proc_macro: add dependency on rustc_hash and update to 2.0

Author: Lukas Markeffsky

library/Cargo.lock

@@ -227,6 +227,7 @@ name = "proc_macro"
 version = "0.0.0"
 dependencies = [
  "core",
+ "rustc-hash",
  "std",
 ]
 
@@ -292,6 +293,15 @@ dependencies = [
  "rustc-std-workspace-core",
 ]
 
+[[package]]
+name = "rustc-hash"
+version = "2.2.0"
+source = "git+https://github.com/lukas-code/rustc-hash.git?branch=dep-of-std#893c45b6a827d3cc6ecfa0c04830793f7a960d84"
+dependencies = [
+ "rustc-std-workspace-core",
+ "rustc-std-workspace-std",
+]
+
 [[package]]
 name = "rustc-std-workspace-alloc"
 version = "1.99.0"

library/proc_macro/Cargo.toml

@@ -9,3 +9,10 @@ std = { path = "../std" }
 # `core` when resolving doc links. Without this line a different `core` will be
 # loaded from sysroot causing duplicate lang items and other similar errors.
 core = { path = "../core" }
+
+[dependencies.rustc-hash]
+version = "2.2.0"
+git = "https://github.com/lukas-code/rustc-hash.git"
+branch = "dep-of-std"
+default-features = false
+features = ["rustc-dep-of-std"]

library/proc_macro/src/bridge/fxhash.rs

@@ -6,7 +6,7 @@ use std::num::NonZero;
 use std::ops::{Index, IndexMut};
 use std::sync::atomic::{AtomicU32, Ordering};
 
-use super::fxhash::FxHashMap;
+use rustc_hash::FxHashMap;
 
 pub(super) type Handle = NonZero<u32>;
 

library/proc_macro/src/bridge/handle.rs

@@ -155,8 +155,6 @@ pub mod client;
 #[allow(unsafe_code)]
 mod closure;
 #[forbid(unsafe_code)]
-mod fxhash;
-#[forbid(unsafe_code)]
 mod handle;
 #[macro_use]
 #[forbid(unsafe_code)]

library/proc_macro/src/bridge/mod.rs

@@ -128,7 +128,7 @@ impl<S> DecodeMut<'_, '_, S> for Symbol {
 thread_local! {
     static INTERNER: RefCell<Interner> = RefCell::new(Interner {
         arena: arena::Arena::new(),
-        names: fxhash::FxHashMap::default(),
+        names: rustc_hash::FxHashMap::default(),
         strings: Vec::new(),
         // Start with a base of 1 to make sure that `NonZero<u32>` works.
         sym_base: NonZero::new(1).unwrap(),
@@ -141,7 +141,7 @@ struct Interner {
     // SAFETY: These `'static` lifetimes are actually references to data owned
     // by the Arena. This is safe, as we never return them as static references
     // from `Interner`.
-    names: fxhash::FxHashMap<&'static str, Symbol>,
+    names: rustc_hash::FxHashMap<&'static str, Symbol>,
     strings: Vec<&'static str>,
     // The offset to apply to symbol names stored in the interner. This is used
     // to ensure that symbol names are not re-used after the interner is

library/proc_macro/src/bridge/symbol.rs

@@ -479,6 +479,7 @@ const PERMITTED_STDLIB_DEPENDENCIES: &[&str] = &[
     "rand_core",
     "rand_xorshift",
     "rustc-demangle",
+    "rustc-hash",
     "shlex",
     "unicode-width",
     "unwinding",