Revert "Reapply "[Clang][Sema] Refactor collection of multi-level template argument lists (#106585)" (#111173)" (#111766)

This reverts commit 4da8ac34f76e707ab94380b94f616457cfd2cb83.

1 files changed, 17 insertions, 12 deletions

diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index e36ee06..998a148 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -585,8 +585,8 @@ static bool CheckConstraintSatisfaction(
 
   ArrayRef<TemplateArgument> TemplateArgs =
       TemplateArgsLists.getNumSubstitutedLevels() > 0
-          ? TemplateArgsLists.getInnermost()
-          : ArrayRef<TemplateArgument>{};
+          ? TemplateArgsLists.getOutermost()
+          : ArrayRef<TemplateArgument> {};
   Sema::InstantiatingTemplate Inst(S, TemplateIDRange.getBegin(),
       Sema::InstantiatingTemplate::ConstraintsCheck{},
       const_cast<NamedDecl *>(Template), TemplateArgs, TemplateIDRange);
@@ -834,6 +834,7 @@ Sema::SetupConstraintCheckingTemplateArgumentsAndScope(
       getTemplateInstantiationArgs(FD, FD->getLexicalDeclContext(),
                                    /*Final=*/false, /*Innermost=*/std::nullopt,
                                    /*RelativeToPrimary=*/true,
+                                   /*Pattern=*/nullptr,
                                    /*ForConstraintInstantiation=*/true);
   if (SetupConstraintScope(FD, TemplateArgs, MLTAL, Scope))
     return std::nullopt;
@@ -909,13 +910,15 @@ bool Sema::CheckFunctionConstraints(const FunctionDecl *FD,
 // Figure out the to-translation-unit depth for this function declaration for
 // the purpose of seeing if they differ by constraints. This isn't the same as
 // getTemplateDepth, because it includes already instantiated parents.
-static unsigned CalculateTemplateDepthForConstraints(Sema &S,
-                                                     const NamedDecl *ND) {
+static unsigned
+CalculateTemplateDepthForConstraints(Sema &S, const NamedDecl *ND,
+                                     bool SkipForSpecialization = false) {
   MultiLevelTemplateArgumentList MLTAL = S.getTemplateInstantiationArgs(
       ND, ND->getLexicalDeclContext(), /*Final=*/false,
       /*Innermost=*/std::nullopt,
       /*RelativeToPrimary=*/true,
-      /*ForConstraintInstantiation=*/true);
+      /*Pattern=*/nullptr,
+      /*ForConstraintInstantiation=*/true, SkipForSpecialization);
   return MLTAL.getNumLevels();
 }
 
@@ -954,7 +957,8 @@ static const Expr *SubstituteConstraintExpressionWithoutSatisfaction(
       DeclInfo.getDecl(), DeclInfo.getLexicalDeclContext(), /*Final=*/false,
       /*Innermost=*/std::nullopt,
       /*RelativeToPrimary=*/true,
-      /*ForConstraintInstantiation=*/true);
+      /*Pattern=*/nullptr, /*ForConstraintInstantiation=*/true,
+      /*SkipForSpecialization*/ false);
 
   if (MLTAL.getNumSubstitutedLevels() == 0)
     return ConstrExpr;
@@ -1064,16 +1068,16 @@ bool Sema::AreConstraintExpressionsEqual(const NamedDecl *Old,
 bool Sema::FriendConstraintsDependOnEnclosingTemplate(const FunctionDecl *FD) {
   assert(FD->getFriendObjectKind() && "Must be a friend!");
 
-  FunctionTemplateDecl *FTD = FD->getDescribedFunctionTemplate();
   // The logic for non-templates is handled in ASTContext::isSameEntity, so we
   // don't have to bother checking 'DependsOnEnclosingTemplate' for a
   // non-function-template.
-  assert(FTD && "Non-function templates don't need to be checked");
+  assert(FD->getDescribedFunctionTemplate() &&
+         "Non-function templates don't need to be checked");
 
   SmallVector<const Expr *, 3> ACs;
-  FTD->getAssociatedConstraints(ACs);
+  FD->getDescribedFunctionTemplate()->getAssociatedConstraints(ACs);
 
-  unsigned OldTemplateDepth = FTD->getTemplateParameters()->getDepth();
+  unsigned OldTemplateDepth = CalculateTemplateDepthForConstraints(*this, FD);
   for (const Expr *Constraint : ACs)
     if (ConstraintExpressionDependsOnEnclosingTemplate(FD, OldTemplateDepth,
                                                        Constraint))
@@ -1520,6 +1524,7 @@ static bool substituteParameterMappings(Sema &S, NormalizedConstraint &N,
       CSE->getNamedConcept(), CSE->getNamedConcept()->getLexicalDeclContext(),
       /*Final=*/false, CSE->getTemplateArguments(),
       /*RelativeToPrimary=*/true,
+      /*Pattern=*/nullptr,
       /*ForConstraintInstantiation=*/true);
 
   return substituteParameterMappings(S, N, CSE->getNamedConcept(), MLTAL,
@@ -1800,8 +1805,8 @@ bool Sema::IsAtLeastAsConstrained(NamedDecl *D1,
     return false;
   }
 
-  unsigned Depth1 = CalculateTemplateDepthForConstraints(*this, D1);
-  unsigned Depth2 = CalculateTemplateDepthForConstraints(*this, D2);
+  unsigned Depth1 = CalculateTemplateDepthForConstraints(*this, D1, true);
+  unsigned Depth2 = CalculateTemplateDepthForConstraints(*this, D2, true);
 
   for (size_t I = 0; I != AC1.size() && I != AC2.size(); ++I) {
     if (Depth2 > Depth1) {