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CSDiagnostics.cpp
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//===--- CSDiagnostics.cpp - Constraint Diagnostics -----------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements diagnostics for constraint system.
//
//===----------------------------------------------------------------------===//
#include "CSDiagnostics.h"
#include "ConstraintSystem.h"
#include "MiscDiagnostics.h"
#include "TypoCorrection.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/Decl.h"
#include "swift/AST/ExistentialLayout.h"
#include "swift/AST/Expr.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/Initializer.h"
#include "swift/AST/ParameterList.h"
#include "swift/AST/Pattern.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/ProtocolConformanceRef.h"
#include "swift/AST/SourceFile.h"
#include "swift/AST/Stmt.h"
#include "swift/AST/Types.h"
#include "swift/Basic/SourceLoc.h"
#include "swift/Parse/Lexer.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallString.h"
#include <string>
using namespace swift;
using namespace constraints;
FailureDiagnostic::~FailureDiagnostic() {}
bool FailureDiagnostic::diagnose(bool asNote) {
return asNote ? diagnoseAsNote() : diagnoseAsError();
}
bool FailureDiagnostic::diagnoseAsNote() {
return false;
}
Expr *FailureDiagnostic::computeAnchor() const {
auto &cs = getConstraintSystem();
auto *locator = getLocator();
// Resolve the locator to a specific expression.
SourceRange range;
ConstraintLocator *resolved = simplifyLocator(cs, locator, range);
if (!resolved || !resolved->getAnchor())
return locator->getAnchor();
Expr *anchor = resolved->getAnchor();
// FIXME: Work around an odd locator representation that doesn't separate the
// base of a subscript member from the member access.
if (locator->isLastElement<LocatorPathElt::SubscriptMember>()) {
if (auto subscript = dyn_cast<SubscriptExpr>(anchor))
anchor = subscript->getBase();
}
return anchor;
}
Type FailureDiagnostic::getType(Expr *expr, bool wantRValue) const {
return resolveType(S.getType(expr), /*reconstituteSugar=*/false, wantRValue);
}
Type FailureDiagnostic::getType(const TypeLoc &loc, bool wantRValue) const {
return resolveType(S.getType(&loc), /*reconstituteSugar=*/false, wantRValue);
}
template <typename... ArgTypes>
InFlightDiagnostic
FailureDiagnostic::emitDiagnostic(ArgTypes &&... Args) const {
return emitDiagnosticAt(getLoc(), std::forward<ArgTypes>(Args)...);
}
template <typename... ArgTypes>
InFlightDiagnostic
FailureDiagnostic::emitDiagnosticAt(ArgTypes &&... Args) const {
auto &DE = getASTContext().Diags;
return DE.diagnose(std::forward<ArgTypes>(Args)...);
}
Expr *FailureDiagnostic::findParentExpr(Expr *subExpr) const {
auto &cs = getConstraintSystem();
return cs.getParentExpr(subExpr);
}
Expr *
FailureDiagnostic::getArgumentListExprFor(ConstraintLocator *locator) const {
auto path = locator->getPath();
auto iter = path.begin();
if (!locator->findFirst<LocatorPathElt::ApplyArgument>(iter))
return nullptr;
// Form a new locator that ends at the ApplyArgument element, then simplify
// to get the argument list.
auto newPath = ArrayRef<LocatorPathElt>(path.begin(), iter + 1);
auto &cs = getConstraintSystem();
auto argListLoc = cs.getConstraintLocator(locator->getAnchor(), newPath);
return simplifyLocatorToAnchor(argListLoc);
}
Expr *FailureDiagnostic::getBaseExprFor(Expr *anchor) const {
if (!anchor)
return nullptr;
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor))
return UDE->getBase();
else if (auto *SE = dyn_cast<SubscriptExpr>(anchor))
return SE->getBase();
else if (auto *MRE = dyn_cast<MemberRefExpr>(anchor))
return MRE->getBase();
else if (auto *call = dyn_cast<CallExpr>(anchor)) {
auto fnType = getType(call->getFn());
if (fnType->isCallableNominalType(getDC())) {
return call->getFn();
}
}
return nullptr;
}
Type FailureDiagnostic::restoreGenericParameters(
Type type,
llvm::function_ref<void(GenericTypeParamType *, Type)> substitution) {
llvm::SmallPtrSet<GenericTypeParamType *, 4> processed;
return type.transform([&](Type type) -> Type {
if (auto *typeVar = type->getAs<TypeVariableType>()) {
type = resolveType(typeVar);
if (auto *GP = typeVar->getImpl().getGenericParameter()) {
if (processed.insert(GP).second)
substitution(GP, type);
return GP;
}
}
return type;
});
}
Type RequirementFailure::getOwnerType() const {
auto *anchor = getRawAnchor();
// If diagnostic is anchored at assignment expression
// it means that requirement failure happend while trying
// to convert source to destination, which means that
// owner type is actually not an assignment expression
// itself but its source.
