[clang] Implement `ByteAddressBuffer` Load/Store methods (PR #176058)

[Kaitlin Peng via cfe-commits]

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@@ -6901,8 +6901,20 @@ NamedDecl *Sema::FindInstantiatedDecl(SourceLocation Loc, NamedDecl *D,
   //    whose type is not instantiation dependent, do nothing to the decl
   //  - otherwise find its instantiated decl.
   if (isa<ParmVarDecl>(D) && !ParentDependsOnArgs &&
-      !cast<ParmVarDecl>(D)->getType()->isInstantiationDependentType())
-    return D;
+      !cast<ParmVarDecl>(D)->getType()->isInstantiationDependentType()) {
+    // Check if D belongs to a function template
+    auto *PVD = cast<ParmVarDecl>(D);
+    bool IsFromFunctionTemplate =
+        llvm::any_of(ParentDC->decls(), [PVD](Decl *D) {
+          if (auto *FTD = dyn_cast<FunctionTemplateDecl>(D))
+            return llvm::is_contained(FTD->getTemplatedDecl()->parameters(),
+                                      PVD);
+          return false;
+        });
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kmpeng wrote:

Actually it does seem like `ParmVarDecl` is being created wrong. It's using `Method->getDeclContext()` as the declaration context when it should just be `Method`. Made that change and edited this to use `getDescribedFunctionTemplate()`

https://github.com/llvm/llvm-project/pull/176058