3 files changed, 8 insertions, 32 deletions
diff --git a/compiler/rustc_resolve/src/errors.rs b/compiler/rustc_resolve/src/errors.rs
index 2ae6892bc93..e26b300f13e 100644
--- a/compiler/rustc_resolve/src/errors.rs
+++ b/compiler/rustc_resolve/src/errors.rs
@@ -966,15 +966,6 @@ pub(crate) struct StaticLifetimeIsReserved {
 }
 
 #[derive(Diagnostic)]
-#[diag(resolve_attempt_to_define_builtin_macro_twice, code = E0773)]
-pub(crate) struct AttemptToDefineBuiltinMacroTwice {
-    #[primary_span]
-    pub(crate) span: Span,
-    #[note]
-    pub(crate) note_span: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(resolve_variable_is_not_bound_in_all_patterns, code = E0408)]
 pub(crate) struct VariableIsNotBoundInAllPatterns {
     #[primary_span]
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index 447d5283e27..ff31af0025b 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -1010,12 +1010,6 @@ impl ExternPreludeEntry<'_> {
     }
 }
 
-/// Used for better errors for E0773
-enum BuiltinMacroState {
-    NotYetSeen(SyntaxExtensionKind),
-    AlreadySeen(Span),
-}
-
 struct DeriveData {
     resolutions: Vec<DeriveResolution>,
     helper_attrs: Vec<(usize, Ident)>,
@@ -1134,7 +1128,7 @@ pub struct Resolver<'ra, 'tcx> {
 
     used_extern_options: FxHashSet<Symbol>,
     macro_names: FxHashSet<Ident>,
-    builtin_macros: FxHashMap<Symbol, BuiltinMacroState>,
+    builtin_macros: FxHashMap<Symbol, SyntaxExtensionKind>,
     registered_tools: &'tcx RegisteredTools,
     macro_use_prelude: FxIndexMap<Symbol, NameBinding<'ra>>,
     macro_map: FxHashMap<DefId, MacroData>,
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 7100d89ad61..c94846e95d4 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -40,9 +40,9 @@ use crate::errors::{
 };
 use crate::imports::Import;
 use crate::{
-    BindingKey, BuiltinMacroState, DeriveData, Determinacy, Finalize, InvocationParent, MacroData,
-    ModuleKind, ModuleOrUniformRoot, NameBinding, NameBindingKind, ParentScope, PathResult,
-    ResolutionError, Resolver, ScopeSet, Segment, ToNameBinding, Used,
+    BindingKey, DeriveData, Determinacy, Finalize, InvocationParent, MacroData, ModuleKind,
+    ModuleOrUniformRoot, NameBinding, NameBindingKind, ParentScope, PathResult, ResolutionError,
+    Resolver, ScopeSet, Segment, ToNameBinding, Used,
 };
 
 type Res = def::Res<NodeId>;
@@ -194,7 +194,7 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
     }
 
     fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind) {
-        if self.builtin_macros.insert(name, BuiltinMacroState::NotYetSeen(ext)).is_some() {
+        if self.builtin_macros.insert(name, ext).is_some() {
             self.dcx().bug(format!("built-in macro `{name}` was already registered"));
         }
     }
@@ -1127,20 +1127,11 @@ 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_macro) = self.builtin_macros.get_mut(&builtin_name) {
+            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.
-                // If we already loaded this builtin macro, give a better error message than 'no such builtin macro'.
-                match mem::replace(builtin_macro, BuiltinMacroState::AlreadySeen(span)) {
-                    BuiltinMacroState::NotYetSeen(builtin_ext) => {
-                        ext.kind = builtin_ext;
-                        rule_spans = Vec::new();
-                    }
-                    BuiltinMacroState::AlreadySeen(note_span) => {
-                        self.dcx()
-                            .emit_err(errors::AttemptToDefineBuiltinMacroTwice { span, note_span });
-                    }
-                }
+                ext.kind = builtin_ext_kind.clone();
+                rule_spans = Vec::new();
             } else {
                 self.dcx().emit_err(errors::CannotFindBuiltinMacroWithName { span, ident });
             }