Revert "[clang] CTAD: Fix require-clause is not transformed."

clang/lib/Sema/SemaTemplate.cpp

@@ -2962,6 +2962,19 @@ void DeclareImplicitDeductionGuidesForTypeAlias(
           Context.getCanonicalTemplateArgument(
               Context.getInjectedTemplateArg(NewParam));
     }
+    // Substitute new template parameters into requires-clause if present.
+    Expr *RequiresClause =
+        transformRequireClause(SemaRef, F, TemplateArgsForBuildingFPrime);
+    // FIXME: implement the is_deducible constraint per C++
+    // [over.match.class.deduct]p3.3:
+    //    ... and a constraint that is satisfied if and only if the arguments
+    //    of A are deducible (see below) from the return type.
+    auto *FPrimeTemplateParamList = TemplateParameterList::Create(
+        Context, AliasTemplate->getTemplateParameters()->getTemplateLoc(),
+        AliasTemplate->getTemplateParameters()->getLAngleLoc(),
+        FPrimeTemplateParams,
+        AliasTemplate->getTemplateParameters()->getRAngleLoc(),
+        /*RequiresClause=*/RequiresClause);
 
     // To form a deduction guide f' from f, we leverage clang's instantiation
     // mechanism, we construct a template argument list where the template
@@ -3007,20 +3020,6 @@ void DeclareImplicitDeductionGuidesForTypeAlias(
             F, TemplateArgListForBuildingFPrime, AliasTemplate->getLocation(),
             Sema::CodeSynthesisContext::BuildingDeductionGuides)) {
       auto *GG = cast<CXXDeductionGuideDecl>(FPrime);
-      // Substitute new template parameters into requires-clause if present.
-      Expr *RequiresClause =
-          transformRequireClause(SemaRef, F, TemplateArgsForBuildingFPrime);
-      // FIXME: implement the is_deducible constraint per C++
-      // [over.match.class.deduct]p3.3:
-      //    ... and a constraint that is satisfied if and only if the arguments
-      //    of A are deducible (see below) from the return type.
-      auto *FPrimeTemplateParamList = TemplateParameterList::Create(
-          Context, AliasTemplate->getTemplateParameters()->getTemplateLoc(),
-          AliasTemplate->getTemplateParameters()->getLAngleLoc(),
-          FPrimeTemplateParams,
-          AliasTemplate->getTemplateParameters()->getRAngleLoc(),
-          /*RequiresClause=*/RequiresClause);
-
       buildDeductionGuide(SemaRef, AliasTemplate, FPrimeTemplateParamList,
                           GG->getCorrespondingConstructor(),
                           GG->getExplicitSpecifier(), GG->getTypeSourceInfo(),

clang/lib/Sema/SemaTemplateInstantiate.cpp

@@ -2502,7 +2502,10 @@ TemplateInstantiator::TransformTemplateTypeParmType(TypeLocBuilder &TLB,
       assert(Arg.getKind() == TemplateArgument::Type &&
              "unexpected nontype template argument kind in template rewrite");
       QualType NewT = Arg.getAsType();
-      TLB.pushTrivial(SemaRef.Context, NewT, TL.getNameLoc());
+      assert(isa<TemplateTypeParmType>(NewT) &&
+             "type parm not rewritten to type parm");
+      auto NewTL = TLB.push<TemplateTypeParmTypeLoc>(NewT);
+      NewTL.setNameLoc(TL.getNameLoc());
       return NewT;
     }
 

clang/test/SemaCXX/cxx20-ctad-type-alias.cpp

@@ -289,21 +289,3 @@ using String = Array<char, N>;
 // Verify no crash on constructing the aggregate deduction guides.
 String s("hello");
 } // namespace test21
-
-// GH89013
-namespace test22 {
-class Base {};
-template <typename T>
-class Derived final : public Base {};
-
-template <typename T, typename D>
-requires __is_base_of(Base, D)
-struct Foo {
-  explicit Foo(D) {}
-};
-
-template <typename U>
-using AFoo = Foo<int, Derived<U>>;
-
-AFoo a(Derived<int>{});
-} // namespace test22

clang/test/SemaTemplate/deduction-guide.cpp

@@ -260,31 +260,3 @@ AG ag = {1};
 // CHECK:   |-TemplateArgument type 'int'
 // CHECK:   | `-BuiltinType {{.*}} 'int'
 // CHECK:   `-ParmVarDecl {{.*}} 'int'
-
-template <typename D>
-requires (sizeof(D) == 4)
-struct Foo {
-  Foo(D);
-};
-
-template <typename U>
-using AFoo = Foo<G<U>>;
-// Verify that the require-clause from the Foo deduction guide is transformed.
-// The D occurrence should be rewritten to G<type-parameter-0-0>.
-//
-// CHECK-LABEL: Dumping <deduction guide for AFoo>
-// CHECK: FunctionTemplateDecl {{.*}} implicit <deduction guide for AFoo>
-// CHECK-NEXT: |-TemplateTypeParmDecl {{.*}} typename depth 0 index 0 U
-// CHECK-NEXT: |-ParenExpr {{.*}} 'bool'
-// CHECK-NEXT: | `-BinaryOperator {{.*}} 'bool' '=='
-// CHECK-NEXT: |   |-UnaryExprOrTypeTraitExpr {{.*}} 'unsigned long' sizeof 'G<type-parameter-0-0>'
-// CHECK-NEXT: |   `-ImplicitCastExpr {{.*}} 'unsigned long' <IntegralCast>
-// CHECK-NEXT: |     `-IntegerLiteral {{.*}} 'int' 4
-// CHECK-NEXT: |-CXXDeductionGuideDecl {{.*}} implicit <deduction guide for AFoo> 'auto (G<type-parameter-0-0>) -> Foo<G<type-parameter-0-0>>'
-// CHECK-NEXT: | `-ParmVarDecl {{.*}} 'G<type-parameter-0-0>'
-// CHECK-NEXT: `-CXXDeductionGuideDecl {{.*}} implicit used <deduction guide for AFoo> 'auto (G<int>) -> Foo<G<int>>' implicit_instantiation
-// CHECK-NEXT:   |-TemplateArgument type 'int'
-// CHECK-NEXT:   | `-BuiltinType {{.*}} 'int'
-// CHECK-NEXT:   `-ParmVarDecl {{.*}} 'G<int>'
-
-AFoo aa(G<int>{});