[libclang] Return the proper pointee type for 'auto' deduced to pointer

[yvvan]

Summary

Currently the resulting type is always invalid in such case.

[michaelwu]

It shouldn't be too hard to make a test using c-index-test. -test-print-type will print out the pointee type if it's valid.

tools/libclang/CXType.cpp

448

Seems like this might make sense for Type::DeducedTemplateSpecialization too.

[yvvan]

You are completely right! Thanks!
I did not think that -test-print-type also checks for the pointee.

[yvvan]

Comments addressed

[michaelwu]

LGTM

tools/libclang/CXType.cpp

 
 CXType clang_getPointeeType(CXType CT) {
   QualType T = GetQualType(CT);
   const Type *TP = T.getTypePtrOrNull();
 
   if (!TP)
     return MakeCXType(QualType(), GetTU(CT));
 
+try_again:
   switch (TP->getTypeClass()) {
     case Type::Pointer:
       T = cast<PointerType>(TP)->getPointeeType();
       break;
     case Type::BlockPointer:
       T = cast<BlockPointerType>(TP)->getPointeeType();
       break;
     case Type::LValueReference:
     case Type::RValueReference:
       T = cast<ReferenceType>(TP)->getPointeeType();
       break;
     case Type::ObjCObjectPointer:
       T = cast<ObjCObjectPointerType>(TP)->getPointeeType();
       break;
     case Type::MemberPointer:
       T = cast<MemberPointerType>(TP)->getPointeeType();
       break;
+    case Type::Auto:
+      TP = cast<DeducedType>(TP)->getDeducedType().getTypePtrOrNull();
+      if (TP)
+        goto try_again;
+      break;
     default:
       T = QualType();
       break;
   }
   return MakeCXType(T, GetTU(CT));
 }
 
 CXCursor clang_getTypeDeclaration(CXType CT) {