[clang] [Clang] diagnose deleted/default redeclaration of defined friend functions (PR #136717)

[Oleksandr T. via cfe-commits]

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@@ -142,6 +142,14 @@ NamedDecl *Parser::ParseCXXInlineMethodDef(
       SkipUntil(tok::semi);
     }
 
+    if (FunctionDecl *FD =
+            dyn_cast_if_present<FunctionDecl>(FnD->getPreviousDecl())) {
+      if (isa<CXXRecordDecl>(FD->getLexicalDeclContext()) ||
+          Actions.getDefaultedFunctionKind(FD).asComparison() ==
+              Sema::DefaultedComparisonKind::None)
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a-tarasyuk wrote:

> I strongly prefer/would like to see some exploration in this direction because it aligns with our overall design

Ok

https://github.com/llvm/llvm-project/pull/136717