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fuchsia / third_party / swift / 439335ddb0b2d046902e13afb0b891aac9f3697b / . / lib / Sema / 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/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/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"
using namespace swift;
using namespace constraints;
FailureDiagnostic::~FailureDiagnostic() {}
bool FailureDiagnostic::diagnose(bool asNote) {
return asNote ? diagnoseAsNote() : diagnoseAsError();
}
bool FailureDiagnostic::diagnoseAsNote() {
return false;
}
std::pair<Expr *, bool> FailureDiagnostic::computeAnchor() const {
auto &cs = getConstraintSystem();
auto *locator = getLocator();
// Resolve the locator to a specific expression.
SourceRange range;
bool isSubscriptMember =
(!locator->getPath().empty() && locator->getPath().back().getKind() ==
ConstraintLocator::SubscriptMember);
ConstraintLocator *resolved = simplifyLocator(cs, locator, range);
if (!resolved || !resolved->getAnchor())
return {locator->getAnchor(), true};
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 (isSubscriptMember) {
if (auto subscript = dyn_cast<SubscriptExpr>(anchor))
anchor = subscript->getBase();
}
return {anchor, !resolved->getPath().empty()};
}
Type FailureDiagnostic::getType(Expr *expr) const {
return resolveType(CS.getType(expr));
}
template <typename... ArgTypes>
InFlightDiagnostic
FailureDiagnostic::emitDiagnostic(ArgTypes &&... Args) const {
auto &cs = getConstraintSystem();
return cs.TC.diagnose(std::forward<ArgTypes>(Args)...);
}
Expr *FailureDiagnostic::findParentExpr(Expr *subExpr) const {
return E ? E->getParentMap()[subExpr] : nullptr;
}
Expr *FailureDiagnostic::getArgumentExprFor(Expr *anchor) const {
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor)) {
if (auto *call = dyn_cast_or_null<CallExpr>(findParentExpr(UDE)))
return call->getArg();
} else if (auto *UME = dyn_cast<UnresolvedMemberExpr>(anchor)) {
return UME->getArgument();
} else if (auto *call = dyn_cast<CallExpr>(anchor)) {
return call->getArg();
} else if (auto *SE = dyn_cast<SubscriptExpr>(anchor)) {
return SE->getIndex();
}
return nullptr;
}
Type RequirementFailure::getOwnerType() const {
return getType(getRawAnchor())
->getInOutObjectType()
->getMetatypeInstanceType();
}
const GenericContext *RequirementFailure::getGenericContext() const {
if (auto *genericCtx = AffectedDecl->getAsGenericContext())
return genericCtx;
return AffectedDecl->getDeclContext()->getAsDecl()->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 path = locator->getPath();
assert(!path.empty());
if (!path.back().isConditionalRequirement()) {
assert(path.back().isTypeParameterRequirement());
return nullptr;
}
auto *typeReqLoc = cs.getConstraintLocator(getRawAnchor(), path.drop_back(),
/*summaryFlags=*/0);
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 {
auto &cs = getConstraintSystem();
auto &TC = getTypeChecker();
auto *anchor = getRawAnchor();
auto *locator = cs.getConstraintLocator(anchor);
if (isFromContextualType()) {
auto type = cs.getContextualType();
assert(type);
auto *alias = dyn_cast<TypeAliasType>(type.getPointer());
return alias ? alias->getDecl() : type->getAnyGeneric();
}
if (auto *AE = dyn_cast<CallExpr>(anchor)) {
// NOTE: In valid code, the function can only be a TypeExpr
assert(isa<TypeExpr>(AE->getFn()) ||
isa<OverloadedDeclRefExpr>(AE->getFn()));
ConstraintLocatorBuilder ctor(locator);
locator = cs.getConstraintLocator(
ctor.withPathElement(PathEltKind::ApplyFunction)
.withPathElement(PathEltKind::ConstructorMember));
} else if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor)) {
ConstraintLocatorBuilder member(locator);
if (TC.getSelfForInitDelegationInConstructor(getDC(), UDE)) {
member = member.withPathElement(PathEltKind::ConstructorMember);
} else {
member = member.withPathElement(PathEltKind::Member);
}
locator = cs.getConstraintLocator(member);
} else if (auto *UME = dyn_cast<UnresolvedMemberExpr>(anchor)) {
locator = cs.getConstraintLocator(locator, PathEltKind::UnresolvedMember);
} else if (isa<SubscriptExpr>(anchor)) {
ConstraintLocatorBuilder subscript(locator);
locator = cs.getConstraintLocator(
subscript.withPathElement(PathEltKind::SubscriptMember));
} else if (isa<MemberRefExpr>(anchor)) {
ConstraintLocatorBuilder memberRef(locator);
locator =
cs.getConstraintLocator(memberRef.withPathElement(PathEltKind::Member));
}
auto overload = getOverloadChoiceIfAvailable(locator);
if (overload)
return overload->choice.getDecl();
auto ownerType = getOwnerType();
if (auto *NA = dyn_cast<TypeAliasType>(ownerType.getPointer()))
return NA->getDecl();
return ownerType->getAnyGeneric();
}
GenericSignature *RequirementFailure::getSignature(ConstraintLocator *locator) {
if (isConditional())
return Conformance->getGenericSignature();
auto path = locator->getPath();
for (auto iter = path.rbegin(); iter != path.rend(); ++iter) {
const auto &elt = *iter;
if (elt.getKind() == ConstraintLocator::OpenedGeneric)
return elt.getGenericSignature();
}
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() {
if (!canDiagnoseFailure())
return false;
auto *anchor = getRawAnchor();
const auto *reqDC = getRequirementDC();
auto *genericCtx = getGenericContext();
auto lhs = resolveType(getLHS());
auto rhs = resolveType(getRHS());
if (genericCtx != reqDC && (genericCtx->isChildContextOf(reqDC) ||
isStaticOrInstanceMember(AffectedDecl))) {
auto *NTD = reqDC->getSelfNominalTypeDecl();
emitDiagnostic(anchor->getLoc(), getDiagnosticInRereference(),
AffectedDecl->getDescriptiveKind(),
AffectedDecl->getFullName(), NTD->getDeclaredType(), lhs,
rhs);
} else {
emitDiagnostic(anchor->getLoc(), 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();
emitDiagnostic(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 (isConditional()) {
emitDiagnostic(anchor, diag::requirement_implied_by_conditional_conformance,
resolveType(Conformance->getType()),
Conformance->getProtocol()->getDeclaredInterfaceType());
return;
}
if (rhs->isEqual(req.getSecondType())) {
emitDiagnostic(anchor, diag::where_requirement_failure_one_subst,
req.getFirstType(), lhs);
return;
}
if (lhs->isEqual(req.getFirstType())) {
emitDiagnostic(anchor, diag::where_requirement_failure_one_subst,
req.getSecondType(), rhs);
return;
}
emitDiagnostic(anchor, diag::where_requirement_failure_both_subst,
req.getFirstType(), lhs, req.getSecondType(), rhs);
}
bool MissingConformanceFailure::diagnoseAsError() {
if (!canDiagnoseFailure())
return false;
auto *anchor = getAnchor();
auto ownerType = getOwnerType();
auto nonConformingType = getLHS();
auto protocolType = getRHS();
auto getArgumentAt = [](const ApplyExpr *AE, unsigned index) -> Expr * {
assert(AE);
auto *arg = AE->getArg();
if (auto *TE = dyn_cast<TupleExpr>(arg))
return TE->getElement(index);
assert(index == 0);
if (auto *PE = dyn_cast<ParenExpr>(arg))
return PE->getSubExpr();
return arg;
};
Optional<unsigned> atParameterPos;
// Sometimes fix is recorded by type-checking sub-expression
// during normal diagnostics, in such case call expression
// is unavailable.
if (Apply) {
if (auto *fnType = ownerType->getAs<AnyFunctionType>()) {
auto parameters = fnType->getParams();
for (auto index : indices(parameters)) {
if (parameters[index].getOldType()->isEqual(nonConformingType)) {
atParameterPos = index;
break;
}
}
}
}
if (nonConformingType->isExistentialType()) {
auto diagnostic = diag::protocol_does_not_conform_objc;
if (nonConformingType->isObjCExistentialType())
diagnostic = diag::protocol_does_not_conform_static;
emitDiagnostic(anchor->getLoc(), diagnostic, nonConformingType,
protocolType);
return true;
}
if (atParameterPos) {
// Requirement comes from one of the parameter types,
// let's try to point diagnostic to the argument expression.
auto *argExpr = getArgumentAt(Apply, *atParameterPos);
emitDiagnostic(argExpr->getLoc(),
diag::cannot_convert_argument_value_protocol,
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 LabelingFailure::diagnoseAsError() {
auto &cs = getConstraintSystem();
auto *anchor = getRawAnchor();
auto *argExpr = getArgumentExprFor(anchor);
if (!argExpr)
return false;
return diagnoseArgumentLabelError(cs.getASTContext(), argExpr, CorrectLabels,
isa<SubscriptExpr>(anchor));
}
bool NoEscapeFuncToTypeConversionFailure::diagnoseAsError() {
auto *anchor = getAnchor();
if (ConvertTo) {
emitDiagnostic(anchor->getLoc(), diag::converting_noescape_to_type,
ConvertTo);
return true;
}
auto path = getLocator()->getPath();
if (path.empty())
return false;
auto &last = path.back();
if (last.getKind() != ConstraintLocator::GenericParameter)
return false;
auto *paramTy = last.getGenericParameter();
emitDiagnostic(anchor->getLoc(), diag::converting_noescape_to_type,
paramTy);
return true;
}
bool MissingForcedDowncastFailure::diagnoseAsError() {
if (hasComplexLocator())
return false;
auto &TC = getTypeChecker();
auto *expr = getAnchor();
if (auto *assignExpr = dyn_cast<AssignExpr>(expr))
expr = assignExpr->getSrc();
auto *coerceExpr = dyn_cast<CoerceExpr>(expr);
if (!coerceExpr)
return false;
auto *subExpr = coerceExpr->getSubExpr();
auto fromType = getType(subExpr)->getRValueType();
auto toType = resolveType(coerceExpr->getCastTypeLoc().getType());
auto castKind =
TC.typeCheckCheckedCast(fromType, toType, CheckedCastContextKind::None,
getDC(), coerceExpr->getLoc(), subExpr,
coerceExpr->getCastTypeLoc().getSourceRange());
switch (castKind) {
// Invalid cast.
