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Jul 23, 2025
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nested-requirements.cpp #52

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e111dcf
Remove unused headers
zyn0217 Jul 4, 2025
33f34eb
checkpoint
zyn0217 Jul 9, 2025
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3 changes: 2 additions & 1 deletion clang/include/clang/Sema/Sema.h
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Original file line number Diff line number Diff line change
Expand Up @@ -14801,7 +14801,8 @@ class Sema final : public SemaBase {
ArrayRef<AssociatedConstraint> AssociatedConstraints,
const MultiLevelTemplateArgumentList &TemplateArgLists,
SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction,
const ConceptReference *TopLevelConceptId = nullptr);
const ConceptReference *TopLevelConceptId = nullptr,
Expr **ConvertedExpr = nullptr);

/// \brief Check whether the given non-dependent constraint expression is
/// satisfied. Returns false and updates Satisfaction with the satisfaction
Expand Down
204 changes: 113 additions & 91 deletions clang/lib/Sema/SemaConcept.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,6 @@
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/WithColor.h"
#include <cstddef>
#include <optional>

Expand Down Expand Up @@ -345,7 +343,7 @@ static ExprResult EvaluateAtomicConstraint(
return SubstitutedExpression;
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const NormalizedConstraint &Constraint, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction, UnsignedOrNone PackSubstitutionIndex);
Expand Down Expand Up @@ -417,7 +415,7 @@ SubstitutionInTemplateArguments(
return std::move(MLTAL);
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const AtomicConstraint &Constraint, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction,
Expand Down Expand Up @@ -497,7 +495,7 @@ static bool calculateConstraintSatisfaction(
if (!Satisfaction.IsSatisfied)
Satisfaction.Details.emplace_back(SubstitutedAtomicExpr.get());

return SubstitutedAtomicExpr.isUsable();
return SubstitutedAtomicExpr;
}

static UnsignedOrNone EvaluateFoldExpandedConstraintSize(
Expand Down Expand Up @@ -533,7 +531,7 @@ static UnsignedOrNone EvaluateFoldExpandedConstraintSize(
return NumExpansions;
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const FoldExpandedConstraint &FE, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction) {
Expand Down Expand Up @@ -568,12 +566,13 @@ static bool calculateConstraintSatisfaction(
Sema::ArgPackSubstIndexRAII SubstIndex(S, I);
Satisfaction.IsSatisfied = false;
Satisfaction.ContainsErrors = false;
bool Success = calculateConstraintSatisfaction(
// FIXME
ExprResult Expr = calculateConstraintSatisfaction(
S, FE.getNormalizedPattern(), Template, TemplateNameLoc,
*SubstitutedArgs, Satisfaction, UnsignedOrNone(I));
// SFINAE errors shouldn't prevent disjunction from evaluating
// FIXME: Does !Success == SFINAE errors occurred?
if (!Success && Conjunction)
if (!Expr.isUsable() && Conjunction)
return false;
if (!Conjunction && Satisfaction.IsSatisfied) {
Satisfaction.Details.erase(Satisfaction.Details.begin() +
Expand All @@ -589,25 +588,12 @@ static bool calculateConstraintSatisfaction(
return true;
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const ConceptIdConstraint &Constraint, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction,
UnsignedOrNone PackSubstitutionIndex) {

// If the expression has been calculated, e.g. when we are in a nested
// requirement, do not compute it repeatedly.
if (auto *Expr = Constraint.getConceptSpecializationExpr();
Expr && Expr->getDependence() == ExprDependence::None) {
auto &Calculated = Expr->getSatisfaction();
Satisfaction.ContainsErrors = Calculated.ContainsErrors;
Satisfaction.IsSatisfied = Calculated.IsSatisfied;
Satisfaction.Details.insert(Satisfaction.Details.end(),
Calculated.records().begin(),
Calculated.records().end());
return !Satisfaction.ContainsErrors;
}

