| //===--- CSDiag.cpp - Constraint Diagnostics ------------------------------===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See http://swift.org/LICENSE.txt for license information |
| // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements diagnostics for the type checker. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ConstraintSystem.h" |
| #include "llvm/Support/SaveAndRestore.h" |
| #include "swift/AST/ASTWalker.h" |
| |
| using namespace swift; |
| using namespace constraints; |
| |
| static bool isUnresolvedOrTypeVarType(Type ty) { |
| return ty->is<TypeVariableType>() || ty->is<UnresolvedType>(); |
| } |
| |
| void Failure::dump(SourceManager *sm) const { |
| dump(sm, llvm::errs()); |
| } |
| |
| void Failure::dump(SourceManager *sm, raw_ostream &out) const { |
| out << "("; |
| if (locator) { |
| out << "@"; |
| locator->dump(sm, out); |
| out << ": "; |
| } |
| |
| switch (getKind()) { |
| case IsNotBridgedToObjectiveC: |
| out << getFirstType().getString() << "is not bridged to Objective-C"; |
| break; |
| |
| case IsForbiddenLValue: |
| out << "disallowed l-value binding of " << getFirstType().getString() |
| << " and " << getSecondType().getString(); |
| break; |
| |
| case NoPublicInitializers: |
| out << getFirstType().getString() |
| << " does not have any public initializers"; |
| break; |
| |
| case IsNotMaterializable: |
| out << getFirstType().getString() << " is not materializable"; |
| break; |
| } |
| |
| out << ")\n"; |
| } |
| |
| /// Given a subpath of an old locator, compute its summary flags. |
| static unsigned recomputeSummaryFlags(ConstraintLocator *oldLocator, |
| ArrayRef<LocatorPathElt> path) { |
| if (oldLocator->getSummaryFlags() != 0) |
| return ConstraintLocator::getSummaryFlagsForPath(path); |
| return 0; |
| } |
| |
| ConstraintLocator * |
| constraints::simplifyLocator(ConstraintSystem &cs, ConstraintLocator *locator, |
| SourceRange &range, |
| ConstraintLocator **targetLocator) { |
| // Clear out the target locator result. |
| if (targetLocator) |
| *targetLocator = nullptr; |
| |
| // The path to be tacked on to the target locator to identify the specific |
| // target. |
| Expr *targetAnchor; |
| SmallVector<LocatorPathElt, 4> targetPath; |
| |
| auto path = locator->getPath(); |
| auto anchor = locator->getAnchor(); |
| simplifyLocator(anchor, path, targetAnchor, targetPath, range); |
| |
| |
| // If we have a target anchor, build and simplify the target locator. |
| if (targetLocator && targetAnchor) { |
| SourceRange targetRange; |
| unsigned targetFlags = recomputeSummaryFlags(locator, targetPath); |
| auto loc = cs.getConstraintLocator(targetAnchor, targetPath, targetFlags); |
| *targetLocator = simplifyLocator(cs, loc, targetRange); |
| } |
| |
| // If we didn't simplify anything, just return the input. |
| if (anchor == locator->getAnchor() && |
| path.size() == locator->getPath().size()) { |
| return locator; |
| } |
| |
| // Recompute the summary flags if we had any to begin with. This is |
| // necessary because we might remove e.g. tuple elements from the path. |
| unsigned summaryFlags = recomputeSummaryFlags(locator, path); |
| return cs.getConstraintLocator(anchor, path, summaryFlags); |
| } |
| |
| void constraints::simplifyLocator(Expr *&anchor, |
| ArrayRef<LocatorPathElt> &path, |
| Expr *&targetAnchor, |
| SmallVectorImpl<LocatorPathElt> &targetPath, |
| SourceRange &range) { |
| range = SourceRange(); |
| targetAnchor = nullptr; |
| |
| while (!path.empty()) { |
| switch (path[0].getKind()) { |
| case ConstraintLocator::ApplyArgument: |
| // Extract application argument. |
| if (auto applyExpr = dyn_cast<ApplyExpr>(anchor)) { |
| // The target anchor is the function being called. |
| targetAnchor = applyExpr->getFn(); |
| targetPath.push_back(path[0]); |
| |
| anchor = applyExpr->getArg(); |
| path = path.slice(1); |
| continue; |
| } |
| |
| if (auto objectLiteralExpr = dyn_cast<ObjectLiteralExpr>(anchor)) { |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| anchor = objectLiteralExpr->getArg(); |
| path = path.slice(1); |
| continue; |
| } |
| break; |
| |
| case ConstraintLocator::ApplyFunction: |
| // Extract application function. |
| if (auto applyExpr = dyn_cast<ApplyExpr>(anchor)) { |
| // No additional target locator information. |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| anchor = applyExpr->getFn(); |
| path = path.slice(1); |
| continue; |
| } |
| |
| // The unresolved member itself is the function. |
| if (auto unresolvedMember = dyn_cast<UnresolvedMemberExpr>(anchor)) { |
| if (unresolvedMember->getArgument()) { |
| // No additional target locator information. |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| anchor = unresolvedMember; |
| path = path.slice(1); |
| } |
| continue; |
| } |
| |
| break; |
| |
| case ConstraintLocator::Load: |
| case ConstraintLocator::RvalueAdjustment: |
| case ConstraintLocator::ScalarToTuple: |
| case ConstraintLocator::UnresolvedMember: |
| // Loads, rvalue adjustment, and scalar-to-tuple conversions are implicit. |
| path = path.slice(1); |
| continue; |
| |
| case ConstraintLocator::NamedTupleElement: |
| case ConstraintLocator::TupleElement: |
| // Extract tuple element. |
| if (auto tupleExpr = dyn_cast<TupleExpr>(anchor)) { |
| unsigned index = path[0].getValue(); |
| if (index < tupleExpr->getNumElements()) { |
| // Append this extraction to the target locator path. |
| if (targetAnchor) { |
| targetPath.push_back(path[0]); |
| } |
| |
| anchor = tupleExpr->getElement(index); |
| path = path.slice(1); |
| continue; |
| } |
| } |
| break; |
| |
| case ConstraintLocator::ApplyArgToParam: |
| // Extract tuple element. |
| if (auto tupleExpr = dyn_cast<TupleExpr>(anchor)) { |
| unsigned index = path[0].getValue(); |
| if (index < tupleExpr->getNumElements()) { |
| // Append this extraction to the target locator path. |
| if (targetAnchor) { |
| targetPath.push_back(path[0]); |
| } |
| |
| anchor = tupleExpr->getElement(index); |
| path = path.slice(1); |
| continue; |
| } |
| } |
| |
| // Extract subexpression in parentheses. |
| if (auto parenExpr = dyn_cast<ParenExpr>(anchor)) { |
| assert(path[0].getValue() == 0); |
| |
| // Append this extraction to the target locator path. |
| if (targetAnchor) { |
| targetPath.push_back(path[0]); |
| } |
| |
| anchor = parenExpr->getSubExpr(); |
| path = path.slice(1); |
| } |
| break; |
| |
| case ConstraintLocator::ConstructorMember: |
| if (auto typeExpr = dyn_cast<TypeExpr>(anchor)) { |
| // This is really an implicit 'init' MemberRef, so point at the base, |
| // i.e. the TypeExpr. |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| range = SourceRange(); |
| anchor = typeExpr; |
| path = path.slice(1); |
| continue; |
| } |
| SWIFT_FALLTHROUGH; |
| |
| case ConstraintLocator::Member: |
| case ConstraintLocator::MemberRefBase: |
| if (auto UDE = dyn_cast<UnresolvedDotExpr>(anchor)) { |
| // No additional target locator information. |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| range = UDE->getNameLoc(); |
| anchor = UDE->getBase(); |
| path = path.slice(1); |
| continue; |
| } |
| if (auto USE = dyn_cast<UnresolvedSelectorExpr>(anchor)) { |
| // No additional target locator information. |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| range = USE->getNameRange(); |
| anchor = USE->getBase(); |
| path = path.slice(1); |
| continue; |
| } |
| break; |
| |
| case ConstraintLocator::InterpolationArgument: |
| if (auto interp = dyn_cast<InterpolatedStringLiteralExpr>(anchor)) { |
| unsigned index = path[0].getValue(); |
| if (index < interp->getSegments().size()) { |
| // No additional target locator information. |
| // FIXME: Dig out the constructor we're trying to call? |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| |
| anchor = interp->getSegments()[index]; |
| path = path.slice(1); |
| continue; |
| } |
| } |
| break; |
| |
| case ConstraintLocator::SubscriptIndex: |
| if (auto subscript = dyn_cast<SubscriptExpr>(anchor)) { |
| targetAnchor = subscript->getBase(); |
| targetPath.clear(); |
| |
| anchor = subscript->getIndex(); |
| path = path.slice(1); |
| continue; |
| } |
| break; |
| case ConstraintLocator::SubscriptMember: |
| if (auto subscript = dyn_cast<SubscriptExpr>(anchor)) { |
| anchor = subscript->getBase(); |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| path = path.slice(1); |
| continue; |
| } |
| break; |
| |
| case ConstraintLocator::ClosureResult: |
| if (auto CE = dyn_cast<ClosureExpr>(anchor)) { |
| if (CE->hasSingleExpressionBody()) { |
| targetAnchor = nullptr; |
| targetPath.clear(); |
| anchor = CE->getSingleExpressionBody(); |
| path = path.slice(1); |
| continue; |
| } |
| } |
| break; |
| |
| default: |
| // FIXME: Lots of other cases to handle. |
| break; |
| } |
| |
| // If we get here, we couldn't simplify the path further. |
| break; |
| } |
| } |
| |
| /// Simplify the given locator down to a specific anchor expression, |
| /// if possible. |
| /// |
| /// \returns the anchor expression if it fully describes the locator, or |
| /// null otherwise. |
| static Expr *simplifyLocatorToAnchor(ConstraintSystem &cs, |
| ConstraintLocator *locator) { |
| if (!locator || !locator->getAnchor()) |
| return nullptr; |
| |
| SourceRange range; |
| locator = simplifyLocator(cs, locator, range); |
| if (!locator->getAnchor() || !locator->getPath().empty()) |
| return nullptr; |
| |
| return locator->getAnchor(); |
| } |
| |
| /// Retrieve the argument pattern for the given declaration. |
| /// |
| static ParameterList *getParameterList(ValueDecl *decl) { |
| if (auto func = dyn_cast<FuncDecl>(decl)) |
| return func->getParameterList(0); |
| if (auto constructor = dyn_cast<ConstructorDecl>(decl)) |
| return constructor->getParameterList(1); |
| if (auto subscript = dyn_cast<SubscriptDecl>(decl)) |
| return subscript->getIndices(); |
| |
| // FIXME: Variables of function type? |
| return nullptr; |
| } |
| |
| ResolvedLocator constraints::resolveLocatorToDecl( |
| ConstraintSystem &cs, |
| ConstraintLocator *locator, |
| std::function<Optional<SelectedOverload>(ConstraintLocator *)> findOvlChoice, |
| std::function<ConcreteDeclRef (ValueDecl *decl, |
| Type openedType)> getConcreteDeclRef) |
| { |
| assert(locator && "Null locator"); |
| if (!locator->getAnchor()) |
| return ResolvedLocator(); |
| |
| ConcreteDeclRef declRef; |
| auto anchor = locator->getAnchor(); |
| // Unwrap any specializations, constructor calls, implicit conversions, and |
| // '.'s. |
| // FIXME: This is brittle. |
| do { |
| if (auto specialize = dyn_cast<UnresolvedSpecializeExpr>(anchor)) { |
| anchor = specialize->getSubExpr(); |
| continue; |
| } |
| |
| if (auto implicit = dyn_cast<ImplicitConversionExpr>(anchor)) { |
| anchor = implicit->getSubExpr(); |
| continue; |
| } |
| |
| if (auto identity = dyn_cast<IdentityExpr>(anchor)) { |
| anchor = identity->getSubExpr(); |
| continue; |
| } |
| |
| if (auto tryExpr = dyn_cast<AnyTryExpr>(anchor)) { |
| if (isa<OptionalTryExpr>(tryExpr)) |
| break; |
| |
| anchor = tryExpr->getSubExpr(); |
| continue; |
| } |
| |
| if (auto selfApply = dyn_cast<SelfApplyExpr>(anchor)) { |
| anchor = selfApply->getFn(); |
| continue; |
| } |
| |
| if (auto dotSyntax = dyn_cast<DotSyntaxBaseIgnoredExpr>(anchor)) { |
| anchor = dotSyntax->getRHS(); |
| continue; |
| } |
| break; |
| } while (true); |
| |
| auto getConcreteDeclRefFromOverload |
| = [&](const SelectedOverload &selected) -> ConcreteDeclRef { |
| return getConcreteDeclRef(selected.choice.getDecl(), |
| selected.openedType); |
| }; |
| |
| if (auto dre = dyn_cast<DeclRefExpr>(anchor)) { |
| // Simple case: direct reference to a declaration. |
| declRef = dre->getDeclRef(); |
| } else if (auto mre = dyn_cast<MemberRefExpr>(anchor)) { |
| // Simple case: direct reference to a declaration. |
| declRef = mre->getMember(); |
| } else if (isa<OverloadedDeclRefExpr>(anchor) || |
| isa<OverloadedMemberRefExpr>(anchor) || |
| isa<UnresolvedDeclRefExpr>(anchor)) { |
| // Overloaded and unresolved cases: find the resolved overload. |
| auto anchorLocator = cs.getConstraintLocator(anchor); |
| if (auto selected = findOvlChoice(anchorLocator)) { |
| if (selected->choice.isDecl()) |
| declRef = getConcreteDeclRefFromOverload(*selected); |
| } |
| } else if (isa<UnresolvedMemberExpr>(anchor)) { |
| // Unresolved member: find the resolved overload. |
| auto anchorLocator = cs.getConstraintLocator( |
| anchor, |
| ConstraintLocator::UnresolvedMember); |
| if (auto selected = findOvlChoice(anchorLocator)) { |
| if (selected->choice.isDecl()) |
| declRef = getConcreteDeclRefFromOverload(*selected); |
| } |
| } else if (auto ctorRef = dyn_cast<OtherConstructorDeclRefExpr>(anchor)) { |
| declRef = ctorRef->getDeclRef(); |
| } |
| |
| // If we didn't find the declaration, we're out of luck. |
| if (!declRef) |
| return ResolvedLocator(); |
| |
| // Use the declaration and the path to produce a more specific result. |
| // FIXME: This is an egregious hack. We'd be far better off |
| // FIXME: Perform deeper path resolution? |
| auto path = locator->getPath(); |
| ParameterList *parameterList = nullptr; |
| bool impliesFullPattern = false; |
| while (!path.empty()) { |
| switch (path[0].getKind()) { |
| case ConstraintLocator::ApplyArgument: |
| // If we're calling into something that has parameters, dig into the |
| // actual parameter pattern. |
| parameterList = getParameterList(declRef.getDecl()); |
| if (!parameterList) |
| break; |
| |
| impliesFullPattern = true; |
| path = path.slice(1); |
| continue; |
| |
| case ConstraintLocator::ApplyArgToParam: { |
| if (!parameterList) break; |
| |
| unsigned index = path[0].getValue2(); |
| if (index < parameterList->size()) { |
| auto param = parameterList->get(index); |
| return ResolvedLocator(ResolvedLocator::ForVar, param); |
| } |
| break; |
| } |
| |
| default: |
| break; |
| } |
| |
| break; |
| } |
| |
| // Otherwise, do the best we can with the declaration we found. |
| if (isa<FuncDecl>(declRef.getDecl())) |
| return ResolvedLocator(ResolvedLocator::ForFunction, declRef); |
| if (isa<ConstructorDecl>(declRef.getDecl())) |
| return ResolvedLocator(ResolvedLocator::ForConstructor, declRef); |
| |
| // FIXME: Deal with the other interesting cases here, e.g., |
| // subscript declarations. |
| return ResolvedLocator(); |
| } |
| |
| /// Emit a note referring to the target of a diagnostic, e.g., the function |
| /// or parameter being used. |
| static void noteTargetOfDiagnostic(ConstraintSystem &cs, |
| const Failure *failure, |
