clarify comment, add concept AST test

Author: bob80905

clang/lib/Sema/HLSLExternalSemaSource.cpp

@@ -374,8 +374,9 @@ struct TemplateParameterListBuilder {
     TemplateTypeParmDecl *ConceptTTPD = dyn_cast<TemplateTypeParmDecl>(
         CD->getTemplateParameters()->getParam(0));
 
-    // this fake TemplateTypeParmDecl is used to construct a template argument
-    // that will be used to construct the ImplicitConceptSpecializationDecl
+    // this TemplateTypeParmDecl is the template for the resource, and is
+    // used to construct a template argumentthat will be used
+    // to construct the ImplicitConceptSpecializationDecl
     TemplateTypeParmDecl *T = TemplateTypeParmDecl::Create(
         Context,                          // AST context
         Context.getTranslationUnitDecl(), // DeclContext

clang/test/AST/HLSL/is_typed_resource_element_compatible_concept.hlsl

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-library -x hlsl -ast-dump -ast-dump-filter=__is_typed_resource_element_compatible %s | FileCheck %s
+
+// CHECK: ConceptDecl 0x{{[0-9a-f]+}} <<invalid sloc>> <invalid sloc> __is_typed_resource_element_compatible
+// CHECK: |-TemplateTypeParmDecl 0x{{[0-9a-f]+}} <<invalid sloc>> <invalid sloc> referenced typename depth 0 index 0 element_type
+// CHECK: `-BinaryOperator 0x{{[0-9a-f]+}} <<invalid sloc>> 'bool' lvalue '<='
+// CHECK:   |-UnaryExprOrTypeTraitExpr 0x{{[0-9a-f]+}} <<invalid sloc>> 'unsigned long' sizeof 'element_type'
+// CHECK:   `-IntegerLiteral 0x{{[0-9a-f]+}} <<invalid sloc>> 'unsigned long' 16
+
+
+RWBuffer<float> Buffer;