Sema::ContextRAII CurContext(
S, Constraint.getConceptId()->getNamedConcept()->getDeclContext(),
/*NewThisContext=*/false);
Expand All @@ -620,67 +606,73 @@ static bool calculateConstraintSatisfaction(

auto Size = Satisfaction.Details.size();

bool Ok = calculateConstraintSatisfaction(
ExprResult E = calculateConstraintSatisfaction(
S, Constraint.getNormalizedConstraint(), Template, TemplateNameLoc, MLTAL,
Satisfaction, PackSubstitutionIndex);

if (Size != Satisfaction.Details.size()) {
if (!E.isUsable())
return E;

llvm::SmallVector<TemplateArgument> SubstitutedOuterMost;
std::optional<MultiLevelTemplateArgumentList> SubstitutedArgs =
SubstitutionInTemplateArguments(S, Constraint, Template, MLTAL,
SubstitutedOuterMost,
PackSubstitutionIndex);
llvm::SmallVector<TemplateArgument> SubstitutedOuterMost;
std::optional<MultiLevelTemplateArgumentList> SubstitutedArgs =
SubstitutionInTemplateArguments(S, Constraint, Template, MLTAL,
SubstitutedOuterMost,
PackSubstitutionIndex);

if (!SubstitutedArgs)
return Ok;
if (!SubstitutedArgs)
return E.isUsable();

Sema::SFINAETrap Trap(S);
Sema::ArgPackSubstIndexRAII SubstIndex(
S, Constraint.getPackSubstitutionIndex()
? Constraint.getPackSubstitutionIndex()
: PackSubstitutionIndex);
Sema::SFINAETrap Trap(S);
Sema::ArgPackSubstIndexRAII SubstIndex(
S, Constraint.getPackSubstitutionIndex()
? Constraint.getPackSubstitutionIndex()
: PackSubstitutionIndex);

const ASTTemplateArgumentListInfo *Ori =
Constraint.getConceptId()->getTemplateArgsAsWritten();
TemplateArgumentListInfo OutArgs(Ori->LAngleLoc, Ori->RAngleLoc);

TemplateArgumentListInfo TransArgs(Ori->LAngleLoc, Ori->RAngleLoc);
unsigned Depth = Template && Template->getTemplateDepth()
? Template->getTemplateDepth() - 1
: 0;
AdjustConstraintDepth Adjust(S, Depth);
if (Adjust.TransformTemplateArguments(Ori->getTemplateArgs(),
Ori->NumTemplateArgs, TransArgs))
return false;

const ASTTemplateArgumentListInfo *Ori =
Constraint.getConceptId()->getTemplateArgsAsWritten();
TemplateArgumentListInfo OutArgs(Ori->LAngleLoc, Ori->RAngleLoc);

TemplateArgumentListInfo TransArgs(Ori->LAngleLoc, Ori->RAngleLoc);
unsigned Depth = Template && Template->getTemplateDepth()
? Template->getTemplateDepth() - 1
: 0;
AdjustConstraintDepth Adjust(S, Depth);
if (Adjust.TransformTemplateArguments(Ori->getTemplateArgs(),
Ori->NumTemplateArgs, TransArgs))
return Ok;

if (S.SubstTemplateArguments(TransArgs.arguments(), *SubstitutedArgs,
OutArgs) ||
Trap.hasErrorOccurred())
return Ok;
if (S.SubstTemplateArguments(TransArgs.arguments(), *SubstitutedArgs,
OutArgs) ||
Trap.hasErrorOccurred()) {
Satisfaction.ContainsErrors = true;
Satisfaction.IsSatisfied = false;
return false;
}

CXXScopeSpec SS;
SS.Adopt(Constraint.getConceptId()->getNestedNameSpecifierLoc());
ExprResult SubstitutedConceptId = S.CheckConceptTemplateId(
SS, Constraint.getConceptId()->getTemplateKWLoc(),
Constraint.getConceptId()->getConceptNameInfo(),
Constraint.getConceptId()->getFoundDecl(),
Constraint.getConceptId()->getNamedConcept(), &OutArgs,
/*CheckConstraintSatisfaction=*/false);
CXXScopeSpec SS;
SS.Adopt(Constraint.getConceptId()->getNestedNameSpecifierLoc());
ExprResult SubstitutedConceptId = S.CheckConceptTemplateId(
SS, Constraint.getConceptId()->getTemplateKWLoc(),
Constraint.getConceptId()->getConceptNameInfo(),
Constraint.getConceptId()->getFoundDecl(),
Constraint.getConceptId()->getNamedConcept(), &OutArgs,
/*CheckConstraintSatisfaction=*/false);