| ConstraintLocator *targetLocator) { |
| // If there's no anchor, there's nothing we can do. |
| if (!targetLocator->getAnchor()) |
| return; |
| |
| // Try to resolve the locator to a particular declaration. |
| auto resolved |
| = resolveLocatorToDecl(cs, targetLocator, |
| [&](ConstraintLocator *locator) -> Optional<SelectedOverload> { |
| if (!failure) return None; |
| for (auto resolved = failure->getResolvedOverloadSets(); |
| resolved; resolved = resolved->Previous) { |
| if (resolved->Locator == locator) |
| return SelectedOverload{resolved->Choice, |
| resolved->OpenedFullType, |
| // FIXME: opened type? |
| Type()}; |
| } |
| |
| return None; |
| }, |
| [&](ValueDecl *decl, |
| Type openedType) -> ConcreteDeclRef { |
| return decl; |
| }); |
| |
| // We couldn't resolve the locator to a declaration, so we're done. |
| if (!resolved) |
| return; |
| |
| switch (resolved.getKind()) { |
| case ResolvedLocatorKind::Unresolved: |
| // Can't emit any diagnostic here. |
| return; |
| |
| case ResolvedLocatorKind::Function: { |
| auto name = resolved.getDecl().getDecl()->getName(); |
| cs.getTypeChecker().diagnose(resolved.getDecl().getDecl(), |
| name.isOperator()? diag::note_call_to_operator |
| : diag::note_call_to_func, |
| resolved.getDecl().getDecl()->getName()); |
| return; |
| } |
| |
| case ResolvedLocatorKind::Constructor: |
| // FIXME: Specialize for implicitly-generated constructors. |
| cs.getTypeChecker().diagnose(resolved.getDecl().getDecl(), |
| diag::note_call_to_initializer); |
| return; |
| |
| case ResolvedLocatorKind::Parameter: |
| cs.getTypeChecker().diagnose(resolved.getDecl().getDecl(), |
| diag::note_init_parameter, |
| resolved.getDecl().getDecl()->getName()); |
| return; |
| } |
| } |
| |
| /// \brief Emit a diagnostic for the given failure. |
| /// |
| /// \param cs The constraint system in which the diagnostic was generated. |
| /// \param failure The failure to emit. |
| /// \param expr The expression associated with the failure. |
| /// \param useExprLoc If the failure lacks a location, use the one associated |
| /// with expr. |
| /// |
| /// \returns true if the diagnostic was emitted successfully. |
| static bool diagnoseFailure(ConstraintSystem &cs, Failure &failure, |
| Expr *expr, bool useExprLoc) { |
| ConstraintLocator *cloc; |
| if (!failure.getLocator() || !failure.getLocator()->getAnchor()) { |
| if (useExprLoc) |
| cloc = cs.getConstraintLocator(expr); |
| else |
| return false; |
| } else { |
| cloc = failure.getLocator(); |
| } |
| |
| SourceRange range; |
| |
| ConstraintLocator *targetLocator; |
| auto locator = simplifyLocator(cs, cloc, range, &targetLocator); |
| auto &tc = cs.getTypeChecker(); |
| |
| auto anchor = locator->getAnchor(); |
| auto loc = anchor->getLoc(); |
| switch (failure.getKind()) { |
| case Failure::IsNotBridgedToObjectiveC: |
| tc.diagnose(loc, diag::type_not_bridged, failure.getFirstType()); |
| if (targetLocator) |
| noteTargetOfDiagnostic(cs, &failure, targetLocator); |
| break; |
| |
| case Failure::IsForbiddenLValue: |
| // FIXME: Probably better handled by InOutExpr later. |
| if (auto iotTy = failure.getSecondType()->getAs<InOutType>()) { |
| tc.diagnose(loc, diag::reference_non_inout, iotTy->getObjectType()) |
| .highlight(range); |
| return true; |
| } |
| // FIXME: diagnose other cases |
| return false; |
| |
| case Failure::NoPublicInitializers: { |
| tc.diagnose(loc, diag::no_accessible_initializers, failure.getFirstType()) |
| .highlight(range); |
| if (targetLocator && !useExprLoc) |
| noteTargetOfDiagnostic(cs, &failure, targetLocator); |
| break; |
| } |
| |
| case Failure::IsNotMaterializable: { |
| tc.diagnose(loc, diag::cannot_bind_generic_parameter_to_type, |
| failure.getFirstType()) |
| .highlight(range); |
| if (!useExprLoc) |
| noteTargetOfDiagnostic(cs, &failure, locator); |
| break; |
| } |
| } |
| |
| return true; |
| } |
| |
| /// \brief Determine the number of distinct overload choices in the |
| /// provided set. |
| static unsigned countDistinctOverloads(ArrayRef<OverloadChoice> choices) { |
| llvm::SmallPtrSet<void *, 4> uniqueChoices; |
| unsigned result = 0; |
| for (auto choice : choices) { |
| if (uniqueChoices.insert(choice.getOpaqueChoiceSimple()).second) |
| ++result; |
| } |
| return result; |
| } |
| |
| /// \brief Determine the name of the overload in a set of overload choices. |
| static DeclName getOverloadChoiceName(ArrayRef<OverloadChoice> choices) { |
| for (auto choice : choices) { |
| if (choice.isDecl()) |
| return choice.getDecl()->getFullName(); |
| } |
| |
| return DeclName(); |
| } |
| |
| static bool diagnoseAmbiguity(ConstraintSystem &cs, |
| ArrayRef<Solution> solutions, |
| Expr *expr) { |
| // Produce a diff of the solutions. |
| SolutionDiff diff(solutions); |
| |
| // Find the locators which have the largest numbers of distinct overloads. |
| Optional<unsigned> bestOverload; |
| unsigned maxDistinctOverloads = 0; |
| unsigned maxDepth = 0; |
| unsigned minIndex = std::numeric_limits<unsigned>::max(); |
| |
| // Get a map of expressions to their depths and post-order traversal indices. |
| // Heuristically, all other things being equal, we should complain about the |
| // ambiguous expression that (1) has the most overloads, (2) is deepest, or |
| // (3) comes earliest in the expression. |
| auto depthMap = expr->getDepthMap(); |
| auto indexMap = expr->getPreorderIndexMap(); |
| |
| for (unsigned i = 0, n = diff.overloads.size(); i != n; ++i) { |
| auto &overload = diff.overloads[i]; |
| |
| // If we can't resolve the locator to an anchor expression with no path, |
| // we can't diagnose this well. |
| auto *anchor = simplifyLocatorToAnchor(cs, overload.locator); |
| if (!anchor) |
| continue; |
| auto it = indexMap.find(anchor); |
| if (it == indexMap.end()) |
| continue; |
| unsigned index = it->second; |
| it = depthMap.find(anchor); |
| if (it == depthMap.end()) |
| continue; |
| unsigned depth = it->second; |
| |
| // If we don't have a name to hang on to, it'll be hard to diagnose this |
| // overload. |
| if (!getOverloadChoiceName(overload.choices)) |
| continue; |
| |
| unsigned distinctOverloads = countDistinctOverloads(overload.choices); |
| |
| // We need at least two overloads to make this interesting. |
| if (distinctOverloads < 2) |
| continue; |
| |
| // If we have more distinct overload choices for this locator than for |
| // prior locators, just keep this locator. |
| |
| bool better = false; |
| if (bestOverload) { |
| if (distinctOverloads > maxDistinctOverloads) { |
| better = true; |
| } else if (distinctOverloads == maxDistinctOverloads) { |
| if (depth > maxDepth) { |
| better = true; |
| } else if (depth == maxDepth) { |
| if (index < minIndex) { |
| better = true; |
| } |
| } |
| } |
| } |
| |
| if (!bestOverload || better) { |
| bestOverload = i; |
| maxDistinctOverloads = distinctOverloads; |
| maxDepth = depth; |
| minIndex = index; |
| continue; |
| } |
| |
| // We have better results. Ignore this one. |
| } |
| |
| // FIXME: Should be able to pick the best locator, e.g., based on some |
| // depth-first numbering of expressions. |
| if (bestOverload) { |
| auto &overload = diff.overloads[*bestOverload]; |
| auto name = getOverloadChoiceName(overload.choices); |
| auto anchor = simplifyLocatorToAnchor(cs, overload.locator); |
| |
| // Emit the ambiguity diagnostic. |
| auto &tc = cs.getTypeChecker(); |
| tc.diagnose(anchor->getLoc(), |
| name.isOperator() ? diag::ambiguous_operator_ref |
| : diag::ambiguous_decl_ref, |
| name); |
| |
| // Emit candidates. Use a SmallPtrSet to make sure only emit a particular |
| // candidate once. FIXME: Why is one candidate getting into the overload |
| // set multiple times? |
| SmallPtrSet<Decl*, 8> EmittedDecls; |
| for (auto choice : overload.choices) { |
| switch (choice.getKind()) { |
| case OverloadChoiceKind::Decl: |
| case OverloadChoiceKind::DeclViaDynamic: |
| case OverloadChoiceKind::TypeDecl: |
| case OverloadChoiceKind::DeclViaBridge: |
| case OverloadChoiceKind::DeclViaUnwrappedOptional: |
| // FIXME: show deduced types, etc, etc. |
| if (EmittedDecls.insert(choice.getDecl()).second) |
| tc.diagnose(choice.getDecl(), diag::found_candidate); |
| break; |
| |
| case OverloadChoiceKind::BaseType: |
| case OverloadChoiceKind::TupleIndex: |
| // FIXME: Actually diagnose something here. |
| break; |
| } |
| } |
| |
| return true; |
| } |
| |
| // FIXME: If we inferred different types for literals (for example), |
| // could diagnose ambiguity that way as well. |
| |
| return false; |
| } |
| |
| static std::string getTypeListString(Type type) { |
| // Assemble the parameter type list. |
| auto tupleType = type->getAs<TupleType>(); |
| if (!tupleType) { |
| if (auto PT = dyn_cast<ParenType>(type.getPointer())) |
| type = PT->getUnderlyingType(); |
| |
| return "(" + type->getString() + ")"; |
| } |
| |
| std::string result = "("; |
| for (auto field : tupleType->getElements()) { |
| if (result.size() != 1) |
| result += ", "; |
| if (!field.getName().empty()) { |
| result += field.getName().str(); |
| result += ": "; |
| } |
| |
| if (!field.isVararg()) |
| result += field.getType()->getString(); |
| else { |
| result += field.getVarargBaseTy()->getString(); |
| result += "..."; |
| } |
| } |
| result += ")"; |
| return result; |
| } |
| |
| |
| /// If an UnresolvedDotExpr, SubscriptMember, etc has been resolved by the |
| /// constraint system, return the decl that it references. |
| static ValueDecl *findResolvedMemberRef(ConstraintLocator *locator, |
| ConstraintSystem &CS) { |
| auto *resolvedOverloadSets = CS.getResolvedOverloadSets(); |
| if (!resolvedOverloadSets) return nullptr; |
| |
| // Search through the resolvedOverloadSets to see if we have a resolution for |
| // this member. This is an O(n) search, but only happens when producing an |
| // error diagnostic. |
| for (auto resolved = resolvedOverloadSets; |
| resolved; resolved = resolved->Previous) { |
| if (resolved->Locator != locator) continue; |
| |
| // We only handle the simplest decl binding. |
| if (resolved->Choice.getKind() != OverloadChoiceKind::Decl) |
| return nullptr; |
| return resolved->Choice.getDecl(); |
| } |
| |
| return nullptr; |
| } |
| |
| |
| /// Given an expression that has a non-lvalue type, dig into it until we find |
| /// the part of the expression that prevents the entire subexpression from being |
| /// mutable. For example, in a sequence like "x.v.v = 42" we want to complain |
| /// about "x" being a let property if "v.v" are both mutable. |
| /// |
| /// This returns the base subexpression that looks immutable (or that can't be |
| /// analyzed any further) along with a decl extracted from it if we could. |
| /// |
| static std::pair<Expr*, ValueDecl*> |
| resolveImmutableBase(Expr *expr, ConstraintSystem &CS) { |
| 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>(findResolvedMemberRef(loc, CS)); |
| } |
| |
| // If it isn't settable, return it. |
| if (member) { |
| if (!member->isSettable() || |
| !member->isSetterAccessibleFrom(CS.DC)) |
| return { expr, member }; |
| } |
| |
| // If it is settable, then the base must be the problem, recurse. |
| return resolveImmutableBase(SE->getBase(), CS); |
| } |
| |
| // 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 = dyn_cast_or_null<VarDecl>(findResolvedMemberRef(loc, CS)); |
| |
| // If the member isn't settable, then it is the problem: return it. |
| if (member) { |
| if (!member->isSettable(nullptr) || |
| !member->isSetterAccessibleFrom(CS.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(), CS); |
| } |
| |
| 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(CS.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(), CS); |
| } |
| |
| 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(), CS); |
| |
| // Look through x? |
| if (auto *BOE = dyn_cast<BindOptionalExpr>(expr)) |
| return resolveImmutableBase(BOE->getSubExpr(), CS); |
| |
| return { expr, nullptr }; |
| } |
| |
| static void diagnoseSubElementFailure(Expr *destExpr, |
| SourceLoc loc, |
| ConstraintSystem &CS, |
| Diag<StringRef> diagID, |
| Diag<Type> unknownDiagID) { |
| auto &TC = CS.getTypeChecker(); |
| |
| // 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, CS); |
| |
| // 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 += "'"; |
| |
| if (VD->isImplicit()) |
| message += " is immutable"; |
| else if (VD->isLet()) |
| message += " is a 'let' constant"; |
| else if (!VD->isSettable(CS.DC)) |
| message += " is a get-only property"; |
| else if (!VD->isSetterAccessibleFrom(CS.DC)) |
| message += " setter is inaccessible"; |
| else { |
| message += " is immutable"; |
| } |
| TC.diagnose(loc, diagID, message) |
| .highlight(immInfo.first->getSourceRange()); |
| |
| // If this is a simple variable marked with a 'let', emit a note to fixit |
| // hint it to 'var'. |
| VD->emitLetToVarNoteIfSimple(CS.DC); |
| return; |
| } |
| |
| // 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(CS.DC)) |
| message = "subscript setter is inaccessible"; |
| else |
| message = "subscript is immutable"; |
| |
| TC.diagnose(loc, diagID, message) |
| .highlight(immInfo.first->getSourceRange()); |
| return; |
| } |
| |
| // 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)) { |
| 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()->getName().str().str() + "'"; |
| |
| TC.diagnose(loc, diagID, name + " returns immutable value") |
| .highlight(AE->getSourceRange()); |
| return; |
| } |
| |
| if (auto *ICE = dyn_cast<ImplicitConversionExpr>(immInfo.first)) |
| if (isa<LoadExpr>(ICE->getSubExpr())) { |
| TC.diagnose(loc, diagID, "implicit conversion from '" + |
| ICE->getSubExpr()->getType()->getString() + "' to '" + |
| ICE->getType()->getString() + "' requires a temporary") |
| .highlight(ICE->getSourceRange()); |
| return; |
| } |
| |
| |
| TC.diagnose(loc, unknownDiagID, destExpr->getType()) |
| .highlight(immInfo.first->getSourceRange()); |
| } |
| |
| namespace { |
| /// Each match in an ApplyExpr is evaluated for how close of a match it is. |
| /// The result is captured in this enum value, where the earlier entries are |
| /// most specific. |
| enum CandidateCloseness { |
| CC_ExactMatch, ///< This is a perfect match for the arguments. |
| CC_Unavailable, ///< Marked unavailable with @available. |
| CC_NonLValueInOut, ///< First arg is inout but no lvalue present. |
| CC_SelfMismatch, ///< Self argument mismatches. |
| CC_OneArgumentNearMismatch, ///< All arguments except one match, near miss. |
| CC_OneArgumentMismatch, ///< All arguments except one match. |
