTyExt,
diff --git a/crates/hir-ty/src/chalk_db.rs b/crates/hir-ty/src/chalk_db.rs
index b47a22c3425..d68703ce1d4 100644
--- a/crates/hir-ty/src/chalk_db.rs
+++ b/crates/hir-ty/src/chalk_db.rs
@@ -391,7 +391,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn generator_datum(
         &self,
         id: chalk_ir::GeneratorId<Interner>,
-    ) -> std::sync::Arc<chalk_solve::rust_ir::GeneratorDatum<Interner>> {
+    ) -> Arc<chalk_solve::rust_ir::GeneratorDatum<Interner>> {
         let (parent, expr) = self.db.lookup_intern_generator(id.into());
 
         // We fill substitution with unknown type, because we only need to know whether the generic
@@ -432,7 +432,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn generator_witness_datum(
         &self,
         id: chalk_ir::GeneratorId<Interner>,
-    ) -> std::sync::Arc<chalk_solve::rust_ir::GeneratorWitnessDatum<Interner>> {
+    ) -> Arc<chalk_solve::rust_ir::GeneratorWitnessDatum<Interner>> {
         // FIXME: calculate inner types
         let inner_types =
             rust_ir::GeneratorWitnessExistential { types: wrap_empty_binders(vec![]) };
diff --git a/crates/hir-ty/src/db.rs b/crates/hir-ty/src/db.rs
index d8bd5b34817..b37d90c7589 100644
--- a/crates/hir-ty/src/db.rs
+++ b/crates/hir-ty/src/db.rs
@@ -1,7 +1,7 @@
 //! The home of `HirDatabase`, which is the Salsa database containing all the
 //! type inference-related queries.
 
-use std::sync::Arc;
+use std::sync;
 
 use base_db::{impl_intern_key, salsa, CrateId, Upcast};
 use hir_def::{
@@ -11,6 +11,7 @@ use hir_def::{
 };
 use la_arena::ArenaMap;
 use smallvec::SmallVec;
+use triomphe::Arc;
 
 use crate::{
     chalk_db,
@@ -154,24 +155,34 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     fn intern_generator(&self, id: (DefWithBodyId, ExprId)) -> InternedGeneratorId;
 
     #[salsa::invoke(chalk_db::associated_ty_data_query)]
-    fn associated_ty_data(&self, id: chalk_db::AssocTypeId) -> Arc<chalk_db::AssociatedTyDatum>;
+    fn associated_ty_data(
+        &self,
+        id: chalk_db::AssocTypeId,
+    ) -> sync::Arc<chalk_db::AssociatedTyDatum>;
 
     #[salsa::invoke(chalk_db::trait_datum_query)]
-    fn trait_datum(&self, krate: CrateId, trait_id: chalk_db::TraitId)
-        -> Arc<chalk_db::TraitDatum>;
+    fn trait_datum(
+        &self,
+        krate: CrateId,
+        trait_id: chalk_db::TraitId,
+    ) -> sync::Arc<chalk_db::TraitDatum>;
 
     #[salsa::invoke(chalk_db::struct_datum_query)]
     fn struct_datum(
         &self,
         krate: CrateId,
         struct_id: chalk_db::AdtId,
-    ) -> Arc<chalk_db::StructDatum>;
+    ) -> sync::Arc<chalk_db::StructDatum>;
 
     #[salsa::invoke(chalk_db::impl_datum_query)]
-    fn impl_datum(&self, krate: CrateId, impl_id: chalk_db::ImplId) -> Arc<chalk_db::ImplDatum>;
+    fn impl_datum(
+        &self,
+        krate: CrateId,
+        impl_id: chalk_db::ImplId,
+    ) -> sync::Arc<chalk_db::ImplDatum>;
 
     #[salsa::invoke(chalk_db::fn_def_datum_query)]
-    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> Arc<chalk_db::FnDefDatum>;
+    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> sync::Arc<chalk_db::FnDefDatum>;
 
     #[salsa::invoke(chalk_db::fn_def_variance_query)]
     fn fn_def_variance(&self, fn_def_id: FnDefId) -> chalk_db::Variances;
@@ -184,7 +195,7 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         &self,
         krate: CrateId,
         id: chalk_db::AssociatedTyValueId,
-    ) -> Arc<chalk_db::AssociatedTyValue>;
+    ) -> sync::Arc<chalk_db::AssociatedTyValue>;
 
     #[salsa::invoke(crate::traits::normalize_projection_query)]
     #[salsa::transparent]
diff --git a/crates/hir-ty/src/diagnostics/expr.rs b/crates/hir-ty/src/diagnostics/expr.rs
index f346910da09..ab34dc88d87 100644
--- a/crates/hir-ty/src/diagnostics/expr.rs
+++ b/crates/hir-ty/src/diagnostics/expr.rs
@@ -3,7 +3,6 @@
 //! fields, etc.
 
 use std::fmt;
-use std::sync::Arc;
 
 use either::Either;
 use hir_def::lang_item::LangItem;
@@ -12,6 +11,7 @@ use hir_def::{ItemContainerId, Lookup};
 use hir_expand::name;
 use itertools::Itertools;
 use rustc_hash::FxHashSet;
+use triomphe::Arc;
 use typed_arena::Arena;
 
 use crate::{
diff --git a/crates/hir-ty/src/infer.rs b/crates/hir-ty/src/infer.rs
index ba0b6d254b7..0e9b7206d04 100644
--- a/crates/hir-ty/src/infer.rs
+++ b/crates/hir-ty/src/infer.rs
@@ -13,7 +13,6 @@
 //! to certain types. To record this, we use the union-find implementation from
 //! the `ena` crate, which is extracted from rustc.
 
-use std::sync::Arc;
 use std::{convert::identity, ops::Index};
 
 use chalk_ir::{
@@ -39,6 +38,7 @@ use hir_expand::name::{name, Name};
 use la_arena::{ArenaMap, Entry};
 use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::{always, never};
+use triomphe::Arc;
 
 use crate::{
     db::HirDatabase, fold_tys, infer::coerce::CoerceMany, lower::ImplTraitLoweringMode,
diff --git a/crates/hir-ty/src/infer/coerce.rs b/crates/hir-ty/src/infer/coerce.rs
index d613a5ff504..e9c94449cfc 100644
--- a/crates/hir-ty/src/infer/coerce.rs
+++ b/crates/hir-ty/src/infer/coerce.rs
@@ -5,7 +5,7 @@
 //! See <https://doc.rust-lang.org/nomicon/coercions.html> and
 //! `rustc_hir_analysis/check/coercion.rs`.
 