case CheckedCastKind::Unresolved:
// Fix didn't work, let diagnoseFailureForExpr handle this.
return false;
case CheckedCastKind::Coercion:
case CheckedCastKind::BridgingCoercion:
llvm_unreachable("Coercions handled in other disjunction branch");
// Valid casts.
case CheckedCastKind::ArrayDowncast:
case CheckedCastKind::DictionaryDowncast:
case CheckedCastKind::SetDowncast:
case CheckedCastKind::ValueCast:
emitDiagnostic(coerceExpr->getLoc(), diag::missing_forced_downcast,
fromType, toType)
.highlight(coerceExpr->getSourceRange())
.fixItReplace(coerceExpr->getLoc(), "as!");
return true;
}
llvm_unreachable("unhandled cast kind");
}
bool MissingAddressOfFailure::diagnoseAsError() {
if (hasComplexLocator())
return false;
auto *anchor = getAnchor();
auto type = getType(anchor)->getRValueType();
emitDiagnostic(anchor->getLoc(), diag::missing_address_of, type)
.fixItInsert(anchor->getStartLoc(), "&");
return true;
}
bool MissingExplicitConversionFailure::diagnoseAsError() {
if (hasComplexLocator())
return false;
auto *DC = getDC();
auto &TC = getTypeChecker();
auto *anchor = getAnchor();
if (auto *assign = dyn_cast<AssignExpr>(anchor))
anchor = assign->getSrc();
if (auto *paren = dyn_cast<ParenExpr>(anchor))
anchor = paren->getSubExpr();
auto fromType = getType(anchor)->getRValueType();
Type toType = resolveType(ConvertingTo);
bool useAs = TC.isExplicitlyConvertibleTo(fromType, toType, DC);
bool useAsBang = !useAs && TC.checkedCastMaySucceed(fromType, toType, DC);
if (!useAs && !useAsBang)
return false;
auto *expr = getParentExpr();
// 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(anchor->getLoc(), diagID, fromType, toType);
if (!insertBefore.empty()) {
diag.fixItInsert(anchor->getStartLoc(), insertBefore);
}
diag.fixItInsertAfter(anchor->getEndLoc(), insertAfter);
return true;
}
bool MemberAccessOnOptionalBaseFailure::diagnoseAsError() {
if (hasComplexLocator())
return false;
auto *anchor = getAnchor();
auto type = getType(anchor)->getRValueType();
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 = getResolvedOverload(getLocator());
if (overload && overload->ImpliedType->getOptionalObjectType())
resultIsOptional = true;
return diagnoseBaseUnwrapForMemberAccess(anchor, type, Member,
resultIsOptional, SourceRange());
}
Optional<AnyFunctionType::Param>
MissingOptionalUnwrapFailure::getOperatorParameterFor(Expr *expr) const {
auto *parentExpr = findParentExpr(expr);
if (!parentExpr)
return None;
auto getArgIdx = [](TupleExpr *tuple, Expr *argExpr) -> unsigned {
for (unsigned i = 0, n = tuple->getNumElements(); i != n; ++i) {
if (tuple->getElement(i) == argExpr)
return i;
}
llvm_unreachable("argument is not in enclosing tuple?!");
};
auto *tupleExpr = dyn_cast<TupleExpr>(parentExpr);
if (!(tupleExpr && tupleExpr->isImplicit()))
return None;
parentExpr = findParentExpr(tupleExpr);
if (!(parentExpr && isa<ApplyExpr>(parentExpr)))
return None;
auto &cs = getConstraintSystem();
auto *fnExpr = cast<ApplyExpr>(parentExpr)->getFn();
if (auto overload =
getOverloadChoiceIfAvailable(cs.getConstraintLocator(fnExpr))) {
if (auto *decl = overload->choice.getDecl()) {
if (!decl->isOperator())
return None;
auto *fnType = overload->openedType->castTo<FunctionType>();
return fnType->getParams()[getArgIdx(tupleExpr, expr)];
}
}
return None;
}
void MissingOptionalUnwrapFailure::offerDefaultValueUnwrapFixIt(
DeclContext *DC, Expr *expr) const {
auto *anchor = getAnchor();
// If anchor is an explicit address-of, or expression which produces
// an l-value (e.g. first argument of `+=` operator), let's not
// suggest default value here because that would produce r-value type.
if (isa<InOutExpr>(anchor))
return;
if (auto param = getOperatorParameterFor(anchor)) {
if (param->isInOut())
return;
}
auto diag = emitDiagnostic(expr->getLoc(), diag::unwrap_with_default_value);
auto &TC = getTypeChecker();
// Figure out what we need to parenthesize.
bool needsParensInside =
exprNeedsParensBeforeAddingNilCoalescing(TC, DC, expr);
bool needsParensOutside =
exprNeedsParensAfterAddingNilCoalescing(TC, DC, expr, getParentExpr());
llvm::SmallString<2> insertBefore;
llvm::SmallString<32> insertAfter;
if (needsParensOutside) {
insertBefore += "(";
}
if (needsParensInside) {
insertBefore += "(";
insertAfter += ")";
}
insertAfter += " ?? <" "#default value#" ">";
if (needsParensOutside)
insertAfter += ")";
if (!insertBefore.empty()) {
diag.fixItInsert(expr->getStartLoc(), insertBefore);
}
diag.fixItInsertAfter(expr->getEndLoc(), insertAfter);
}
// Suggest a force-unwrap.
void MissingOptionalUnwrapFailure::offerForceUnwrapFixIt(Expr *expr) const {
auto diag = emitDiagnostic(expr->getLoc(), diag::unwrap_with_force_value);
// If expr is optional as the result of an optional chain and this last
// dot isn't a member returning optional, then offer to force the last
// link in the chain, rather than an ugly parenthesized postfix force.
if (auto optionalChain = dyn_cast<OptionalEvaluationExpr>(expr)) {
if (auto dotExpr =
dyn_cast<UnresolvedDotExpr>(optionalChain->getSubExpr())) {
auto bind = dyn_cast<BindOptionalExpr>(dotExpr->getBase());
if (bind && !getType(dotExpr)->getOptionalObjectType()) {
diag.fixItReplace(SourceRange(bind->getLoc()), "!");
return;
}
}
}
if (expr->canAppendPostfixExpression(true)) {
diag.fixItInsertAfter(expr->getEndLoc(), "!");
} else {
diag.fixItInsert(expr->getStartLoc(), "(")
.fixItInsertAfter(expr->getEndLoc(), ")!");
}
}
class VarDeclMultipleReferencesChecker : public ASTWalker {
VarDecl *varDecl;
int count;
std::pair<bool, Expr *> walkToExprPre(Expr *E) {
if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
if (DRE->getDecl() == varDecl)
count++;
}
return { true, E };
}
public:
VarDeclMultipleReferencesChecker(VarDecl *varDecl) : varDecl(varDecl),count(0) {}
int referencesCount() { return count; }
};
bool MissingOptionalUnwrapFailure::diagnoseAsError() {
if (hasComplexLocator())
return false;
auto *anchor = getAnchor();
if (auto assignExpr = dyn_cast<AssignExpr>(anchor))
anchor = assignExpr->getSrc();
auto *unwrappedExpr = anchor->getValueProvidingExpr();
if (auto *tryExpr = dyn_cast<OptionalTryExpr>(unwrappedExpr)) {
bool isSwift5OrGreater = getASTContext().isSwiftVersionAtLeast(5);
auto subExprType = getType(tryExpr->getSubExpr());
bool subExpressionIsOptional = (bool)subExprType->getOptionalObjectType();
if (isSwift5OrGreater && subExpressionIsOptional) {
// Using 'try!' won't change the type for a 'try?' with an optional
// sub-expr under Swift 5+, so just report that a missing unwrap can't be
// handled here.
return false;
}
emitDiagnostic(tryExpr->getTryLoc(), diag::missing_unwrap_optional_try,
getType(anchor)->getRValueType())
.fixItReplace({tryExpr->getTryLoc(), tryExpr->getQuestionLoc()},
"try!");
return true;
}
auto baseType = getBaseType();
auto unwrappedType = getUnwrappedType();
assert(!baseType->hasTypeVariable() &&
"Base type must not be a type variable");
assert(!unwrappedType->hasTypeVariable() &&
"Unwrapped type must not be a type variable");
if (!baseType->getOptionalObjectType())
return false;
emitDiagnostic(unwrappedExpr->getLoc(), diag::optional_not_unwrapped,
baseType, unwrappedType);
// If the expression we're unwrapping is the only reference to a
// local variable whose type isn't explicit in the source, then
// offer unwrapping fixits on the initializer as well.
