Use hashbrown from crates.io

Cargo.lock

@@ -1491,6 +1491,7 @@ version = "0.15.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
 dependencies = [
+ "allocator-api2",
  "foldhash",
  "serde",
 ]
@@ -3479,6 +3480,7 @@ dependencies = [
  "either",
  "elsa",
  "ena",
+ "hashbrown 0.15.2",
  "indexmap",
  "jobserver",
  "libc",
@@ -4257,6 +4259,7 @@ dependencies = [
 name = "rustc_query_system"
 version = "0.0.0"
 dependencies = [
+ "hashbrown 0.15.2",
  "parking_lot",
  "rustc-rayon-core",
  "rustc_abi",

compiler/rustc_data_structures/Cargo.toml

@@ -29,6 +29,11 @@ thin-vec = "0.2.12"
 tracing = "0.1"
 # tidy-alphabetical-end
 
+[dependencies.hashbrown]
+version = "0.15.2"
+default-features = false
+features = ["nightly"] # for may_dangle
+
 [dependencies.parking_lot]
 version = "0.12"
 

compiler/rustc_data_structures/src/lib.rs

@@ -38,8 +38,6 @@
 #![feature(unwrap_infallible)]
 // tidy-alphabetical-end
 
-extern crate hashbrown;
-
 use std::fmt;
 
 pub use atomic_ref::AtomicRef;

compiler/rustc_query_system/Cargo.toml

@@ -24,3 +24,8 @@ rustc_span = { path = "../rustc_span" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 # tidy-alphabetical-end
+
+[dependencies.hashbrown]
+version = "0.15.2"
+default-features = false
+features = ["nightly"] # for may_dangle

compiler/rustc_query_system/src/lib.rs

@@ -7,8 +7,6 @@
 #![feature(min_specialization)]
 // tidy-alphabetical-end
 
-extern crate hashbrown;
-
 pub mod cache;
 pub mod dep_graph;
 mod error;