| CC_ArgumentNearMismatch, ///< Argument list mismatch, near miss. |
| CC_ArgumentMismatch, ///< Argument list mismatch. |
| CC_ArgumentLabelMismatch, ///< Argument label mismatch. |
| CC_ArgumentCountMismatch, ///< This candidate has wrong # arguments. |
| CC_GeneralMismatch ///< Something else is wrong. |
| }; |
| |
| /// This is a candidate for a callee, along with an uncurry level. |
| /// |
| /// The uncurry level specifies how far much of a curried value has already |
| /// been applied. For example, in a funcdecl of: |
| /// func f(a:Int)(b:Double) -> Int |
| /// Uncurry level of 0 indicates that we're looking at the "a" argument, an |
| /// uncurry level of 1 indicates that we're looking at the "b" argument. |
| /// |
| /// The declType specifies a specific type to use for this decl that may be |
| /// more resolved than the decls type. For example, it may have generic |
| /// arguments substituted in. |
| struct UncurriedCandidate { |
| ValueDecl *decl; |
| unsigned level; |
| Type declType; |
| |
| UncurriedCandidate(ValueDecl *decl, unsigned level) |
| : decl(decl), level(level), declType(decl->getType()) { |
| } |
| |
| AnyFunctionType *getUncurriedFunctionType() const { |
| // Start with the known type of the decl. |
| auto type = declType; |
| |
| // If this is an operator func decl in a type context, the 'self' isn't |
| // actually going to be applied. |
| if (auto *fd = dyn_cast<FuncDecl>(decl)) |
| if (fd->isOperator() && fd->getDeclContext()->isTypeContext()) { |
| if (type->is<ErrorType>()) |
| return nullptr; |
| type = type->castTo<AnyFunctionType>()->getResult(); |
| } |
| |
| for (unsigned i = 0, e = level; i != e; ++i) { |
| auto funcTy = type->getAs<AnyFunctionType>(); |
| if (!funcTy) return nullptr; |
| type = funcTy->getResult(); |
| } |
| |
| return type->getAs<AnyFunctionType>(); |
| } |
| |
| /// Given a function candidate with an uncurry level, return the parameter |
| /// type at the specified uncurry level. If there is an error getting to |
| /// the specified input, this returns a null Type. |
| Type getArgumentType() const { |
| if (auto *funcTy = getUncurriedFunctionType()) |
| return funcTy->getInput(); |
| return Type(); |
| } |
| |
| /// Given a function candidate with an uncurry level, return the parameter |
| /// type at the specified uncurry level. If there is an error getting to |
| /// the specified input, this returns a null Type. |
| Type getResultType() const { |
| if (auto *funcTy = getUncurriedFunctionType()) |
| return funcTy->getResult(); |
| return Type(); |
| } |
| |
| void dump() const { |
| decl->dumpRef(llvm::errs()); |
| llvm::errs() << " - uncurry level " << level; |
| |
| if (auto FT = getUncurriedFunctionType()) |
| llvm::errs() << " - type: " << Type(FT) << "\n"; |
| else |
| llvm::errs() << " - type <<NONFUNCTION>>: " << decl->getType() << "\n"; |
| } |
| }; |
| |
| |
| /// This struct represents an analyzed function pointer to determine the |
| /// candidates that could be called, or the one concrete decl that will be |
| /// called if not ambiguous. |
| class CalleeCandidateInfo { |
| ConstraintSystem *CS; |
| public: |
| /// This is the name of the callee as extracted from the call expression. |
| /// This can be empty in cases like calls to closure exprs. |
| std::string declName; |
| |
| /// True if the call site for this callee syntactically has a trailing |
| /// closure specified. |
| bool hasTrailingClosure; |
| |
| /// This is the list of candidates identified. |
| SmallVector<UncurriedCandidate, 4> candidates; |
| |
| /// This tracks how close the candidates are, after filtering. |
| CandidateCloseness closeness = CC_GeneralMismatch; |
| |
| /// When we have a candidate that differs by a single argument mismatch, we |
| /// keep track of which argument passed to the call is failed, and what the |
| /// expected type is. If the candidate set disagrees, or if there is more |
| /// than a single argument mismatch, then this is "{ -1, Type() }". |
| struct FailedArgumentInfo { |
| int argumentNumber = -1; ///< Arg # at the call site. |
| Type parameterType = Type(); ///< Expected type at the decl site. |
| |
| bool isValid() const { return argumentNumber != -1; } |
| |
| bool operator!=(const FailedArgumentInfo &other) { |
| if (argumentNumber != other.argumentNumber) return true; |
| // parameterType can be null, and isEqual doesn't handle this. |
| if (!parameterType || !other.parameterType) |
| return parameterType.getPointer() != other.parameterType.getPointer(); |
| return !parameterType->isEqual(other.parameterType); |
| } |
| }; |
| FailedArgumentInfo failedArgument = FailedArgumentInfo(); |
| |
| /// Analyze a function expr and break it into a candidate set. On failure, |
| /// this leaves the candidate list empty. |
| CalleeCandidateInfo(Expr *Fn, bool hasTrailingClosure, |
| ConstraintSystem *CS) |
| : CS(CS), hasTrailingClosure(hasTrailingClosure) { |
| collectCalleeCandidates(Fn); |
| } |
| |
| CalleeCandidateInfo(Type baseType, ArrayRef<OverloadChoice> candidates, |
| unsigned UncurryLevel, bool hasTrailingClosure, |
| ConstraintSystem *CS); |
| |
| typedef std::pair<CandidateCloseness, FailedArgumentInfo> ClosenessResultTy; |
| typedef const std::function<ClosenessResultTy(UncurriedCandidate)> |
| &ClosenessPredicate; |
| |
| /// After the candidate list is formed, it can be filtered down to discard |
| /// obviously mismatching candidates and compute a "closeness" for the |
| /// resultant set. |
| void filterList(ArrayRef<CallArgParam> actualArgs); |
| void filterList(Type actualArgsType) { |
| return filterList(decomposeArgParamType(actualArgsType)); |
| } |
| void filterList(ClosenessPredicate predicate); |
| void filterContextualMemberList(Expr *argExpr); |
| |
| bool empty() const { return candidates.empty(); } |
| unsigned size() const { return candidates.size(); } |
| UncurriedCandidate operator[](unsigned i) const { |
| return candidates[i]; |
| } |
| |
| /// Given a set of parameter lists from an overload group, and a list of |
| /// arguments, emit a diagnostic indicating any partially matching |
| /// overloads. |
| void suggestPotentialOverloads(SourceLoc loc, bool isResult = false); |
| |
| /// If the candidate set has been narrowed down to a specific structural |
| /// problem, e.g. that there are too few parameters specified or that |
| /// argument labels don't match up, diagnose that error and return true. |
| bool diagnoseAnyStructuralArgumentError(Expr *fnExpr, Expr *argExpr); |
| |
| void dump() const LLVM_ATTRIBUTE_USED; |
| |
| private: |
| void collectCalleeCandidates(Expr *fnExpr); |
| }; |
| } |
| |
| void CalleeCandidateInfo::dump() const { |
| llvm::errs() << "CalleeCandidateInfo for '" << declName << "': closeness=" |
| << unsigned(closeness) << "\n"; |
| llvm::errs() << candidates.size() << " candidates:\n"; |
| for (auto c : candidates) { |
| llvm::errs() << " "; |
| c.dump(); |
| } |
| } |
| |
| |
| /// Given a candidate list, this computes the narrowest closeness to the match |
| /// we're looking for and filters out any worse matches. The predicate |
| /// indicates how close a given candidate is to the desired match. |
| void CalleeCandidateInfo::filterList(ClosenessPredicate predicate) { |
| closeness = CC_GeneralMismatch; |
| |
| // If we couldn't find anything, give up. |
| if (candidates.empty()) |
| return; |
| |
| // Now that we have the candidate list, figure out what the best matches from |
| // the candidate list are, and remove all the ones that aren't at that level. |
| SmallVector<ClosenessResultTy, 4> closenessList; |
| closenessList.reserve(candidates.size()); |
| for (auto decl : candidates) { |
| auto declCloseness = predicate(decl); |
| |
| // If this candidate otherwise matched but was marked unavailable, then |
| // treat it as unavailable, which is a very close failure. |
| if (declCloseness.first == CC_ExactMatch && |
| decl.decl->getAttrs().isUnavailable(CS->getASTContext()) && |
| !CS->TC.getLangOpts().DisableAvailabilityChecking) |
| declCloseness.first = CC_Unavailable; |
| |
| closenessList.push_back(declCloseness); |
| closeness = std::min(closeness, closenessList.back().first); |
| } |
| |
| // Now that we know the minimum closeness, remove all the elements that aren't |
| // as close. Keep track of argument failure information if the entire |
| // matching candidate set agrees. |
| unsigned NextElt = 0; |
| for (unsigned i = 0, e = candidates.size(); i != e; ++i) { |
| // If this decl in the result list isn't a close match, ignore it. |
| if (closeness != closenessList[i].first) |
| continue; |
| |
| // Otherwise, preserve it. |
| candidates[NextElt++] = candidates[i]; |
| |
| if (NextElt == 1) |
| failedArgument = closenessList[i].second; |
| else if (failedArgument != closenessList[i].second) |
| failedArgument = FailedArgumentInfo(); |
| } |
| |
| candidates.erase(candidates.begin()+NextElt, candidates.end()); |
| } |
| |
| |
| |
| /// Given an incompatible argument being passed to a parameter, decide whether |
| /// it is a "near" miss or not. We consider something to be a near miss if it |
| /// is due to a common sort of problem (e.g. function type passed to wrong |
| /// function type, or T? passed to something expecting T) where a far miss is a |
| /// completely incompatible type (Int where Float is expected). The notion of a |
| /// near miss is used to refine overload sets to a smaller candidate set that is |
| /// the most relevant options. |
| static bool argumentMismatchIsNearMiss(Type argType, Type paramType) { |
| // If T? was passed to something expecting T, then it is a near miss. |
| if (auto argOptType = argType->getOptionalObjectType()) |
| if (argOptType->isEqual(paramType)) |
| return true; |
| |
| // If these are both function types, then they are near misses. We consider |
| // incompatible function types to be near so that functions and non-function |
| // types are considered far. |
| if (argType->is<AnyFunctionType>() && paramType->is<AnyFunctionType>()) |
| return true; |
| |
| // Otherwise, this is some other sort of incompatibility. |
| return false; |
| } |
| |
| /// Determine how close an argument list is to an already decomposed argument |
| /// list. If the closeness is a miss by a single argument, then this returns |
| /// information about that failure. |
| static std::pair<CandidateCloseness, CalleeCandidateInfo::FailedArgumentInfo> |
| evaluateCloseness(Type candArgListType, ArrayRef<CallArgParam> actualArgs, |
| bool argsHaveTrailingClosure) { |
| auto candArgs = decomposeArgParamType(candArgListType); |
| |
| struct OurListener : public MatchCallArgumentListener { |
| CandidateCloseness result = CC_ExactMatch; |
| public: |
| CandidateCloseness getResult() const { |
| return result; |
| } |
| void extraArgument(unsigned argIdx) override { |
| result = CC_ArgumentCountMismatch; |
| } |
| void missingArgument(unsigned paramIdx) override { |
| result = CC_ArgumentCountMismatch; |
| } |
| void outOfOrderArgument(unsigned argIdx, unsigned prevArgIdx) override { |
| result = CC_ArgumentLabelMismatch; |
| } |
| bool relabelArguments(ArrayRef<Identifier> newNames) override { |
| result = CC_ArgumentLabelMismatch; |
| return true; |
| } |
| } listener; |
| |
| // Use matchCallArguments to determine how close the argument list is (in |
| // shape) to the specified candidates parameters. This ignores the concrete |
| // types of the arguments, looking only at the argument labels etc. |
| SmallVector<ParamBinding, 4> paramBindings; |
| if (matchCallArguments(actualArgs, candArgs, argsHaveTrailingClosure, |
| /*allowFixes:*/ true, |
| listener, paramBindings)) |
| // On error, get our closeness from whatever problem the listener saw. |
| return { listener.getResult(), {}}; |
| |
| // If we found a mapping, check to see if the matched up arguments agree in |
| // their type and count the number of mismatched arguments. |
| unsigned mismatchingArgs = 0; |
| |
| // We classify an argument mismatch as being a "near" miss if it is a very |
| // likely match due to a common sort of problem (e.g. wrong flags on a |
| // function type, optional where none was expected, etc). This allows us to |
| // heuristically filter large overload sets better. |
| bool mismatchesAreNearMisses = true; |
| |
| CalleeCandidateInfo::FailedArgumentInfo failureInfo; |
| |
| for (unsigned i = 0, e = paramBindings.size(); i != e; ++i) { |
| // Bindings specify the arguments that source the parameter. The only case |
| // this returns a non-singular value is when there are varargs in play. |
| auto &bindings = paramBindings[i]; |
| auto paramType = candArgs[i].Ty; |
| |
| for (auto argNo : bindings) { |
| auto argType = actualArgs[argNo].Ty; |
| |
| // If the argument has an unresolved type, then we're not actually |
| // matching against it. |
| if (argType->getRValueType()->is<UnresolvedType>()) |
| continue; |
| |
| // FIXME: Right now, a "matching" overload is one with a parameter whose |
| // type is identical to one of the argument types. We can obviously do |
| // something more sophisticated with this. |
| // FIXME: Definitely need to handle archetypes for same-type constraints. |
| // FIXME: Use TC.isConvertibleTo? |
| if (argType->getRValueType()->isEqual(paramType)) |
| continue; |
| |
| ++mismatchingArgs; |
| |
| // Keep track of whether this argument was a near miss or not. |
| mismatchesAreNearMisses &= argumentMismatchIsNearMiss(argType, paramType); |
| |
| failureInfo.argumentNumber = argNo; |
| failureInfo.parameterType = paramType; |
| } |
| } |
| |
| if (mismatchingArgs == 0) |
| return { CC_ExactMatch, {}}; |
| |
| // Check to see if the first argument expects an inout argument, but is not |
| // an lvalue. |
| if (candArgs[0].Ty->is<InOutType>() && !actualArgs[0].Ty->isLValueType()) |
| return { CC_NonLValueInOut, {}}; |
| |
| // If we have exactly one argument mismatching, classify it specially, so that |
| // close matches are prioritized against obviously wrong ones. |
| if (mismatchingArgs == 1) { |
| auto closeness = mismatchesAreNearMisses ? CC_OneArgumentNearMismatch |
| : CC_OneArgumentMismatch; |
| // Return information about the single failing argument. |
| return { closeness, failureInfo }; |
| } |
| |
| auto closeness = mismatchesAreNearMisses ? CC_ArgumentNearMismatch |
| : CC_ArgumentMismatch; |
| return { closeness, {}}; |
| } |
| |
| void CalleeCandidateInfo::collectCalleeCandidates(Expr *fn) { |
| fn = fn->getValueProvidingExpr(); |
| |
