[clang] Implement resource binding type prefix mismatch errors (PR #87578)

[Justin Bogner via cfe-commits]

================
@@ -7367,8 +7367,72 @@ static void handleHLSLResourceBindingAttr(Sema &S, Decl *D,
     return;
   }
 
-  // FIXME: check reg type match decl. Issue
-  // https://github.com/llvm/llvm-project/issues/57886.
+  VarDecl *VD = dyn_cast<VarDecl>(D);
+  HLSLBufferDecl *BD = dyn_cast<HLSLBufferDecl>(D);
+
+  if (VD || BD) {
+    llvm::hlsl::ResourceClass RC;
+    std::string varTy = "";
+    if (VD) {
+
+      const Type *Ty = VD->getType()->getPointeeOrArrayElementType();
+      if (!Ty)
+        return;
+      QualType t = ((ElaboratedType *)Ty)->getNamedType();
+      const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
+      if (!RD)
+        return;
+
+      if (auto TDecl = dyn_cast<ClassTemplateSpecializationDecl>(RD))
+        RD = TDecl->getSpecializedTemplate()->getTemplatedDecl();
+      RD = RD->getCanonicalDecl();
+      const auto *Attr = RD->getAttr<HLSLResourceAttr>();
+      if (!Attr)
+        return;
----------------
bogner wrote:

Actually, is it even correct to just give up in some of these cases? Is it possible to get here with a type that isn't a resource, or did we diagnose that earlier? If this is possible, we probably need to diagnose that. If it isn't, we should probably just verify this with asserts.

https://github.com/llvm/llvm-project/pull/87578