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[Diagnostics] Extract requirement declaration context retrieval into … #18752

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Merged
merged 1 commit into from
Aug 16, 2018
Merged

[Diagnostics] Extract requirement declaration context retrieval into … #18752

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45 changes: 28 additions & 17 deletions lib/Sema/CSDiagnostics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,11 @@
//
//===----------------------------------------------------------------------===//

#include "ConstraintSystem.h"
#include "CSDiagnostics.h"
#include "ConstraintSystem.h"
#include "MiscDiagnostics.h"
#include "swift/AST/Expr.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/Types.h"
#include "llvm/ADT/ArrayRef.h"

Expand Down Expand Up @@ -67,7 +68,7 @@ Type RequirementFailure::getOwnerType() const {
return getType(getAnchor())->getInOutObjectType()->getMetatypeInstanceType();
}

const Requirement &RequirementFailure::getRequirement() {
const Requirement &RequirementFailure::getRequirement() const {
auto *genericCtx = AffectedDecl->getAsGenericContext();
return genericCtx->getGenericRequirements()[getRequirementIndex()];
}
Expand Down Expand Up @@ -100,6 +101,27 @@ ValueDecl *RequirementFailure::getDeclRef() const {
return ownerType->getAnyGeneric();
}

const DeclContext *RequirementFailure::getRequirementDC() const {
const auto &req = getRequirement();
auto *DC = AffectedDecl->getDeclContext();

do {
auto *D = DC->getInnermostDeclarationDeclContext();
if (!D)
break;

if (auto *GC = D->getAsGenericContext()) {
auto *sig = GC->getGenericSignature();
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This looks like you just want DC->getGenericSignatureOfContext() and avoid all this?

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I don't think I can because getGenericSignatureOfContext is going to traverse parents until it finds one with generic signature and it would only return signature from it, but I wouldn't know which parent that was.

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getGenericSignatureOfContext() does not traverse parents, but non-generic decls in generic context inherit the generic signature of their parent, so getGenericSignature() has the same behavior.

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Good to know, I'll give it a try.

if (sig && sig->isRequirementSatisfied(req))
return DC;
}

DC = DC->getParent();
} while (DC);

return AffectedDecl->getAsGenericContext();
}

bool MissingConformanceFailure::diagnose() {
auto *anchor = getAnchor();
auto ownerType = getOwnerType();
Expand Down Expand Up @@ -175,21 +197,10 @@ bool MissingConformanceFailure::diagnose() {
} else {
const auto &req = getRequirement();
auto *genericCtx = AffectedDecl->getAsGenericContext();
const auto *reqDC = getRequirementDC();

std::function<const DeclContext *(Type)> getAffectedCtx =
[&](Type type) -> const DeclContext * {
if (auto *DMT = type->getAs<DependentMemberType>())
return getAffectedCtx(DMT->getBase());

if (auto *GPT = type->getAs<GenericTypeParamType>())
return GPT->getDecl()->getDeclContext();

return genericCtx;
};

const auto *affected = getAffectedCtx(req.getFirstType());
if (affected != genericCtx) {
auto *NTD = affected->getAsNominalTypeOrNominalTypeExtensionContext();
if (reqDC != genericCtx) {
auto *NTD = reqDC->getAsNominalTypeOrNominalTypeExtensionContext();
emitDiagnostic(anchor->getLoc(), diag::type_does_not_conform_in_decl_ref,
AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(), NTD->getDeclaredType(), type,
Expand All @@ -200,7 +211,7 @@ bool MissingConformanceFailure::diagnose() {
AffectedDecl->getFullName(), type, protocolType);
}

emitDiagnostic(affected->getAsDeclOrDeclExtensionContext(),
emitDiagnostic(reqDC->getAsDeclOrDeclExtensionContext(),
diag::where_type_does_not_conform_type, req.getFirstType(),
type);
}
Expand Down
7 changes: 6 additions & 1 deletion lib/Sema/CSDiagnostics.h
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Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,12 @@ class RequirementFailure : public FailureDiagnostic {
Type getOwnerType() const;

/// Generic requirement associated with the failure.
const Requirement &getRequirement();
const Requirement &getRequirement() const;

protected:
/// Retrieve declaration contextual where current
/// requirement has been introduced.
const DeclContext *getRequirementDC() const;

private:
/// Retrieve declaration associated with failing generic requirement.
Expand Down