| // Treat a call to a load of a variable as a call to that variable, it is just |
| // the lvalue'ness being removed. |
| if (auto load = dyn_cast<LoadExpr>(fn)) { |
| if (isa<DeclRefExpr>(load->getSubExpr())) |
| return collectCalleeCandidates(load->getSubExpr()); |
| } |
| |
| if (auto declRefExpr = dyn_cast<DeclRefExpr>(fn)) { |
| candidates.push_back({ declRefExpr->getDecl(), 0 }); |
| declName = declRefExpr->getDecl()->getNameStr().str(); |
| return; |
| } |
| |
| if (auto declRefExpr = dyn_cast<OtherConstructorDeclRefExpr>(fn)) { |
| auto decl = declRefExpr->getDecl(); |
| candidates.push_back({ decl, 0 }); |
| |
| if (auto fTy = decl->getType()->getAs<AnyFunctionType>()) |
| declName = fTy->getInput()->getRValueInstanceType()->getString()+".init"; |
| else |
| declName = "init"; |
| return; |
| } |
| |
| if (auto overloadedDRE = dyn_cast<OverloadedDeclRefExpr>(fn)) { |
| for (auto cand : overloadedDRE->getDecls()) { |
| candidates.push_back({ cand, 0 }); |
| } |
| |
| if (!candidates.empty()) |
| declName = candidates[0].decl->getNameStr().str(); |
| return; |
| } |
| |
| if (auto TE = dyn_cast<TypeExpr>(fn)) { |
| // It's always a metatype type, so use the instance type name. |
| auto instanceType =TE->getType()->castTo<MetatypeType>()->getInstanceType(); |
| |
| // TODO: figure out right value for isKnownPrivate |
| if (!instanceType->getAs<TupleType>()) { |
| auto ctors = CS->TC.lookupConstructors(CS->DC, instanceType); |
| for (auto ctor : ctors) |
| if (ctor->hasType()) |
| candidates.push_back({ ctor, 1 }); |
| } |
| |
| declName = instanceType->getString(); |
| return; |
| } |
| |
| if (auto *DSBI = dyn_cast<DotSyntaxBaseIgnoredExpr>(fn)) { |
| collectCalleeCandidates(DSBI->getRHS()); |
| return; |
| } |
| |
| if (auto AE = dyn_cast<ApplyExpr>(fn)) { |
| collectCalleeCandidates(AE->getFn()); |
| |
| // If this is a DotSyntaxCallExpr, then the callee is a method, and the |
| // argument list of this apply is the base being applied to the method. |
| // If we have a type for that, capture it so that we can calculate a |
| // substituted type, which resolves many generic arguments. |
| Type baseType; |
| if (isa<SelfApplyExpr>(AE) && |
| !isUnresolvedOrTypeVarType(AE->getArg()->getType())) |
| baseType = AE->getArg()->getType()->getLValueOrInOutObjectType(); |
| |
| // If we found a candidate list with a recursive walk, try adjust the curry |
| // level for the applied subexpression in this call. |
| if (!candidates.empty()) { |
| for (auto &C : candidates) { |
| C.level += 1; |
| |
| // Compute a new substituted type if we have a base type to apply. |
| if (baseType && C.level == 1) |
| C.declType = baseType->getTypeOfMember(CS->DC->getParentModule(), |
| C.decl, nullptr); |
| } |
| |
| return; |
| } |
| } |
| |
| if (auto *OVE = dyn_cast<OpenExistentialExpr>(fn)) { |
| collectCalleeCandidates(OVE->getSubExpr()); |
| return; |
| } |
| |
| if (auto *CFCE = dyn_cast<CovariantFunctionConversionExpr>(fn)) { |
| collectCalleeCandidates(CFCE->getSubExpr()); |
| return; |
| } |
| |
| |
| // Otherwise, we couldn't tell structurally what is going on here, so try to |
| // dig something out of the constraint system. |
| unsigned uncurryLevel = 0; |
| |
| // The candidate list of an unresolved_dot_expr is the candidate list of the |
| // base uncurried by one level, and we refer to the name of the member, not to |
| // the name of any base. |
| if (auto UDE = dyn_cast<UnresolvedDotExpr>(fn)) { |
| declName = UDE->getName().str().str(); |
| uncurryLevel = 1; |
| |
| // If we actually resolved the member to use, return it. |
| auto loc = CS->getConstraintLocator(UDE, ConstraintLocator::Member); |
| if (auto *member = findResolvedMemberRef(loc, *CS)) { |
| candidates.push_back({ member, uncurryLevel }); |
| return; |
| } |
| // Otherwise, look for a disjunction constraint explaining what the set is. |
| } |
| |
| // Calls to super.init() are automatically uncurried one level. |
| if (auto *UCE = dyn_cast<UnresolvedConstructorExpr>(fn)) { |
| uncurryLevel = 1; |
| |
| auto selfTy = UCE->getSubExpr()->getType()->getLValueOrInOutObjectType(); |
| if (selfTy->hasTypeVariable()) |
| declName = "init"; |
| else |
| declName = selfTy.getString() + ".init"; |
| } |
| |
| if (isa<MemberRefExpr>(fn)) |
| uncurryLevel = 1; |
| |
| // Scan to see if we have a disjunction constraint for this callee. |
| for (auto &constraint : CS->getConstraints()) { |
| if (constraint.getKind() != ConstraintKind::Disjunction) continue; |
| |
| auto locator = constraint.getLocator(); |
| if (!locator || locator->getAnchor() != fn) continue; |
| |
| for (auto *bindOverload : constraint.getNestedConstraints()) { |
| if (bindOverload->getKind() != ConstraintKind::BindOverload) |
| continue; |
| auto c = bindOverload->getOverloadChoice(); |
| if (c.isDecl()) |
| candidates.push_back({ c.getDecl(), uncurryLevel }); |
| } |
| |
| // If we found some candidates, then we're done. |
| if (candidates.empty()) continue; |
| |
| if (declName.empty()) |
| declName = candidates[0].decl->getNameStr().str(); |
| return; |
| } |
| } |
| |
| /// After the candidate list is formed, it can be filtered down to discard |
| /// obviously mismatching candidates and compute a "closeness" for the |
| /// resultant set. |
| void CalleeCandidateInfo::filterList(ArrayRef<CallArgParam> actualArgs) { |
| // Now that we have the candidate list, figure out what the best matches from |
| // the candidate list are, and remove all the ones that aren't at that level. |
| filterList([&](UncurriedCandidate candidate) -> ClosenessResultTy { |
| auto inputType = candidate.getArgumentType(); |
| // If this isn't a function or isn't valid at this uncurry level, treat it |
| // as a general mismatch. |
| if (!inputType) return { CC_GeneralMismatch, {}}; |
| return evaluateCloseness(inputType, actualArgs, hasTrailingClosure); |
| }); |
| } |
| |
| void CalleeCandidateInfo::filterContextualMemberList(Expr *argExpr) { |
| auto URT = CS->getASTContext().TheUnresolvedType; |
| |
| // If the argument is not present then we expect members without arguments. |
| if (!argExpr) { |
| return filterList([&](UncurriedCandidate candidate) -> ClosenessResultTy { |
| auto inputType = candidate.getArgumentType(); |
| // If this candidate has no arguments, then we're a match. |
| if (!inputType) return { CC_ExactMatch, {}}; |
| |
| // Otherwise, if this is a function candidate with an argument, we |
| // mismatch argument count. |
| return { CC_ArgumentCountMismatch, {}}; |
| }); |
| } |
| |
| // Build an argument list type to filter against based on the expression we |
| // have. This really just provides us a structure to match against. |
| // Normally, an argument list is a TupleExpr or a ParenExpr, though sometimes |
| // the ParenExpr goes missing. |
| auto *argTuple = dyn_cast<TupleExpr>(argExpr); |
| if (!argTuple) { |
| // If we have a single argument, look through the paren expr. |
| if (auto *PE = dyn_cast<ParenExpr>(argExpr)) |
| argExpr = PE->getSubExpr(); |
| |
| Type argType = URT; |
| // If the argument has an & specified, then we expect an lvalue. |
| if (isa<InOutExpr>(argExpr)) |
| argType = LValueType::get(argType); |
| |
| CallArgParam param; |
| param.Ty = argType; |
| return filterList(param); |
| } |
| |
| // If we have a tuple expression, form a tuple type. |
| SmallVector<CallArgParam, 4> ArgElts; |
| for (unsigned i = 0, e = argTuple->getNumElements(); i != e; ++i) { |
| // If the argument has an & specified, then we expect an lvalue. |
| Type argType = URT; |
| if (isa<InOutExpr>(argTuple->getElement(i))) |
| argType = LValueType::get(argType); |
| |
| CallArgParam param; |
| param.Ty = argType; |
| param.Label = argTuple->getElementName(i); |
| ArgElts.push_back(param); |
| } |
| |
| return filterList(ArgElts); |
| } |
| |
| CalleeCandidateInfo::CalleeCandidateInfo(Type baseType, |
| ArrayRef<OverloadChoice> overloads, |
| unsigned uncurryLevel, |
| bool hasTrailingClosure, |
| ConstraintSystem *CS) |
| : CS(CS), hasTrailingClosure(hasTrailingClosure) { |
| |
| // If we have a useful base type for the candidate set, we'll want to |
| // substitute it into each member. If not, ignore it. |
| if (isUnresolvedOrTypeVarType(baseType)) |
| baseType = Type(); |
| |
| for (auto cand : overloads) { |
| if (!cand.isDecl()) continue; |
| |
| auto decl = cand.getDecl(); |
| candidates.push_back({ decl, uncurryLevel }); |
| |
| if (baseType) { |
| auto substType = baseType->getTypeOfMember(CS->DC->getParentModule(), |
| decl, nullptr); |
| if (substType) |
| candidates.back().declType = substType; |
| } |
| } |
| |
| if (!candidates.empty()) |
| declName = candidates[0].decl->getNameStr().str(); |
| } |
| |
| |
| /// Given a set of parameter lists from an overload group, and a list of |
| /// arguments, emit a diagnostic indicating any partially matching overloads. |
| void CalleeCandidateInfo:: |
| suggestPotentialOverloads(SourceLoc loc, bool isResult) { |
| std::string suggestionText = ""; |
| std::set<std::string> dupes; |
| |
| // FIXME2: For (T,T) & (Self, Self), emit this as two candidates, one using |
| // the LHS and one using the RHS type for T's. |
| for (auto cand : candidates) { |
| Type type; |
| |
| if (auto *SD = dyn_cast<SubscriptDecl>(cand.decl)) { |
| type = isResult ? SD->getElementType() : SD->getIndicesType(); |
| } else { |
| type = isResult ? cand.getResultType() : cand.getArgumentType(); |
| } |
| |
| if (type.isNull()) |
| continue; |
| |
| // If we've already seen this (e.g. decls overridden on the result type), |
| // ignore this one. |
| auto name = isResult ? type->getString() : getTypeListString(type); |
| if (!dupes.insert(name).second) |
| continue; |
| |
| if (!suggestionText.empty()) |
| suggestionText += ", "; |
| suggestionText += name; |
| } |
| |
| if (suggestionText.empty()) |
| return; |
| |
| if (dupes.size() == 1) { |
| CS->TC.diagnose(loc, diag::suggest_expected_match, isResult, |
| suggestionText); |
| } else { |
| CS->TC.diagnose(loc, diag::suggest_partial_overloads, isResult, declName, |
| suggestionText); |
| } |
| } |
| |
| |
| /// If the candidate set has been narrowed down to a specific structural |
| /// problem, e.g. that there are too few parameters specified or that argument |
| /// labels don't match up, diagnose that error and return true. |
| bool CalleeCandidateInfo::diagnoseAnyStructuralArgumentError(Expr *fnExpr, |
| Expr *argExpr) { |
| // TODO: We only handle the situation where there is exactly one candidate |
| // here. |
| if (size() != 1) return false; |
| |
| |
| auto args = decomposeArgParamType(argExpr->getType()); |
| |
| auto argTy = candidates[0].getArgumentType(); |
| if (!argTy) return false; |
| |
| auto params = decomposeArgParamType(argTy); |
| |
| // It is a somewhat common error to try to access an instance method as a |
| // curried member on the type, instead of using an instance, e.g. the user |
| // wrote: |
| // |
| // Foo.doThing(42, b: 19) |
| // |
| // instead of: |
| // |
| // myFoo.doThing(42, b: 19) |
| // |
| // Check for this situation and handle it gracefully. |
| if (params.size() == 1 && candidates[0].decl->isInstanceMember() && |
| candidates[0].level == 0) { |
| if (auto UDE = dyn_cast<UnresolvedDotExpr>(fnExpr)) |
| if (isa<TypeExpr>(UDE->getBase())) { |
| auto baseType = candidates[0].getArgumentType(); |
| CS->TC.diagnose(UDE->getLoc(), diag::instance_member_use_on_type, |
| baseType, UDE->getName()) |
| .highlight(UDE->getBase()->getSourceRange()); |
| return true; |
| } |
| } |
| |
| // We only handle structural errors here. |
| if (closeness != CC_ArgumentLabelMismatch && |
| closeness != CC_ArgumentCountMismatch) |
| return false; |
| |
| SmallVector<Identifier, 4> correctNames; |
| unsigned OOOArgIdx = ~0U, OOOPrevArgIdx = ~0U; |
| unsigned extraArgIdx = ~0U, missingParamIdx = ~0U; |
| |
| // If we have a single candidate that failed to match the argument list, |
| // attempt to use matchCallArguments to diagnose the problem. |
| struct OurListener : public MatchCallArgumentListener { |
| SmallVectorImpl<Identifier> &correctNames; |
| unsigned &OOOArgIdx, &OOOPrevArgIdx; |
| unsigned &extraArgIdx, &missingParamIdx; |
| |
| public: |
| OurListener(SmallVectorImpl<Identifier> &correctNames, |
| unsigned &OOOArgIdx, unsigned &OOOPrevArgIdx, |
| unsigned &extraArgIdx, unsigned &missingParamIdx) |
| : correctNames(correctNames), |
| OOOArgIdx(OOOArgIdx), OOOPrevArgIdx(OOOPrevArgIdx), |
| extraArgIdx(extraArgIdx), missingParamIdx(missingParamIdx) {} |
| void extraArgument(unsigned argIdx) override { |
| extraArgIdx = argIdx; |
| } |
| void missingArgument(unsigned paramIdx) override { |
| missingParamIdx = paramIdx; |
| } |
| void outOfOrderArgument(unsigned argIdx, unsigned prevArgIdx) override{ |
| OOOArgIdx = argIdx; |
| OOOPrevArgIdx = prevArgIdx; |
| } |
| bool relabelArguments(ArrayRef<Identifier> newNames) override { |
| correctNames.append(newNames.begin(), newNames.end()); |
| return true; |
| } |
| } listener(correctNames, OOOArgIdx, OOOPrevArgIdx, |
| extraArgIdx, missingParamIdx); |
| |
| // Use matchCallArguments to determine how close the argument list is (in |
| // shape) to the specified candidates parameters. This ignores the |
| // concrete types of the arguments, looking only at the argument labels. |
| SmallVector<ParamBinding, 4> paramBindings; |
| if (!matchCallArguments(args, params, hasTrailingClosure, |
| /*allowFixes:*/true, listener, paramBindings)) |
| return false; |
| |
| |
| // If we are missing a parameter, diagnose that. |
| if (missingParamIdx != ~0U) { |
| Identifier name = params[missingParamIdx].Label; |
| auto loc = argExpr->getStartLoc(); |
| if (name.empty()) |
| CS->TC.diagnose(loc, diag::missing_argument_positional, |
| missingParamIdx+1); |
| else |
| CS->TC.diagnose(loc, diag::missing_argument_named, name); |
| return true; |
| } |
| |
| if (extraArgIdx != ~0U) { |
| auto name = args[extraArgIdx].Label; |
| Expr *arg = argExpr; |
| auto tuple = dyn_cast<TupleExpr>(argExpr); |
| if (tuple) |
| arg = tuple->getElement(extraArgIdx); |
| auto loc = arg->getLoc(); |
| if (tuple && extraArgIdx == tuple->getNumElements()-1 && |
| tuple->hasTrailingClosure()) |
| CS->TC.diagnose(loc, diag::extra_trailing_closure_in_call) |
| .highlight(arg->getSourceRange()); |
| else if (params.empty()) |
| CS->TC.diagnose(loc, diag::extra_argument_to_nullary_call) |
| .highlight(argExpr->getSourceRange()); |
| else if (name.empty()) |
| CS->TC.diagnose(loc, diag::extra_argument_positional) |
| .highlight(arg->getSourceRange()); |
| else |
| CS->TC.diagnose(loc, diag::extra_argument_named, name) |