-use std::{iter, sync::Arc};
+use std::iter;
 
 use chalk_ir::{cast::Cast, BoundVar, Goal, Mutability, TyKind, TyVariableKind};
 use hir_def::{
@@ -13,6 +13,7 @@ use hir_def::{
     lang_item::{LangItem, LangItemTarget},
 };
 use stdx::always;
+use triomphe::Arc;
 
 use crate::{
     autoderef::{Autoderef, AutoderefKind},
diff --git a/crates/hir-ty/src/infer/expr.rs b/crates/hir-ty/src/infer/expr.rs
index 06ca9b026e3..96218e4fb09 100644
--- a/crates/hir-ty/src/infer/expr.rs
+++ b/crates/hir-ty/src/infer/expr.rs
@@ -3,7 +3,6 @@
 use std::{
     iter::{repeat, repeat_with},
     mem,
-    sync::Arc,
 };
 
 use chalk_ir::{
@@ -21,6 +20,7 @@ use hir_def::{
 use hir_expand::name::{name, Name};
 use stdx::always;
 use syntax::ast::RangeOp;
+use triomphe::Arc;
 
 use crate::{
     autoderef::{builtin_deref, deref_by_trait, Autoderef},
diff --git a/crates/hir-ty/src/infer/unify.rs b/crates/hir-ty/src/infer/unify.rs
index 2988c710398..b735a11adfb 100644
--- a/crates/hir-ty/src/infer/unify.rs
+++ b/crates/hir-ty/src/infer/unify.rs
@@ -1,6 +1,6 @@
 //! Unification and canonicalization logic.
 
-use std::{fmt, iter, mem, sync::Arc};
+use std::{fmt, iter, mem};
 
 use chalk_ir::{
     cast::Cast, fold::TypeFoldable, interner::HasInterner, zip::Zip, CanonicalVarKind, FloatTy,
@@ -11,6 +11,7 @@ use either::Either;
 use ena::unify::UnifyKey;
 use hir_expand::name;
 use stdx::never;
+use triomphe::Arc;
 
 use super::{InferOk, InferResult, InferenceContext, TypeError};
 use crate::{
diff --git a/crates/hir-ty/src/interner.rs b/crates/hir-ty/src/interner.rs
index 19bb7f169f1..89f7d9c4f4a 100644
--- a/crates/hir-ty/src/interner.rs
+++ b/crates/hir-ty/src/interner.rs
@@ -7,7 +7,8 @@ use chalk_ir::{Goal, GoalData};
 use hir_def::TypeAliasId;
 use intern::{impl_internable, Interned};
 use smallvec::SmallVec;
-use std::{fmt, sync::Arc};
+use std::fmt;
+use triomphe::Arc;
 
 #[derive(Debug, Copy, Clone, Hash, PartialOrd, Ord, PartialEq, Eq)]
 pub struct Interner;
diff --git a/crates/hir-ty/src/layout.rs b/crates/hir-ty/src/layout.rs
index ebbf16caee1..f74a2253a42 100644
--- a/crates/hir-ty/src/layout.rs
+++ b/crates/hir-ty/src/layout.rs
@@ -1,7 +1,5 @@
 //! Compute the binary representation of a type
 
-use std::sync::Arc;
-
 use base_db::CrateId;
 use chalk_ir::{AdtId, TyKind};
 use hir_def::{
@@ -13,6 +11,7 @@ use hir_def::{
 };
 use la_arena::{Idx, RawIdx};
 use stdx::never;
+use triomphe::Arc;
 
 use crate::{
     consteval::try_const_usize, db::HirDatabase, infer::normalize, layout::adt::struct_variant_idx,
diff --git a/crates/hir-ty/src/layout/target.rs b/crates/hir-ty/src/layout/target.rs
index adfae0a1abb..04b940afbe8 100644
--- a/crates/hir-ty/src/layout/target.rs
+++ b/crates/hir-ty/src/layout/target.rs
@@ -1,9 +1,8 @@
 //! Target dependent parameters needed for layouts
 
-use std::sync::Arc;
-
 use base_db::CrateId;
 use hir_def::layout::TargetDataLayout;
+use triomphe::Arc;
 
 use crate::db::HirDatabase;
 
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index 071d95839ec..6e726042f6c 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -35,7 +35,7 @@ mod tests;
 #[cfg(test)]
 mod test_db;
 
-use std::{collections::HashMap, hash::Hash, sync::Arc};
+use std::{collections::HashMap, hash::Hash};
 
 use chalk_ir::{
     fold::{Shift, TypeFoldable},
@@ -50,6 +50,7 @@ use la_arena::{Arena, Idx};
 use mir::{MirEvalError, VTableMap};
 use rustc_hash::FxHashSet;
 use traits::FnTrait;
+use triomphe::Arc;
 use utils::Generics;
 
 use crate::{
@@ -289,16 +290,19 @@ impl CallableSig {
     pub fn from_fn_ptr(fn_ptr: &FnPointer) -> CallableSig {
         CallableSig {
             // FIXME: what to do about lifetime params? -> return PolyFnSig
-            params_and_return: fn_ptr
-                .substitution
-                .clone()
-                .shifted_out_to(Interner, DebruijnIndex::ONE)
-                .expect("unexpected lifetime vars in fn ptr")
-                .0
-                .as_slice(Interner)
-                .iter()
-                .map(|arg| arg.assert_ty_ref(Interner).clone())
-                .collect(),
+            // FIXME: use `Arc::from_iter` when it becomes available
+            params_and_return: Arc::from(
+                fn_ptr
+                    .substitution
+                    .clone()
+                    .shifted_out_to(Interner, DebruijnIndex::ONE)
+                    .expect("unexpected lifetime vars in fn ptr")
+                    .0
+                    .as_slice(Interner)
+                    .iter()
+                    .map(|arg| arg.assert_ty_ref(Interner).clone())
+                    .collect::<Vec<_>>(),
+            ),
             is_varargs: fn_ptr.sig.variadic,
             safety: fn_ptr.sig.safety,
         }
diff --git a/crates/hir-ty/src/lower.rs b/crates/hir-ty/src/lower.rs
index 7da747b9497..4000ba5c14c 100644
--- a/crates/hir-ty/src/lower.rs
+++ b/crates/hir-ty/src/lower.rs
@@ -8,7 +8,6 @@
 use std::{
     cell::{Cell, RefCell, RefMut},
     iter,
-    sync::Arc,
 };
 
 use base_db::CrateId;
@@ -39,6 +38,7 @@ use rustc_hash::FxHashSet;
 use smallvec::SmallVec;
 use stdx::{impl_from, never};
 use syntax::ast;
+use triomphe::Arc;
 
 use crate::{
     all_super_traits,
@@ -1441,7 +1441,8 @@ pub(crate) fn generic_predicates_for_param_recover(
     _param_id: &TypeOrConstParamId,
     _assoc_name: &Option<Name>,
 ) -> Arc<[Binders<QuantifiedWhereClause>]> {
-    Arc::new([])
+    // FIXME: use `Arc::from_iter` when it becomes available
+    Arc::from(vec![])
 }
 
 pub(crate) fn trait_environment_for_body_query(
@@ -1579,30 +1580,33 @@ pub(crate) fn generic_defaults_query(
     let generic_params = generics(db.upcast(), def);
     let parent_start_idx = generic_params.len_self();
 