if (auto *assignment = dyn_cast<AssignExpr>(anchor))
anchor = assignment->getSrc();
return getType(anchor)->getInOutObjectType()->getMetatypeInstanceType();
}
const GenericContext *RequirementFailure::getGenericContext() const {
if (auto *genericCtx = AffectedDecl->getAsGenericContext())
return genericCtx;
auto parentDecl = AffectedDecl->getDeclContext()->getAsDecl();
if (!parentDecl)
return nullptr;
return parentDecl->getAsGenericContext();
}
const Requirement &RequirementFailure::getRequirement() const {
// If this is a conditional requirement failure we need to
// fetch conformance from constraint system associated with
// type requirement this conditional conformance belongs to.
auto requirements = isConditional()
? Conformance->getConditionalRequirements()
: Signature->getRequirements();
return requirements[getRequirementIndex()];
}
ProtocolConformance *RequirementFailure::getConformanceForConditionalReq(
ConstraintLocator *locator) {
auto &cs = getConstraintSystem();
auto reqElt = locator->castLastElementTo<LocatorPathElt::AnyRequirement>();
if (!reqElt.isConditionalRequirement())
return nullptr;
auto path = locator->getPath();
auto *typeReqLoc = getConstraintLocator(getRawAnchor(), path.drop_back());
auto result = llvm::find_if(
cs.CheckedConformances,
[&](const std::pair<ConstraintLocator *, ProtocolConformanceRef>
&conformance) { return conformance.first == typeReqLoc; });
assert(result != cs.CheckedConformances.end());
auto conformance = result->second;
assert(conformance.isConcrete());
return conformance.getConcrete();
}
ValueDecl *RequirementFailure::getDeclRef() const {
// Get a declaration associated with given type (if any).
// This is used to retrieve affected declaration when
// failure is in any way contextual, and declaration can't
// be fetched directly from constraint system.
auto getAffectedDeclFromType = [](Type type) -> ValueDecl * {
assert(type);
// If problem is related to a typealias, let's point this
// diagnostic directly to its declaration without desugaring.
if (auto *alias = dyn_cast<TypeAliasType>(type.getPointer()))
return alias->getDecl();
if (auto *opaque = type->getAs<OpaqueTypeArchetypeType>())
return opaque->getDecl();
return type->getAnyGeneric();
};
if (isFromContextualType())
return getAffectedDeclFromType(
getContextualType(getLocator()->getAnchor()));
if (auto overload = getCalleeOverloadChoiceIfAvailable(getLocator())) {
// If there is a declaration associated with this
// failure e.g. an overload choice of the call
// expression, let's see whether failure is
// associated with it directly or rather with
// one of its parents.
if (auto *decl = overload->choice.getDeclOrNull()) {
// If declaration is an operator let's always use
// it to produce `in reference to` diagnostics.
if (decl->isOperator())
return decl;
auto *DC = decl->getDeclContext();
do {
if (auto *parent = DC->getAsDecl()) {
if (auto *GC = parent->getAsGenericContext()) {
// FIXME: Is this intending an exact match?
if (GC->getGenericSignature().getPointer() != Signature.getPointer())
continue;
// If this is a signature if an extension
// then it means that code has referenced
// something incorrectly and diagnostic
// should point to the referenced declaration.
