[Clang] `FunctionDecl::getFunctionTypeLoc` returns None when function attributes present

[v01dXYZ]

Use case

I try to add a custom Function Attribute that implies the function returns an int. In the case of the user using void as return type, I would like to add at least a fix-it hint to replace void by int. Unfortunately, the current implementation won't try to walk the AttributedTypeLoc chain and returns an empty FunctionTypeLoc. Thus getReturnTypeLoc returns None too.

Discussion

I don't know if it is an acceptable behavior to make it go through the AttributeTypeLoc chain to extract the final FunctionTypeLoc. If it is, I would like to submit a few-lines patch.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Robert Dazi (v01dXYZ)

### Use case

I try to add a custom Function Attribute that implies the function returns an int. In the case of the user using void as return type, I would like to add at least a fix-it hint to replace void by int. Unfortunately, the current implementation won't try to walk the AttributedTypeLoc chain and returns an empty FunctionTypeLoc. Thus getReturnTypeLoc returns None too.

Discussion

I don't know if it is an acceptable behavior to make it go through the AttributeTypeLoc chain to extract the final FunctionTypeLoc. If it is, I would like to submit a few-lines patch.

[shafik]

CC @erichkeane

[erichkeane]

I'd probably have to see the patch, but I don't immediately see a problem here. It makes sense to me to have the AttributedType expose the type as modified by the attribute. If the type doesn't GET modified, I'd expect it to return the underlying type.