-    let defaults = generic_params
-        .iter()
-        .enumerate()
-        .map(|(idx, (id, p))| {
-            let p = match p {
-                TypeOrConstParamData::TypeParamData(p) => p,
-                TypeOrConstParamData::ConstParamData(_) => {
-                    // FIXME: implement const generic defaults
-                    let val = unknown_const_as_generic(
-                        db.const_param_ty(ConstParamId::from_unchecked(id)),
-                    );
-                    return make_binders(db, &generic_params, val);
-                }
-            };
-            let mut ty =
-                p.default.as_ref().map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t));
-
-            // Each default can only refer to previous parameters.
-            // Type variable default referring to parameter coming
-            // after it is forbidden (FIXME: report diagnostic)
-            ty = fallback_bound_vars(ty, idx, parent_start_idx);
-            crate::make_binders(db, &generic_params, ty.cast(Interner))
-        })
-        .collect();
+    let defaults = Arc::from(
+        generic_params
+            .iter()
+            .enumerate()
+            .map(|(idx, (id, p))| {
+                let p = match p {
+                    TypeOrConstParamData::TypeParamData(p) => p,
+                    TypeOrConstParamData::ConstParamData(_) => {
+                        // FIXME: implement const generic defaults
+                        let val = unknown_const_as_generic(
+                            db.const_param_ty(ConstParamId::from_unchecked(id)),
+                        );
+                        return make_binders(db, &generic_params, val);
+                    }
+                };
+                let mut ty =
+                    p.default.as_ref().map_or(TyKind::Error.intern(Interner), |t| ctx.lower_ty(t));
+
+                // Each default can only refer to previous parameters.
+                // Type variable default referring to parameter coming
+                // after it is forbidden (FIXME: report diagnostic)
+                ty = fallback_bound_vars(ty, idx, parent_start_idx);
+                crate::make_binders(db, &generic_params, ty.cast(Interner))
+            })
+            // FIXME: use `Arc::from_iter` when it becomes available
+            .collect::<Vec<_>>(),
+    );
 
     defaults
 }
@@ -1615,18 +1619,21 @@ pub(crate) fn generic_defaults_recover(
     let generic_params = generics(db.upcast(), *def);
     // FIXME: this code is not covered in tests.
     // we still need one default per parameter
-    let defaults = generic_params
-        .iter_id()
-        .map(|id| {
-            let val = match id {
-                Either::Left(_) => {
-                    GenericArgData::Ty(TyKind::Error.intern(Interner)).intern(Interner)
-                }
-                Either::Right(id) => unknown_const_as_generic(db.const_param_ty(id)),
-            };
-            crate::make_binders(db, &generic_params, val)
-        })
-        .collect();
+    let defaults = Arc::from(
+        generic_params
+            .iter_id()
+            .map(|id| {
+                let val = match id {
+                    Either::Left(_) => {
+                        GenericArgData::Ty(TyKind::Error.intern(Interner)).intern(Interner)
+                    }
+                    Either::Right(id) => unknown_const_as_generic(db.const_param_ty(id)),
+                };
+                crate::make_binders(db, &generic_params, val)
+            })
+            // FIXME: use `Arc::from_iter` when it becomes available
+            .collect::<Vec<_>>(),
+    );
 
     defaults
 }
diff --git a/crates/hir-ty/src/method_resolution.rs b/crates/hir-ty/src/method_resolution.rs
index 159544f6dc0..912efc3a896 100644
--- a/crates/hir-ty/src/method_resolution.rs
+++ b/crates/hir-ty/src/method_resolution.rs
@@ -2,7 +2,7 @@
 //! For details about how this works in rustc, see the method lookup page in the
 //! [rustc guide](https://rust-lang.github.io/rustc-guide/method-lookup.html)
 //! and the corresponding code mostly in rustc_hir_analysis/check/method/probe.rs.
-use std::{ops::ControlFlow, sync::Arc};
+use std::ops::ControlFlow;
 
 use base_db::{CrateId, Edition};
 use chalk_ir::{cast::Cast, Mutability, TyKind, UniverseIndex, WhereClause};
@@ -17,6 +17,7 @@ use hir_expand::name::Name;
 use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::{smallvec, SmallVec};
 use stdx::never;
+use triomphe::Arc;
 
 use crate::{
     autoderef::{self, AutoderefKind},
@@ -166,7 +167,13 @@ impl TraitImpls {
     ) -> Arc<[Arc<Self>]> {
         let _p = profile::span("trait_impls_in_deps_query").detail(|| format!("{krate:?}"));
         let crate_graph = db.crate_graph();
-        crate_graph.transitive_deps(krate).map(|krate| db.trait_impls_in_crate(krate)).collect()
+        // FIXME: use `Arc::from_iter` when it becomes available
+        Arc::from(
+            crate_graph
+                .transitive_deps(krate)
+                .map(|krate| db.trait_impls_in_crate(krate))
+                .collect::<Vec<_>>(),
+        )
     }
 
     fn shrink_to_fit(&mut self) {
diff --git a/crates/hir-ty/src/mir/borrowck.rs b/crates/hir-ty/src/mir/borrowck.rs
index 7b99fbf42f0..b2425d94c61 100644
--- a/crates/hir-ty/src/mir/borrowck.rs
+++ b/crates/hir-ty/src/mir/borrowck.rs
@@ -3,11 +3,12 @@
 // Currently it is an ad-hoc implementation, only useful for mutability analysis. Feel free to remove all of these
 // if needed for implementing a proper borrow checker.
 
-use std::{iter, sync::Arc};
+use std::iter;
 
 use hir_def::DefWithBodyId;
 use la_arena::ArenaMap;
 use stdx::never;
+use triomphe::Arc;
 
 use crate::{db::HirDatabase, ClosureId};
 
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 7ff68774bc9..8ce16df8295 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -1,6 +1,6 @@
 //! This module provides a MIR interpreter, which is used in const eval.
 