if (isa<ExtensionDecl>(parent))
break;
return cast<ValueDecl>(parent);
}
}
} while ((DC = DC->getParent()));
return decl;
}
}
return getAffectedDeclFromType(getOwnerType());
}
GenericSignature RequirementFailure::getSignature(ConstraintLocator *locator) {
if (isConditional())
return Conformance->getGenericSignature();
if (auto genericElt = locator->findLast<LocatorPathElt::OpenedGeneric>())
return genericElt->getSignature();
llvm_unreachable("Type requirement failure should always have signature");
}
bool RequirementFailure::isFromContextualType() const {
auto path = getLocator()->getPath();
assert(!path.empty());
return path.front().getKind() == ConstraintLocator::ContextualType;
}
const DeclContext *RequirementFailure::getRequirementDC() const {
// In case of conditional requirement failure, we don't
// have to guess where the it comes from.
if (isConditional())
return Conformance->getDeclContext();
const auto &req = getRequirement();
auto *DC = AffectedDecl->getDeclContext();
do {
if (auto sig = DC->getGenericSignatureOfContext()) {
if (sig->isRequirementSatisfied(req))
return DC;
}
} while ((DC = DC->getParent()));
return AffectedDecl->getAsGenericContext();
}
bool RequirementFailure::isStaticOrInstanceMember(const ValueDecl *decl) {
if (decl->isInstanceMember())
return true;
if (auto *AFD = dyn_cast<AbstractFunctionDecl>(decl))
return AFD->isStatic() && !AFD->isOperator();
return decl->isStatic();
}
bool RequirementFailure::diagnoseAsError() {
const auto *reqDC = getRequirementDC();
auto *genericCtx = getGenericContext();
auto lhs = getLHS();
auto rhs = getRHS();
if (auto *OTD = dyn_cast<OpaqueTypeDecl>(AffectedDecl)) {
auto *namingDecl = OTD->getNamingDecl();
emitDiagnostic(diag::type_does_not_conform_in_opaque_return,
namingDecl->getDescriptiveKind(), namingDecl->getFullName(),
lhs, rhs, rhs->isAnyObject());
if (auto *repr = namingDecl->getOpaqueResultTypeRepr()) {
emitDiagnosticAt(repr->getLoc(), diag::opaque_return_type_declared_here)
.highlight(repr->getSourceRange());
}
return true;
}
if (reqDC->isTypeContext() && genericCtx != reqDC &&
(genericCtx->isChildContextOf(reqDC) ||
isStaticOrInstanceMember(AffectedDecl))) {
auto *NTD = reqDC->getSelfNominalTypeDecl();
emitDiagnostic(
getDiagnosticInRereference(), AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(), NTD->getDeclaredType(), lhs, rhs);
} else {
emitDiagnostic(getDiagnosticOnDecl(), AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(), lhs, rhs);
}
emitRequirementNote(reqDC->getAsDecl(), lhs, rhs);
return true;
}
bool RequirementFailure::diagnoseAsNote() {
const auto &req = getRequirement();
const auto *reqDC = getRequirementDC();
emitDiagnosticAt(reqDC->getAsDecl(), getDiagnosticAsNote(), getLHS(),
getRHS(), req.getFirstType(), req.getSecondType(), "");
return true;
}
void RequirementFailure::emitRequirementNote(const Decl *anchor, Type lhs,
Type rhs) const {
auto &req = getRequirement();
if (req.getKind() != RequirementKind::SameType) {
if (auto wrappedType = lhs->getOptionalObjectType()) {
auto kind = (req.getKind() == RequirementKind::Superclass ?
