Add a list of symbols for stable standard library crates

compiler/rustc_expand/src/config.rs

@@ -18,7 +18,7 @@ use rustc_lint_defs::BuiltinLintDiag;
 use rustc_parse::validate_attr;
 use rustc_session::Session;
 use rustc_session::parse::feature_err;
-use rustc_span::{Span, Symbol, sym};
+use rustc_span::{STDLIB_STABLE_CRATES, Span, Symbol, sym};
 use thin_vec::ThinVec;
 use tracing::instrument;
 
@@ -107,14 +107,11 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -
 
             // If the enabled feature is unstable, record it.
             if UNSTABLE_LANG_FEATURES.iter().find(|f| name == f.name).is_some() {
-                // When the ICE comes from core, alloc or std (approximation of the standard
-                // library), there's a chance that the person hitting the ICE may be using
-                // -Zbuild-std or similar with an untested target. The bug is probably in the
-                // standard library and not the compiler in that case, but that doesn't really
-                // matter - we want a bug report.
-                if features.internal(name)
-                    && ![sym::core, sym::alloc, sym::std].contains(&crate_name)
-                {
+                // When the ICE comes a standard library crate, there's a chance that the person
+                // hitting the ICE may be using -Zbuild-std or similar with an untested target.
+                // The bug is probably in the standard library and not the compiler in that case,
+                // but that doesn't really matter - we want a bug report.
+                if features.internal(name) && !STDLIB_STABLE_CRATES.contains(&crate_name) {
                     sess.using_internal_features.store(true, std::sync::atomic::Ordering::Relaxed);
                 }
 
@@ -133,7 +130,7 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -
 
             // Similar to above, detect internal lib features to suppress
             // the ICE message that asks for a report.
-            if features.internal(name) && ![sym::core, sym::alloc, sym::std].contains(&crate_name) {
+            if features.internal(name) && !STDLIB_STABLE_CRATES.contains(&crate_name) {
                 sess.using_internal_features.store(true, std::sync::atomic::Ordering::Relaxed);
             }
         }

compiler/rustc_hir_typeck/src/method/prelude_edition_lints.rs

@@ -8,7 +8,7 @@ use rustc_lint::{ARRAY_INTO_ITER, BOXED_SLICE_INTO_ITER};
 use rustc_middle::span_bug;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::lint::builtin::{RUST_2021_PRELUDE_COLLISIONS, RUST_2024_PRELUDE_COLLISIONS};
-use rustc_span::{Ident, Span, kw, sym};
+use rustc_span::{Ident, STDLIB_STABLE_CRATES, Span, kw, sym};
 use rustc_trait_selection::infer::InferCtxtExt;
 use tracing::debug;
 
@@ -76,7 +76,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         };
 
         // No need to lint if method came from std/core, as that will now be in the prelude
-        if matches!(self.tcx.crate_name(pick.item.def_id.krate), sym::std | sym::core) {
+        if STDLIB_STABLE_CRATES.contains(&self.tcx.crate_name(pick.item.def_id.krate)) {
             return;
         }
 
@@ -252,7 +252,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         // No need to lint if method came from std/core, as that will now be in the prelude
-        if matches!(self.tcx.crate_name(pick.item.def_id.krate), sym::std | sym::core) {
+        if STDLIB_STABLE_CRATES.contains(&self.tcx.crate_name(pick.item.def_id.krate)) {
             return;
         }
 

compiler/rustc_span/src/lib.rs

@@ -67,7 +67,7 @@ mod span_encoding;
 pub use span_encoding::{DUMMY_SP, Span};
 
 pub mod symbol;
-pub use symbol::{Ident, MacroRulesNormalizedIdent, Symbol, kw, sym};
+pub use symbol::{Ident, MacroRulesNormalizedIdent, STDLIB_STABLE_CRATES, Symbol, kw, sym};
 
 mod analyze_source_file;
 pub mod fatal_error;

compiler/rustc_span/src/symbol.rs

@@ -2240,6 +2240,10 @@ symbols! {
     }
 }
 
+/// Symbols for crates that are part of the stable standard library: `std`, `core`, `alloc`, and
+/// `proc_macro`.
+pub const STDLIB_STABLE_CRATES: &[Symbol] = &[sym::std, sym::core, sym::alloc, sym::proc_macro];
+
 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
 pub struct Ident {
     pub name: Symbol,

compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs

@@ -27,7 +27,7 @@ use rustc_middle::ty::{
     self, ToPolyTraitRef, TraitRef, Ty, TyCtxt, TypeFoldable, TypeVisitableExt, Upcast,
 };
 use rustc_middle::{bug, span_bug};
-use rustc_span::{BytePos, DUMMY_SP, Span, Symbol, sym};
+use rustc_span::{BytePos, DUMMY_SP, STDLIB_STABLE_CRATES, Span, Symbol, sym};
 use tracing::{debug, instrument};
 
 use super::on_unimplemented::{AppendConstMessage, OnUnimplementedNote};
@@ -520,7 +520,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                             match obligation.cause.span.ctxt().outer_expn_data().macro_def_id {
                                 Some(macro_def_id) => {
                                     let crate_name = tcx.crate_name(macro_def_id.krate);
-                                    crate_name == sym::std || crate_name == sym::core
+                                    STDLIB_STABLE_CRATES.contains(&crate_name)
                                 }
                                 None => false,
                             };