-use std::{borrow::Cow, collections::HashMap, fmt::Write, iter, ops::Range, sync::Arc};
+use std::{borrow::Cow, collections::HashMap, fmt::Write, iter, ops::Range};
 
 use base_db::{CrateId, FileId};
 use chalk_ir::{
@@ -20,6 +20,7 @@ use intern::Interned;
 use la_arena::ArenaMap;
 use rustc_hash::FxHashMap;
 use syntax::{SyntaxNodePtr, TextRange};
+use triomphe::Arc;
 
 use crate::{
     consteval::{intern_const_scalar, ConstEvalError},
diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index 733f58e8f6b..66b1d840bdc 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -1,6 +1,6 @@
 //! This module generates a polymorphic MIR from a hir body
 
-use std::{fmt::Write, iter, mem, sync::Arc};
+use std::{fmt::Write, iter, mem};
 
 use base_db::FileId;
 use chalk_ir::{BoundVar, ConstData, DebruijnIndex, TyKind};
@@ -20,6 +20,7 @@ use hir_expand::name::Name;
 use la_arena::ArenaMap;
 use rustc_hash::FxHashMap;
 use syntax::TextRange;
+use triomphe::Arc;
 
 use crate::{
     consteval::ConstEvalError,
diff --git a/crates/hir-ty/src/test_db.rs b/crates/hir-ty/src/test_db.rs
index ca96a8d1724..1276a4c5e14 100644
--- a/crates/hir-ty/src/test_db.rs
+++ b/crates/hir-ty/src/test_db.rs
@@ -1,9 +1,6 @@
 //! Database used for testing `hir`.
 
-use std::{
-    fmt, panic,
-    sync::{Arc, Mutex},
-};
+use std::{fmt, panic, sync::Mutex};
 
 use base_db::{
     salsa::{self, Durability},
@@ -15,6 +12,7 @@ use rustc_hash::FxHashSet;
 use stdx::hash::NoHashHashMap;
 use syntax::TextRange;
 use test_utils::extract_annotations;
+use triomphe::Arc;
 
 #[salsa::database(
     base_db::SourceDatabaseExtStorage,
diff --git a/crates/hir-ty/src/tests.rs b/crates/hir-ty/src/tests.rs
index af482e5cc6d..a2adad31696 100644
--- a/crates/hir-ty/src/tests.rs
+++ b/crates/hir-ty/src/tests.rs
@@ -10,7 +10,7 @@ mod display_source_code;
 mod incremental;
 mod diagnostics;
 
-use std::{collections::HashMap, env, sync::Arc};
+use std::{collections::HashMap, env};
 
 use base_db::{fixture::WithFixture, FileRange, SourceDatabaseExt};
 use expect_test::Expect;
@@ -32,6 +32,7 @@ use syntax::{
 };
 use tracing_subscriber::{layer::SubscriberExt, EnvFilter, Registry};
 use tracing_tree::HierarchicalLayer;
+use triomphe::Arc;
 
 use crate::{
     db::HirDatabase,
diff --git a/crates/hir-ty/src/tests/incremental.rs b/crates/hir-ty/src/tests/incremental.rs
index 788eb30e28c..bb15ca8c436 100644
--- a/crates/hir-ty/src/tests/incremental.rs
+++ b/crates/hir-ty/src/tests/incremental.rs
@@ -1,6 +1,5 @@
-use std::sync::Arc;
-
 use base_db::{fixture::WithFixture, SourceDatabaseExt};
+use triomphe::Arc;
 
 use crate::{db::HirDatabase, test_db::TestDB};
 
diff --git a/crates/hir-ty/src/traits.rs b/crates/hir-ty/src/traits.rs
index 8bc38aca472..2808fe64351 100644
--- a/crates/hir-ty/src/traits.rs
+++ b/crates/hir-ty/src/traits.rs
@@ -1,6 +1,6 @@
 //! Trait solving using Chalk.
 
-use std::{env::var, sync::Arc};
+use std::env::var;
 
 use chalk_ir::GoalData;
 use chalk_recursive::Cache;
@@ -13,6 +13,7 @@ use hir_def::{
 };
 use hir_expand::name::{name, Name};
 use stdx::panic_context;
+use triomphe::Arc;
 
 use crate::{
     db::HirDatabase, infer::unify::InferenceTable, AliasEq, AliasTy, Canonical, DomainGoal, Goal,
diff --git a/crates/hir/Cargo.toml b/crates/hir/Cargo.toml
index ef40a8902d7..a20aff93f19 100644
--- a/crates/hir/Cargo.toml
+++ b/crates/hir/Cargo.toml
@@ -17,6 +17,7 @@ either = "1.7.0"
 arrayvec = "0.7.2"
 itertools = "0.10.5"
 smallvec.workspace = true
+triomphe.workspace = true
 once_cell = "1.17.0"
 
 # local deps
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 49417d945ce..d9cb2a7b6da 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -33,7 +33,7 @@ pub mod symbols;
 
 mod display;
 
-use std::{iter, ops::ControlFlow, sync::Arc};
+use std::{iter, ops::ControlFlow};
 
 use arrayvec::ArrayVec;
 use base_db::{CrateDisplayName, CrateId, CrateOrigin, Edition, FileId, ProcMacroKind};
@@ -80,6 +80,7 @@ use syntax::{
     ast::{self, HasAttrs as _, HasDocComments, HasName},
     AstNode, AstPtr, SmolStr, SyntaxNode, SyntaxNodePtr, TextRange, T,
 };
+use triomphe::Arc;
 
 use crate::db::{DefDatabase, HirDatabase};
 
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index a6a51e4907c..19179d11ef8 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -5,10 +5,7 @@
 //!
 //! So, this modules should not be used during hir construction, it exists
 //! purely for "IDE needs".
-use std::{
-    iter::{self, once},
-    sync::Arc,
-};
+use std::iter::{self, once};
 
 use either::Either;
 use hir_def::{
@@ -49,6 +46,7 @@ use syntax::{
     ast::{self, AstNode},
     SyntaxKind, SyntaxNode, TextRange, TextSize,
 };
+use triomphe::Arc;
 
 use crate::{
     db::HirDatabase, semantics::PathResolution, Adt, AssocItem, BindingMode, BuiltinAttr,
diff --git a/crates/ide-db/Cargo.toml b/crates/ide-db/Cargo.toml
index 57daaf623df..fccd6d2b6db 100644
--- a/crates/ide-db/Cargo.toml
+++ b/crates/ide-db/Cargo.toml
@@ -23,6 +23,7 @@ itertools = "0.10.5"
 arrayvec = "0.7.2"
 indexmap = "1.9.1"
 memchr = "2.5.0"
+triomphe.workspace = true
 
 # local deps
 base-db.workspace = true
diff --git a/crates/ide-db/src/apply_change.rs b/crates/ide-db/src/apply_change.rs
index 8d14371d034..8edda432ce3 100644
--- a/crates/ide-db/src/apply_change.rs
+++ b/crates/ide-db/src/apply_change.rs
@@ -1,13 +1,12 @@
 //! Applies changes to the IDE state transactionally.
 