| .highlight(arg->getSourceRange()); |
| return true; |
| } |
| |
| // If this is an argument label mismatch, then diagnose that error now. |
| if (!correctNames.empty() && |
| CS->diagnoseArgumentLabelError(argExpr, correctNames, |
| /*isSubscript=*/false)) |
| return true; |
| |
| // If we have an out-of-order argument, diagnose it as such. |
| if (OOOArgIdx != ~0U && isa<TupleExpr>(argExpr)) { |
| auto tuple = cast<TupleExpr>(argExpr); |
| Identifier first = tuple->getElementName(OOOArgIdx); |
| Identifier second = tuple->getElementName(OOOPrevArgIdx); |
| |
| SourceLoc diagLoc; |
| if (!first.empty()) |
| diagLoc = tuple->getElementNameLoc(OOOArgIdx); |
| else |
| diagLoc = tuple->getElement(OOOArgIdx)->getStartLoc(); |
| |
| if (!second.empty()) { |
| CS->TC.diagnose(diagLoc, diag::argument_out_of_order, first, second) |
| .highlight(tuple->getElement(OOOArgIdx)->getSourceRange()) |
| .highlight(SourceRange(tuple->getElementNameLoc(OOOPrevArgIdx), |
| tuple->getElement(OOOPrevArgIdx)->getEndLoc())); |
| return true; |
| } |
| |
| CS->TC.diagnose(diagLoc, diag::argument_out_of_order_named_unnamed, first, |
| OOOPrevArgIdx) |
| .highlight(tuple->getElement(OOOArgIdx)->getSourceRange()) |
| .highlight(tuple->getElement(OOOPrevArgIdx)->getSourceRange()); |
| return true; |
| } |
| return false; |
| } |
| |
| |
| |
| |
| |
| /// Flags that can be used to control name lookup. |
| enum TCCFlags { |
| /// Allow the result of the subexpression to be an lvalue. If this is not |
| /// specified, any lvalue will be forced to be loaded into an rvalue. |
| TCC_AllowLValue = 0x01, |
| |
| /// Re-type-check the given subexpression even if the expression has already |
| /// been checked already. The client is asserting that infinite recursion is |
| /// not possible because it has relaxed a constraint on the system. |
| TCC_ForceRecheck = 0x02 |
| }; |
| |
| typedef OptionSet<TCCFlags> TCCOptions; |
| |
| inline TCCOptions operator|(TCCFlags flag1, TCCFlags flag2) { |
| return TCCOptions(flag1) | flag2; |
| } |
| |
| |
| namespace { |
| /// If a constraint system fails to converge on a solution for a given |
| /// expression, this class can produce a reasonable diagnostic for the failure |
| /// by analyzing the remnants of the failed constraint system. (Specifically, |
| /// left-over inactive, active and failed constraints.) |
| /// This class does not tune its diagnostics for a specific expression kind, |
| /// for that, you'll want to use an instance of the FailureDiagnosis class. |
| class FailureDiagnosis :public ASTVisitor<FailureDiagnosis, /*exprresult*/bool>{ |
| friend class ASTVisitor<FailureDiagnosis, /*exprresult*/bool>; |
| |
| Expr *expr = nullptr; |
| ConstraintSystem *const CS; |
| public: |
| FailureDiagnosis(Expr *expr, ConstraintSystem *cs) : expr(expr), CS(cs) { |
| assert(expr && CS); |
| } |
| |
| template<typename ...ArgTypes> |
| InFlightDiagnostic diagnose(ArgTypes &&...Args) { |
| return CS->TC.diagnose(std::forward<ArgTypes>(Args)...); |
| } |
| |
| /// Attempt to diagnose a failure without taking into account the specific |
| /// kind of expression that could not be type checked. |
| bool diagnoseConstraintFailure(); |
| |
| /// Unless we've already done this, retypecheck the specified child of the |
| /// current expression on its own, without including any contextual |
| /// constraints or the parent expr nodes. This is more likely to succeed than |
| /// type checking the original expression. |
| /// |
| /// This mention may only be used on immediate children of the current expr |
| /// node, because ClosureExpr parameters need to be treated specially. |
| /// |
| /// This can return a new expression (for e.g. when a UnresolvedDeclRef gets |
| /// resolved) and returns null when the subexpression fails to typecheck. |
| /// |
| Expr *typeCheckChildIndependently(Expr *subExpr, Type convertType = Type(), |
| ContextualTypePurpose convertTypePurpose = CTP_Unused, |
| TCCOptions options = TCCOptions(), |
| ExprTypeCheckListener *listener = nullptr); |
| Expr *typeCheckChildIndependently(Expr *subExpr, TCCOptions options) { |
| return typeCheckChildIndependently(subExpr, Type(), CTP_Unused, options); |
| } |
| |
| Type getTypeOfTypeCheckedChildIndependently(Expr *subExpr, |
| TCCOptions options = TCCOptions()) { |
| auto e = typeCheckChildIndependently(subExpr, options); |
| return e ? e->getType() : Type(); |
| } |
| |
| /// This is the same as typeCheckChildIndependently, but works on an arbitrary |
| /// subexpression of the current node because it handles ClosureExpr parents |
| /// of the specified node. |
| Expr *typeCheckArbitrarySubExprIndependently(Expr *subExpr, |
| TCCOptions options = TCCOptions()); |
| |
| /// Special magic to handle inout exprs and tuples in argument lists. |
| Expr *typeCheckArgumentChildIndependently(Expr *argExpr, Type argType, |
| const CalleeCandidateInfo &candidates); |
| |
| /// Attempt to diagnose a specific failure from the info we've collected from |
| /// the failed constraint system. |
| bool diagnoseExprFailure(); |
| |
| /// Emit an ambiguity diagnostic about the specified expression. |
| void diagnoseAmbiguity(Expr *E); |
| |
| /// Attempt to produce a diagnostic for a mismatch between an expression's |
| /// type and its assumed contextual type. |
| bool diagnoseContextualConversionError(); |
| |
| /// For an expression being type checked with a CTP_CalleeResult contextual |
| /// type, try to diagnose a problem. |
| bool diagnoseCalleeResultContextualConversionError(); |
| |
| private: |
| |
| /// Produce a diagnostic for a general member-lookup failure (irrespective of |
| /// the exact expression kind). |
| bool diagnoseGeneralMemberFailure(Constraint *constraint); |
| |
| /// Given a result of name lookup that had no viable results, diagnose the |
| /// unviable ones. |
| void diagnoseUnviableLookupResults(MemberLookupResult &lookupResults, |
| Type baseObjTy, Expr *baseExpr, |
| DeclName memberName, SourceLoc nameLoc, |
| SourceLoc loc); |
| |
| /// Produce a diagnostic for a general overload resolution failure |
| /// (irrespective of the exact expression kind). |
| bool diagnoseGeneralOverloadFailure(Constraint *constraint); |
| |
| /// Produce a diagnostic for a general conversion failure (irrespective of the |
| /// exact expression kind). |
| bool diagnoseGeneralConversionFailure(Constraint *constraint); |
| |
| bool visitExpr(Expr *E); |
| bool visitIdentityExpr(IdentityExpr *E); |
| bool visitTupleExpr(TupleExpr *E); |
| |
| bool visitUnresolvedMemberExpr(UnresolvedMemberExpr *E); |
| bool visitArrayExpr(ArrayExpr *E); |
| bool visitDictionaryExpr(DictionaryExpr *E); |
| bool visitObjectLiteralExpr(ObjectLiteralExpr *E); |
| |
| bool visitForceValueExpr(ForceValueExpr *FVE); |
| bool visitBindOptionalExpr(BindOptionalExpr *BOE); |
| |
| bool visitSubscriptExpr(SubscriptExpr *SE); |
| bool visitApplyExpr(ApplyExpr *AE); |
| bool visitAssignExpr(AssignExpr *AE); |
| bool visitInOutExpr(InOutExpr *IOE); |
| bool visitCoerceExpr(CoerceExpr *CE); |
| bool visitIfExpr(IfExpr *IE); |
| bool visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *E); |
| bool visitClosureExpr(ClosureExpr *CE); |
| }; |
| } // end anonymous namespace. |
| |
| |
| |
| static bool isMemberConstraint(Constraint *C) { |
| return C->getClassification() == ConstraintClassification::Member; |
| } |
| |
| static bool isOverloadConstraint(Constraint *C) { |
| if (C->getKind() == ConstraintKind::BindOverload) |
| return true; |
| |
| if (C->getKind() != ConstraintKind::Disjunction) |
| return false; |
| |
| return C->getNestedConstraints().front()->getKind() == |
| ConstraintKind::BindOverload; |
| } |
| |
| /// Return true if this constraint is a conversion or requirement between two |
| /// types. |
| static bool isConversionConstraint(const Constraint *C) { |
| return C->getClassification() == ConstraintClassification::Relational; |
| } |
| |
| /// Return true if this member constraint is a low priority for diagnostics, so |
| /// low that we would only like to issue an error message about it if there is |
| /// nothing else interesting we can scrape out of the constraint system. |
| static bool isLowPriorityConstraint(Constraint *C) { |
| // If the member constraint is a ".Generator" lookup to find the generator |
| // type in a foreach loop, or a ".Element" lookup to find its element type, |
| // then it is very low priority: We will get a better and more useful |
| // diagnostic from the failed conversion to SequenceType that will fail as |
| // well. |
| if (C->getKind() == ConstraintKind::TypeMember) { |
| if (auto *loc = C->getLocator()) |
| for (auto Elt : loc->getPath()) |
| if (Elt.getKind() == ConstraintLocator::GeneratorElementType || |
| Elt.getKind() == ConstraintLocator::SequenceGeneratorType) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /// Attempt to diagnose a failure without taking into account the specific |
| /// kind of expression that could not be type checked. |
| bool FailureDiagnosis::diagnoseConstraintFailure() { |
| // This is the priority order in which we handle constraints. Things earlier |
| // in the list are considered to have higher specificity (and thus, higher |
| // priority) than things lower in the list. |
| enum ConstraintRanking { |
| CR_MemberConstraint, |
| CR_ConversionConstraint, |
| CR_OverloadConstraint, |
| CR_OtherConstraint |
| }; |
| |
| // Start out by classifying all the constraints. |
| typedef std::pair<Constraint*, ConstraintRanking> RCElt; |
| std::vector<RCElt> rankedConstraints; |
| |
| // This is a predicate that classifies constraints according to our |
| // priorities. |
| std::function<void (Constraint*)> classifyConstraint = [&](Constraint *C) { |
| if (isLowPriorityConstraint(C)) |
| return rankedConstraints.push_back({C, CR_OtherConstraint}); |
| |
| if (isMemberConstraint(C)) |
| return rankedConstraints.push_back({C, CR_MemberConstraint}); |
| |
| if (isOverloadConstraint(C)) |
| return rankedConstraints.push_back({C, CR_OverloadConstraint}); |
| |
| if (isConversionConstraint(C)) |
| return rankedConstraints.push_back({C, CR_ConversionConstraint}); |
| |
| // We occasionally end up with disjunction constraints containing an |
| // original constraint along with one considered with a fix. If we find |
| // this situation, add the original one to our list for diagnosis. |
| if (C->getKind() == ConstraintKind::Disjunction) { |
| Constraint *Orig = nullptr; |
| bool AllOthersHaveFixes = true; |
| for (auto DC : C->getNestedConstraints()) { |
| // If this is a constraint inside of the disjunction with a fix, ignore |
| // it. |
| if (DC->getFix()) |
| continue; |
| |
| // If we already found a candidate without a fix, we can't do this. |
| if (Orig) { |
| AllOthersHaveFixes = false; |
| break; |
| } |
| |
| // Remember this as the exemplar to use. |
| Orig = DC; |
| } |
| |
| if (Orig && AllOthersHaveFixes) |
| return classifyConstraint(Orig); |
| |
| // If we got all the way down to a truly ambiguous disjunction constraint |
| // with a conversion in it, the problem could be that none of the options |
| // in the disjunction worked. |
| // |
| // We don't have a lot of great options here, so (if all else fails), |
| // we'll attempt to diagnose the issue as though the first option was the |
| // problem. |
| rankedConstraints.push_back({ |
| C->getNestedConstraints()[0], |
| CR_OtherConstraint |
| }); |
| return; |
| } |
| |
| return rankedConstraints.push_back({C, CR_OtherConstraint}); |
| }; |
| |
| // Look at the failed constraint and the general constraint list. Processing |
| // the failed constraint first slightly biases it in the ranking ahead of |
| // other failed constraints at the same level. |
| if (CS->failedConstraint) |
| classifyConstraint(CS->failedConstraint); |
| for (auto &C : CS->getConstraints()) |
| classifyConstraint(&C); |
| |
| // Okay, now that we've classified all the constraints, sort them by their |
| // priority and privilege the favored constraints. |
| std::stable_sort(rankedConstraints.begin(), rankedConstraints.end(), |
| [&] (RCElt LHS, RCElt RHS) { |
| // Rank things by their kind as the highest priority. |
| if (LHS.second < RHS.second) |
| return true; |
| if (LHS.second > RHS.second) |
| return false; |
| // Next priority is favored constraints. |
| if (LHS.first->isFavored() != RHS.first->isFavored()) |
| return LHS.first->isFavored(); |
| return false; |
| }); |
| |
| // Now that we have a sorted precedence of constraints to diagnose, charge |
| // through them. |
| for (auto elt : rankedConstraints) { |
| auto C = elt.first; |
| if (isMemberConstraint(C) && diagnoseGeneralMemberFailure(C)) |
| return true; |
| |
| if (isConversionConstraint(C) && diagnoseGeneralConversionFailure(C)) |
| return true; |
| |
| if (isOverloadConstraint(C) && diagnoseGeneralOverloadFailure(C)) |
| return true; |
| |
| |
| // TODO: There can be constraints that aren't handled here! When this |
| // happens, we end up diagnosing them as ambiguities that don't make sense. |
| // This isn't as bad as it seems though, because most of these will be |
| // diagnosed by expr diagnostics. |
| } |
| |
| // Otherwise, all the constraints look ok, diagnose this as an ambiguous |
| // expression. |
| return false; |
| } |
| |
| |
| bool FailureDiagnosis::diagnoseGeneralMemberFailure(Constraint *constraint) { |
| assert(isMemberConstraint(constraint)); |
| |
| auto memberName = constraint->getMember(); |
| |
| // Get the referenced base expression from the failed constraint, along with |
| // the SourceRange for the member ref. In "x.y", this returns the expr for x |
| // and the source range for y. |
| auto anchor = expr; |
| SourceRange memberRange = anchor->getSourceRange(); |
| if (auto locator = constraint->getLocator()) { |
| locator = simplifyLocator(*CS, locator, memberRange); |
| if (locator->getAnchor()) |
| anchor = locator->getAnchor(); |
| } |
| |
| // Retypecheck the anchor type, which is the base of the member expression. |
| anchor = typeCheckArbitrarySubExprIndependently(anchor, TCC_AllowLValue); |
| if (!anchor) return true; |
| |
| auto baseTy = anchor->getType(); |
| auto baseObjTy = baseTy->getRValueType(); |
| |
| // If the base type is an IUO, look through it. Odds are, the code is not |
| // trying to find a member of it. |
| if (auto objTy = CS->lookThroughImplicitlyUnwrappedOptionalType(baseObjTy)) |
| baseTy = baseObjTy = objTy; |
| |
| |
| if (auto moduleTy = baseObjTy->getAs<ModuleType>()) { |