if (auto declRef = dyn_cast<DeclRefExpr>(unwrappedExpr)) {
if (auto varDecl = dyn_cast<VarDecl>(declRef->getDecl())) {
bool singleUse = false;
AbstractFunctionDecl *AFD = nullptr;
if (auto contextDecl = varDecl->getDeclContext()->getAsDecl()) {
if ((AFD = dyn_cast<AbstractFunctionDecl>(contextDecl))) {
auto checker = VarDeclMultipleReferencesChecker(varDecl);
AFD->getBody()->walk(checker);
singleUse = checker.referencesCount() == 1;
}
}
PatternBindingDecl *binding = varDecl->getParentPatternBinding();
if (singleUse && binding && binding->getNumPatternEntries() == 1 &&
varDecl->getTypeSourceRangeForDiagnostics().isInvalid()) {
Expr *initializer = varDecl->getParentInitializer();
if (auto declRefExpr = dyn_cast<DeclRefExpr>(initializer)) {
if (declRefExpr->getDecl()
->getAttrs()
.hasAttribute<ImplicitlyUnwrappedOptionalAttr>()) {
emitDiagnostic(declRefExpr->getLoc(), diag::unwrap_iuo_initializer,
baseType);
}
}
auto fnTy = AFD->getInterfaceType()->castTo<AnyFunctionType>();
bool voidReturn =
fnTy->getResult()->isEqual(TupleType::getEmpty(getASTContext()));
auto diag = emitDiagnostic(varDecl->getLoc(), diag::unwrap_with_guard);
diag.fixItInsert(binding->getStartLoc(), "guard ");
if (voidReturn) {
diag.fixItInsertAfter(binding->getEndLoc(), " else { return }");
} else {
diag.fixItInsertAfter(binding->getEndLoc(), " else { return <"
"#default value#"
"> }");
}
diag.flush();
offerDefaultValueUnwrapFixIt(varDecl->getDeclContext(), initializer);
offerForceUnwrapFixIt(initializer);
}
}
}
offerDefaultValueUnwrapFixIt(getDC(), unwrappedExpr);
offerForceUnwrapFixIt(unwrappedExpr);
return true;
}
bool RValueTreatedAsLValueFailure::diagnoseAsError() {
Diag<StringRef> subElementDiagID;
Diag<Type> rvalueDiagID = diag::assignment_lhs_not_lvalue;
Expr *diagExpr = getRawAnchor();
SourceLoc loc = diagExpr->getLoc();
if (auto assignExpr = dyn_cast<AssignExpr>(diagExpr)) {
diagExpr = assignExpr->getDest();
}
if (auto callExpr = dyn_cast<ApplyExpr>(diagExpr)) {
Expr *argExpr = callExpr->getArg();
loc = callExpr->getFn()->getLoc();
if (isa<PrefixUnaryExpr>(callExpr) || isa<PostfixUnaryExpr>(callExpr)) {
subElementDiagID = diag::cannot_apply_lvalue_unop_to_subelement;
rvalueDiagID = diag::cannot_apply_lvalue_unop_to_rvalue;
diagExpr = argExpr;
} else if (isa<BinaryExpr>(callExpr)) {
subElementDiagID = diag::cannot_apply_lvalue_binop_to_subelement;
rvalueDiagID = diag::cannot_apply_lvalue_binop_to_rvalue;
auto argTuple = dyn_cast<TupleExpr>(argExpr);
diagExpr = argTuple->getElement(0);
} else if (getLocator()->getPath().size() > 0) {
auto lastPathElement = getLocator()->getPath().back();
assert(lastPathElement.getKind() ==
ConstraintLocator::PathElementKind::ApplyArgToParam);
subElementDiagID = diag::cannot_pass_rvalue_inout_subelement;
rvalueDiagID = diag::cannot_pass_rvalue_inout;
if (auto argTuple = dyn_cast<TupleExpr>(argExpr))
diagExpr = argTuple->getElement(lastPathElement.getValue());
else if (auto parens = dyn_cast<ParenExpr>(argExpr))
diagExpr = parens->getSubExpr();
} else {
subElementDiagID = diag::assignment_lhs_is_apply_expression;
}
} else if (auto inoutExpr = dyn_cast<InOutExpr>(diagExpr)) {
if (auto restriction = getRestrictionForType(getType(inoutExpr))) {
PointerTypeKind pointerKind;
if (restriction->second == ConversionRestrictionKind::ArrayToPointer &&
restriction->first->getAnyPointerElementType(pointerKind) &&
(pointerKind == PTK_UnsafePointer ||
pointerKind == PTK_UnsafeRawPointer)) {
// If we're converting to an UnsafePointer, then the programmer
// specified an & unnecessarily. Produce a fixit hint to remove it.
emitDiagnostic(inoutExpr->getLoc(),
diag::extra_address_of_unsafepointer, restriction->first)
.highlight(inoutExpr->getSourceRange())
.fixItRemove(inoutExpr->getStartLoc());
return true;
}
}
subElementDiagID = diag::cannot_pass_rvalue_inout_subelement;
rvalueDiagID = diag::cannot_pass_rvalue_inout;
diagExpr = inoutExpr->getSubExpr();
} else if (isa<DeclRefExpr>(diagExpr)) {
subElementDiagID = diag::assignment_lhs_is_immutable_variable;
} else if (isa<ForceValueExpr>(diagExpr)) {
subElementDiagID = diag::assignment_bang_has_immutable_subcomponent;
} else if (isa<MemberRefExpr>(diagExpr)) {
subElementDiagID = diag::assignment_lhs_is_immutable_property;
} else if (auto member = dyn_cast<UnresolvedDotExpr>(diagExpr)) {
subElementDiagID = diag::assignment_lhs_is_immutable_property;
if (auto *ctor = dyn_cast<ConstructorDecl>(getDC())) {
if (auto *baseRef = dyn_cast<DeclRefExpr>(member->getBase())) {
if (baseRef->getDecl() == ctor->getImplicitSelfDecl() &&
ctor->getDelegatingOrChainedInitKind(nullptr) ==
ConstructorDecl::BodyInitKind::Delegating) {
emitDiagnostic(loc, diag::assignment_let_property_delegating_init,
member->getName());
if (auto *ref = getResolvedMemberRef(member)) {
emitDiagnostic(ref, diag::decl_declared_here, member->getName());
}
return true;
}
}
}
if (auto resolvedOverload = getResolvedOverload(getLocator())) {
if (resolvedOverload->Choice.getKind() ==
OverloadChoiceKind::DynamicMemberLookup)
subElementDiagID = diag::assignment_dynamic_property_has_immutable_base;
if (resolvedOverload->Choice.getKind() ==
OverloadChoiceKind::KeyPathDynamicMemberLookup) {
if (!getType(member->getBase())->hasLValueType())
subElementDiagID =
diag::assignment_dynamic_property_has_immutable_base;
}
}
} else if (auto sub = dyn_cast<SubscriptExpr>(diagExpr)) {
subElementDiagID = diag::assignment_subscript_has_immutable_base;
} else {
subElementDiagID = diag::assignment_lhs_is_immutable_variable;
}
AssignmentFailure failure(diagExpr, getConstraintSystem(), loc,
subElementDiagID, rvalueDiagID);
return failure.diagnose();
}
bool TrailingClosureAmbiguityFailure::diagnoseAsNote() {
const auto *expr = getParentExpr();
auto *callExpr = dyn_cast<CallExpr>(expr);
if (!callExpr)
return false;
if (!callExpr->hasTrailingClosure())
return false;
if (callExpr->getFn() != getAnchor())
return false;
llvm::SmallMapVector<Identifier, const ValueDecl *, 8> choicesByLabel;
for (const auto &choice : Choices) {
auto *callee = dyn_cast<AbstractFunctionDecl>(choice.getDecl());
if (!callee)
return false;
const ParameterList *paramList = callee->getParameters();
const ParamDecl *param = paramList->getArray().back();
// Sanity-check that the trailing closure corresponds to this parameter.
if (!param->hasValidSignature() ||
!param->getInterfaceType()->is<AnyFunctionType>())
return false;
Identifier trailingClosureLabel = param->getArgumentName();
auto &choiceForLabel = choicesByLabel[trailingClosureLabel];
// FIXME: Cargo-culted from diagnoseAmbiguity: apparently the same decl can
// appear more than once?
if (choiceForLabel == callee)
continue;
// If just providing the trailing closure label won't solve the ambiguity,
// don't bother offering the fix-it.
if (choiceForLabel != nullptr)
return false;
choiceForLabel = callee;
}
// If we got here, then all of the choices have unique labels. Offer them in
// order.
for (const auto &choicePair : choicesByLabel) {
auto diag = emitDiagnostic(
expr->getLoc(), diag::ambiguous_because_of_trailing_closure,
choicePair.first.empty(), choicePair.second->getFullName());
swift::fixItEncloseTrailingClosure(getTypeChecker(), diag, callExpr,
choicePair.first);
}
return true;
}
AssignmentFailure::AssignmentFailure(Expr *destExpr, ConstraintSystem &cs,
SourceLoc diagnosticLoc)
: FailureDiagnostic(destExpr, cs, cs.getConstraintLocator(destExpr)),
Loc(diagnosticLoc),
DeclDiagnostic(findDeclDiagonstic(cs.getASTContext(), destExpr)),
TypeDiagnostic(diag::assignment_lhs_not_lvalue) {}
bool AssignmentFailure::diagnoseAsError() {
auto &cs = getConstraintSystem();
auto *DC = getDC();
auto *destExpr = getParentExpr();
// Walk through the destination expression, resolving what the problem is. If
// we find a node in the lvalue path that is problematic, this returns it.
auto immInfo = resolveImmutableBase(destExpr);
// Otherwise, we cannot resolve this because the available setter candidates
// are all mutating and the base must be mutating. If we dug out a
// problematic decl, we can produce a nice tailored diagnostic.
if (auto *VD = dyn_cast_or_null<VarDecl>(immInfo.second)) {
std::string message = "'";
message += VD->getName().str().str();
message += "'";
auto type = getType(immInfo.first);
auto bgt = type ? type->getAs<BoundGenericType>() : nullptr;
if (bgt && bgt->getDecl() == getASTContext().getKeyPathDecl())
message += " is a read-only key path";
else if (VD->isCaptureList())
message += " is an immutable capture";
else if (VD->isImplicit())
message += " is immutable";
else if (VD->isLet())
message += " is a 'let' constant";
else if (!VD->isSettable(DC))
message += " is a get-only property";
else if (!VD->isSetterAccessibleFrom(DC))
message += " setter is inaccessible";
else {
message += " is immutable";
}
emitDiagnostic(Loc, DeclDiagnostic, message)
.highlight(immInfo.first->getSourceRange());
// If there is a masked instance variable of the same type, emit a
// note to fixit prepend a 'self.'.
if (auto typeContext = DC->getInnermostTypeContext()) {
UnqualifiedLookup lookup(VD->getFullName(), typeContext,
getASTContext().getLazyResolver());
for (auto &result : lookup.Results) {
const VarDecl *typeVar = dyn_cast<VarDecl>(result.getValueDecl());
if (typeVar && typeVar != VD && typeVar->isSettable(DC) &&
typeVar->isSetterAccessibleFrom(DC) &&
typeVar->getType()->isEqual(VD->getType())) {
// But not in its own accessor.
auto AD =
dyn_cast_or_null<AccessorDecl>(DC->getInnermostMethodContext());
if (!AD || AD->getStorage() != typeVar) {
emitDiagnostic(Loc, diag::masked_instance_variable,
typeContext->getSelfTypeInContext())
.fixItInsert(Loc, "self.");
}
}
}
}
// If this is a simple variable marked with a 'let', emit a note to fixit
// hint it to 'var'.