-use std::sync::Arc;
-
 use base_db::{
     salsa::{Database, Durability},
     Change, SourceRootId,
 };
 use profile::{memory_usage, Bytes};
 use rustc_hash::FxHashSet;
+use triomphe::Arc;
 
 use crate::{symbol_index::SymbolsDatabase, RootDatabase};
 
diff --git a/crates/ide-db/src/lib.rs b/crates/ide-db/src/lib.rs
index 0c6b0f20cf5..5263271fa6f 100644
--- a/crates/ide-db/src/lib.rs
+++ b/crates/ide-db/src/lib.rs
@@ -43,13 +43,14 @@ pub mod syntax_helpers {
     pub use parser::LexedStr;
 }
 
-use std::{fmt, mem::ManuallyDrop, sync::Arc};
+use std::{fmt, mem::ManuallyDrop};
 
 use base_db::{
     salsa::{self, Durability},
     AnchoredPath, CrateId, FileId, FileLoader, FileLoaderDelegate, SourceDatabase, Upcast,
 };
 use hir::db::{DefDatabase, ExpandDatabase, HirDatabase};
+use triomphe::Arc;
 
 use crate::{line_index::LineIndex, symbol_index::SymbolsDatabase};
 pub use rustc_hash::{FxHashMap, FxHashSet, FxHasher};
diff --git a/crates/ide-db/src/search.rs b/crates/ide-db/src/search.rs
index 2557c65a106..f58a96d595a 100644
--- a/crates/ide-db/src/search.rs
+++ b/crates/ide-db/src/search.rs
@@ -4,7 +4,7 @@
 //! get a super-set of matches. Then, we we confirm each match using precise
 //! name resolution.
 
-use std::{mem, sync::Arc};
+use std::mem;
 
 use base_db::{FileId, FileRange, SourceDatabase, SourceDatabaseExt};
 use hir::{
@@ -15,6 +15,7 @@ use once_cell::unsync::Lazy;
 use parser::SyntaxKind;
 use stdx::hash::NoHashHashMap;
 use syntax::{ast, match_ast, AstNode, TextRange, TextSize};
+use triomphe::Arc;
 
 use crate::{
     defs::{Definition, NameClass, NameRefClass},
diff --git a/crates/ide-db/src/symbol_index.rs b/crates/ide-db/src/symbol_index.rs
index a6f86c83df7..fa796ae13b2 100644
--- a/crates/ide-db/src/symbol_index.rs
+++ b/crates/ide-db/src/symbol_index.rs
@@ -25,7 +25,6 @@ use std::{
     fmt,
     hash::{Hash, Hasher},
     mem,
-    sync::Arc,
 };
 
 use base_db::{
@@ -40,6 +39,7 @@ use hir::{
 };
 use rayon::prelude::*;
 use rustc_hash::FxHashSet;
+use triomphe::Arc;
 
 use crate::RootDatabase;
 
diff --git a/crates/ide-ssr/Cargo.toml b/crates/ide-ssr/Cargo.toml
index 04efa7b91d8..b8625fc1be9 100644
--- a/crates/ide-ssr/Cargo.toml
+++ b/crates/ide-ssr/Cargo.toml
@@ -15,6 +15,7 @@ doctest = false
 [dependencies]
 cov-mark = "2.0.0-pre.1"
 itertools = "0.10.5"
+triomphe.workspace = true
 
 # local deps
 hir.workspace = true
diff --git a/crates/ide-ssr/src/tests.rs b/crates/ide-ssr/src/tests.rs
index 61698fca80f..424ba3d7fd5 100644
--- a/crates/ide-ssr/src/tests.rs
+++ b/crates/ide-ssr/src/tests.rs
@@ -3,8 +3,8 @@ use ide_db::{
     base_db::{salsa::Durability, FileId, FilePosition, FileRange, SourceDatabaseExt},
     FxHashSet,
 };
-use std::sync::Arc;
 use test_utils::RangeOrOffset;
+use triomphe::Arc;
 
 use crate::{MatchFinder, SsrRule};
 
diff --git a/crates/ide/Cargo.toml b/crates/ide/Cargo.toml
index 30e514e4136..c3dcb60490c 100644
--- a/crates/ide/Cargo.toml
+++ b/crates/ide/Cargo.toml
@@ -23,6 +23,7 @@ pulldown-cmark = { version = "0.9.1", default-features = false }
 url = "2.3.1"
 dot = "0.1.4"
 smallvec.workspace = true
+triomphe.workspace = true
 
 # local deps
 cfg.workspace = true
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index 1af4d39265f..b84d5df8107 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -61,7 +61,7 @@ mod view_item_tree;
 mod shuffle_crate_graph;
 mod fetch_crates;
 
-use std::{ffi::OsStr, sync::Arc};
+use std::ffi::OsStr;
 
 use cfg::CfgOptions;
 use fetch_crates::CrateInfo;
@@ -73,6 +73,7 @@ use ide_db::{
     symbol_index, FxHashMap, FxIndexSet, LineIndexDatabase,
 };
 use syntax::SourceFile;
+use triomphe::Arc;
 
 use crate::navigation_target::{ToNav, TryToNav};
 
diff --git a/crates/ide/src/shuffle_crate_graph.rs b/crates/ide/src/shuffle_crate_graph.rs
index d94b15f60c8..f85700daf1f 100644
--- a/crates/ide/src/shuffle_crate_graph.rs
+++ b/crates/ide/src/shuffle_crate_graph.rs
@@ -1,9 +1,8 @@
-use std::sync::Arc;
-
 use ide_db::{
     base_db::{salsa::Durability, CrateGraph, ProcMacros, SourceDatabase},
     FxHashMap, RootDatabase,
 };
+use triomphe::Arc;
 
 // Feature: Shuffle Crate Graph
 //
diff --git a/crates/ide/src/ssr.rs b/crates/ide/src/ssr.rs
index 497eb1cc130..deaf3c9c416 100644
--- a/crates/ide/src/ssr.rs
+++ b/crates/ide/src/ssr.rs
@@ -56,8 +56,6 @@ pub(crate) fn ssr_assists(
 
 #[cfg(test)]
 mod tests {
-    use std::sync::Arc;
-
     use expect_test::expect;
     use ide_assists::{Assist, AssistResolveStrategy};
     use ide_db::{
@@ -65,6 +63,7 @@ mod tests {
         symbol_index::SymbolsDatabase,
         FxHashSet, RootDatabase,
     };
+    use triomphe::Arc;
 
     use super::ssr_assists;
 
diff --git a/crates/ide/src/status.rs b/crates/ide/src/status.rs
index 3dfbc1874b3..70bff41121d 100644
--- a/crates/ide/src/status.rs
+++ b/crates/ide/src/status.rs
@@ -1,4 +1,4 @@
-use std::{fmt, marker::PhantomData, sync::Arc};
+use std::{fmt, marker::PhantomData};
 
 use hir::{
     db::{AstIdMapQuery, AttrsQuery, ParseMacroExpansionQuery},
@@ -23,6 +23,7 @@ use profile::{memory_usage, Bytes};
 use std::env;
 use stdx::format_to;
 use syntax::{ast, Parse, SyntaxNode};
+use triomphe::Arc;
 