ConstraintKind::Subtype : ConstraintKind::ConformsTo);
if (TypeChecker::typesSatisfyConstraint(wrappedType, rhs,
/*openArchetypes=*/false,
kind, getDC()))
emitDiagnostic(diag::wrapped_type_satisfies_requirement, wrappedType);
}
}
if (isConditional()) {
emitDiagnosticAt(anchor,
diag::requirement_implied_by_conditional_conformance,
resolveType(Conformance->getType()),
Conformance->getProtocol()->getDeclaredInterfaceType());
return;
}
if (req.getKind() == RequirementKind::Layout ||
rhs->isEqual(req.getSecondType())) {
emitDiagnosticAt(anchor, diag::where_requirement_failure_one_subst,
req.getFirstType(), lhs);
return;
}
if (lhs->isEqual(req.getFirstType())) {
emitDiagnosticAt(anchor, diag::where_requirement_failure_one_subst,
req.getSecondType(), rhs);
return;
}
emitDiagnosticAt(anchor, diag::where_requirement_failure_both_subst,
req.getFirstType(), lhs, req.getSecondType(), rhs);
}
bool MissingConformanceFailure::diagnoseAsError() {
auto *anchor = getAnchor();
auto nonConformingType = getLHS();
auto protocolType = getRHS();
// If this is a requirement of a pattern-matching operator,
// let's see whether argument already has a fix associated
// with it and if so skip conformance error, otherwise we'd
// produce an unrelated `<type> doesn't conform to Equatable protocol`
// diagnostic.
if (isPatternMatchingOperator(anchor)) {
if (auto *binaryOp = dyn_cast_or_null<BinaryExpr>(findParentExpr(anchor))) {
auto *caseExpr = binaryOp->getArg()->getElement(0);
auto &cs = getConstraintSystem();
llvm::SmallPtrSet<Expr *, 4> anchors;
for (const auto *fix : cs.getFixes())
anchors.insert(fix->getAnchor());
bool hasFix = false;
caseExpr->forEachChildExpr([&](Expr *expr) -> Expr * {
hasFix |= anchors.count(expr);
return hasFix ? nullptr : expr;
});
if (hasFix)
return false;
}
}
if (diagnoseAsAmbiguousOperatorRef())
return true;
if (nonConformingType->isObjCExistentialType()) {
emitDiagnostic(diag::protocol_does_not_conform_static, nonConformingType,
protocolType);
return true;
}
if (diagnoseTypeCannotConform(nonConformingType, protocolType))
return true;
// If none of the special cases could be diagnosed,
// let's fallback to the most general diagnostic.
return RequirementFailure::diagnoseAsError();
}
bool MissingConformanceFailure::diagnoseTypeCannotConform(
Type nonConformingType, Type protocolType) const {
if (getRequirement().getKind() == RequirementKind::Layout ||
!(nonConformingType->is<AnyFunctionType>() ||
nonConformingType->is<TupleType>() ||
nonConformingType->isExistentialType() ||
nonConformingType->is<AnyMetatypeType>())) {
return false;
}
emitDiagnostic(diag::type_cannot_conform,
nonConformingType->isExistentialType(), nonConformingType,
protocolType);
if (auto *OTD = dyn_cast<OpaqueTypeDecl>(AffectedDecl)) {
auto *namingDecl = OTD->getNamingDecl();
if (auto *repr = namingDecl->getOpaqueResultTypeRepr()) {
emitDiagnosticAt(repr->getLoc(), diag::required_by_opaque_return,
namingDecl->getDescriptiveKind(),
namingDecl->getFullName())
.highlight(repr->getSourceRange());
}
return true;
}
auto &req = getRequirement();
auto *reqDC = getRequirementDC();
auto *genericCtx = getGenericContext();
auto noteLocation = reqDC->getAsDecl()->getLoc();
if (!noteLocation.isValid())
noteLocation = getLoc();
if (isConditional()) {
emitDiagnosticAt(noteLocation,
diag::requirement_implied_by_conditional_conformance,
resolveType(Conformance->getType()),
Conformance->getProtocol()->getDeclaredInterfaceType());
} else if (genericCtx != reqDC && (genericCtx->isChildContextOf(reqDC) ||
isStaticOrInstanceMember(AffectedDecl))) {
emitDiagnosticAt(noteLocation, diag::required_by_decl_ref,
AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(),
reqDC->getSelfNominalTypeDecl()->getDeclaredType(),
req.getFirstType(), nonConformingType);
} else {
emitDiagnosticAt(noteLocation, diag::required_by_decl,
AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(), req.getFirstType(),
nonConformingType);
}
return true;
}
bool MissingConformanceFailure::diagnoseAsAmbiguousOperatorRef() {
auto *anchor = getRawAnchor();
auto *ODRE = dyn_cast<OverloadedDeclRefExpr>(anchor);
if (!ODRE)
return false;
auto name = ODRE->getDecls().front()->getBaseName();
if (!(name.isOperator() && getLHS()->isStdlibType() && getRHS()->isStdlibType()))
return false;
// If this is an operator reference and both types are from stdlib,
// let's produce a generic diagnostic about invocation and a note
// about missing conformance just in case.