VD->emitLetToVarNoteIfSimple(DC);
return true;
}
// If the underlying expression was a read-only subscript, diagnose that.
if (auto *SD = dyn_cast_or_null<SubscriptDecl>(immInfo.second)) {
StringRef message;
if (!SD->isSettable())
message = "subscript is get-only";
else if (!SD->isSetterAccessibleFrom(DC))
message = "subscript setter is inaccessible";
else
message = "subscript is immutable";
emitDiagnostic(Loc, DeclDiagnostic, message)
.highlight(immInfo.first->getSourceRange());
return true;
}
// If we're trying to set an unapplied method, say that.
if (auto *VD = immInfo.second) {
std::string message = "'";
message += VD->getBaseName().getIdentifier().str();
message += "'";
auto diagID = DeclDiagnostic;
if (auto *AFD = dyn_cast<AbstractFunctionDecl>(VD)) {
if (AFD->hasImplicitSelfDecl()) {
message += " is a method";
diagID = diag::assignment_lhs_is_immutable_variable;
} else {
message += " is a function";
}
} else
message += " is not settable";
emitDiagnostic(Loc, diagID, message)
.highlight(immInfo.first->getSourceRange());
return true;
}
// If a keypath was the problem but wasn't resolved into a vardecl
// it is ambiguous or unable to be used for setting.
if (auto *KPE = dyn_cast_or_null<KeyPathExpr>(immInfo.first)) {
emitDiagnostic(Loc, DeclDiagnostic, "immutable key path")
.highlight(KPE->getSourceRange());
return true;
}
if (auto LE = dyn_cast<LiteralExpr>(immInfo.first)) {
emitDiagnostic(Loc, DeclDiagnostic, "literals are not mutable")
.highlight(LE->getSourceRange());
return true;
}
// If the expression is the result of a call, it is an rvalue, not a mutable
// lvalue.
if (auto *AE = dyn_cast<ApplyExpr>(immInfo.first)) {
// Handle literals, which are a call to the conversion function.
auto argsTuple =
dyn_cast<TupleExpr>(AE->getArg()->getSemanticsProvidingExpr());
if (isa<CallExpr>(AE) && AE->isImplicit() && argsTuple &&
argsTuple->getNumElements() == 1) {
if (auto LE = dyn_cast<LiteralExpr>(
argsTuple->getElement(0)->getSemanticsProvidingExpr())) {
emitDiagnostic(Loc, DeclDiagnostic, "literals are not mutable")
.highlight(LE->getSourceRange());
return true;
}
}
std::string name = "call";
if (isa<PrefixUnaryExpr>(AE) || isa<PostfixUnaryExpr>(AE))
name = "unary operator";
else if (isa<BinaryExpr>(AE))
name = "binary operator";
else if (isa<CallExpr>(AE))
name = "function call";
else if (isa<DotSyntaxCallExpr>(AE) || isa<DotSyntaxBaseIgnoredExpr>(AE))
name = "method call";
if (auto *DRE = dyn_cast<DeclRefExpr>(AE->getFn()->getValueProvidingExpr()))
name = std::string("'") +
DRE->getDecl()->getBaseName().getIdentifier().str().str() + "'";
emitDiagnostic(Loc, DeclDiagnostic, name + " returns immutable value")
.highlight(AE->getSourceRange());
return true;
}
if (auto contextualType = cs.getContextualType(immInfo.first)) {
Type neededType = contextualType->getInOutObjectType();
Type actualType = getType(immInfo.first)->getInOutObjectType();
if (!neededType->isEqual(actualType)) {
if (DeclDiagnostic.ID == diag::cannot_pass_rvalue_inout_subelement.ID) {
// We have a special diagnostic with tailored wording for this
// common case.
emitDiagnostic(Loc, diag::cannot_pass_rvalue_inout_converted,
actualType, neededType)
.highlight(immInfo.first->getSourceRange());
if (auto inoutExpr = dyn_cast<InOutExpr>(immInfo.first))
fixItChangeInoutArgType(inoutExpr->getSubExpr(), actualType,
neededType);
} else {
emitDiagnostic(Loc, DeclDiagnostic,
"implicit conversion from '" + actualType->getString() +
"' to '" + neededType->getString() +
"' requires a temporary")
.highlight(immInfo.first->getSourceRange());
}
return true;
}
}
if (auto IE = dyn_cast<IfExpr>(immInfo.first)) {
if (isLoadedLValue(IE)) {
emitDiagnostic(Loc, DeclDiagnostic,
"result of conditional operator '? :' is never mutable")
.highlight(IE->getQuestionLoc())
.highlight(IE->getColonLoc());
return true;
}
}
emitDiagnostic(Loc, TypeDiagnostic, getType(destExpr))
.highlight(immInfo.first->getSourceRange());
return true;
}
void AssignmentFailure::fixItChangeInoutArgType(const Expr *arg,
Type actualType,
Type neededType) const {
auto *DC = getDC();
auto *DRE = dyn_cast<DeclRefExpr>(arg);
if (!DRE)
return;
auto *VD = dyn_cast_or_null<VarDecl>(DRE->getDecl());
if (!VD)
return;
// Don't emit for non-local variables.
// (But in script-mode files, we consider module-scoped
// variables in the same file to be local variables.)
auto VDC = VD->getDeclContext();
bool isLocalVar = VDC->isLocalContext();
if (!isLocalVar && VDC->isModuleScopeContext()) {
auto argFile = DC->getParentSourceFile();
auto varFile = VDC->getParentSourceFile();
isLocalVar = (argFile == varFile && argFile->isScriptMode());
}
if (!isLocalVar)
return;
SmallString<32> scratch;
SourceLoc endLoc; // Filled in if we decide to diagnose this
SourceLoc startLoc; // Left invalid if we're inserting
auto isSimpleTypelessPattern = [](Pattern *P) -> bool {
if (auto VP = dyn_cast_or_null<VarPattern>(P))
P = VP->getSubPattern();
return P && isa<NamedPattern>(P);
};
auto typeRange = VD->getTypeSourceRangeForDiagnostics();
if (typeRange.isValid()) {
startLoc = typeRange.Start;
endLoc = typeRange.End;
} else if (isSimpleTypelessPattern(VD->getParentPattern())) {
endLoc = VD->getNameLoc();
scratch += ": ";
}
if (endLoc.isInvalid())
return;
scratch += neededType.getString();
// Adjust into the location where we actually want to insert
endLoc = Lexer::getLocForEndOfToken(getASTContext().SourceMgr, endLoc);
// Since we already adjusted endLoc, this will turn an insertion
// into a zero-character replacement.
if (!startLoc.isValid())
startLoc = endLoc;
emitDiagnostic(VD->getLoc(), diag::inout_change_var_type_if_possible,
actualType, neededType)
.fixItReplaceChars(startLoc, endLoc, scratch);
}
std::pair<Expr *, ValueDecl *>
AssignmentFailure::resolveImmutableBase(Expr *expr) const {
auto &cs = getConstraintSystem();
auto *DC = getDC();
expr = expr->getValueProvidingExpr();
// Provide specific diagnostics for assignment to subscripts whose base expr
// is known to be an rvalue.
if (auto *SE = dyn_cast<SubscriptExpr>(expr)) {
// If we found a decl for the subscript, check to see if it is a set-only
// subscript decl.
SubscriptDecl *member = nullptr;
if (SE->hasDecl())
member = dyn_cast_or_null<SubscriptDecl>(SE->getDecl().getDecl());
if (!member) {
auto loc =
cs.getConstraintLocator(SE, ConstraintLocator::SubscriptMember);
member = dyn_cast_or_null<SubscriptDecl>(getMemberRef(loc));
}
// If it isn't settable, return it.
if (member) {
if (!member->isSettable() || !member->isSetterAccessibleFrom(DC))
return {expr, member};
}
if (auto tupleExpr = dyn_cast<TupleExpr>(SE->getIndex())) {
if (tupleExpr->getNumElements() == 1 &&
tupleExpr->getElementName(0).str() == "keyPath") {
auto indexType = getType(tupleExpr->getElement(0));
if (auto bgt = indexType->getAs<BoundGenericType>()) {
if (bgt->getDecl() == getASTContext().getKeyPathDecl())
return resolveImmutableBase(tupleExpr->getElement(0));
}
}
}
// If it is settable, then the base must be the problem, recurse.
return resolveImmutableBase(SE->getBase());
}
// Look through property references.
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(expr)) {
// If we found a decl for the UDE, check it.
auto loc = cs.getConstraintLocator(UDE, ConstraintLocator::Member);
auto *member = getMemberRef(loc);
// If we can resolve a member, we can determine whether it is settable in
// this context.
if (member) {
auto *memberVD = dyn_cast<VarDecl>(member);
// If the member isn't a vardecl (e.g. its a funcdecl), or it isn't
// settable, then it is the problem: return it.
if (!memberVD || !member->isSettable(nullptr) ||
!memberVD->isSetterAccessibleFrom(DC))
return {expr, member};
}
// If we weren't able to resolve a member or if it is mutable, then the
// problem must be with the base, recurse.
return resolveImmutableBase(UDE->getBase());
}
if (auto *MRE = dyn_cast<MemberRefExpr>(expr)) {
// If the member isn't settable, then it is the problem: return it.
if (auto member = dyn_cast<AbstractStorageDecl>(MRE->getMember().getDecl()))
if (!member->isSettable(nullptr) || !member->isSetterAccessibleFrom(DC))
return {expr, member};
// If we weren't able to resolve a member or if it is mutable, then the
// problem must be with the base, recurse.
return resolveImmutableBase(MRE->getBase());
}
if (auto *DRE = dyn_cast<DeclRefExpr>(expr))
return {expr, DRE->getDecl()};
// Look through x!
if (auto *FVE = dyn_cast<ForceValueExpr>(expr))
return resolveImmutableBase(FVE->getSubExpr());
// Look through x?
