Fix enum scope used inside template function. (#4859)

While enums were introduced in HLSL 2017, this code should only be reached
on HLSL if we are HLSL 2021 or greater, so an additional language version
check does not appear necessary here.

Author: tex3d

tools/clang/lib/Sema/TreeTransform.h

@@ -3276,7 +3276,7 @@ TreeTransform<Derived>::TransformNestedNameSpecifierLoc(
         return NestedNameSpecifierLoc();
 
       if (TL.getType()->isDependentType() || TL.getType()->isRecordType() ||
-          (SemaRef.getLangOpts().CPlusPlus11 &&
+          ((SemaRef.getLangOpts().CPlusPlus11 || SemaRef.getLangOpts().HLSL) &&
            TL.getType()->isEnumeralType())) {
         assert(!TL.getType().hasLocalQualifiers() &&
                "Can't get cv-qualifiers here");

tools/clang/test/HLSLFileCheck/hlsl/template/enum-scope-in-template-func.hlsl

@@ -0,0 +1,33 @@
+// RUN: %dxc -T vs_6_0 -HV 2021 -ast-dump %s | FileCheck %s
+
+// CHECK-NOT: error
+
+// CHECK: FunctionDecl {{.*}} used genericDoStuff 'void (Foo)'
+// CHECK-NEXT: TemplateArgument
+// CHECK-NEXT: ParmVarDecl
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: CallExpr
+// CHECK-NEXT: ImplicitCastExpr
+// CHECK-NEXT: DeclRefExpr
+// CHECK-NEXT: DeclRefExpr
+// CHECK-SAME: 'Food' EnumConstant
+// CHECK-SAME: 'Pizza' 'Food'
+
+enum class Food { Pizza };
+
+void write(Food f, uint val) {}
+
+template <typename Generic>
+void genericDoStuff(Generic g)
+{
+    write(Food::Pizza, g.get());
+}
+
+class Foo {
+    uint get() { return 0; }
+};
+
+void main() {
+    Foo foo;
+    genericDoStuff(foo);
+}