auto operatorID = name.getIdentifier();
auto *fnType = getType(anchor)->getAs<AnyFunctionType>();
auto params = fnType->getParams();
if (params.size() == 2) {
auto lhsType = params[0].getPlainType();
auto rhsType = params[1].getPlainType();
if (lhsType->isEqual(rhsType)) {
emitDiagnostic(diag::cannot_apply_binop_to_same_args, operatorID.str(),
lhsType);
} else {
emitDiagnostic(diag::cannot_apply_binop_to_args, operatorID.str(),
lhsType, rhsType);
}
} else {
emitDiagnostic(diag::cannot_apply_unop_to_arg, operatorID.str(),
params[0].getPlainType());
}
diagnoseAsNote();
return true;
}
Optional<Diag<Type, Type>> GenericArgumentsMismatchFailure::getDiagnosticFor(
ContextualTypePurpose context) {
switch (context) {
case CTP_Initialization:
case CTP_AssignSource:
return diag::cannot_convert_assign;
case CTP_ReturnStmt:
case CTP_ReturnSingleExpr:
return diag::cannot_convert_to_return_type;
case CTP_DefaultParameter:
case CTP_AutoclosureDefaultParameter:
return diag::cannot_convert_default_arg_value;
case CTP_YieldByValue:
return diag::cannot_convert_yield_value;
case CTP_CallArgument:
return diag::cannot_convert_argument_value;
case CTP_ClosureResult:
return diag::cannot_convert_closure_result;
case CTP_ArrayElement:
return diag::cannot_convert_array_element;
case CTP_DictionaryKey:
return diag::cannot_convert_dict_key;
case CTP_DictionaryValue:
return diag::cannot_convert_dict_value;
case CTP_CoerceOperand:
return diag::cannot_convert_coerce;
case CTP_SubscriptAssignSource:
return diag::cannot_convert_subscript_assign;
case CTP_Condition:
return diag::cannot_convert_condition_value;
case CTP_ThrowStmt:
case CTP_ForEachStmt:
case CTP_Unused:
case CTP_CannotFail:
case CTP_YieldByReference:
case CTP_CalleeResult:
case CTP_EnumCaseRawValue:
break;
}
return None;
}
void GenericArgumentsMismatchFailure::emitNoteForMismatch(int position) {
auto *locator = getLocator();
// Since there could be implicit conversions assoicated with argument
// to parameter conversions, let's use parameter type as a source of
// generic parameter information.
auto paramSourceTy =
locator->isLastElement<LocatorPathElt::ApplyArgToParam>() ? getRequired()
: getActual();
auto genericTypeDecl = paramSourceTy->getAnyGeneric();
auto param = genericTypeDecl->getGenericParams()->getParams()[position];
auto lhs = getActual()->getGenericArgs()[position];
auto rhs = getRequired()->getGenericArgs()[position];
auto noteLocation = param->getLoc();
if (!noteLocation.isValid())
noteLocation = getLoc();
emitDiagnosticAt(noteLocation, diag::generic_argument_mismatch,
param->getName(), lhs, rhs);
}
bool GenericArgumentsMismatchFailure::diagnoseAsError() {
auto *anchor = getAnchor();
auto path = getLocator()->getPath();
auto fromType = getFromType();
auto toType = getToType();
Optional<Diag<Type, Type>> diagnostic;
if (path.empty()) {
if (isa<AssignExpr>(anchor)) {
diagnostic = getDiagnosticFor(CTP_AssignSource);
} else if (isa<CoerceExpr>(anchor)) {
diagnostic = getDiagnosticFor(CTP_CoerceOperand);
} else {
return false;
}
} else {
const auto &last = path.back();
switch (last.getKind()) {
case ConstraintLocator::ContextualType: {
auto purpose = getContextualTypePurpose();
assert(!(purpose == CTP_Unused || purpose == CTP_CannotFail));
// If this is call to a closure e.g. `let _: A = { B() }()`
// let's point diagnostic to its result.