if (auto *BOE = dyn_cast<BindOptionalExpr>(expr))
return resolveImmutableBase(BOE->getSubExpr());
// Look through implicit conversions
if (auto *ICE = dyn_cast<ImplicitConversionExpr>(expr))
if (!isa<LoadExpr>(ICE->getSubExpr()))
return resolveImmutableBase(ICE->getSubExpr());
if (auto *SAE = dyn_cast<SelfApplyExpr>(expr))
return resolveImmutableBase(SAE->getFn());
return {expr, nullptr};
}
ValueDecl *AssignmentFailure::getMemberRef(ConstraintLocator *locator) const {
auto member = getOverloadChoiceIfAvailable(locator);
if (!member || !member->choice.isDecl())
return nullptr;
auto *DC = getDC();
auto &TC = getTypeChecker();
auto *decl = member->choice.getDecl();
if (isa<SubscriptDecl>(decl) &&
isValidDynamicMemberLookupSubscript(cast<SubscriptDecl>(decl), DC, TC)) {
auto *subscript = cast<SubscriptDecl>(decl);
// If this is a keypath dynamic member lookup, we have to
// adjust the locator to find member referred by it.
if (isValidKeyPathDynamicMemberLookup(subscript, TC)) {
auto &cs = getConstraintSystem();
// Type has a following format:
// `(Self) -> (dynamicMember: {Writable}KeyPath<T, U>) -> U`
auto *fullType = member->openedFullType->castTo<FunctionType>();
auto *fnType = fullType->getResult()->castTo<FunctionType>();
auto paramTy = fnType->getParams()[0].getPlainType();
auto keyPath = paramTy->getAnyNominal();
auto memberLoc = cs.getConstraintLocator(
locator, LocatorPathElt::getKeyPathDynamicMember(keyPath));
auto memberRef = getOverloadChoiceIfAvailable(memberLoc);
return memberRef ? memberRef->choice.getDecl() : nullptr;
}
// If this is a string based dynamic lookup, there is no member declaration.
return nullptr;
}
return decl;
}
Diag<StringRef> AssignmentFailure::findDeclDiagonstic(ASTContext &ctx,
Expr *destExpr) {
if (isa<ApplyExpr>(destExpr) || isa<SelfApplyExpr>(destExpr))
return diag::assignment_lhs_is_apply_expression;
if (isa<UnresolvedDotExpr>(destExpr) || isa<MemberRefExpr>(destExpr))
return diag::assignment_lhs_is_immutable_property;
if (auto *subscript = dyn_cast<SubscriptExpr>(destExpr)) {
auto diagID = diag::assignment_subscript_has_immutable_base;
// If the destination is a subscript with a 'dynamicLookup:' label and if
// the tuple is implicit, then this was actually a @dynamicMemberLookup
// access. Emit a more specific diagnostic.
if (subscript->getIndex()->isImplicit() &&
subscript->getArgumentLabels().size() == 1 &&
subscript->getArgumentLabels().front() == ctx.Id_dynamicMember)
diagID = diag::assignment_dynamic_property_has_immutable_base;
return diagID;
}
return diag::assignment_lhs_is_immutable_variable;
}
bool ContextualFailure::diagnoseAsError() {
auto *anchor = getAnchor();
auto path = getLocator()->getPath();
assert(!path.empty());
if (diagnoseMissingFunctionCall())
return true;
Diag<Type, Type> diagnostic;
switch (path.back().getKind()) {
case ConstraintLocator::ClosureResult: {
diagnostic = diag::cannot_convert_closure_result;
break;
}
default:
return false;
}
auto diag = emitDiagnostic(anchor->getLoc(), diagnostic, FromType, ToType);
diag.highlight(anchor->getSourceRange());
(void)trySequenceSubsequenceFixIts(diag, getConstraintSystem(), FromType,
ToType, anchor);
return true;
}
bool ContextualFailure::diagnoseMissingFunctionCall() const {
auto &TC = getTypeChecker();
auto *srcFT = FromType->getAs<FunctionType>();
if (!srcFT || !srcFT->getParams().empty())
return false;
if (ToType->is<AnyFunctionType>() ||
!TC.isConvertibleTo(srcFT->getResult(), ToType, getDC()))
return false;
auto *anchor = getAnchor();
emitDiagnostic(anchor->getLoc(), diag::missing_nullary_call,
srcFT->getResult())
.highlight(anchor->getSourceRange())
.fixItInsertAfter(anchor->getEndLoc(), "()");
tryComputedPropertyFixIts(anchor);
return true;
}
bool ContextualFailure::trySequenceSubsequenceFixIts(InFlightDiagnostic &diag,
ConstraintSystem &CS,
Type fromType, Type toType,
Expr *expr) {
if (!CS.TC.Context.getStdlibModule())
return false;
auto String = CS.TC.getStringType(CS.DC);
auto Substring = CS.TC.getSubstringType(CS.DC);
if (!String || !Substring)
return false;
// Substring -> String conversion
// Wrap in String.init
if (fromType->isEqual(Substring)) {
if (toType->isEqual(String)) {
auto range = expr->getSourceRange();
diag.fixItInsert(range.Start, "String(");
diag.fixItInsertAfter(range.End, ")");
return true;
}
}
return false;
}
void ContextualFailure::tryComputedPropertyFixIts(Expr *expr) const {
if (!isa<ClosureExpr>(expr))
return;
// It is possible that we're looking at a stored property being
// initialized with a closure. Something like:
//
// var foo: Int = { return 0 }
//
// Let's offer another fix-it to remove the '=' to turn the stored
// property into a computed property. If the variable is immutable, then
// replace the 'let' with a 'var'.
PatternBindingDecl *PBD = nullptr;
if (auto TLCD = dyn_cast<TopLevelCodeDecl>(getDC())) {
if (TLCD->getBody()->isImplicit()) {
if (auto decl = TLCD->getBody()->getElement(0).dyn_cast<Decl *>()) {
if (auto binding = dyn_cast<PatternBindingDecl>(decl)) {
PBD = binding;
}
}
}
} else if (auto PBI = dyn_cast<PatternBindingInitializer>(getDC())) {
PBD = PBI->getBinding();
}
if (PBD) {
if (auto VD = PBD->getSingleVar()) {
auto entry = PBD->getPatternEntryForVarDecl(VD);
if (!VD->isStatic() &&
!VD->getAttrs().getAttribute<DynamicReplacementAttr>() &&
entry.getInit() && isa<ClosureExpr>(entry.getInit())) {
auto diag = emitDiagnostic(expr->getLoc(),
diag::extension_stored_property_fixit,
VD->getName());
diag.fixItRemove(entry.getEqualLoc());
if (VD->isLet()) {
diag.fixItReplace(PBD->getStartLoc(), getTokenText(tok::kw_var));
}
}
}
}
}
bool AutoClosureForwardingFailure::diagnoseAsError() {
auto path = getLocator()->getPath();
assert(!path.empty());
auto &last = path.back();
assert(last.getKind() == ConstraintLocator::ApplyArgToParam);
// We need a raw anchor here because `getAnchor()` is simplified
// to the argument expression.
auto *argExpr = getArgumentExpr(getRawAnchor(), last.getValue());
emitDiagnostic(argExpr->getLoc(), diag::invalid_autoclosure_forwarding)
.highlight(argExpr->getSourceRange())
.fixItInsertAfter(argExpr->getEndLoc(), "()");
return true;
}
bool NonOptionalUnwrapFailure::diagnoseAsError() {
auto *anchor = getAnchor();
auto diagnostic = diag::invalid_optional_chain;
if (isa<ForceValueExpr>(anchor))
diagnostic = diag::invalid_force_unwrap;
emitDiagnostic(anchor->getLoc(), diagnostic, BaseType)
.highlight(anchor->getSourceRange())
.fixItRemove(anchor->getEndLoc());
return true;
}
bool MissingCallFailure::diagnoseAsError() {
auto *baseExpr = getAnchor();
SourceLoc insertLoc = baseExpr->getEndLoc();
if (auto *FVE = dyn_cast<ForceValueExpr>(baseExpr))
baseExpr = FVE->getSubExpr();
if (auto *DRE = dyn_cast<DeclRefExpr>(baseExpr)) {
emitDiagnostic(baseExpr->getLoc(), diag::did_not_call_function,
DRE->getDecl()->getBaseName().getIdentifier())
.fixItInsertAfter(insertLoc, "()");
return true;
}
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(baseExpr)) {
emitDiagnostic(baseExpr->getLoc(), diag::did_not_call_method,
UDE->getName().getBaseIdentifier())
.fixItInsertAfter(insertLoc, "()");
return true;
}
if (auto *DSCE = dyn_cast<DotSyntaxCallExpr>(baseExpr)) {
if (auto *DRE = dyn_cast<DeclRefExpr>(DSCE->getFn())) {
emitDiagnostic(baseExpr->getLoc(), diag::did_not_call_method,
DRE->getDecl()->getBaseName().getIdentifier())
.fixItInsertAfter(insertLoc, "()");
return true;
}
}
emitDiagnostic(baseExpr->getLoc(), diag::did_not_call_function_value)
.fixItInsertAfter(insertLoc, "()");
return true;
}
bool SubscriptMisuseFailure::diagnoseAsError() {
auto &sourceMgr = getASTContext().SourceMgr;
auto *memberExpr = cast<UnresolvedDotExpr>(getRawAnchor());
auto *baseExpr = getAnchor();
auto memberRange = baseExpr->getSourceRange();
(void)simplifyLocator(getConstraintSystem(), getLocator(), memberRange);
auto nameLoc = DeclNameLoc(memberRange.Start);
auto diag = emitDiagnostic(baseExpr->getLoc(),
diag::could_not_find_subscript_member_did_you_mean,
getType(baseExpr));
diag.highlight(memberRange).highlight(nameLoc.getSourceRange());
auto *parentExpr = findParentExpr(memberExpr);
assert(parentExpr && "Couldn't find a parent expression for a member call?!");
auto *argExpr = cast<ApplyExpr>(parentExpr)->getArg();
auto toCharSourceRange = Lexer::getCharSourceRangeFromSourceRange;
auto lastArgSymbol = toCharSourceRange(sourceMgr, argExpr->getEndLoc());
diag.fixItReplace(SourceRange(argExpr->getStartLoc()),
getTokenText(tok::l_square));
diag.fixItRemove(nameLoc.getSourceRange());
diag.fixItRemove(SourceRange(memberExpr->getDotLoc()));
if (sourceMgr.extractText(lastArgSymbol) == getTokenText(tok::r_paren))
diag.fixItReplace(SourceRange(argExpr->getEndLoc()),
getTokenText(tok::r_square));
else
diag.fixItInsertAfter(argExpr->getEndLoc(), getTokenText(tok::r_square));
diag.flush();
if (auto overload = getOverloadChoiceIfAvailable(getLocator())) {
emitDiagnostic(overload->choice.getDecl(), diag::kind_declared_here,
DescriptiveDeclKind::Subscript);
}
return true;
}
bool SubscriptMisuseFailure::diagnoseAsNote() {
if (auto overload = getOverloadChoiceIfAvailable(getLocator())) {
emitDiagnostic(overload->choice.getDecl(), diag::found_candidate);
return true;
}
return false;
}
/// When a user refers a enum case with a wrong member name, we try to find a
/// enum element whose name differs from the wrong name only in convention;
/// meaning their lower case counterparts are identical.
