[clang] [clang-tools-extra] [Clang] Make the SizeType, SignedSizeType and PtrdiffType be named sugar types instead of built-in types (PR #143653)

[Matheus Izvekov via cfe-commits]

================
@@ -1567,6 +1567,8 @@ class ASTContext : public RefCountedBase<ASTContext> {
   /// and bit count.
   QualType getDependentBitIntType(bool Unsigned, Expr *BitsExpr) const;
 
+  QualType getPredefinedSugarType(uint32_t KD) const;
----------------
mizvekov wrote:

It would be more helpful and less error prone to use the enum type here.

https://github.com/llvm/llvm-project/pull/143653