[clang] [HLSL][OpenCL] Strip addrspace from implicit cast diags (PR #135830)

[Justin Bogner via cfe-commits]

================
@@ -11360,6 +11360,14 @@ static void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
 static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T,
                             SourceLocation CContext, unsigned diag,
                             bool pruneControlFlow = false) {
+  // For languages like HLSL and OpenCL, implicit conversion diagnostics listing
+  // address space annotations isn't really useful. The warnings aren't because
+  // you're converting a `private int` to `unsigned int`, it is because you're
+  // conerting `int` to `unsigned int`.
+  if (SourceType.hasAddressSpace())
+    SourceType = S.getASTContext().removeAddrSpaceQualType(SourceType);
+  if (T.hasAddressSpace())
+    T = S.getASTContext().removeAddrSpaceQualType(T);
----------------
bogner wrote:

Should we assert here that `SourceType` and `T` aren't identical after stripping address spaces to protect against misuse of the function?

https://github.com/llvm/llvm-project/pull/135830