[Concept] Fix incorrect check for containsUnexpandedParameterPack in CSE

We previously checked for containsUnexpandedParameterPack in CSEs by observing the property
in the converted arguments of the CSE. This may not work if the argument is an expanded
type-alias that contains a pack-expansion (see added test).

Check the as-written arguments when determining containsUnexpandedParameterPack and isInstantiationDependent.

Author: saarraz

clang/include/clang/AST/ExprConcepts.h

@@ -63,6 +63,12 @@ class ConceptSpecializationExpr final : public Expr, public ConceptReference,
                             ArrayRef<TemplateArgument> ConvertedArgs,
                             const ConstraintSatisfaction *Satisfaction);
 
+  ConceptSpecializationExpr(const ASTContext &C, ConceptDecl *NamedConcept,
+                            ArrayRef<TemplateArgument> ConvertedArgs,
+                            const ConstraintSatisfaction *Satisfaction,
+                            bool Dependent,
+                            bool ContainsUnexpandedParameterPack);
+
   ConceptSpecializationExpr(EmptyShell Empty, unsigned NumTemplateArgs);
 
 public:
@@ -75,6 +81,13 @@ class ConceptSpecializationExpr final : public Expr, public ConceptReference,
          ArrayRef<TemplateArgument> ConvertedArgs,
          const ConstraintSatisfaction *Satisfaction);
 
+  static ConceptSpecializationExpr *
+  Create(const ASTContext &C, ConceptDecl *NamedConcept,
+         ArrayRef<TemplateArgument> ConvertedArgs,
+         const ConstraintSatisfaction *Satisfaction,
+         bool Dependent,
+         bool ContainsUnexpandedParameterPack);
+
   static ConceptSpecializationExpr *
   Create(ASTContext &C, EmptyShell Empty, unsigned NumTemplateArgs);
 

clang/lib/AST/ASTContext.cpp

@@ -731,12 +731,8 @@ canonicalizeImmediatelyDeclaredConstraint(const ASTContext &C, Expr *IDC,
       NewConverted.push_back(Arg);
   }
   Expr *NewIDC = ConceptSpecializationExpr::Create(
-      C, NestedNameSpecifierLoc(), /*TemplateKWLoc=*/SourceLocation(),
-      CSE->getConceptNameInfo(), /*FoundDecl=*/CSE->getNamedConcept(),
-      CSE->getNamedConcept(),
-      // Actually canonicalizing a TemplateArgumentLoc is difficult so we
-      // simply omit the ArgsAsWritten
-      /*ArgsAsWritten=*/nullptr, NewConverted, nullptr);
+      C, CSE->getNamedConcept(), NewConverted, nullptr,
+      CSE->isInstantiationDependent(), CSE->containsUnexpandedParameterPack());
 
   if (auto *OrigFold = dyn_cast<CXXFoldExpr>(IDC))
     NewIDC = new (C) CXXFoldExpr(OrigFold->getType(), SourceLocation(), NewIDC,

clang/lib/AST/ExprConcepts.cpp

@@ -46,24 +46,12 @@ ConceptSpecializationExpr::ConceptSpecializationExpr(const ASTContext &C,
                    ASTConstraintSatisfaction::Create(C, *Satisfaction) :
                    nullptr) {
   setTemplateArguments(ConvertedArgs);
-}
-
-ConceptSpecializationExpr::ConceptSpecializationExpr(EmptyShell Empty,
-    unsigned NumTemplateArgs)
-    : Expr(ConceptSpecializationExprClass, Empty), ConceptReference(),
-      NumTemplateArgs(NumTemplateArgs) { }
-
-void ConceptSpecializationExpr::setTemplateArguments(
-    ArrayRef<TemplateArgument> Converted) {
-  assert(Converted.size() == NumTemplateArgs);
-  std::uninitialized_copy(Converted.begin(), Converted.end(),
-                          getTrailingObjects<TemplateArgument>());
   bool IsInstantiationDependent = false;
   bool ContainsUnexpandedParameterPack = false;
-  for (const TemplateArgument& Arg : Converted) {
-    if (Arg.isInstantiationDependent())
+  for (const TemplateArgumentLoc& ArgLoc : ArgsAsWritten->arguments()) {
+    if (ArgLoc.getArgument().isInstantiationDependent())
       IsInstantiationDependent = true;
-    if (Arg.containsUnexpandedParameterPack())
+    if (ArgLoc.getArgument().containsUnexpandedParameterPack())
       ContainsUnexpandedParameterPack = true;
     if (ContainsUnexpandedParameterPack && IsInstantiationDependent)
       break;
@@ -80,6 +68,18 @@ void ConceptSpecializationExpr::setTemplateArguments(
          "should not be value-dependent");
 }
 