/// - DeclName is valid when such a correct case is found; invalid otherwise.
DeclName MissingMemberFailure::findCorrectEnumCaseName(
Type Ty, TypoCorrectionResults &corrections, DeclName memberName) {
if (memberName.isSpecial() || !memberName.isSimpleName())
return DeclName();
if (!Ty->getEnumOrBoundGenericEnum())
return DeclName();
auto candidate =
corrections.getUniqueCandidateMatching([&](ValueDecl *candidate) {
return (isa<EnumElementDecl>(candidate) &&
candidate->getFullName().getBaseIdentifier().str().equals_lower(
memberName.getBaseIdentifier().str()));
});
return (candidate ? candidate->getFullName() : DeclName());
}
bool MissingMemberFailure::diagnoseAsError() {
auto &TC = getTypeChecker();
auto *anchor = getRawAnchor();
auto *baseExpr = getAnchor();
if (!anchor || !baseExpr)
return false;
if (auto *typeVar = BaseType->getAs<TypeVariableType>()) {
auto &CS = getConstraintSystem();
auto *memberLoc = typeVar->getImpl().getLocator();
// Don't try to diagnose anything besides first missing
// member in the chain. e.g. `x.foo().bar()` let's make
// sure to diagnose only `foo()` as missing because we
// don't really know much about what `bar()` is supposed
// to be.
if (CS.MissingMembers.count(memberLoc))
return false;
}
auto baseType = resolveType(BaseType)->getWithoutSpecifierType();
DeclNameLoc nameLoc(anchor->getStartLoc());
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor)) {
nameLoc = UDE->getNameLoc();
} else if (auto *UME = dyn_cast<UnresolvedMemberExpr>(anchor)) {
nameLoc = UME->getNameLoc();
}
auto emitBasicError = [&](Type baseType) {
auto diagnostic = diag::could_not_find_value_member;
if (auto *metatype = baseType->getAs<MetatypeType>()) {
baseType = metatype->getInstanceType();
diagnostic = diag::could_not_find_type_member;
}
if (baseType->is<TupleType>())
diagnostic = diag::could_not_find_tuple_member;
emitDiagnostic(anchor->getLoc(), diagnostic, baseType, Name)
.highlight(baseExpr->getSourceRange())
.highlight(nameLoc.getSourceRange());
};
TypoCorrectionResults corrections(TC, Name, nameLoc);
auto tryTypoCorrection = [&] {
TC.performTypoCorrection(getDC(), DeclRefKind::Ordinary, baseType,
defaultMemberLookupOptions, corrections);
};
if (Name.getBaseName().getKind() == DeclBaseName::Kind::Subscript) {
emitDiagnostic(anchor->getLoc(), diag::could_not_find_value_subscript,
baseType)
.highlight(baseExpr->getSourceRange());
} else if (Name.getBaseName() == "deinit") {
// Specialised diagnostic if trying to access deinitialisers
emitDiagnostic(anchor->getLoc(), diag::destructor_not_accessible)
.highlight(baseExpr->getSourceRange());
} else if (auto metatypeTy = baseType->getAs<MetatypeType>()) {
auto instanceTy = metatypeTy->getInstanceType();
tryTypoCorrection();
if (DeclName rightName =
findCorrectEnumCaseName(instanceTy, corrections, Name)) {
emitDiagnostic(anchor->getLoc(), diag::could_not_find_enum_case,
instanceTy, Name, rightName)
.fixItReplace(nameLoc.getBaseNameLoc(),
rightName.getBaseIdentifier().str());
return true;
}
if (auto correction = corrections.claimUniqueCorrection()) {
auto diagnostic = emitDiagnostic(
anchor->getLoc(), diag::could_not_find_type_member_corrected,
instanceTy, Name, correction->CorrectedName);
diagnostic.highlight(baseExpr->getSourceRange())
.highlight(nameLoc.getSourceRange());
correction->addFixits(diagnostic);
} else {
emitBasicError(baseType);
}
} else if (auto moduleTy = baseType->getAs<ModuleType>()) {
emitDiagnostic(baseExpr->getLoc(), diag::no_member_of_module,
moduleTy->getModule()->getName(), Name)
.highlight(baseExpr->getSourceRange())
.highlight(nameLoc.getSourceRange());
return true;
} else {
// Check for a few common cases that can cause missing members.
auto *ED = baseType->getEnumOrBoundGenericEnum();
if (ED && Name.isSimpleName("rawValue")) {
auto loc = ED->getNameLoc();
if (loc.isValid()) {
emitBasicError(baseType);
emitDiagnostic(loc, diag::did_you_mean_raw_type);
return true;
}
} else if (baseType->isAny()) {
emitBasicError(baseType);
emitDiagnostic(anchor->getLoc(), diag::any_as_anyobject_fixit)
.fixItInsert(baseExpr->getStartLoc(), "(")
.fixItInsertAfter(baseExpr->getEndLoc(), " as AnyObject)");
return true;
}
tryTypoCorrection();
if (auto correction = corrections.claimUniqueCorrection()) {
auto diagnostic = emitDiagnostic(
anchor->getLoc(), diag::could_not_find_value_member_corrected,
baseType, Name, correction->CorrectedName);
diagnostic.highlight(baseExpr->getSourceRange())
.highlight(nameLoc.getSourceRange());
correction->addFixits(diagnostic);
} else {
emitBasicError(baseType);
}
}
// Note all the correction candidates.
corrections.noteAllCandidates();
return true;
}
bool AllowTypeOrInstanceMemberFailure::diagnoseAsError() {
auto loc = getAnchor()->getLoc();
auto &cs = getConstraintSystem();
auto locator = getLocator();
if (loc.isInvalid()) {
return true;
}
Expr *expr = getParentExpr();
SourceRange baseRange = expr ? expr->getSourceRange() : SourceRange();
auto resolvedOverloadChoice = getResolvedOverload(locator)->Choice;
ValueDecl *decl = nullptr;
if (!resolvedOverloadChoice.isDecl()) {
if (auto MT = resolvedOverloadChoice.getBaseType()->getAs<MetatypeType>()) {
if (auto VD = dyn_cast<ValueDecl>(
MT->getMetatypeInstanceType()->getAnyNominal()->getAsDecl())) {
decl = VD;
}
} else {
return true;
}
}
auto member = decl ? decl : resolvedOverloadChoice.getDecl();
// If the base is an implicit self type reference, and we're in a
// an initializer, then the user wrote something like:
//
// class Foo { let x = 1, y = x }
//
// which runs in type context, not instance context, or
//
// class Bar {
// let otherwise = 1 // instance member
// var x: Int
// func init(x: Int =otherwise) { // default parameter
// self.x = x
// }
// }
//
// in which an instance member is used as a default value for a
// parameter.
//
// Produce a tailored diagnostic for these cases since this
// comes up and is otherwise non-obvious what is going on.
if (Name.isSimpleName(DeclBaseName::createConstructor()) &&
!BaseType->getRValueType()->is<AnyMetatypeType>()) {
if (auto ctorRef = dyn_cast<UnresolvedDotExpr>(getRawAnchor())) {
if (isa<SuperRefExpr>(ctorRef->getBase())) {
emitDiagnostic(loc, diag::super_initializer_not_in_initializer);
return true;
}
SourceRange fixItRng = ctorRef->getNameLoc().getSourceRange();
emitDiagnostic(loc, diag::init_not_instance_member)
.fixItInsert(fixItRng.Start, "type(of: ")
.fixItInsertAfter(fixItRng.End, ")");
return true;
}
}
if (BaseType->is<AnyMetatypeType>() && !member->isStatic()) {
auto instanceTy = BaseType->getRValueType();
if (auto *AMT = instanceTy->getAs<AnyMetatypeType>()) {
instanceTy = AMT->getInstanceType();
}
if (getRawAnchor() &&
cs.DC->getContextKind() == DeclContextKind::Initializer) {
auto *TypeDC = cs.DC->getParent();
bool propertyInitializer = true;
// If the parent context is not a type context, we expect it
// to be a defaulted parameter in a function declaration.
if (!TypeDC->isTypeContext()) {
assert(TypeDC->getContextKind() ==
DeclContextKind::AbstractFunctionDecl &&
"Expected function decl context for initializer!");
TypeDC = TypeDC->getParent();
propertyInitializer = false;
}
assert(TypeDC->isTypeContext() && "Expected type decl context!");
if (TypeDC->getSelfNominalTypeDecl() == instanceTy->getAnyNominal()) {
if (propertyInitializer) {
emitDiagnostic(loc, diag::instance_member_in_initializer, Name);
return true;
} else {
emitDiagnostic(loc, diag::instance_member_in_default_parameter, Name);
return true;
}
}
}
auto maybeCallExpr = getRawAnchor();
if (auto UDE = dyn_cast<UnresolvedDotExpr>(maybeCallExpr)) {
maybeCallExpr = UDE->getBase();
}
if (auto callExpr = dyn_cast<ApplyExpr>(maybeCallExpr)) {
auto fnExpr = callExpr->getFn();
auto fnType = cs.getType(fnExpr)->getRValueType();
auto arg = callExpr->getArg();
if (fnType->is<ExistentialMetatypeType>()) {
emitDiagnostic(arg->getStartLoc(),
diag::missing_init_on_metatype_initialization)
.highlight(fnExpr->getSourceRange());
return true;
}
}
// Check whether the instance member is declared on parent context and if so
// provide more specialized message.