if (auto *call = dyn_cast<CallExpr>(anchor)) {
auto *fnExpr = call->getFn();
if (auto *closure = dyn_cast<ClosureExpr>(fnExpr)) {
purpose = CTP_ClosureResult;
if (closure->hasSingleExpressionBody())
anchor = closure->getSingleExpressionBody();
}
}
diagnostic = getDiagnosticFor(purpose);
break;
}
case ConstraintLocator::AutoclosureResult:
case ConstraintLocator::ApplyArgToParam:
case ConstraintLocator::ApplyArgument: {
diagnostic = diag::cannot_convert_argument_value;
break;
}
case ConstraintLocator::ParentType: {
diagnostic = diag::cannot_convert_parent_type;
break;
}
case ConstraintLocator::ClosureBody:
case ConstraintLocator::ClosureResult: {
diagnostic = diag::cannot_convert_closure_result;
break;
}
case ConstraintLocator::GenericArgument: {
break;
}
case ConstraintLocator::OptionalPayload: {
// If we have an inout expression, this comes from an
// InoutToPointer argument mismatch failure.
if (isa<InOutExpr>(anchor)) {
diagnostic = diag::cannot_convert_argument_value;
auto applyInfo = getFunctionArgApplyInfo(getLocator());
if (applyInfo)
toType = applyInfo->getParamType();
}
break;
}
case ConstraintLocator::TupleElement: {
auto *anchor = getRawAnchor();
if (isa<ArrayExpr>(anchor)) {
diagnostic = getDiagnosticFor(CTP_ArrayElement);
} else if (isa<DictionaryExpr>(anchor)) {
auto eltLoc = last.castTo<LocatorPathElt::TupleElement>();
diagnostic = getDiagnosticFor(
eltLoc.getIndex() == 0 ? CTP_DictionaryKey : CTP_DictionaryValue);
}
break;
}
default:
return false;
}
}
if (!diagnostic) {
// Handle all mismatches involving an `AssignExpr`
if (auto *assignExpr = dyn_cast<AssignExpr>(anchor)) {
diagnostic = getDiagnosticFor(CTP_AssignSource);
fromType = getType(assignExpr->getSrc());
toType = getType(assignExpr->getDest());
} else {
// If we couldn't find a specific diagnostic let's fallback to
// attempt to handle cases where we have an apply arg to param.
auto applyInfo = getFunctionArgApplyInfo(getLocator());
if (applyInfo) {
diagnostic = diag::cannot_convert_argument_value;
fromType = applyInfo->getArgType();
toType = applyInfo->getParamType();
}
}
}
if (!diagnostic)
return false;
emitDiagnosticAt(anchor->getLoc(), *diagnostic, fromType, toType);
emitNotesForMismatches();
return true;
}
bool LabelingFailure::diagnoseAsError() {
auto *argExpr = getArgumentListExprFor(getLocator());
if (!argExpr)
return false;
auto &cs = getConstraintSystem();
auto *anchor = getRawAnchor();
return diagnoseArgumentLabelError(cs.getASTContext(), argExpr, CorrectLabels,
isa<SubscriptExpr>(anchor));
}
bool LabelingFailure::diagnoseAsNote() {
auto *argExpr = getArgumentListExprFor(getLocator());
if (!argExpr)
return false;
SmallVector<Identifier, 4> argLabels;
if (isa<ParenExpr>(argExpr)) {
argLabels.push_back(Identifier());
} else if (auto *tuple = dyn_cast<TupleExpr>(argExpr)) {
argLabels.append(tuple->getElementNames().begin(),
tuple->getElementNames().end());
} else {
return false;
}
auto stringifyLabels = [](ArrayRef<Identifier> labels) -> std::string {
std::string str;
for (auto label : labels) {
str += label.empty() ? "_" : label.str();
str += ':';
}
return "(" + str + ")";
};
auto selectedOverload = getCalleeOverloadChoiceIfAvailable(getLocator());
if (!selectedOverload)
return false;
const auto &choice = selectedOverload->choice;
if (auto *decl = choice.getDeclOrNull()) {
emitDiagnosticAt(decl, diag::candidate_expected_different_labels,
stringifyLabels(argLabels),
stringifyLabels(CorrectLabels));
return true;
}
return false;
}
bool NoEscapeFuncToTypeConversionFailure::diagnoseAsError() {
if (diagnoseParameterUse())
return true;
if (auto *typeVar = getRawFromType()->getAs<TypeVariableType>()) {
if (auto *GP = typeVar->getImpl().getGenericParameter()) {
emitDiagnostic(diag::converting_noescape_to_type, GP);
return true;
}
}
emitDiagnostic(diag::converting_noescape_to_type, getToType());
return true;
}
bool NoEscapeFuncToTypeConversionFailure::diagnoseParameterUse() const {
auto convertTo = getToType();
// If the other side is not a function, we have common case diagnostics
// which handle function-to-type conversion diagnostics.
