Fix SemaTemplate/concepts-lambda.cpp

Author: zyn0217

clang/include/clang/Sema/Sema.h

@@ -13134,6 +13134,8 @@ class Sema final : public SemaBase {
     /// Whether we're substituting into constraints.
     bool InConstraintSubstitution;
 
+    bool InParameterMappingSubstitution;
+
     /// The point of instantiation or synthesis within the source code.
     SourceLocation PointOfInstantiation;
 
@@ -13873,11 +13875,17 @@ class Sema final : public SemaBase {
   }
 
   /// Determine whether we are currently performing constraint substitution.
+  // FIXME: Rename it
   bool inConstraintSubstitution() const {
     return !CodeSynthesisContexts.empty() &&
            CodeSynthesisContexts.back().InConstraintSubstitution;
   }
 
+  bool inParameterMappingSubstitution() const {
+    return !CodeSynthesisContexts.empty() &&
+           CodeSynthesisContexts.back().InParameterMappingSubstitution;
+  }
+
   using EntityPrinter = llvm::function_ref<void(llvm::raw_ostream &)>;
 
   /// \brief create a Requirement::SubstitutionDiagnostic with only a

clang/include/clang/Sema/Template.h

@@ -261,6 +261,7 @@ enum class TemplateSubstitutionKind : char {
       //         ==
       //             AssociatedDecl) &&
       //        "Trying to change incorrect declaration?");
+      TemplateArgumentLists.back().AssociatedDeclAndFinal.setPointer(AssociatedDecl);
       TemplateArgumentLists.back().Args = Args;
     }
 

clang/lib/Sema/SemaConcept.cpp

@@ -1659,7 +1659,9 @@ static bool substituteParameterMappings(Sema &S, NormalizedConstraint &N,
       /*RelativeToPrimary=*/true,
       /*Pattern=*/nullptr,
       /*ForConstraintInstantiation=*/true);
-
+  // Don't build Subst* nodes to model lambda expressions.
+  // The transform of Subst* is oblivious to the lambda type.
+  MLTAL.setKind(TemplateSubstitutionKind::Rewrite);
   return substituteParameterMappings(S, N, MLTAL,
                                      CSE->getTemplateArgsAsWritten());
 }

clang/lib/Sema/SemaTemplate.cpp

@@ -1165,7 +1165,9 @@ static ExprResult formImmediatelyDeclaredConstraint(
   ExprResult ImmediatelyDeclaredConstraint = S.CheckConceptTemplateId(
       SS, /*TemplateKWLoc=*/SourceLocation(), NameInfo,
       /*FoundDecl=*/FoundDecl ? FoundDecl : NamedConcept, NamedConcept,
-      &ConstraintArgs);
+      &ConstraintArgs,
+      /*DoCheckConstraintSatisfaction=*/
+      !S.inParameterMappingSubstitution());
   if (ImmediatelyDeclaredConstraint.isInvalid() || !EllipsisLoc.isValid())
     return ImmediatelyDeclaredConstraint;
 
@@ -4742,7 +4744,7 @@ ExprResult Sema::CheckConceptTemplateId(
           *TemplateArgs, CTAI.CanonicalConverted);
   MultiLevelTemplateArgumentList MLTAL(NamedConcept, CTAI.CanonicalConverted,
                                        /*Final=*/false);
-      auto *CL = ConceptReference::Create(
+  auto *CL = ConceptReference::Create(
       Context,
       SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
       TemplateKWLoc, ConceptNameInfo, FoundDecl, NamedConcept,

clang/lib/Sema/SemaTemplateInstantiate.cpp

@@ -623,10 +623,15 @@ Sema::InstantiatingTemplate::InstantiatingTemplate(
     Inst.DeductionInfo = DeductionInfo;
     Inst.InstantiationRange = InstantiationRange;
     Inst.InConstraintSubstitution =
-        Inst.Kind == CodeSynthesisContext::ConstraintSubstitution;
-    if (!SemaRef.CodeSynthesisContexts.empty())
+        Inst.Kind == CodeSynthesisContext::ConstraintsCheck;
+    Inst.InParameterMappingSubstitution =
+        Inst.Kind == CodeSynthesisContext::ParameterMappingSubstitution;
+    if (!SemaRef.CodeSynthesisContexts.empty()) {
       Inst.InConstraintSubstitution |=
           SemaRef.CodeSynthesisContexts.back().InConstraintSubstitution;
+      Inst.InParameterMappingSubstitution |=
+          SemaRef.CodeSynthesisContexts.back().InParameterMappingSubstitution;
+    }
 
     SemaRef.pushCodeSynthesisContext(Inst);
 
@@ -2225,6 +2230,14 @@ TemplateInstantiator::TransformTemplateParmRefExpr(DeclRefExpr *E,
     // We're rewriting the template parameter as a reference to another
     // template parameter.
     Arg = getTemplateArgumentPackPatternForRewrite(Arg);
+    if (Arg.getKind() != TemplateArgument::Expression) {
+      assert(SemaRef.inParameterMappingSubstitution());
+      // FIXME: SourceLocation()?
+      ExprResult E = SemaRef.BuildExpressionFromNonTypeTemplateArgument(Arg, SourceLocation());
+      if (E.isInvalid())
+        return E;
+      Arg = TemplateArgument(E.get(), /*IsCanonical=*/false);
+    }
     assert(Arg.getKind() == TemplateArgument::Expression &&
            "unexpected nontype template argument kind in template rewrite");
     // FIXME: This can lead to the same subexpression appearing multiple times
@@ -3249,7 +3262,7 @@ bool Sema::SubstTypeConstraint(
   const ASTTemplateArgumentListInfo *TemplArgInfo =
       TC->getTemplateArgsAsWritten();
 
-  if (!EvaluateConstraints) {
+  if (!EvaluateConstraints && !inParameterMappingSubstitution()) {
     UnsignedOrNone Index = TC->getArgPackSubstIndex();
     if (!Index)
       Index = SemaRef.ArgPackSubstIndex;