auto memberTypeContext = member->getDeclContext()->getInnermostTypeContext();
auto currentTypeContext = cs.DC->getInnermostTypeContext();
if (memberTypeContext && currentTypeContext &&
memberTypeContext->getSemanticDepth() <
currentTypeContext->getSemanticDepth()) {
emitDiagnostic(loc, diag::could_not_use_instance_member_on_type,
currentTypeContext->getDeclaredInterfaceType(), Name,
memberTypeContext->getDeclaredInterfaceType(), true)
.highlight(baseRange)
.highlight(member->getSourceRange());
return true;
}
if (isa<TypeExpr>(getRawAnchor())) {
emitDiagnostic(loc, diag::instance_member_use_on_type, instanceTy, Name)
.highlight(getRawAnchor()->getSourceRange());
return true;
}
// Just emit a generic "instance member cannot be used" error
emitDiagnostic(loc, diag::could_not_use_instance_member_on_type, instanceTy,
Name, instanceTy, false)
.highlight(getAnchor()->getSourceRange());
return true;
} else {
// If the base of the lookup is a protocol metatype, suggest
// to replace the metatype with 'Self'
// error saying the lookup cannot be on a protocol metatype
Optional<InFlightDiagnostic> Diag;
auto baseObjTy = BaseType->getRValueType();
if (auto metatypeTy = baseObjTy->getAs<MetatypeType>()) {
auto instanceTy = metatypeTy->getInstanceType();
// This will only happen if we have an unresolved dot expression
// (.foo) where foo is a protocol member and the contextual type is
// an optional protocol metatype.
if (auto objectTy = instanceTy->getOptionalObjectType()) {
instanceTy = objectTy;
baseObjTy = MetatypeType::get(objectTy);
}
assert(instanceTy->isExistentialType());
// Give a customized message if we're accessing a member type
// of a protocol -- otherwise a diagnostic talking about
// static members doesn't make a whole lot of sense
if (auto TAD = dyn_cast<TypeAliasDecl>(member)) {
Diag.emplace(emitDiagnostic(loc, diag::typealias_outside_of_protocol,
TAD->getName()));
} else if (auto ATD = dyn_cast<AssociatedTypeDecl>(member)) {
Diag.emplace(emitDiagnostic(loc, diag::assoc_type_outside_of_protocol,
ATD->getName()));
} else if (isa<ConstructorDecl>(member)) {
Diag.emplace(emitDiagnostic(loc, diag::construct_protocol_by_name,
instanceTy));
} else {
Diag.emplace(emitDiagnostic(loc,
diag::could_not_use_type_member_on_protocol_metatype,
baseObjTy, Name));
}
Diag->highlight(baseRange).highlight(getAnchor()->getSourceRange());
// See through function decl context
if (auto parent = cs.DC->getInnermostTypeContext()) {
// If we are in a protocol extension of 'Proto' and we see
// 'Proto.static', suggest 'Self.static'
if (auto extensionContext = parent->getExtendedProtocolDecl()) {
if (extensionContext->getDeclaredType()->isEqual(instanceTy)) {
Diag->fixItReplace(getAnchor()->getSourceRange(), "Self");
}
}
}
return true;
}
if (isa<EnumElementDecl>(member)) {
Diag.emplace(emitDiagnostic(loc, diag::could_not_use_enum_element_on_instance,
Name));
}
else {
Diag.emplace(emitDiagnostic(loc, diag::could_not_use_type_member_on_instance,
baseObjTy, Name));
}
Diag->highlight(getAnchor()->getSourceRange());
if (Name.isSimpleName(DeclBaseName::createConstructor()) &&
!baseObjTy->is<AnyMetatypeType>()) {
if (auto ctorRef = dyn_cast<UnresolvedDotExpr>(getRawAnchor())) {
SourceRange fixItRng = ctorRef->getNameLoc().getSourceRange();
Diag->fixItInsert(fixItRng.Start, "type(of: ");
Diag->fixItInsertAfter(fixItRng.End, ")");
return true;
}
}
// Determine the contextual type of the expression
Type contextualType;
for (auto iterateCS = &cs; contextualType.isNull() && iterateCS;
iterateCS = iterateCS->baseCS) {
contextualType = iterateCS->getContextualType();
}
// Try to provide a fix-it that only contains a '.'
if (contextualType) {
if (baseObjTy->isEqual(contextualType)) {
Diag->fixItInsert(loc, ".");
return true;
}
}
// Check if the expression is the matching operator ~=, most often used in
// case statements. If so, try to provide a single dot fix-it
const Expr *contextualTypeNode = nullptr;
ConstraintSystem *lastCS = nullptr;
for (auto iterateCS = &cs; iterateCS; iterateCS = iterateCS->baseCS) {
lastCS = iterateCS;
contextualTypeNode = iterateCS->getContextualTypeNode();
}
// The '~=' operator is an overloaded decl ref inside a binaryExpr
if (auto binaryExpr = dyn_cast<BinaryExpr>(contextualTypeNode)) {
if (auto overloadedFn
= dyn_cast<OverloadedDeclRefExpr>(binaryExpr->getFn())) {
if (!overloadedFn->getDecls().empty()) {
// Fetch any declaration to check if the name is '~='
ValueDecl *decl0 = overloadedFn->getDecls()[0];
if (decl0->getBaseName() == decl0->getASTContext().Id_MatchOperator) {
assert(binaryExpr->getArg()->getElements().size() == 2);
// If the rhs of '~=' is the enum type, a single dot suffixes
// since the type can be inferred
Type secondArgType =
lastCS->getType(binaryExpr->getArg()->getElement(1));
if (secondArgType->isEqual(baseObjTy)) {
Diag->fixItInsert(loc, ".");
return true;
}
}
}
}
}
// Fall back to a fix-it with a full type qualifier
auto nominal = member->getDeclContext()->getSelfNominalTypeDecl();
SmallString<32> typeName;
llvm::raw_svector_ostream typeNameStream(typeName);
typeNameStream << nominal->getSelfInterfaceType() << ".";
Diag->fixItInsert(loc, typeNameStream.str());
return true;
}
return false;
}
bool PartialApplicationFailure::diagnoseAsError() {
auto &cs = getConstraintSystem();
auto *anchor = cast<UnresolvedDotExpr>(getRawAnchor());
RefKind kind = RefKind::MutatingMethod;
// If this is initializer delegation chain, we have a tailored message.
if (getOverloadChoiceIfAvailable(cs.getConstraintLocator(
anchor, ConstraintLocator::ConstructorMember))) {
kind = anchor->getBase()->isSuperExpr() ? RefKind::SuperInit
: RefKind::SelfInit;
}
auto diagnostic = CompatibilityWarning
? diag::partial_application_of_function_invalid_swift4
: diag::partial_application_of_function_invalid;
emitDiagnostic(anchor->getNameLoc(), diagnostic, kind);
return true;
}
bool InvalidDynamicInitOnMetatypeFailure::diagnoseAsError() {
auto *anchor = getRawAnchor();
emitDiagnostic(anchor->getLoc(), diag::dynamic_construct_class,
BaseType->getMetatypeInstanceType())
.highlight(BaseRange);
emitDiagnostic(Init, diag::note_nonrequired_initializer, Init->isImplicit(),
Init->getFullName());
return true;
}
bool InitOnProtocolMetatypeFailure::diagnoseAsError() {
auto *anchor = getRawAnchor();
if (IsStaticallyDerived) {
emitDiagnostic(anchor->getLoc(), diag::construct_protocol_by_name,
BaseType->getMetatypeInstanceType())
.highlight(BaseRange);
} else {
emitDiagnostic(anchor->getLoc(), diag::construct_protocol_value, BaseType)
.highlight(BaseRange);
}
return true;
}
bool ImplicitInitOnNonConstMetatypeFailure::diagnoseAsError() {
auto *apply = cast<ApplyExpr>(getRawAnchor());
auto loc = apply->getArg()->getStartLoc();
emitDiagnostic(loc, diag::missing_init_on_metatype_initialization)
.fixItInsert(loc, ".init");
return true;
}
bool MissingArgumentsFailure::diagnoseAsError() {
auto *locator = getLocator();
auto path = locator->getPath();
// TODO: Currently this is only intended to diagnose contextual failures.
if (path.empty() ||
!(path.back().getKind() == ConstraintLocator::ApplyArgToParam ||
path.back().getKind() == ConstraintLocator::ContextualType))
return false;
if (auto *closure = dyn_cast<ClosureExpr>(getAnchor()))
return diagnoseTrailingClosure(closure);
return false;
}
bool MissingArgumentsFailure::diagnoseTrailingClosure(ClosureExpr *closure) {
auto diff = Fn->getNumParams() - NumSynthesized;
// If the closure didn't specify any arguments and it is in a context that
// needs some, produce a fixit to turn "{...}" into "{ _,_ in ...}".
if (diff == 0) {
auto diag =
emitDiagnostic(closure->getStartLoc(),
diag::closure_argument_list_missing, NumSynthesized);
std::string fixText; // Let's provide fixits for up to 10 args.
if (Fn->getNumParams() <= 10) {
fixText += " ";
interleave(
Fn->getParams(),
[&fixText](const AnyFunctionType::Param &param) { fixText += '_'; },
[&fixText] { fixText += ','; });
fixText += " in ";
}
if (!fixText.empty()) {
// Determine if there is already a space after the { in the closure to
// make sure we introduce the right whitespace.
auto afterBrace = closure->getStartLoc().getAdvancedLoc(1);
auto text = getASTContext().SourceMgr.extractText({afterBrace, 1});
if (text.size() == 1 && text == " ")
fixText = fixText.erase(fixText.size() - 1);
else
fixText = fixText.erase(0, 1);
diag.fixItInsertAfter(closure->getStartLoc(), fixText);
}
return true;
}
auto params = closure->getParameters();
bool onlyAnonymousParams =
std::all_of(params->begin(), params->end(),
[](ParamDecl *param) { return !param->hasName(); });
auto diag =
emitDiagnostic(params->getStartLoc(), diag::closure_argument_list_tuple,
resolveType(Fn), Fn->getNumParams(), diff, diff == 1);
// If the number of parameters is less than number of inferred
// let's try to suggest a fix-it with the rest of the missing parameters.