| diagnose(anchor->getLoc(), diag::no_member_of_module, |
| moduleTy->getModule()->getName(), memberName) |
| .highlight(anchor->getSourceRange()).highlight(memberRange); |
| return true; |
| } |
| |
| // If the base of this property access is a function that takes an empty |
| // argument list, then the most likely problem is that the user wanted to |
| // call the function, e.g. in "a.b.c" where they had to write "a.b().c". |
| // Produce a specific diagnostic + fixit for this situation. |
| if (auto baseFTy = baseObjTy->getAs<AnyFunctionType>()) { |
| if (baseFTy->getInput()->isVoid()) { |
| SourceLoc insertLoc = anchor->getEndLoc(); |
| |
| if (auto *DRE = dyn_cast<DeclRefExpr>(anchor)) { |
| diagnose(anchor->getLoc(), diag::did_not_call_function, |
| DRE->getDecl()->getName()) |
| .fixItInsertAfter(insertLoc, "()"); |
| return true; |
| } |
| |
| if (auto *DSCE = dyn_cast<DotSyntaxCallExpr>(anchor)) |
| if (auto *DRE = dyn_cast<DeclRefExpr>(DSCE->getFn())) { |
| diagnose(anchor->getLoc(), diag::did_not_call_method, |
| DRE->getDecl()->getName()) |
| .fixItInsertAfter(insertLoc, "()"); |
| return true; |
| } |
| |
| diagnose(anchor->getLoc(), diag::did_not_call_function_value) |
| .fixItInsertAfter(insertLoc, "()"); |
| return true; |
| } |
| } |
| |
| if (baseObjTy->is<TupleType>()) { |
| diagnose(anchor->getLoc(), diag::could_not_find_tuple_member, |
| baseObjTy, memberName) |
| .highlight(anchor->getSourceRange()).highlight(memberRange); |
| return true; |
| } |
| |
| MemberLookupResult result = |
| CS->performMemberLookup(constraint->getKind(), constraint->getMember(), |
| baseTy, constraint->getLocator()); |
| |
| switch (result.OverallResult) { |
| case MemberLookupResult::Unsolved: |
| // Diagnose 'super.init', which can only appear inside another initializer, |
| // specially. |
| if (memberName.isSimpleName(CS->TC.Context.Id_init) && |
| !baseObjTy->is<MetatypeType>()) { |
| if (auto ctorRef = dyn_cast<UnresolvedConstructorExpr>(anchor)) { |
| if (isa<SuperRefExpr>(ctorRef->getSubExpr())) { |
| diagnose(anchor->getLoc(), |
| diag::super_initializer_not_in_initializer); |
| return true; |
| } |
| |
| // Suggest inserting '.dynamicType' to construct another object of the |
| // same dynamic type. |
| SourceLoc fixItLoc = ctorRef->getConstructorLoc().getAdvancedLoc(-1); |
| |
| // Place the '.dynamicType' right before the init. |
| diagnose(anchor->getLoc(), diag::init_not_instance_member) |
| .fixItInsert(fixItLoc, ".dynamicType"); |
| return true; |
| } |
| } |
| |
| // If we couldn't resolve a specific type for the base expression, then we |
| // cannot produce a specific diagnostic. |
| return false; |
| |
| case MemberLookupResult::ErrorAlreadyDiagnosed: |
| // If an error was already emitted, then we're done, don't emit anything |
| // redundant. |
| return true; |
| |
| case MemberLookupResult::HasResults: |
| break; |
| } |
| |
| // If this is a failing lookup, it has no viable candidates here. |
| if (result.ViableCandidates.empty()) { |
| diagnoseUnviableLookupResults(result, baseObjTy, anchor, memberName, |
| memberRange.Start, anchor->getLoc()); |
| return true; |
| } |
| |
| |
| bool allUnavailable = !CS->TC.getLangOpts().DisableAvailabilityChecking; |
| for (auto match : result.ViableCandidates) { |
| if (!match.isDecl() || |
| !match.getDecl()->getAttrs().isUnavailable(CS->getASTContext())) |
| allUnavailable = false; |
| } |
| |
| if (allUnavailable) { |
| auto firstDecl = result.ViableCandidates[0].getDecl(); |
| if (CS->TC.diagnoseExplicitUnavailability(firstDecl, anchor->getLoc(), |
| CS->DC)) |
| return true; |
| } |
| |
| // Otherwise, we don't know why this failed. |
| return false; |
| } |
| |
| |
| /// Given a result of name lookup that had no viable results, diagnose the |
| /// unviable ones. |
| void FailureDiagnosis:: |
| diagnoseUnviableLookupResults(MemberLookupResult &result, Type baseObjTy, |
| Expr *baseExpr, |
| DeclName memberName, SourceLoc nameLoc, |
| SourceLoc loc) { |
| SourceRange baseRange = baseExpr ? baseExpr->getSourceRange() : SourceRange(); |
| |
| // If we found no results at all, mention that fact. |
| if (result.UnviableCandidates.empty()) { |
| // TODO: This should handle tuple member lookups, like x.1231 as well. |
| if (memberName.isSimpleName("subscript")) { |
| diagnose(loc, diag::type_not_subscriptable, baseObjTy) |
| .highlight(baseRange); |
| } else if (auto MTT = baseObjTy->getAs<MetatypeType>()) { |
| diagnose(loc, diag::could_not_find_type_member, |
| MTT->getInstanceType(), memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| } else { |
| diagnose(loc, diag::could_not_find_value_member, |
| baseObjTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| } |
| return; |
| } |
| |
| |
| |
| |
| // Otherwise, we have at least one (and potentially many) viable candidates |
| // sort them out. If all of the candidates have the same problem (commonly |
| // because there is exactly one candidate!) diagnose this. |
| bool sameProblem = true; |
| auto firstProblem = result.UnviableCandidates[0].second; |
| for (auto cand : result.UnviableCandidates) |
| sameProblem &= cand.second == firstProblem; |
| |
| auto instanceTy = baseObjTy; |
| if (auto *MTT = instanceTy->getAs<AnyMetatypeType>()) |
| instanceTy = MTT->getInstanceType(); |
| |
| if (sameProblem) { |
| switch (firstProblem) { |
| case MemberLookupResult::UR_LabelMismatch: |
| break; |
| case MemberLookupResult::UR_UnavailableInExistential: |
| diagnose(loc, diag::could_not_use_member_on_existential, |
| instanceTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| return; |
| case MemberLookupResult::UR_InstanceMemberOnType: |
| diagnose(loc, diag::could_not_use_instance_member_on_type, |
| instanceTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| return; |
| case MemberLookupResult::UR_TypeMemberOnInstance: |
| diagnose(loc, diag::could_not_use_type_member_on_instance, |
| baseObjTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| return; |
| |
| case MemberLookupResult::UR_MutatingMemberOnRValue: |
| case MemberLookupResult::UR_MutatingGetterOnRValue: { |
| auto diagIDsubelt = diag::cannot_pass_rvalue_mutating_subelement; |
| auto diagIDmember = diag::cannot_pass_rvalue_mutating; |
| if (firstProblem == MemberLookupResult::UR_MutatingGetterOnRValue) { |
| diagIDsubelt = diag::cannot_pass_rvalue_mutating_getter_subelement; |
| diagIDmember = diag::cannot_pass_rvalue_mutating_getter; |
| } |
| assert(baseExpr && "Cannot have a mutation failure without a base"); |
| diagnoseSubElementFailure(baseExpr, loc, *CS, |
| diagIDsubelt, diagIDmember); |
| return; |
| } |
| } |
| } |
| |
| // FIXME: Emit candidate set.... |
| |
| |
| // Otherwise, we don't have a specific issue to diagnose. Just say the vague |
| // 'cannot use' diagnostic. |
| if (!baseObjTy->isEqual(instanceTy)) |
| diagnose(loc, diag::could_not_use_type_member, |
| instanceTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| else |
| diagnose(loc, diag::could_not_use_value_member, |
| baseObjTy, memberName) |
| .highlight(baseRange).highlight(nameLoc); |
| return; |
| } |
| |
| // In the absence of a better conversion constraint failure, point out the |
| // inability to find an appropriate overload. |
| bool FailureDiagnosis::diagnoseGeneralOverloadFailure(Constraint *constraint) { |
| Constraint *bindOverload = constraint; |
| if (constraint->getKind() == ConstraintKind::Disjunction) |
| bindOverload = constraint->getNestedConstraints().front(); |
| |
| auto overloadChoice = bindOverload->getOverloadChoice(); |
| std::string overloadName = overloadChoice.getDecl()->getNameStr(); |
| |
| if (auto *CD = dyn_cast<ConstructorDecl>(overloadChoice.getDecl())) |
| if (auto *SD = CD->getImplicitSelfDecl()) |
| overloadName = SD->getType()->getInOutObjectType().getString() + ".init"; |
| |
| // Get the referenced expression from the failed constraint. |
| auto anchor = expr; |
| if (auto locator = bindOverload->getLocator()) { |
| anchor = simplifyLocatorToAnchor(*CS, locator); |
| if (!anchor) |
| return false; |
| } |
| |
| // The anchor for the constraint is almost always an OverloadedDeclRefExpr or |
| // UnresolvedDotExpr. Look at the parent node in the AST to find the Apply to |
| // give a better diagnostic. |
| Expr *call = expr->getParentMap()[anchor]; |
| // We look through some simple things that get in between the overload set |
| // and the apply. |
| while (call && |
| (isa<IdentityExpr>(call) || |
| isa<TryExpr>(call) || isa<ForceTryExpr>(call))) { |
| call = expr->getParentMap()[call]; |
| } |
| |
| // FIXME: This is only needed because binops don't respect contextual types. |
| if (call && isa<ApplyExpr>(call)) |
| return false; |
| |
| // This happens, for example, with ambiguous OverloadedDeclRefExprs. We should |
| // just implement visitOverloadedDeclRefExprs and nuke this. |
| |
| // If we couldn't resolve an argument, then produce a generic "ambiguity" |
| // diagnostic. |
| diagnose(anchor->getLoc(), diag::ambiguous_member_overload_set, |
| overloadName) |
| .highlight(anchor->getSourceRange()); |
| |
| if (constraint->getKind() == ConstraintKind::Disjunction) { |
| for (auto elt : constraint->getNestedConstraints()) { |
| if (elt->getKind() != ConstraintKind::BindOverload) continue; |
| auto candidate = elt->getOverloadChoice().getDecl(); |
| diagnose(candidate, diag::found_candidate); |
| } |
| } |
| |
| return true; |
| } |
| |
| bool FailureDiagnosis::diagnoseGeneralConversionFailure(Constraint *constraint){ |
| auto anchor = expr; |
| bool resolvedAnchorToExpr = false; |
| |
| if (auto locator = constraint->getLocator()) { |
| anchor = simplifyLocatorToAnchor(*CS, locator); |
| if (anchor) |
| resolvedAnchorToExpr = true; |
| else |
| anchor = locator->getAnchor(); |
| } |
| |
| Type fromType = CS->simplifyType(constraint->getFirstType()); |
| |
| if (fromType->hasTypeVariable() && resolvedAnchorToExpr) { |
| TCCOptions options; |
| |
| // If we know we're removing a contextual constraint, then we can force a |
| // type check of the subexpr because we know we're eliminating that |
| // constraint. |
| if (CS->getContextualTypePurpose() != CTP_Unused) |
| options |= TCC_ForceRecheck; |
| |
| auto sub = typeCheckArbitrarySubExprIndependently(anchor, options); |
| if (!sub) return true; |
| fromType = sub->getType(); |
| } |
| |
| fromType = fromType->getRValueType(); |
| auto toType = CS->simplifyType(constraint->getSecondType()); |
| |
| // If the second type is a type variable, the expression itself is |
| // ambiguous. Bail out so the general ambiguity diagnosing logic can handle |
| // it. |
| if (isUnresolvedOrTypeVarType(fromType) || |
| isUnresolvedOrTypeVarType(toType) || |
| // FIXME: Why reject unbound generic types here? |
| fromType->is<UnboundGenericType>()) |
| return false; |
| |
| // Try to simplify irrelevant details of function types. For example, if |
| // someone passes a "() -> Float" function to a "() throws -> Int" |
| // parameter, then uttering the "throws" may confuse them into thinking that |
| // that is the problem, even though there is a clear subtype relation. |
| if (auto srcFT = fromType->getAs<FunctionType>()) |
| if (auto destFT = toType->getAs<FunctionType>()) { |
| auto destExtInfo = destFT->getExtInfo(); |
| |
| if (!srcFT->isNoEscape()) destExtInfo = destExtInfo.withNoEscape(false); |
| if (!srcFT->throws()) destExtInfo = destExtInfo.withThrows(false); |
| if (destExtInfo != destFT->getExtInfo()) |
| toType = FunctionType::get(destFT->getInput(), |
| destFT->getResult(), destExtInfo); |
| |
| // If this is a function conversion that discards throwability or |
| // noescape, emit a specific diagnostic about that. |
| if (srcFT->throws() && !destFT->throws()) { |
| diagnose(expr->getLoc(), diag::throws_functiontype_mismatch, |
| fromType, toType) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| if (srcFT->isNoEscape() && !destFT->isNoEscape()) { |
| diagnose(expr->getLoc(), diag::noescape_functiontype_mismatch, |
| fromType, toType) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| } |
| |
| // If this is a callee that mismatches an expected return type, we can emit a |
| // very nice and specific error. In this case, what we'll generally see is |
| // a failed conversion constraint of "A -> B" to "_ -> C", where the error is |
| // that B isn't convertible to C. |
| if (CS->getContextualTypePurpose() == CTP_CalleeResult) { |
| if (auto destFT = toType->getAs<FunctionType>()) { |
| auto srcFT = fromType->getAs<FunctionType>(); |
| if (!isUnresolvedOrTypeVarType(srcFT->getResult())) { |
| // Otherwise, the error is that the result types mismatch. |
| diagnose(expr->getLoc(), diag::invalid_callee_result_type, |
| srcFT->getResult(), destFT->getResult()) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| } |
| } |
| |
| if (auto PT = toType->getAs<ProtocolType>()) { |
| // Check for "=" converting to BooleanType. The user probably meant ==. |
| if (auto *AE = dyn_cast<AssignExpr>(expr->getValueProvidingExpr())) |
| if (PT->getDecl()->isSpecificProtocol(KnownProtocolKind::BooleanType)) { |
| diagnose(AE->getEqualLoc(), diag::use_of_equal_instead_of_equality) |
| .fixItReplace(AE->getEqualLoc(), "==") |
| .highlight(AE->getDest()->getLoc()) |
| .highlight(AE->getSrc()->getLoc()); |
| return true; |
| } |
| |
| if (isa<NilLiteralExpr>(expr->getValueProvidingExpr())) { |
| diagnose(expr->getLoc(), diag::cannot_use_nil_with_this_type, toType) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| // Emit a conformance error through conformsToProtocol. If this succeeds |
| // and yields a valid protocol conformance, then keep searching. |
| ProtocolConformance *Conformance = nullptr; |
| if (CS->TC.conformsToProtocol(fromType, PT->getDecl(), CS->DC, |
| ConformanceCheckFlags::InExpression, |
| &Conformance, expr->getLoc())) { |
| if (!Conformance || !Conformance->isInvalid()) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| // If simplification has turned this into the same types, then this isn't the |
| // broken constraint that we're looking for. |
| if (fromType->isEqual(toType)) |
| return false; |
| |
| |
| // If we have two tuples with mismatching types, produce a tailored |
| // diagnostic. |
| if (auto fromTT = fromType->getAs<TupleType>()) |
| if (auto toTT = toType->getAs<TupleType>()) |
| if (fromTT->getNumElements() != toTT->getNumElements()) { |
| diagnose(anchor->getLoc(), diag::tuple_types_not_convertible, |
| fromTT, toTT) |
| .highlight(anchor->getSourceRange()); |
| return true; |
| } |
| |