if (!convertTo->is<FunctionType>())
return false;
auto *anchor = getAnchor();
auto diagnostic = diag::general_noescape_to_escaping;
ParamDecl *PD = nullptr;
if (auto *DRE = dyn_cast<DeclRefExpr>(anchor)) {
PD = dyn_cast<ParamDecl>(DRE->getDecl());
// If anchor is not a parameter declaration there
// is no need to dig up more information.
if (!PD)
return false;
// Let's check whether this is a function parameter passed
// as an argument to another function which accepts @escaping
// function at that position.
if (auto argApplyInfo = getFunctionArgApplyInfo(getLocator())) {
auto paramInterfaceTy = argApplyInfo->getParamInterfaceType();
if (paramInterfaceTy->isTypeParameter()) {
auto diagnoseGenericParamFailure = [&](GenericTypeParamDecl *decl) {
emitDiagnostic(diag::converting_noespace_param_to_generic_type,
PD->getName(), paramInterfaceTy);
auto declLoc = decl->getLoc();
if (declLoc.isValid())
emitDiagnosticAt(decl, diag::generic_parameters_always_escaping);
};
// If this is a situation when non-escaping parameter is passed
// to the argument which represents generic parameter, there is
// a tailored diagnostic for that.
if (auto *DMT = paramInterfaceTy->getAs<DependentMemberType>()) {
diagnoseGenericParamFailure(DMT->getRootGenericParam()->getDecl());
return true;
}
if (auto *GP = paramInterfaceTy->getAs<GenericTypeParamType>()) {
diagnoseGenericParamFailure(GP->getDecl());
return true;
}
}
// If there are no generic parameters involved, this could
// only mean that parameter is expecting @escaping function type.
diagnostic = diag::passing_noescape_to_escaping;
}
} else if (auto *AE = dyn_cast<AssignExpr>(getRawAnchor())) {
if (auto *DRE = dyn_cast<DeclRefExpr>(AE->getSrc())) {
PD = dyn_cast<ParamDecl>(DRE->getDecl());
diagnostic = diag::assigning_noescape_to_escaping;
}
}
if (!PD)
return false;
emitDiagnostic(diagnostic, PD->getName());
// Give a note and fix-it
auto note = emitDiagnosticAt(PD, diag::noescape_parameter, PD->getName());
if (!PD->isAutoClosure()) {
SourceLoc reprLoc;
if (auto *repr = PD->getTypeRepr())
reprLoc = repr->getStartLoc();
note.fixItInsert(reprLoc, "@escaping ");
} // TODO: add in a fixit for autoclosure
return true;
}
Expr *MissingForcedDowncastFailure::getAnchor() const {
auto *expr = FailureDiagnostic::getAnchor();
if (auto *assignExpr = dyn_cast<AssignExpr>(expr))
return assignExpr->getSrc();
return expr;
}
bool MissingForcedDowncastFailure::diagnoseAsError() {
auto fromType = getFromType();
auto toType = getToType();
emitDiagnostic(diag::missing_forced_downcast, fromType, toType)
.highlight(getSourceRange())
.fixItReplace(getLoc(), "as!");
return true;
}
bool MissingAddressOfFailure::diagnoseAsError() {
auto argTy = getFromType();
auto paramTy = getToType();
if (paramTy->getAnyPointerElementType()) {
emitDiagnostic(diag::cannot_convert_argument_value, argTy, paramTy)
.fixItInsert(getSourceRange().Start, "&");
} else {
emitDiagnostic(diag::missing_address_of, argTy)
.fixItInsert(getSourceRange().Start, "&");
}
return true;
}
Expr *MissingExplicitConversionFailure::getAnchor() const {
