tip for define macro name after macro_rules!

compiler/rustc_resolve/src/errors.rs

@@ -665,6 +665,13 @@ pub(crate) struct ExplicitUnsafeTraits {
     pub(crate) ident: Ident,
 }
 
+#[derive(Subdiagnostic)]
+#[note(resolve_missing_macro_rules_name)]
+pub(crate) struct MaybeMissingMacroRulesName {
+    #[primary_span]
+    pub(crate) span: Span,
+}
+
 #[derive(Subdiagnostic)]
 #[help(resolve_added_macro_use)]
 pub(crate) struct AddedMacroUse;