| diagnose(anchor->getLoc(), diag::types_not_convertible, |
| constraint->getKind() == ConstraintKind::Subtype, |
| fromType, toType) |
| .highlight(anchor->getSourceRange()); |
| |
| // Check to see if this constraint came from a cast instruction. If so, |
| // and if this conversion constraint is different than the types being cast, |
| // produce a note that talks about the overall expression. |
| // |
| // TODO: Using parentMap would be more general, rather than requiring the |
| // issue to be related to the root of the expr under study. |
| if (auto ECE = dyn_cast<ExplicitCastExpr>(expr)) |
| if (constraint->getLocator() && |
| constraint->getLocator()->getAnchor() == ECE->getSubExpr()) { |
| if (!toType->isEqual(ECE->getCastTypeLoc().getType())) |
| diagnose(expr->getLoc(), diag::in_cast_expr_types, |
| ECE->getSubExpr()->getType()->getRValueType(), |
| ECE->getCastTypeLoc().getType()->getRValueType()) |
| .highlight(ECE->getSubExpr()->getSourceRange()) |
| .highlight(ECE->getCastTypeLoc().getSourceRange()); |
| } |
| |
| return true; |
| } |
| |
| namespace { |
| class ExprTypeSaverAndEraser { |
| llvm::DenseMap<Expr*, Type> ExprTypes; |
| llvm::DenseMap<TypeLoc*, std::pair<Type, bool>> TypeLocTypes; |
| llvm::DenseMap<Pattern*, Type> PatternTypes; |
| llvm::DenseMap<ParamDecl*, Type> ParamDeclTypes; |
| ExprTypeSaverAndEraser(const ExprTypeSaverAndEraser&) = delete; |
| void operator=(const ExprTypeSaverAndEraser&) = delete; |
| public: |
| |
| ExprTypeSaverAndEraser(Expr *E) { |
| struct TypeSaver : public ASTWalker { |
| ExprTypeSaverAndEraser *TS; |
| TypeSaver(ExprTypeSaverAndEraser *TS) : TS(TS) {} |
| |
| std::pair<bool, Expr *> walkToExprPre(Expr *expr) override { |
| TS->ExprTypes[expr] = expr->getType(); |
| |
| // Preserve module expr type data to prevent further lookups. |
| if (auto *declRef = dyn_cast<DeclRefExpr>(expr)) |
| if (isa<ModuleDecl>(declRef->getDecl())) |
| return { false, expr }; |
| |
| // Don't strip type info off OtherConstructorDeclRefExpr, because CSGen |
| // doesn't know how to reconstruct it. |
| if (isa<OtherConstructorDeclRefExpr>(expr)) |
| return { false, expr }; |
| |
| // TypeExpr's are relabeled by CSGen. |
| if (isa<TypeExpr>(expr)) |
| return { false, expr }; |
| |
| // If a literal has a Builtin.Int or Builtin.FP type on it already, |
| // then sema has already expanded out a call to |
| // Init.init(<builtinliteral>) |
| // and we don't want it to make |
| // Init.init(Init.init(<builtinliteral>)) |
| // preserve the type info to prevent this from happening. |
| if (isa<LiteralExpr>(expr) && |
| !(expr->getType() && expr->getType()->is<ErrorType>())) |
| return { false, expr }; |
| |
| // If a ClosureExpr's parameter list has types on the decls, and the |
| // types and remove them so that they'll get regenerated from the |
| // associated TypeLocs or resynthesized as fresh typevars. |
| if (auto *CE = dyn_cast<ClosureExpr>(expr)) |
| for (auto P : *CE->getParameters()) |
| if (P->hasType()) { |
| TS->ParamDeclTypes[P] = P->getType(); |
| P->overwriteType(Type()); |
| } |
| |
| expr->setType(nullptr); |
| expr->clearLValueAccessKind(); |
| |
| return { true, expr }; |
| } |
| |
| // If we find a TypeLoc (e.g. in an as? expr), save and erase it. |
| bool walkToTypeLocPre(TypeLoc &TL) override { |
| if (TL.getTypeRepr() && TL.getType()) { |
| TS->TypeLocTypes[&TL] = { TL.getType(), TL.wasValidated() }; |
| TL.setType(Type(), /*was validated*/false); |
| } |
| return true; |
| } |
| |
| std::pair<bool, Pattern*> walkToPatternPre(Pattern *P) override { |
| if (P->hasType()) { |
| TS->PatternTypes[P] = P->getType(); |
| P->setType(Type()); |
| } |
| return { true, P }; |
| } |
| |
| // Don't walk into statements. This handles the BraceStmt in |
| // non-single-expr closures, so we don't walk into their body. |
| std::pair<bool, Stmt *> walkToStmtPre(Stmt *S) override { |
| return { false, S }; |
| } |
| }; |
| |
| E->walk(TypeSaver(this)); |
| } |
| |
| void restore() { |
| for (auto exprElt : ExprTypes) |
| exprElt.first->setType(exprElt.second); |
| |
| for (auto typelocElt : TypeLocTypes) |
| typelocElt.first->setType(typelocElt.second.first, |
| typelocElt.second.second); |
| |
| for (auto patternElt : PatternTypes) |
| patternElt.first->setType(patternElt.second); |
| |
| for (auto paramDeclElt : ParamDeclTypes) |
| paramDeclElt.first->setType(paramDeclElt.second); |
| |
| // Done, don't do redundant work on destruction. |
| ExprTypes.clear(); |
| TypeLocTypes.clear(); |
| PatternTypes.clear(); |
| } |
| |
| // On destruction, if a type got wiped out, reset it from null to its |
| // original type. This is helpful because type checking a subexpression |
| // can lead to replacing the nodes in that subexpression. However, the |
| // failed ConstraintSystem still has locators pointing to the old nodes, |
| // and if expr-specific diagnostics fail to turn up anything useful to say, |
| // we go digging through failed constraints, and expect their locators to |
| // still be meaningful. |
| ~ExprTypeSaverAndEraser() { |
| for (auto exprElt : ExprTypes) |
| if (!exprElt.first->getType()) |
| exprElt.first->setType(exprElt.second); |
| |
| for (auto typelocElt : TypeLocTypes) |
| if (!typelocElt.first->getType()) |
| typelocElt.first->setType(typelocElt.second.first, |
| typelocElt.second.second); |
| |
| for (auto patternElt : PatternTypes) |
| if (!patternElt.first->hasType()) |
| patternElt.first->setType(patternElt.second); |
| |
| for (auto paramDeclElt : ParamDeclTypes) |
| if (!paramDeclElt.first->hasType()) |
| paramDeclElt.first->setType(paramDeclElt.second); |
| |
| } |
| }; |
| } |
| |
| /// Erase an expression tree's open existentials after a re-typecheck operation. |
| /// |
| /// This is done in the case of a typecheck failure, after we re-typecheck |
| /// partially-typechecked subexpressions in a context-free manner. |
| /// |
| static void eraseOpenedExistentials(Expr *&expr) { |
| |
| class ExistentialEraser : public ASTWalker { |
| llvm::SmallDenseMap<OpaqueValueExpr *, Expr *, 4> OpenExistentials; |
| |
| public: |
| std::pair<bool, Expr *> walkToExprPre(Expr *expr) override { |
| if (auto OOE = dyn_cast<OpenExistentialExpr>(expr)) { |
| auto archetypeVal = OOE->getOpaqueValue(); |
| auto base = OOE->getExistentialValue(); |
| |
| // Walk the base expression to ensure we erase any existentials within |
| // it. |
| base = base->walk(*this); |
| |
| bool inserted = OpenExistentials.insert({archetypeVal, base}).second; |
| assert(inserted && "OpaqueValue appears multiple times?"); |
| (void)inserted; |
| return { true, OOE->getSubExpr() }; |
| } |
| |
| if (auto OVE = dyn_cast<OpaqueValueExpr>(expr)) { |
| auto value = OpenExistentials.find(OVE); |
| assert(value != OpenExistentials.end() && |
| "didn't see this OVE in a containing OpenExistentialExpr?"); |
| return { true, value->second }; |
| } |
| |
| return { true, expr }; |
| } |
| |
| Expr *walkToExprPost(Expr *expr) override { |
| Type type = expr->getType(); |
| if (!type || !type->hasOpenedExistential()) |
| return expr; |
| |
| type = type.transform([&](Type type) -> Type { |
| if (auto archetype = type->getAs<ArchetypeType>()) |
| if (auto existentialType = archetype->getOpenedExistentialType()) |
| return existentialType; |
| |
| return type; |
| }); |
| expr->setType(type); |
| |
| return expr; |
| } |
| |
| // Don't walk into statements. This handles the BraceStmt in |
| // non-single-expr closures, so we don't walk into their body. |
| std::pair<bool, Stmt *> walkToStmtPre(Stmt *S) override { |
| return { false, S }; |
| } |
| }; |
| |
| expr = expr->walk(ExistentialEraser()); |
| } |
| |
| /// Rewrite any type variables & archetypes in the specified type with |
| /// UnresolvedType. |
| static Type replaceArchetypesAndTypeVarsWithUnresolved(Type ty) { |
| if (!ty) return ty; |
| |
| auto &ctx = ty->getASTContext(); |
| |
| return ty.transform([&](Type type) -> Type { |
| if (type->is<TypeVariableType>()) |
| return ctx.TheUnresolvedType; |
| if (type->is<ArchetypeType>()) |
| return ctx.TheUnresolvedType; |
| return type; |
| }); |
| } |
| |
| /// Unless we've already done this, retypecheck the specified subexpression on |
| /// its own, without including any contextual constraints or parent expr |
| /// nodes. This is more likely to succeed than type checking the original |
| /// expression. |
| /// |
| /// This can return a new expression (for e.g. when a UnresolvedDeclRef gets |
| /// resolved) and returns null when the subexpression fails to typecheck. |
| Expr *FailureDiagnosis:: |
| typeCheckChildIndependently(Expr *subExpr, Type convertType, |
| ContextualTypePurpose convertTypePurpose, |
| TCCOptions options, |
| ExprTypeCheckListener *listener) { |
| |
| // If this sub-expression is currently being diagnosed, refuse to recheck the |
| // expression (which may lead to infinite recursion). If the client is |
| // telling us that it knows what it is doing, then believe it. |
| if (!options.contains(TCC_ForceRecheck)) { |
| if (Expr *res = CS->TC.isExprBeingDiagnosed(subExpr)) |
| return res; |
| |
| CS->TC.addExprForDiagnosis(subExpr, subExpr); |
| } |
| |
| // If we have a conversion type, but it has type variables (from the current |
| // ConstraintSystem), then we can't use it. |
| if (convertType) { |
| // If we're asked to convert to an autoclosure, then we really want to |
| // convert to the result of it. |
| if (auto *FT = convertType->getAs<AnyFunctionType>()) |
| if (FT->isAutoClosure()) |
| convertType = FT->getResult(); |
| |
| if (convertType->hasTypeVariable() || convertType->hasArchetype()) |
| convertType = replaceArchetypesAndTypeVarsWithUnresolved(convertType); |
| |
| // If the conversion type contains no info, drop it. |
| if (convertType->is<UnresolvedType>() || |
| (convertType->is<MetatypeType>() && convertType->hasUnresolvedType())) { |
| convertType = Type(); |
| convertTypePurpose = CTP_Unused; |
| } |
| } |
| |
| |
| // If we have no contextual type information and the subexpr is obviously a |
| // overload set, don't recursively simplify this. The recursive solver will |
| // sometimes pick one based on arbitrary ranking behavior (e.g. like |
| // which is the most specialized) even then all the constraints are being |
| // fulfilled by UnresolvedType, which doesn't tell us anything. |
| if (convertTypePurpose == CTP_Unused && |
| (isa<OverloadedDeclRefExpr>(subExpr->getValueProvidingExpr()) || |
| isa<OverloadedMemberRefExpr>(subExpr->getValueProvidingExpr()))) { |
| return subExpr; |
| } |
| |
| // Save any existing type data of the subexpr tree, and reset it to null in |
| // prep for re-type-checking the tree. If things fail, we can revert the |
| // types back to their original state. |
| ExprTypeSaverAndEraser SavedTypeData(subExpr); |
| |
| // Store off the sub-expression, in case a new one is provided via the |
| // type check operation. |
| Expr *preCheckedExpr = subExpr; |
| |
| // Disable structural checks, because we know that the overall expression |
| // has type constraint problems, and we don't want to know about any |
| // syntactic issues in a well-typed subexpression (which might be because |
| // the context is missing). |
| TypeCheckExprOptions TCEOptions = TypeCheckExprFlags::DisableStructuralChecks; |
| |
| // Don't walk into non-single expression closure bodies, because |
| // ExprTypeSaver and TypeNullifier skip them too. |
| TCEOptions |= TypeCheckExprFlags::SkipMultiStmtClosures; |
| |
| // Claim that the result is discarded to preserve the lvalue type of |
| // the expression. |
| if (options.contains(TCC_AllowLValue)) |
| TCEOptions |= TypeCheckExprFlags::IsDiscarded; |
| |
| // If there is no contextual type available, tell typeCheckExpression that it |
| // is ok to produce an ambiguous result, it can just fill in holes with |
| // UnresolvedType and we'll deal with it. |
| if (!convertType) |
| TCEOptions |= TypeCheckExprFlags::AllowUnresolvedTypeVariables; |
| |
| bool hadError = CS->TC.typeCheckExpression(subExpr, CS->DC, convertType, |
| convertTypePurpose, TCEOptions, |
| listener); |
| |
| // This is a terrible hack to get around the fact that typeCheckExpression() |
| // might change subExpr to point to a new OpenExistentialExpr. In that case, |
| // since the caller passed subExpr by value here, they would be left |
| // holding on to an expression containing open existential types but |
| // no OpenExistentialExpr, which breaks invariants enforced by the |
| // ASTChecker. |
| eraseOpenedExistentials(subExpr); |
| |
| // If recursive type checking failed, then an error was emitted. Return |
| // null to indicate this to the caller. |
| if (hadError) |
| return nullptr; |
| |
| // If we type checked the result but failed to get a usable output from it, |
| // just pretend as though nothing happened. |
| if (subExpr->getType()->is<ErrorType>()) { |
| subExpr = preCheckedExpr; |
| SavedTypeData.restore(); |
| } |
| |
| CS->TC.addExprForDiagnosis(preCheckedExpr, subExpr); |
| return subExpr; |
| } |
| |
| /// This is the same as typeCheckChildIndependently, but works on an arbitrary |
| /// subexpression of the current node because it handles ClosureExpr parents |
| /// of the specified node. |
| Expr *FailureDiagnosis:: |
| typeCheckArbitrarySubExprIndependently(Expr *subExpr, TCCOptions options) { |
| if (subExpr == expr) |
| return typeCheckChildIndependently(subExpr, options); |
| |
| // Construct a parent map for the expr tree we're investigating. |
| auto parentMap = expr->getParentMap(); |
| |
| ClosureExpr *NearestClosure = nullptr; |
| |
| // Walk the parents of the specified expression, handling any ClosureExprs. |
| for (Expr *node = parentMap[subExpr]; node; node = parentMap[node]) { |
| auto *CE = dyn_cast<ClosureExpr>(node); |
| if (!CE) continue; |
| |
| // Keep track of the innermost closure we see that we're jumping into. |
| if (!NearestClosure) |
| NearestClosure = CE; |
| |
| // If we have a ClosureExpr parent of the specified node, check to make sure |
| // none of its arguments are type variables. If so, these type variables |
| // would be accessible to name lookup of the subexpression and may thus leak |
| // in. Reset them to UnresolvedTypes for safe measures. |
| for (auto param : *CE->getParameters()) { |
| auto VD = param; |
| if (VD->getType()->hasTypeVariable() || VD->getType()->is<ErrorType>()) |
| VD->overwriteType(CS->getASTContext().TheUnresolvedType); |
| } |
| } |
| |
| // When we're type checking a single-expression closure, we need to reset the |
