[clang] [clang][bytecode] Fix assertion failure when returning function type (PR #180681)

[Yanzuo Liu via cfe-commits]

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@@ -937,6 +937,12 @@ std::optional<APValue> Pointer::toRValue(const Context &Ctx,
     llvm_unreachable("invalid value to return");
   };
 
+  // Can't return functions as rvalues.
+  if (ResultType->isFunctionType() || ResultType->isFunctionProtoType() ||
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zwuis wrote:

`FunctionType` is a base class of `FunctionProtoType`.

https://github.com/llvm/llvm-project/pull/180681