Allow builtin macros to be used more than once.

This removes E0773 "A builtin-macro was defined more than once."

Author: m-ou-se

compiler/rustc_ast_lowering/src/item.rs

@@ -23,7 +23,6 @@ use super::{
     AstOwner, FnDeclKind, ImplTraitContext, ImplTraitPosition, LoweringContext, ParamMode,
     ResolverAstLoweringExt,
 };
-use crate::GenericArgsMode;
 
 pub(super) struct ItemLowerer<'a, 'hir> {
     pub(super) tcx: TyCtxt<'hir>,

compiler/rustc_error_codes/src/lib.rs

@@ -515,7 +515,6 @@ E0769: 0769,
 E0770: 0770,
 E0771: 0771,
 E0772: 0772,
-E0773: 0773,
 E0774: 0774,
 E0775: 0775,
 E0776: 0776,

compiler/rustc_hir_analysis/src/check/compare_eii.rs

@@ -7,14 +7,13 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{self as hir, FnSig, HirId, ItemKind};
 use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::{ObligationCause, ObligationCauseCode};
-use rustc_middle::ty;
+use rustc_middle::ty::{self, TypingMode};
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_span::{ErrorGuaranteed, Ident, Span, Symbol};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::regions::InferCtxtRegionExt;
 use rustc_trait_selection::traits::ObligationCtxt;
-use rustc_type_ir::TypingMode;
 use tracing::{debug, instrument};
 
 use super::potentially_plural_count;
@@ -147,7 +146,7 @@ fn compare_number_of_method_arguments<'tcx>(
             })
             .or_else(|| tcx.hir().span_if_local(declaration));
 
-        let (external_impl_sig, _, _) = &tcx.hir().expect_item(external_impl).expect_fn();
+        let (_, external_impl_sig, _, _) = &tcx.hir_expect_item(external_impl).expect_fn();
         let pos = external_impl_number_args.saturating_sub(1);
         let impl_span = external_impl_sig
             .decl
@@ -321,7 +320,7 @@ fn report_eii_mismatch<'tcx>(
             if declaration_sig.inputs().len() == *i {
                 // Suggestion to change output type. We do not suggest in `async` functions
                 // to avoid complex logic or incorrect output.
-                if let ItemKind::Fn { sig, .. } = &tcx.hir().expect_item(external_impl_did).kind
+                if let ItemKind::Fn { sig, .. } = &tcx.hir_expect_item(external_impl_did).kind
                     && !sig.header.asyncness.is_async()
                 {
                     let msg = "change the output type to match the declaration";
@@ -376,11 +375,11 @@ fn extract_spans_for_error_reporting<'tcx>(
 ) -> (Span, Option<Span>, Ident) {
     let tcx = infcx.tcx;
     let (mut external_impl_args, external_impl_name) = {
-        let item = tcx.hir().expect_item(external_impl);
-        let (sig, _, _) = item.expect_fn();
+        let item = tcx.hir_expect_item(external_impl);
+        let (ident, sig, _, _) = item.expect_fn();
         (
             sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span())),
-            item.ident,
+            ident,
         )
     };
 

compiler/rustc_resolve/src/macros.rs

@@ -1135,8 +1135,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         if let Some(builtin_name) = ext.builtin_name {
             // The macro was marked with `#[rustc_builtin_macro]`.
             if let Some(builtin_ext_kind) = self.builtin_macros.get(&builtin_name) {
-                // The macro is a built-in, replace its expander function
-                // while still taking everything else from the source code.
                 ext.kind = builtin_ext_kind.clone();
                 rule_spans = Vec::new();
             } else {