[clang] FunctionDecl::getFunctionTypeLoc: ignore function type attributes (PR #118420)

[Erich Keane via cfe-commits]

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@@ -3876,8 +3876,17 @@ bool FunctionDecl::doesDeclarationForceExternallyVisibleDefinition() const {
 
 FunctionTypeLoc FunctionDecl::getFunctionTypeLoc() const {
   const TypeSourceInfo *TSI = getTypeSourceInfo();
-  return TSI ? TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>()
-             : FunctionTypeLoc();
+
+  if (!TSI)
+    return FunctionTypeLoc();
+
+  TypeLoc TL = TSI->getTypeLoc().IgnoreParens();
+
+  // ignore function type attributes
+  while (auto ATL = TL.getAs<AttributedTypeLoc>())
+    TL = ATL.getModifiedLoc();
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erichkeane wrote:

I don't THINK we want this?  We want to keep around the 'type' as modified by the attributed type (so if it is no_return, we want to make sure we have a noreturn function type for example).  So I would think we would want the `Equivalent` type here? 

https://github.com/llvm/llvm-project/pull/118420