if (SubstitutedConceptId.isInvalid() || Trap.hasErrorOccurred())
return Ok;
if (SubstitutedConceptId.isInvalid() || Trap.hasErrorOccurred())
return false;

if (Size != Satisfaction.Details.size()) {

Satisfaction.Details.insert(
Satisfaction.Details.begin() + Size,
UnsatisfiedConstraintRecord(
SubstitutedConceptId.getAs<ConceptSpecializationExpr>()
->getConceptReference()));
}
return Ok;
return SubstitutedConceptId;
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const CompoundConstraint &Constraint, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction,
Expand All @@ -691,35 +683,49 @@ static bool calculateConstraintSatisfaction(
bool Conjunction =
Constraint.getCompoundKind() == NormalizedConstraint::CCK_Conjunction;

bool Ok = calculateConstraintSatisfaction(
ExprResult LHS = calculateConstraintSatisfaction(
S, Constraint.getLHS(), Template, TemplateNameLoc, MLTAL, Satisfaction,
PackSubstitutionIndex);

if (Conjunction && !Ok)
if (Conjunction && !LHS.isUsable())
return false;

if (!Conjunction && Ok && Satisfaction.IsSatisfied &&
if (!Conjunction && LHS.isUsable() && Satisfaction.IsSatisfied &&
!Satisfaction.ContainsErrors)
return true;
return LHS;

if (Conjunction && Ok &&
if (Conjunction && LHS.isUsable() &&
(!Satisfaction.IsSatisfied || Satisfaction.ContainsErrors))
return true;
return LHS;

Satisfaction.ContainsErrors = false;
Satisfaction.IsSatisfied = false;

Ok = calculateConstraintSatisfaction(S, Constraint.getRHS(), Template,
TemplateNameLoc, MLTAL, Satisfaction,
PackSubstitutionIndex);
if (Ok && Satisfaction.IsSatisfied && !Satisfaction.ContainsErrors)
ExprResult RHS = calculateConstraintSatisfaction(
S, Constraint.getRHS(), Template, TemplateNameLoc, MLTAL, Satisfaction,
PackSubstitutionIndex);
if (RHS.isUsable() && Satisfaction.IsSatisfied && !Satisfaction.ContainsErrors)
Satisfaction.Details.erase(Satisfaction.Details.begin() +
EffectiveDetailEndIndex,
Satisfaction.Details.end());
return Ok;

if (!LHS.isUsable())
return RHS;

if (!RHS.isUsable())
return LHS;

return BinaryOperator::Create(
S.Context, LHS.get(), RHS.get(),
BinaryOperator::getOverloadedOpcode(
Constraint.getCompoundKind() == NormalizedConstraint::CCK_Conjunction
? OO_AmpAmp
: OO_PipePipe),
S.Context.BoolTy, VK_PRValue, OK_Ordinary, Constraint.getBeginLoc(),
FPOptionsOverride{});
}

static bool calculateConstraintSatisfaction(
static ExprResult calculateConstraintSatisfaction(
Sema &S, const NormalizedConstraint &Constraint, const NamedDecl *Template,
SourceLocation TemplateNameLoc, const MultiLevelTemplateArgumentList &MLTAL,
ConstraintSatisfaction &Satisfaction,
Expand Down Expand Up @@ -753,7 +759,10 @@ static bool CheckConstraintSatisfaction(
ArrayRef<AssociatedConstraint> AssociatedConstraints,
const MultiLevelTemplateArgumentList &TemplateArgsLists,
SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction,
const ConceptReference *TopLevelConceptId = nullptr) {
Expr **ConvertedExpr, const ConceptReference *TopLevelConceptId = nullptr) {

if (ConvertedExpr)
*ConvertedExpr = nullptr;

if (AssociatedConstraints.empty()) {
Satisfaction.IsSatisfied = true;
Expand Down Expand Up @@ -792,26 +801,31 @@ static bool CheckConstraintSatisfaction(
S.ArgPackSubstIndex);
}