 // Feature: Status
 //
diff --git a/crates/ide/src/view_crate_graph.rs b/crates/ide/src/view_crate_graph.rs
index 711f7e3f876..8c84461f659 100644
--- a/crates/ide/src/view_crate_graph.rs
+++ b/crates/ide/src/view_crate_graph.rs
@@ -1,10 +1,9 @@
-use std::sync::Arc;
-
 use dot::{Id, LabelText};
 use ide_db::{
     base_db::{CrateGraph, CrateId, Dependency, SourceDatabase, SourceDatabaseExt},
     FxHashSet, RootDatabase,
 };
+use triomphe::Arc;
 
 // Feature: View Crate Graph
 //
diff --git a/crates/intern/Cargo.toml b/crates/intern/Cargo.toml
index c73c368a14e..dcd0d788125 100644
--- a/crates/intern/Cargo.toml
+++ b/crates/intern/Cargo.toml
@@ -18,3 +18,4 @@ dashmap = { version = "=5.4.0", features = ["raw-api"] }
 hashbrown = { version = "0.12.1", default-features = false }
 once_cell = "1.17.0"
 rustc-hash = "1.1.0"
+triomphe.workspace = true
diff --git a/crates/intern/src/lib.rs b/crates/intern/src/lib.rs
index fb2903696b3..d17eddf1560 100644
--- a/crates/intern/src/lib.rs
+++ b/crates/intern/src/lib.rs
@@ -6,13 +6,13 @@ use std::{
     fmt::{self, Debug, Display},
     hash::{BuildHasherDefault, Hash, Hasher},
     ops::Deref,
-    sync::Arc,
 };
 
 use dashmap::{DashMap, SharedValue};
 use hashbrown::HashMap;
 use once_cell::sync::OnceCell;
 use rustc_hash::FxHasher;
+use triomphe::Arc;
 
 type InternMap<T> = DashMap<Arc<T>, (), BuildHasherDefault<FxHasher>>;
 type Guard<T> = dashmap::RwLockWriteGuard<
@@ -83,7 +83,7 @@ impl<T: Internable + ?Sized> Drop for Interned<T> {
     #[inline]
     fn drop(&mut self) {
         // When the last `Ref` is dropped, remove the object from the global map.
-        if Arc::strong_count(&self.arc) == 2 {
+        if Arc::count(&self.arc) == 2 {
             // Only `self` and the global map point to the object.
 
             self.drop_slow();
@@ -102,7 +102,7 @@ impl<T: Internable + ?Sized> Interned<T> {
         // FIXME: avoid double lookup
         let (arc, _) = shard.get_key_value(&self.arc).expect("interned value removed prematurely");
 
-        if Arc::strong_count(arc) != 2 {
+        if Arc::count(arc) != 2 {
             // Another thread has interned another copy
             return;
         }
diff --git a/crates/proc-macro-api/Cargo.toml b/crates/proc-macro-api/Cargo.toml
index e748421f6dd..d3486e75575 100644
--- a/crates/proc-macro-api/Cargo.toml
+++ b/crates/proc-macro-api/Cargo.toml
@@ -22,6 +22,7 @@ object = { version = "0.30.2", default-features = false, features = [
 serde.workspace = true
 serde_json = { workspace = true, features = ["unbounded_depth"] }
 tracing = "0.1.37"
+triomphe.workspace = true
 memmap2 = "0.5.4"
 snap = "1.1.0"
 
diff --git a/crates/proc-macro-api/src/lib.rs b/crates/proc-macro-api/src/lib.rs
index ab15f414bbf..1603458f756 100644
--- a/crates/proc-macro-api/src/lib.rs
+++ b/crates/proc-macro-api/src/lib.rs
@@ -12,10 +12,8 @@ mod process;
 mod version;
 
 use paths::AbsPathBuf;
-use std::{
-    fmt, io,
-    sync::{Arc, Mutex},
-};
+use std::{fmt, io, sync::Mutex};
+use triomphe::Arc;
 
 use serde::{Deserialize, Serialize};
 
diff --git a/crates/project-model/Cargo.toml b/crates/project-model/Cargo.toml
index 080b224e862..efe61eb8f68 100644
--- a/crates/project-model/Cargo.toml
+++ b/crates/project-model/Cargo.toml
@@ -18,6 +18,7 @@ cargo_metadata = "0.15.0"
 semver = "1.0.14"
 serde_json.workspace = true
 serde.workspace = true
+triomphe.workspace = true
 anyhow = "1.0.62"
 la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
 
diff --git a/crates/project-model/src/workspace.rs b/crates/project-model/src/workspace.rs
index 5924287a37f..bfd2cab31fb 100644
--- a/crates/project-model/src/workspace.rs
+++ b/crates/project-model/src/workspace.rs
@@ -2,7 +2,7 @@
 //! metadata` or `rust-project.json`) into representation stored in the salsa
 //! database -- `CrateGraph`.
 
-use std::{collections::VecDeque, fmt, fs, process::Command, sync::Arc};
+use std::{collections::VecDeque, fmt, fs, process::Command, sync};
 
 use anyhow::{format_err, Context, Result};
 use base_db::{
@@ -14,6 +14,7 @@ use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::{FxHashMap, FxHashSet};
 use semver::Version;
 use stdx::always;
+use triomphe::Arc;
 
 use crate::{
     build_scripts::BuildScriptOutput,
@@ -422,7 +423,7 @@ impl ProjectWorkspace {
         let outputs = &mut match WorkspaceBuildScripts::run_once(config, &cargo_ws, progress) {
             Ok(it) => Ok(it.into_iter()),
             // io::Error is not Clone?
-            Err(e) => Err(Arc::new(e)),
+            Err(e) => Err(sync::Arc::new(e)),
         };
 
         workspaces
diff --git a/crates/rust-analyzer/Cargo.toml b/crates/rust-analyzer/Cargo.toml
index ea4f155bfd5..c7c2e341276 100644
--- a/crates/rust-analyzer/Cargo.toml
+++ b/crates/rust-analyzer/Cargo.toml
@@ -45,6 +45,7 @@ tracing-subscriber = { version = "0.3.16", default-features = false, features =
 ] }
 tracing-log = "0.1.3"
 tracing-tree = "0.2.1"
+triomphe.workspace = true
 always-assert = "0.1.2"
 