auto *anchor = FailureDiagnostic::getAnchor();
if (auto *assign = dyn_cast<AssignExpr>(anchor))
return assign->getSrc();
if (auto *paren = dyn_cast<ParenExpr>(anchor))
return paren->getSubExpr();
return anchor;
}
bool MissingExplicitConversionFailure::diagnoseAsError() {
auto *DC = getDC();
auto *anchor = getAnchor();
auto fromType = getFromType();
auto toType = getToType();
if (!toType->hasTypeRepr())
return false;
bool useAs = TypeChecker::isExplicitlyConvertibleTo(fromType, toType, DC);
if (!useAs && !TypeChecker::checkedCastMaySucceed(fromType, toType, DC))
return false;
auto *expr = findParentExpr(anchor);
if (!expr)
expr = anchor;
// If we're performing pattern matching,
// "as" means something completely different...
if (auto binOpExpr = dyn_cast<BinaryExpr>(expr)) {
auto overloadedFn = dyn_cast<OverloadedDeclRefExpr>(binOpExpr->getFn());
if (overloadedFn && !overloadedFn->getDecls().empty()) {
ValueDecl *decl0 = overloadedFn->getDecls()[0];
if (decl0->getBaseName() == decl0->getASTContext().Id_MatchOperator)
return false;
}
}
bool needsParensInside = exprNeedsParensBeforeAddingAs(anchor);
bool needsParensOutside = exprNeedsParensAfterAddingAs(anchor, expr);
llvm::SmallString<2> insertBefore;
llvm::SmallString<32> insertAfter;
if (needsParensOutside) {
insertBefore += "(";
}
if (needsParensInside) {
insertBefore += "(";
insertAfter += ")";
}
insertAfter += useAs ? " as " : " as! ";
insertAfter += toType->getWithoutParens()->getString();
if (needsParensOutside)
insertAfter += ")";
auto diagID =
useAs ? diag::missing_explicit_conversion : diag::missing_forced_downcast;
auto diag = emitDiagnostic(diagID, fromType, toType);
if (!insertBefore.empty()) {
diag.fixItInsert(getSourceRange().Start, insertBefore);
}
diag.fixItInsertAfter(getSourceRange().End, insertAfter);
return true;
}
bool MemberAccessOnOptionalBaseFailure::diagnoseAsError() {
auto *anchor = getAnchor();
auto baseType = getType(anchor);
bool resultIsOptional = ResultTypeIsOptional;
// If we've resolved the member overload to one that returns an optional
// type, then the result of the expression is optional (and we want to offer
// only a '?' fixit) even though the constraint system didn't need to add any
// additional optionality.
auto overload = getOverloadChoiceIfAvailable(getLocator());
if (overload && overload->openedType->getOptionalObjectType())
resultIsOptional = true;
auto unwrappedBaseType = baseType->getOptionalObjectType();
if (!unwrappedBaseType)
return false;
emitDiagnostic(diag::optional_base_not_unwrapped, baseType, Member,
unwrappedBaseType);
// FIXME: It would be nice to immediately offer "base?.member ?? defaultValue"
// for non-optional results where that would be appropriate. For the moment
// always offering "?" means that if the user chooses chaining, we'll end up
// in MissingOptionalUnwrapFailure:diagnose() to offer a default value during
// the next compile.
emitDiagnostic(diag::optional_base_chain, Member)
.fixItInsertAfter(getSourceRange().End, "?");
if (!resultIsOptional) {
emitDiagnostic(diag::unwrap_with_force_value)
.fixItInsertAfter(getSourceRange().End, "!");
}