return !calculateConstraintSatisfaction(
S, *C, Template, TemplateIDRange.getBegin(), TemplateArgsLists,
Satisfaction, S.ArgPackSubstIndex);
ExprResult Res = calculateConstraintSatisfaction(
S, *C, Template, TemplateIDRange.getBegin(), TemplateArgsLists,
Satisfaction, S.ArgPackSubstIndex);

if (ConvertedExpr)
*ConvertedExpr = Res.get();

return !Res.isUsable();
}

bool Sema::CheckConstraintSatisfaction(
ConstrainedDeclOrNestedRequirement Entity,
ArrayRef<AssociatedConstraint> AssociatedConstraints,
const MultiLevelTemplateArgumentList &TemplateArgsLists,
SourceRange TemplateIDRange, ConstraintSatisfaction &OutSatisfaction,
const ConceptReference *TopLevelConceptId) {
const ConceptReference *TopLevelConceptId, Expr **ConvertedExpr) {
if (AssociatedConstraints.empty()) {
OutSatisfaction.IsSatisfied = true;
return false;
}
const auto *Template = Entity.dyn_cast<const NamedDecl *>();
if (!Template) {
return ::CheckConstraintSatisfaction(*this, nullptr, AssociatedConstraints,
TemplateArgsLists, TemplateIDRange,
OutSatisfaction, TopLevelConceptId);
return ::CheckConstraintSatisfaction(
*this, nullptr, AssociatedConstraints, TemplateArgsLists,
TemplateIDRange, OutSatisfaction, ConvertedExpr, TopLevelConceptId);
}
// Invalid templates could make their way here. Substituting them could result
// in dependent expressions.
Expand Down Expand Up @@ -842,13 +856,15 @@ bool Sema::CheckConstraintSatisfaction(

auto Satisfaction =
std::make_unique<ConstraintSatisfaction>(Owner, FlattenedArgs);
if (::CheckConstraintSatisfaction(*this, Template, AssociatedConstraints,
TemplateArgsLists, TemplateIDRange,
*Satisfaction, TopLevelConceptId)) {
if (::CheckConstraintSatisfaction(
*this, Template, AssociatedConstraints, TemplateArgsLists,
TemplateIDRange, *Satisfaction, ConvertedExpr, TopLevelConceptId)) {
OutSatisfaction = *Satisfaction;
return true;
}

// FIXME: cache ConvertedExpr for nested requirements?

if (auto *Cached = SatisfactionCache.FindNodeOrInsertPos(ID, InsertPos)) {
// The evaluation of this constraint resulted in us trying to re-evaluate it
// recursively. This isn't really possible, except we try to form a
Expand Down Expand Up @@ -1595,7 +1611,8 @@ substituteParameterMappings(Sema &S, NormalizedConstraintWithParamMapping &N,
SourceLocation Loc = ArgsAsWritten->NumTemplateArgs > I
? ArgsAsWritten->arguments()[I].getLocation()
: SourceLocation();
// FIXME: Investigate when we couldn't preserve the SourceLoc. What shall we do??
// FIXME: Investigate when we couldn't preserve the SourceLoc. What shall
// we do??
// assert(Loc.isValid());
if (OccurringIndices[I]) {
NamedDecl *Param = TemplateParams->begin()[I];
Expand Down Expand Up @@ -1928,9 +1945,14 @@ NormalizedConstraint *NormalizedConstraint::fromConstraintExpr(
const NormalizedConstraint *Sema::getNormalizedAssociatedConstraints(
ConstrainedDeclOrNestedRequirement ConstrainedDeclOrNestedReq,
ArrayRef<AssociatedConstraint> AssociatedConstraints) {
if (!ConstrainedDeclOrNestedReq)
return NormalizedConstraint::fromAssociatedConstraints(
if (!ConstrainedDeclOrNestedReq) {
auto *Normalized = NormalizedConstraint::fromAssociatedConstraints(
*this, nullptr, AssociatedConstraints);
if (!Normalized || substituteParameterMappings(*this, *Normalized))
return nullptr;

return Normalized;
}

// FIXME: ConstrainedDeclOrNestedReq is never a NestedRequirement!
const NamedDecl *ND =
Expand Down
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