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author | Saar Raz <saar@raz.email> | 2019-10-25 00:09:37 +0300 |
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committer | Saar Raz <saar@raz.email> | 2019-10-25 00:19:51 +0300 |
commit | ffa214ef22892d75340dc6720271863901dc2c90 (patch) | |
tree | 22ac01e56e625a86277515bd3fd76060016265b8 /clang/lib/Sema/SemaOverload.cpp | |
parent | a18818207ab5bb2f81cf1db036d0b23645d5ab83 (diff) | |
download | bcm5719-llvm-ffa214ef22892d75340dc6720271863901dc2c90.tar.gz bcm5719-llvm-ffa214ef22892d75340dc6720271863901dc2c90.zip |
[Concepts] Constraint Enforcement & Diagnostics
Part of the C++20 concepts implementation effort.
- Associated constraints (requires clauses, currently) are now enforced when instantiating/specializing templates and when considering partial specializations and function overloads.
- Elaborated diagnostics give helpful insight as to why the constraints were not satisfied.
Phabricator: D41569
Diffstat (limited to 'clang/lib/Sema/SemaOverload.cpp')
-rw-r--r-- | clang/lib/Sema/SemaOverload.cpp | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp index 47c1e3cec0e..b79855a6afb 100644 --- a/clang/lib/Sema/SemaOverload.cpp +++ b/clang/lib/Sema/SemaOverload.cpp @@ -591,6 +591,12 @@ namespace { TemplateArgumentList *TemplateArgs; unsigned CallArgIndex; }; + // Structure used by DeductionFailureInfo to store information about + // unsatisfied constraints. + struct CNSInfo { + TemplateArgumentList *TemplateArgs; + ConstraintSatisfaction Satisfaction; + }; } /// Convert from Sema's representation of template deduction information @@ -661,6 +667,14 @@ clang::MakeDeductionFailureInfo(ASTContext &Context, } break; + case Sema::TDK_ConstraintsNotSatisfied: { + CNSInfo *Saved = new (Context) CNSInfo; + Saved->TemplateArgs = Info.take(); + Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction; + Result.Data = Saved; + break; + } + case Sema::TDK_Success: case Sema::TDK_NonDependentConversionFailure: llvm_unreachable("not a deduction failure"); @@ -701,6 +715,15 @@ void DeductionFailureInfo::Destroy() { } break; + case Sema::TDK_ConstraintsNotSatisfied: + // FIXME: Destroy the template argument list? + Data = nullptr; + if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) { + Diag->~PartialDiagnosticAt(); + HasDiagnostic = false; + } + break; + // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; @@ -726,6 +749,7 @@ TemplateParameter DeductionFailureInfo::getTemplateParameter() { case Sema::TDK_NonDeducedMismatch: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: + case Sema::TDK_ConstraintsNotSatisfied: return TemplateParameter(); case Sema::TDK_Incomplete: @@ -769,6 +793,9 @@ TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() { case Sema::TDK_SubstitutionFailure: return static_cast<TemplateArgumentList*>(Data); + case Sema::TDK_ConstraintsNotSatisfied: + return static_cast<CNSInfo*>(Data)->TemplateArgs; + // Unhandled case Sema::TDK_MiscellaneousDeductionFailure: break; @@ -789,6 +816,7 @@ const TemplateArgument *DeductionFailureInfo::getFirstArg() { case Sema::TDK_SubstitutionFailure: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: + case Sema::TDK_ConstraintsNotSatisfied: return nullptr; case Sema::TDK_IncompletePack: @@ -820,6 +848,7 @@ const TemplateArgument *DeductionFailureInfo::getSecondArg() { case Sema::TDK_SubstitutionFailure: case Sema::TDK_CUDATargetMismatch: case Sema::TDK_NonDependentConversionFailure: + case Sema::TDK_ConstraintsNotSatisfied: return nullptr; case Sema::TDK_Inconsistent: @@ -1255,6 +1284,8 @@ bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old, return NewTarget != OldTarget; } + // TODO: Concepts: Check function trailing requires clauses here. + // The signatures match; this is not an overload. return false; } @@ -10333,6 +10364,21 @@ static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated, MaybeEmitInheritedConstructorNote(S, Found); return; + case Sema::TDK_ConstraintsNotSatisfied: { + // Format the template argument list into the argument string. + SmallString<128> TemplateArgString; + TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList(); + TemplateArgString = " "; + TemplateArgString += S.getTemplateArgumentBindingsText( + getDescribedTemplate(Templated)->getTemplateParameters(), *Args); + S.Diag(Templated->getLocation(), + diag::note_ovl_candidate_unsatisfied_constraints) + << TemplateArgString; + + S.DiagnoseUnsatisfiedConstraint( + static_cast<CNSInfo*>(DeductionFailure.Data)->Satisfaction); + return; + } case Sema::TDK_TooManyArguments: case Sema::TDK_TooFewArguments: DiagnoseArityMismatch(S, Found, Templated, NumArgs); @@ -10785,6 +10831,7 @@ static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) { case Sema::TDK_SubstitutionFailure: case Sema::TDK_DeducedMismatch: + case Sema::TDK_ConstraintsNotSatisfied: case Sema::TDK_DeducedMismatchNested: case Sema::TDK_NonDeducedMismatch: case Sema::TDK_MiscellaneousDeductionFailure: |