================
@@ -3239,61 +3162,11 @@ bool Sema::SubstTypeConstraint(
TC->getTemplateArgsAsWritten();
if (!EvaluateConstraints) {
- bool ShouldExpandExplicitTemplateArgs =
- TemplArgInfo && ArgumentPackSubstitutionIndex != -1 &&
- llvm::any_of(TemplArgInfo->arguments(), [](auto &Arg) {
- return Arg.getArgument().containsUnexpandedParameterPack();
- });
-
- // We want to transform the packs into Subst* nodes for type constraints
- // inside a pack expansion. For example,
- //
- // template <class... Ts> void foo() {
- // bar([](C<Ts> auto value) {}...);
- // }
- //
- // As we expand Ts in the process of instantiating foo(), and retain
- // the original template depths of Ts until the constraint evaluation, we
- // would otherwise have no chance to expand Ts by the time of evaluating
- // C<auto, Ts>.
- //
- // So we form a Subst* node for Ts along with a proper substitution index
- // here, and substitute the node with a complete MLTAL later in evaluation.
- if (ShouldExpandExplicitTemplateArgs) {
- TemplateArgumentListInfo InstArgs;
- InstArgs.setLAngleLoc(TemplArgInfo->LAngleLoc);
- InstArgs.setRAngleLoc(TemplArgInfo->RAngleLoc);
- if (ExpandPackedTypeConstraints(*this, TemplateArgs)
- .SubstTemplateArguments(TemplArgInfo->arguments(), InstArgs))
- return true;
-
- // The type of the original parameter.
- auto *ConstraintExpr = TC->getImmediatelyDeclaredConstraint();
- QualType ConstrainedType;
-
- if (auto *FE = dyn_cast<CXXFoldExpr>(ConstraintExpr)) {
- assert(FE->getLHS());
- ConstraintExpr = FE->getLHS();
- }
- auto *CSE = cast<ConceptSpecializationExpr>(ConstraintExpr);
- assert(!CSE->getTemplateArguments().empty() &&
- "Empty template arguments?");
- ConstrainedType = CSE->getTemplateArguments()[0].getAsType();
- assert(!ConstrainedType.isNull() &&
- "Failed to extract the original ConstrainedType?");
-
- return AttachTypeConstraint(
- TC->getNestedNameSpecifierLoc(), TC->getConceptNameInfo(),
- TC->getNamedConcept(),
- /*FoundDecl=*/TC->getConceptReference()->getFoundDecl(), &InstArgs,
- Inst, ConstrainedType,
- Inst->isParameterPack()
- ? cast<CXXFoldExpr>(TC->getImmediatelyDeclaredConstraint())
- ->getEllipsisLoc()
- : SourceLocation());
- }
+ auto Index = TC->getArgumentPackSubstitutionIndex();
+ if (Index == -1)
+ Index = SemaRef.ArgumentPackSubstitutionIndex;
----------------
mizvekov wrote:
I am not sure what you mean to see an index mismatch.
If on a first transform pass this is not expanded and we see
`ArgumentPackSubstitutionIndex != -1`, then it becomes expanded.
On subsequent patches if we are already expanded, then nothing changes. This
works the same way in normal instantiation.
https://github.com/llvm/llvm-project/pull/132626
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