+ConceptSpecializationExpr::ConceptSpecializationExpr(EmptyShell Empty,
+    unsigned NumTemplateArgs)
+    : Expr(ConceptSpecializationExprClass, Empty), ConceptReference(),
+      NumTemplateArgs(NumTemplateArgs) { }
+
+void ConceptSpecializationExpr::setTemplateArguments(
+    ArrayRef<TemplateArgument> Converted) {
+  assert(Converted.size() == NumTemplateArgs);
+  std::uninitialized_copy(Converted.begin(), Converted.end(),
+                          getTrailingObjects<TemplateArgument>());
+}
+
 ConceptSpecializationExpr *
 ConceptSpecializationExpr::Create(const ASTContext &C,
                                   NestedNameSpecifierLoc NNS,
@@ -98,6 +98,39 @@ ConceptSpecializationExpr::Create(const ASTContext &C,
                                                 ConvertedArgs, Satisfaction);
 }
 
+ConceptSpecializationExpr::ConceptSpecializationExpr(
+    const ASTContext &C, ConceptDecl *NamedConcept,
+    ArrayRef<TemplateArgument> ConvertedArgs,
+    const ConstraintSatisfaction *Satisfaction, bool Dependent,
+    bool ContainsUnexpandedParameterPack)
+    : Expr(ConceptSpecializationExprClass, C.BoolTy, VK_RValue, OK_Ordinary,
+           /*TypeDependent=*/false,
+           /*ValueDependent=*/!Satisfaction, Dependent,
+           ContainsUnexpandedParameterPack),
+      ConceptReference(NestedNameSpecifierLoc(), SourceLocation(),
+                       DeclarationNameInfo(), NamedConcept,
+                       NamedConcept, nullptr),
+      NumTemplateArgs(ConvertedArgs.size()),
+      Satisfaction(Satisfaction ?
+                   ASTConstraintSatisfaction::Create(C, *Satisfaction) :
+                   nullptr) {
+  setTemplateArguments(ConvertedArgs);
+}
+
+ConceptSpecializationExpr *
+ConceptSpecializationExpr::Create(const ASTContext &C,
+                                  ConceptDecl *NamedConcept,
+                                  ArrayRef<TemplateArgument> ConvertedArgs,
+                                  const ConstraintSatisfaction *Satisfaction,
+                                  bool Dependent,
+                                  bool ContainsUnexpandedParameterPack) {
+  void *Buffer = C.Allocate(totalSizeToAlloc<TemplateArgument>(
+                                ConvertedArgs.size()));
+  return new (Buffer) ConceptSpecializationExpr(
+      C, NamedConcept, ConvertedArgs, Satisfaction, Dependent,
+      ContainsUnexpandedParameterPack);
+}
+
 ConceptSpecializationExpr *
 ConceptSpecializationExpr::Create(ASTContext &C, EmptyShell Empty,
                                   unsigned NumTemplateArgs) {

clang/test/CXX/expr/expr.prim/expr.prim.id/p3.cpp

@@ -183,3 +183,18 @@ concept C8 = sizeof(T) > sizeof(U);
 template<typename... T>
 constexpr bool B8 = C8<T...>;
 // expected-error@-1{{pack expansion used as argument for non-pack parameter of concept}}
+
+
+// Make sure we correctly check for containsUnexpandedParameterPack
+
+template<typename T>
+concept C9 = true;
+
+template <typename Fn, typename... Args>
+using invoke = typename Fn::template invoke<Args...>;
+
+template <typename C, typename... L>
+// The converted argument here will not containsUnexpandedParameterPack, but the
+// as-written one will.
+requires (C9<invoke<C, L>> &&...)
+struct S { };