Rollup merge of #121130 - chenyukang:yukang-fix-121061-macro-later, r=matthiaskrgr

Suggest moving definition if non-found macro_rules! is defined later

Fixes #121061

1 files changed, 22 insertions, 1 deletions

diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index 6b45db7ba83..dc7dfa04d18 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -30,7 +30,10 @@ use rustc_span::{BytePos, Span, SyntaxContext};
 use thin_vec::{thin_vec, ThinVec};
 
 use crate::errors::{AddedMacroUse, ChangeImportBinding, ChangeImportBindingSuggestion};
-use crate::errors::{ConsiderAddingADerive, ExplicitUnsafeTraits, MaybeMissingMacroRulesName};
+use crate::errors::{
+    ConsiderAddingADerive, ExplicitUnsafeTraits, MacroDefinedLater, MacroSuggMovePosition,
+    MaybeMissingMacroRulesName,
+};
 use crate::imports::{Import, ImportKind};
 use crate::late::{PatternSource, Rib};
 use crate::{errors as errs, BindingKey};
@@ -1456,6 +1459,24 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             return;
         }
 
+        let unused_macro = self.unused_macros.iter().find_map(|(def_id, (_, unused_ident))| {
+            if unused_ident.name == ident.name {
+                Some((def_id.clone(), unused_ident.clone()))
+            } else {
+                None
+            }
+        });
+
+        if let Some((def_id, unused_ident)) = unused_macro {
+            let scope = self.local_macro_def_scopes[&def_id];
+            let parent_nearest = parent_scope.module.nearest_parent_mod();
+            if Some(parent_nearest) == scope.opt_def_id() {
+                err.subdiagnostic(self.dcx(), MacroDefinedLater { span: unused_ident.span });
+                err.subdiagnostic(self.dcx(), MacroSuggMovePosition { span: ident.span, ident });
+                return;
+            }
+        }
+
         if self.macro_names.contains(&ident.normalize_to_macros_2_0()) {
             err.subdiagnostic(self.dcx(), AddedMacroUse);
             return;