 # These dependencies are unused, but we pin them to a version here to restrict them for our transitive dependencies
diff --git a/crates/rust-analyzer/src/cli/load_cargo.rs b/crates/rust-analyzer/src/cli/load_cargo.rs
index 625f1f2b193..4e8f9997167 100644
--- a/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -1,6 +1,6 @@
 //! Loads a Cargo project into a static instance of analysis, without support
 //! for incorporating changes.
-use std::{path::Path, sync::Arc};
+use std::path::Path;
 
 use anyhow::{anyhow, Result};
 use crossbeam_channel::{unbounded, Receiver};
@@ -11,6 +11,7 @@ use ide_db::{
 };
 use proc_macro_api::ProcMacroServer;
 use project_model::{CargoConfig, ProjectManifest, ProjectWorkspace};
+use triomphe::Arc;
 use vfs::{loader::Handle, AbsPath, AbsPathBuf};
 
 use crate::reload::{load_proc_macro, ProjectFolders, SourceRootConfig};
diff --git a/crates/rust-analyzer/src/diagnostics.rs b/crates/rust-analyzer/src/diagnostics.rs
index 83b03fe4736..2edb394a0b1 100644
--- a/crates/rust-analyzer/src/diagnostics.rs
+++ b/crates/rust-analyzer/src/diagnostics.rs
@@ -1,11 +1,12 @@
 //! Book keeping for keeping diagnostics easily in sync with the client.
 pub(crate) mod to_proto;
 
-use std::{mem, sync::Arc};
+use std::mem;
 
 use ide::FileId;
 use ide_db::FxHashMap;
 use stdx::hash::{NoHashHashMap, NoHashHashSet};
+use triomphe::Arc;
 
 use crate::lsp_ext;
 
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index 07778d2b59f..0f77eeae4ad 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -3,7 +3,7 @@
 //!
 //! Each tick provides an immutable snapshot of the state as `WorldSnapshot`.
 
-use std::{sync::Arc, time::Instant};
+use std::time::Instant;
 
 use crossbeam_channel::{unbounded, Receiver, Sender};
 use flycheck::FlycheckHandle;
@@ -15,6 +15,7 @@ use proc_macro_api::ProcMacroServer;
 use project_model::{CargoWorkspace, ProjectWorkspace, Target, WorkspaceBuildScripts};
 use rustc_hash::FxHashMap;
 use stdx::hash::NoHashHashMap;
+use triomphe::Arc;
 use vfs::AnchoredPathBuf;
 
 use crate::{
@@ -161,9 +162,11 @@ impl GlobalState {
             source_root_config: SourceRootConfig::default(),
 
             proc_macro_changed: false,
-            proc_macro_clients: Arc::new([]),
+            // FIXME: use `Arc::from_iter` when it becomes available
+            proc_macro_clients: Arc::from(Vec::new()),
 
-            flycheck: Arc::new([]),
+            // FIXME: use `Arc::from_iter` when it becomes available
+            flycheck: Arc::from(Vec::new()),
             flycheck_sender,
             flycheck_receiver,
 
diff --git a/crates/rust-analyzer/src/handlers/notification.rs b/crates/rust-analyzer/src/handlers/notification.rs
index a734f483010..ca9ea77f305 100644
--- a/crates/rust-analyzer/src/handlers/notification.rs
+++ b/crates/rust-analyzer/src/handlers/notification.rs
@@ -1,7 +1,7 @@
 //! This module is responsible for implementing handlers for Language Server
 //! Protocol. This module specifically handles notifications.
 
-use std::{ops::Deref, sync::Arc};
+use std::ops::Deref;
 
 use itertools::Itertools;
 use lsp_types::{
@@ -9,6 +9,7 @@ use lsp_types::{
     DidChangeWatchedFilesParams, DidChangeWorkspaceFoldersParams, DidCloseTextDocumentParams,
     DidOpenTextDocumentParams, DidSaveTextDocumentParams, WorkDoneProgressCancelParams,
 };
+use triomphe::Arc;
 use vfs::{AbsPathBuf, ChangeKind, VfsPath};
 
 use crate::{
diff --git a/crates/rust-analyzer/src/handlers/request.rs b/crates/rust-analyzer/src/handlers/request.rs
index 3a208865a78..9e9dfaaf5a3 100644
--- a/crates/rust-analyzer/src/handlers/request.rs
+++ b/crates/rust-analyzer/src/handlers/request.rs
@@ -5,7 +5,6 @@ use std::{
     fs,
     io::Write as _,
     process::{self, Stdio},
-    sync::Arc,
 };
 
 use anyhow::Context;
@@ -30,6 +29,7 @@ use project_model::{ManifestPath, ProjectWorkspace, TargetKind};
 use serde_json::json;
 use stdx::{format_to, never};
 use syntax::{algo, ast, AstNode, TextRange, TextSize};
+use triomphe::Arc;
 use vfs::{AbsPath, AbsPathBuf, VfsPath};
 
 use crate::{
@@ -48,7 +48,8 @@ use crate::{
 };
 
 pub(crate) fn handle_workspace_reload(state: &mut GlobalState, _: ()) -> Result<()> {
-    state.proc_macro_clients = Arc::new([]);
+    // FIXME: use `Arc::from_iter` when it becomes available
+    state.proc_macro_clients = Arc::from(Vec::new());
     state.proc_macro_changed = false;
 
     state.fetch_workspaces_queue.request_op("reload workspace request".to_string(), ());
@@ -56,7 +57,8 @@ pub(crate) fn handle_workspace_reload(state: &mut GlobalState, _: ()) -> Result<
 }
 
 pub(crate) fn handle_proc_macros_rebuild(state: &mut GlobalState, _: ()) -> Result<()> {
-    state.proc_macro_clients = Arc::new([]);
+    // FIXME: use `Arc::from_iter` when it becomes available
+    state.proc_macro_clients = Arc::from(Vec::new());
     state.proc_macro_changed = false;
 
     state.fetch_build_data_queue.request_op("rebuild proc macros request".to_string(), ());
diff --git a/crates/rust-analyzer/src/integrated_benchmarks.rs b/crates/rust-analyzer/src/integrated_benchmarks.rs
index 6a69f70962b..bd9f471a46d 100644
--- a/crates/rust-analyzer/src/integrated_benchmarks.rs
+++ b/crates/rust-analyzer/src/integrated_benchmarks.rs
@@ -10,8 +10,6 @@
 //! in release mode in VS Code. There's however "rust-analyzer: Copy Run Command Line"
 //! which you can use to paste the command in terminal and add `--release` manually.
 
-use std::sync::Arc;
-
 use ide::{CallableSnippets, Change, CompletionConfig, FilePosition, TextSize};
 use ide_db::{
     imports::insert_use::{ImportGranularity, InsertUseConfig},
@@ -19,6 +17,7 @@ use ide_db::{
 };
 use project_model::CargoConfig;
 use test_utils::project_root;
+use triomphe::Arc;
 use vfs::{AbsPathBuf, VfsPath};
 
 use crate::cli::load_cargo::{load_workspace_at, LoadCargoConfig, ProcMacroServerChoice};
diff --git a/crates/rust-analyzer/src/line_index.rs b/crates/rust-analyzer/src/line_index.rs
index 791cd931d42..15450303ff2 100644
--- a/crates/rust-analyzer/src/line_index.rs
+++ b/crates/rust-analyzer/src/line_index.rs
@@ -5,9 +5,8 @@
 //! This module does line ending conversion and detection (so that we can
 //! convert back to `\r\n` on the way out).
 