if (!closure->hasExplicitResultType() &&
closure->getInLoc().isValid()) {
SmallString<32> fixIt;
llvm::raw_svector_ostream OS(fixIt);
OS << ",";
for (unsigned i = 0; i != NumSynthesized; ++i) {
OS << ((onlyAnonymousParams) ? "_" : "<#arg#>");
OS << ((i == NumSynthesized - 1) ? " " : ",");
}
diag.fixItInsertAfter(params->getEndLoc(), OS.str());
}
return true;
}
bool ClosureParamDestructuringFailure::diagnoseAsError() {
auto *closure = cast<ClosureExpr>(getAnchor());
auto params = closure->getParameters();
// In case of implicit parameters e.g. $0, $1 we
// can't really provide good fix-it because
// structure of parameter type itself is unclear.
for (auto *param : params->getArray()) {
if (param->isImplicit()) {
emitDiagnostic(params->getStartLoc(),
diag::closure_tuple_parameter_destructuring_implicit,
getParameterType());
return true;
}
}
auto diag = emitDiagnostic(params->getStartLoc(),
diag::closure_tuple_parameter_destructuring,
getParameterType());
auto *closureBody = closure->getBody();
if (!closureBody)
return true;
auto &sourceMgr = getASTContext().SourceMgr;
auto bodyStmts = closureBody->getElements();
SourceLoc bodyLoc;
// If the body is empty let's put the cursor
// right after "in", otherwise make it start
// location of the first statement in the body.
if (bodyStmts.empty())
bodyLoc = Lexer::getLocForEndOfToken(sourceMgr, closure->getInLoc());
else
bodyLoc = bodyStmts.front().getStartLoc();
SmallString<64> fixIt;
llvm::raw_svector_ostream OS(fixIt);
// If this is multi-line closure we'd have to insert new lines
// in the suggested 'let' to keep the structure of the code intact,
// otherwise just use ';' to keep everything on the same line.
auto inLine = sourceMgr.getLineNumber(closure->getInLoc());
auto bodyLine = sourceMgr.getLineNumber(bodyLoc);
auto isMultiLineClosure = bodyLine > inLine;
auto indent =
bodyStmts.empty() ? "" : Lexer::getIndentationForLine(sourceMgr, bodyLoc);
SmallString<16> parameter;
llvm::raw_svector_ostream parameterOS(parameter);
parameterOS << "(";
interleave(
params->getArray(),
[&](const ParamDecl *param) { parameterOS << param->getNameStr(); },
[&] { parameterOS << ", "; });
parameterOS << ")";
// Check if there are any explicit types associated
// with parameters, if there are, we'll have to add
// type information to the replacement argument.
bool explicitTypes =
llvm::any_of(params->getArray(), [](const ParamDecl *param) {
return param->getTypeLoc().getTypeRepr();
});
if (isMultiLineClosure)
OS << '\n' << indent;
// Let's form 'let <name> : [<type>]? = arg' expression.
OS << "let " << parameterOS.str() << " = arg"
<< (isMultiLineClosure ? "\n" + indent : "; ");
SmallString<64> argName;
llvm::raw_svector_ostream nameOS(argName);
if (explicitTypes) {
nameOS << "(arg: " << getParameterType()->getString() << ")";
} else {
nameOS << "(arg)";
}
if (closure->hasSingleExpressionBody()) {
// Let's see if we need to add result type to the argument/fix-it:
// - if the there is a result type associated with the closure;
// - and it's not a void type;
// - and it hasn't been explicitly written.
auto resultType = resolveType(ContextualType->getResult());
auto hasResult = [](Type resultType) -> bool {
return resultType && !resultType->isVoid();
};
auto isValidType = [](Type resultType) -> bool {
return resultType && !resultType->hasUnresolvedType() &&
!resultType->hasTypeVariable();
};
// If there an expected result type but it hasn't been explicitly
// provided, let's add it to the argument.
if (hasResult(resultType) && !closure->hasExplicitResultType()) {
nameOS << " -> ";
if (isValidType(resultType))
nameOS << resultType->getString();
else
nameOS << "<#Result#>";
}
if (auto stmt = bodyStmts.front().get<Stmt *>()) {
// If the body is a single expression with implicit return.
if (isa<ReturnStmt>(stmt) && stmt->isImplicit()) {
// And there is non-void expected result type,
// because we add 'let' expression to the body
// we need to make such 'return' explicit.
if (hasResult(resultType))
OS << "return ";
}
}
}
diag.fixItReplace(params->getSourceRange(), nameOS.str())
.fixItInsert(bodyLoc, OS.str());
return true;
}
bool OutOfOrderArgumentFailure::diagnoseAsError() {
auto *anchor = getRawAnchor();
auto *argExpr = isa<TupleExpr>(anchor) ? anchor : getArgumentExprFor(anchor);
if (!argExpr)
return false;
auto *tuple = cast<TupleExpr>(argExpr);
Identifier first = tuple->getElementName(ArgIdx);
Identifier second = tuple->getElementName(PrevArgIdx);
// Build a mapping from arguments to parameters.
SmallVector<unsigned, 4> argBindings(tuple->getNumElements());
for (unsigned paramIdx = 0; paramIdx != Bindings.size(); ++paramIdx) {
for (auto argIdx : Bindings[paramIdx])
argBindings[argIdx] = paramIdx;
}
auto argRange = [&](unsigned argIdx, Identifier label) -> SourceRange {
auto range = tuple->getElement(argIdx)->getSourceRange();
if (!label.empty())
range.Start = tuple->getElementNameLoc(argIdx);
unsigned paramIdx = argBindings[argIdx];
if (Bindings[paramIdx].size() > 1)
range.End = tuple->getElement(Bindings[paramIdx].back())->getEndLoc();
return range;
};
auto firstRange = argRange(ArgIdx, first);
auto secondRange = argRange(PrevArgIdx, second);
SourceLoc diagLoc = firstRange.Start;
auto addFixIts = [&](InFlightDiagnostic diag) {
diag.highlight(firstRange).highlight(secondRange);
// Move the misplaced argument by removing it from one location and
// inserting it in another location. To maintain argument comma
// separation, since the argument is always moving to an earlier index
// the preceding comma and whitespace is removed and a new trailing
// comma and space is inserted with the moved argument.
auto &SM = getASTContext().SourceMgr;
auto text = SM.extractText(
Lexer::getCharSourceRangeFromSourceRange(SM, firstRange));
auto removalRange =
SourceRange(Lexer::getLocForEndOfToken(
SM, tuple->getElement(ArgIdx - 1)->getEndLoc()),
firstRange.End);
diag.fixItRemove(removalRange);
diag.fixItInsert(secondRange.Start, text.str() + ", ");
};
// There are 4 diagnostic messages variations depending on
// labeled/unlabeled arguments.
if (first.empty() && second.empty()) {
addFixIts(emitDiagnostic(diagLoc,
diag::argument_out_of_order_unnamed_unnamed,
ArgIdx + 1, PrevArgIdx + 1));
} else if (first.empty() && !second.empty()) {
addFixIts(emitDiagnostic(diagLoc, diag::argument_out_of_order_unnamed_named,
ArgIdx + 1, second));
} else if (!first.empty() && second.empty()) {
addFixIts(emitDiagnostic(diagLoc, diag::argument_out_of_order_named_unnamed,
first, PrevArgIdx + 1));
} else {
addFixIts(emitDiagnostic(diagLoc, diag::argument_out_of_order_named_named,
first, second));
}
return true;
}
bool InaccessibleMemberFailure::diagnoseAsError() {
auto *anchor = getRawAnchor();
// Let's try to avoid over-diagnosing chains of inaccessible
// members e.g.:
//
// struct A {
// struct B {
// struct C {}
// }
// }
//
// _ = A.B.C()
//
// We'll have a fix for each `B', `C` and `C.init` but it makes
// sense to diagnose only `B` and consider the rest hidden.
Expr *baseExpr = nullptr;
DeclNameLoc nameLoc;
if (auto *UDE = dyn_cast<UnresolvedDotExpr>(anchor)) {
baseExpr = UDE->getBase();
nameLoc = UDE->getNameLoc();
} else if (auto *UME = dyn_cast<UnresolvedMemberExpr>(anchor)) {
nameLoc = UME->getNameLoc();
} else if (auto *SE = dyn_cast<SubscriptExpr>(anchor)) {
baseExpr = SE->getBase();
} else if (auto *call = dyn_cast<CallExpr>(anchor)) {
baseExpr = call->getFn();
}
if (baseExpr) {
auto &cs = getConstraintSystem();
auto *locator =
cs.getConstraintLocator(baseExpr, ConstraintLocator::Member);
if (llvm::any_of(cs.getFixes(), [&](const ConstraintFix *fix) {
return fix->getLocator() == locator;
}))
return false;
}
auto loc = nameLoc.isValid() ? nameLoc.getStartLoc() : anchor->getLoc();
auto accessLevel = Member->getFormalAccessScope().accessLevelForDiagnostics();
if (auto *CD = dyn_cast<ConstructorDecl>(Member)) {
emitDiagnostic(loc, diag::init_candidate_inaccessible,
CD->getResultInterfaceType(), accessLevel)
.highlight(nameLoc.getSourceRange());
} else {
emitDiagnostic(loc, diag::candidate_inaccessible, Member->getBaseName(),
accessLevel)
.highlight(nameLoc.getSourceRange());
}
emitDiagnostic(Member, diag::decl_declared_here, Member->getFullName());
return true;
}
bool KeyPathSubscriptIndexHashableFailure::diagnoseAsError() {
auto *anchor = getRawAnchor();
auto *locator = getLocator();
auto loc = anchor->getLoc();
if (locator->isKeyPathSubscriptComponent()) {
auto *KPE = cast<KeyPathExpr>(anchor);
for (auto &elt : locator->getPath()) {
if (elt.isKeyPathComponent()) {
loc = KPE->getComponents()[elt.getValue()].getLoc();
break;
}
}
}
emitDiagnostic(loc, diag::expr_keypath_subscript_index_not_hashable,
resolveType(NonConformingType));
return true;
}