-use std::sync::Arc;
-
 use ide_db::line_index::WideEncoding;
+use triomphe::Arc;
 
 #[derive(Clone, Copy)]
 pub enum PositionEncoding {
diff --git a/crates/rust-analyzer/src/lsp_utils.rs b/crates/rust-analyzer/src/lsp_utils.rs
index 12e5caf2cc9..9a73da15398 100644
--- a/crates/rust-analyzer/src/lsp_utils.rs
+++ b/crates/rust-analyzer/src/lsp_utils.rs
@@ -1,8 +1,9 @@
 //! Utilities for LSP-related boilerplate code.
-use std::{mem, ops::Range, sync::Arc};
+use std::{mem, ops::Range};
 
 use lsp_server::Notification;
 use lsp_types::request::Request;
+use triomphe::Arc;
 
 use crate::{
     from_proto,
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index d3cfc5e40d6..ea8dbc54388 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -2,7 +2,6 @@
 //! requests/replies and notifications back to the client.
 use std::{
     fmt,
-    sync::Arc,
     time::{Duration, Instant},
 };
 
@@ -12,6 +11,7 @@ use flycheck::FlycheckHandle;
 use ide_db::base_db::{SourceDatabaseExt, VfsPath};
 use lsp_server::{Connection, Notification, Request};
 use lsp_types::notification::Notification as _;
+use triomphe::Arc;
 use vfs::FileId;
 
 use crate::{
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index 87ec040d7b8..4c76392a0e7 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -12,7 +12,7 @@
 //! correct. Instead, we try to provide a best-effort service. Even if the
 //! project is currently loading and we don't have a full project model, we
 //! still want to respond to various  requests.
-use std::{collections::hash_map::Entry, iter, mem, sync::Arc};
+use std::{collections::hash_map::Entry, iter, mem, sync};
 
 use flycheck::{FlycheckConfig, FlycheckHandle};
 use hir::db::DefDatabase;
@@ -28,6 +28,7 @@ use itertools::Itertools;
 use proc_macro_api::{MacroDylib, ProcMacroServer};
 use project_model::{PackageRoot, ProjectWorkspace, WorkspaceBuildScripts};
 use syntax::SmolStr;
+use triomphe::Arc;
 use vfs::{file_set::FileSetConfig, AbsPath, AbsPathBuf, ChangeKind};
 
 use crate::{
@@ -415,30 +416,32 @@ impl GlobalState {
             if self.config.expand_proc_macros() {
                 tracing::info!("Spawning proc-macro servers");
 
-                self.proc_macro_clients = self
-                    .workspaces
-                    .iter()
-                    .map(|ws| {
-                        let path = match self.config.proc_macro_srv() {
-                            Some(path) => path,
-                            None => ws.find_sysroot_proc_macro_srv()?,
-                        };
-
-                        tracing::info!("Using proc-macro server at {}", path.display(),);
-                        ProcMacroServer::spawn(path.clone()).map_err(|err| {
-                            tracing::error!(
-                                "Failed to run proc-macro server from path {}, error: {:?}",
-                                path.display(),
-                                err
-                            );
-                            anyhow::anyhow!(
-                                "Failed to run proc-macro server from path {}, error: {:?}",
-                                path.display(),
-                                err
-                            )
+                // FIXME: use `Arc::from_iter` when it becomes available
+                self.proc_macro_clients = Arc::from(
+                    self.workspaces
+                        .iter()
+                        .map(|ws| {
+                            let path = match self.config.proc_macro_srv() {
+                                Some(path) => path,
+                                None => ws.find_sysroot_proc_macro_srv()?,
+                            };
+
+                            tracing::info!("Using proc-macro server at {}", path.display(),);
+                            ProcMacroServer::spawn(path.clone()).map_err(|err| {
+                                tracing::error!(
+                                    "Failed to run proc-macro server from path {}, error: {:?}",
+                                    path.display(),
+                                    err
+                                );
+                                anyhow::anyhow!(
+                                    "Failed to run proc-macro server from path {}, error: {:?}",
+                                    path.display(),
+                                    err
+                                )
+                            })
                         })
-                    })
-                    .collect()
+                        .collect::<Vec<_>>(),
+                )
             };
         }
 
@@ -773,14 +776,14 @@ pub(crate) fn load_proc_macro(
             proc_macro_api::ProcMacroKind::FuncLike => ProcMacroKind::FuncLike,
             proc_macro_api::ProcMacroKind::Attr => ProcMacroKind::Attr,
         };
-        let expander: Arc<dyn ProcMacroExpander> =
+        let expander: sync::Arc<dyn ProcMacroExpander> =
             if dummy_replace.iter().any(|replace| &**replace == name) {
                 match kind {
-                    ProcMacroKind::Attr => Arc::new(IdentityExpander),
-                    _ => Arc::new(EmptyExpander),
+                    ProcMacroKind::Attr => sync::Arc::new(IdentityExpander),
+                    _ => sync::Arc::new(EmptyExpander),
                 }
             } else {
-                Arc::new(Expander(expander))
+                sync::Arc::new(Expander(expander))
             };
         ProcMacro { name, kind, expander }
     }
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 521db6b0ca9..60292d2ad18 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -1441,9 +1441,8 @@ pub(crate) fn rename_error(err: RenameError) -> crate::LspError {
 
 #[cfg(test)]
 mod tests {
-    use std::sync::Arc;
-
     use ide::Analysis;
+    use triomphe::Arc;
 
     use super::*;
 
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 9109507f75e..ac5b3058b97 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -22,6 +22,7 @@ rustc-hash = "1.1.0"
 once_cell = "1.17.0"
 indexmap = "1.9.1"
 smol_str.workspace = true
+triomphe.workspace = true
 
 parser.workspace = true
 profile.workspace = true
diff --git a/crates/syntax/src/lib.rs b/crates/syntax/src/lib.rs
index 6f57cbad66b..efbf8796644 100644
--- a/crates/syntax/src/lib.rs
+++ b/crates/syntax/src/lib.rs
@@ -43,10 +43,11 @@ pub mod utils;
 pub mod ted;
 pub mod hacks;
 
-use std::{marker::PhantomData, sync::Arc};
+use std::marker::PhantomData;
 
 use stdx::format_to;
 use text_edit::Indel;
+use triomphe::Arc;
 
 pub use crate::{
     ast::{AstNode, AstToken},