| // DeclContext to this closure for the recursive type checking. Otherwise, |
| // if there is a closure in the subexpression, we can violate invariants. |
| auto newDC = NearestClosure ? NearestClosure : CS->DC; |
| llvm::SaveAndRestore<DeclContext*> SavedDC(CS->DC, newDC); |
| |
| // Otherwise, we're ok to type check the subexpr. |
| return typeCheckChildIndependently(subExpr, options); |
| } |
| |
| /// For an expression being type checked with a CTP_CalleeResult contextual |
| /// type, try to diagnose a problem. |
| bool FailureDiagnosis::diagnoseCalleeResultContextualConversionError() { |
| // Try to dig out the conversion constraint in question to find the contextual |
| // result type being specified. |
| Type contextualResultType; |
| for (auto &c : CS->getConstraints()) { |
| if (!isConversionConstraint(&c) || !c.getLocator() || |
| c.getLocator()->getAnchor() != expr) |
| continue; |
| |
| // If we found our contextual type, then we know we have a conversion to |
| // some function type, and that the result type is concrete. If not, |
| // ignore it. |
| auto toType = CS->simplifyType(c.getSecondType()); |
| if (auto *FT = toType->getAs<AnyFunctionType>()) |
| if (!isUnresolvedOrTypeVarType(FT->getResult())) { |
| contextualResultType = FT->getResult(); |
| break; |
| } |
| } |
| if (!contextualResultType) |
| return false; |
| |
| // Retypecheck the callee expression without a contextual type to resolve |
| // whatever we can in it. |
| auto callee = typeCheckChildIndependently(expr, TCC_ForceRecheck); |
| if (!callee) |
| return true; |
| |
| // Based on that, compute an overload set. |
| CalleeCandidateInfo calleeInfo(callee, /*hasTrailingClosure*/false, CS); |
| |
| switch (calleeInfo.size()) { |
| case 0: |
| // If we found no overloads, then there is something else going on here. |
| return false; |
| |
| case 1: |
| diagnose(expr->getLoc(), diag::candidates_no_match_result_type, |
| calleeInfo.declName, calleeInfo[0].getResultType(), |
| contextualResultType); |
| return true; |
| default: |
| diagnose(expr->getLoc(), diag::no_candidates_match_result_type, |
| calleeInfo.declName, contextualResultType); |
| calleeInfo.suggestPotentialOverloads(expr->getLoc(), /*isResult*/true); |
| return true; |
| } |
| } |
| |
| |
| /// Return true if the conversion from fromType to toType is an invalid string |
| /// index operation. |
| static bool isIntegerToStringIndexConversion(Type fromType, Type toType, |
| ConstraintSystem *CS) { |
| auto integerType = |
| CS->TC.getProtocol(SourceLoc(), |
| KnownProtocolKind::IntegerLiteralConvertible); |
| if (!integerType) return false; |
| |
| // If the from type is an integer type, and the to type is |
| // String.CharacterView.Index, then we found one. |
| if (CS->TC.conformsToProtocol(fromType, integerType, CS->DC, |
| ConformanceCheckFlags::InExpression)) { |
| if (toType->getCanonicalType().getString() == "String.CharacterView.Index") |
| return true; |
| } |
| |
| return false; |
| } |
| |
| |
| bool FailureDiagnosis::diagnoseContextualConversionError() { |
| // If the constraint system has a contextual type, then we can test to see if |
| // this is the problem that prevents us from solving the system. |
| Type contextualType = CS->getContextualType(); |
| if (!contextualType) { |
| // This contextual conversion constraint doesn't install an actual type. |
| if (CS->getContextualTypePurpose() == CTP_CalleeResult) |
| return diagnoseCalleeResultContextualConversionError(); |
| |
| return false; |
| } |
| |
| // Try re-type-checking the expression without the contextual type to see if |
| // it can work without it. If so, the contextual type is the problem. We |
| // force a recheck, because "expr" is likely in our table with the extra |
| // contextual constraint that we know we are relaxing. |
| auto exprType = getTypeOfTypeCheckedChildIndependently(expr,TCC_ForceRecheck); |
| |
| // If it failed and diagnosed something, then we're done. |
| if (!exprType) return true; |
| |
| // Try to find the contextual type in a variety of ways. If the constraint |
| // system had a contextual type specified, we use it - it will have a purpose |
| // indicator which allows us to give a very "to the point" diagnostic. |
| Diag<Type, Type> diagID; |
| Diag<Type, Type> diagIDProtocol; |
| Diag<Type> nilDiag; |
| |
| // If this is conversion failure due to a return statement with an argument |
| // that cannot be coerced to the result type of the function, emit a |
| // specific error. |
| switch (CS->getContextualTypePurpose()) { |
| case CTP_Unused: |
| case CTP_CannotFail: |
| llvm_unreachable("These contextual type purposes cannot fail with a " |
| "conversion type specified!"); |
| case CTP_CalleeResult: |
| llvm_unreachable("CTP_CalleeResult does not actually install a " |
| "contextual type"); |
| case CTP_Initialization: |
| diagID = diag::cannot_convert_initializer_value; |
| diagIDProtocol = diag::cannot_convert_initializer_value_protocol; |
| nilDiag = diag::cannot_convert_initializer_value_nil; |
| break; |
| case CTP_ReturnStmt: |
| // Special case the "conversion to void" case. |
| if (contextualType->isVoid()) { |
| diagnose(expr->getLoc(), diag::cannot_return_value_from_void_func) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| diagID = diag::cannot_convert_to_return_type; |
| diagIDProtocol = diag::cannot_convert_to_return_type_protocol; |
| nilDiag = diag::cannot_convert_to_return_type_nil; |
| break; |
| case CTP_ThrowStmt: |
| if (isa<NilLiteralExpr>(expr->getValueProvidingExpr())) { |
| diagnose(expr->getLoc(), diag::cannot_throw_nil); |
| return true; |
| } |
| |
| if (isUnresolvedOrTypeVarType(exprType)) |
| return false; |
| |
| // The conversion destination of throw is always ErrorType (at the moment) |
| // if this ever expands, this should be a specific form like () is for |
| // return. |
| diagnose(expr->getLoc(), diag::cannot_convert_thrown_type, exprType) |
| .highlight(expr->getSourceRange()); |
| return true; |
| |
| case CTP_EnumCaseRawValue: |
| diagID = diag::cannot_convert_raw_initializer_value; |
| diagIDProtocol = diag::cannot_convert_raw_initializer_value; |
| nilDiag = diag::cannot_convert_raw_initializer_value_nil; |
| break; |
| case CTP_DefaultParameter: |
| diagID = diag::cannot_convert_default_arg_value; |
| diagIDProtocol = diag::cannot_convert_default_arg_value_protocol; |
| nilDiag = diag::cannot_convert_default_arg_value_nil; |
| break; |
| |
| case CTP_CallArgument: |
| diagID = diag::cannot_convert_argument_value; |
| diagIDProtocol = diag::cannot_convert_argument_value_protocol; |
| nilDiag = diag::cannot_convert_argument_value_nil; |
| break; |
| case CTP_ClosureResult: |
| diagID = diag::cannot_convert_closure_result; |
| diagIDProtocol = diag::cannot_convert_closure_result_protocol; |
| nilDiag = diag::cannot_convert_closure_result_nil; |
| break; |
| case CTP_ArrayElement: |
| diagID = diag::cannot_convert_array_element; |
| diagIDProtocol = diag::cannot_convert_array_element_protocol; |
| nilDiag = diag::cannot_convert_array_element_nil; |
| break; |
| case CTP_DictionaryKey: |
| diagID = diag::cannot_convert_dict_key; |
| diagIDProtocol = diag::cannot_convert_dict_key_protocol; |
| nilDiag = diag::cannot_convert_dict_key_nil; |
| break; |
| case CTP_DictionaryValue: |
| diagID = diag::cannot_convert_dict_value; |
| diagIDProtocol = diag::cannot_convert_dict_value_protocol; |
| nilDiag = diag::cannot_convert_dict_value_nil; |
| break; |
| case CTP_CoerceOperand: |
| diagID = diag::cannot_convert_coerce; |
| diagIDProtocol = diag::cannot_convert_coerce_protocol; |
| nilDiag = diag::cannot_convert_coerce_nil; |
| break; |
| case CTP_AssignSource: |
| diagID = diag::cannot_convert_assign; |
| diagIDProtocol = diag::cannot_convert_assign_protocol; |
| nilDiag = diag::cannot_convert_assign_nil; |
| break; |
| } |
| |
| // If we're diagnostic an issue with 'nil', produce a specific diagnostic, |
| // instead of uttering NilLiteralConvertible. |
| if (isa<NilLiteralExpr>(expr->getValueProvidingExpr())) { |
| diagnose(expr->getLoc(), nilDiag, contextualType); |
| return true; |
| } |
| |
| // If we don't have a type for the expression, then we cannot use it in |
| // conversion constraint diagnostic generation. |
| if (isUnresolvedOrTypeVarType(exprType)) { |
| // We can't do anything smart. |
| return false; |
| } |
| |
| // If we're trying to convert something of type "() -> T" to T, then we |
| // probably meant to call the value. |
| if (auto srcFT = exprType->getAs<AnyFunctionType>()) { |
| if (srcFT->getInput()->isVoid() && |
| CS->TC.isConvertibleTo(srcFT->getResult(), contextualType, CS->DC)) { |
| diagnose(expr->getLoc(), diag::missing_nullary_call, srcFT->getResult()) |
| .highlight(expr->getSourceRange()) |
| .fixItInsertAfter(expr->getEndLoc(), "()"); |
| return true; |
| } |
| } |
| |
| // If this is a conversion from T to () in a call argument context, it is |
| // almost certainly an extra argument being passed in. |
| if (CS->getContextualTypePurpose() == CTP_CallArgument && |
| contextualType->isVoid()) { |
| diagnose(expr->getLoc(), diag::extra_argument_to_nullary_call) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| exprType = exprType->getRValueType(); |
| |
| // Special case of some common conversions involving Swift.String |
| // indexes, catching cases where people attempt to index them with an integer. |
| if (isIntegerToStringIndexConversion(exprType, contextualType, CS)) { |
| diagnose(expr->getLoc(), diag::string_index_not_integer, |
| exprType->getRValueType()) |
| .highlight(expr->getSourceRange()); |
| diagnose(expr->getLoc(), diag::string_index_not_integer_note); |
| return true; |
| } |
| |
| // When complaining about conversion to a protocol type, complain about |
| // conformance instead of "conversion". |
| if (contextualType->is<ProtocolType>() || |
| contextualType->is<ProtocolCompositionType>()) |
| diagID = diagIDProtocol; |
| |
| // Try to simplify irrelevant details of function types. For example, if |
| // someone passes a "() -> Float" function to a "() throws -> Int" |
| // parameter, then uttering the "throws" may confuse them into thinking that |
| // that is the problem, even though there is a clear subtype relation. |
| if (auto srcFT = exprType->getAs<FunctionType>()) |
| if (auto destFT = contextualType->getAs<FunctionType>()) { |
| auto destExtInfo = destFT->getExtInfo(); |
| |
| if (!srcFT->isNoEscape()) destExtInfo = destExtInfo.withNoEscape(false); |
| if (!srcFT->throws()) destExtInfo = destExtInfo.withThrows(false); |
| if (destExtInfo != destFT->getExtInfo()) |
| contextualType = FunctionType::get(destFT->getInput(), |
| destFT->getResult(), destExtInfo); |
| |
| // If this is a function conversion that discards throwability or |
| // noescape, emit a specific diagnostic about that. |
| if (srcFT->throws() && !destFT->throws()) |
| diagID = diag::throws_functiontype_mismatch; |
| else if (srcFT->isNoEscape() && !destFT->isNoEscape()) |
| diagID = diag::noescape_functiontype_mismatch; |
| } |
| |
| diagnose(expr->getLoc(), diagID, exprType, contextualType) |
| .highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| |
| /// When an assignment to an expression is detected and the destination is |
| /// invalid, emit a detailed error about the condition. |
| void ConstraintSystem::diagnoseAssignmentFailure(Expr *dest, Type destTy, |
| SourceLoc equalLoc) { |
| auto &TC = getTypeChecker(); |
| |
| // Diagnose obvious assignments to literals. |
| if (isa<LiteralExpr>(dest->getValueProvidingExpr())) { |
| TC.diagnose(equalLoc, diag::cannot_assign_to_literal); |
| return; |
| } |
| |
| Diag<StringRef> diagID; |
| if (isa<DeclRefExpr>(dest)) |
| diagID = diag::assignment_lhs_is_immutable_variable; |
| else if (isa<ForceValueExpr>(dest)) |
| diagID = diag::assignment_bang_has_immutable_subcomponent; |
| else if (isa<UnresolvedDotExpr>(dest) || isa<MemberRefExpr>(dest)) |
| diagID = diag::assignment_lhs_is_immutable_property; |
| else if (isa<SubscriptExpr>(dest)) |
| diagID = diag::assignment_subscript_has_immutable_base; |
| else { |
| diagID = diag::assignment_lhs_is_immutable_variable; |
| } |
| |
| diagnoseSubElementFailure(dest, equalLoc, *this, diagID, |
| diag::assignment_lhs_not_lvalue); |
| } |
| |
| |
| /// Special magic to handle inout exprs and tuples in argument lists. |
| Expr *FailureDiagnosis:: |
| typeCheckArgumentChildIndependently(Expr *argExpr, Type argType, |
| const CalleeCandidateInfo &candidates) { |
| // Grab one of the candidates (if present) and get its input list to help |
| // identify operators that have implicit inout arguments. |
| Type exampleInputType; |
| if (!candidates.empty()) { |
| exampleInputType = candidates[0].getArgumentType(); |
| |
| // If we found a single candidate, and have no contextually known argument |
| // type information, use that one candidate as the type information for |
| // subexpr checking. |
| // |
| // TODO: If all candidates have the same type for some argument, we could |
| // pass down partial information. |
| if (candidates.size() == 1 && !argType) |
| argType = candidates[0].getArgumentType(); |
| } |
| |
| // If our candidates are instance members at curry level #0, then the argument |
| // being provided is the receiver type for the instance. We produce better |
| // diagnostics when we don't force the self type down. |
| if (argType && !candidates.empty() && |
| candidates[0].decl->isInstanceMember() && candidates[0].level == 0 && |
| !isa<SubscriptDecl>(candidates[0].decl)) |
| argType = Type(); |
| |
| |
| // FIXME: This should all just be a matter of getting the type of the |
| // sub-expression, but this doesn't work well when typeCheckChildIndependently |
| // is over-conservative w.r.t. TupleExprs. |
| auto *TE = dyn_cast<TupleExpr>(argExpr); |
| if (!TE) { |
| // If the argument isn't a tuple, it is some scalar value for a |
| // single-argument call. |
| TCCOptions options; |
| if (exampleInputType && exampleInputType->is<InOutType>()) |
| options |= TCC_AllowLValue; |
| |
| // If the argtype is a tuple type with default arguments, or a labeled tuple |
| // with a single element, pull the scalar element type for the subexpression |
| // out. If we can't do that and the tuple has default arguments, we have to |
| // punt on passing down the type information, since type checking the |
| // subexpression won't be able to find the default argument provider. |
| if (argType) |
| if (auto argTT = argType->getAs<TupleType>()) { |
| int scalarElt = argTT->getElementForScalarInit(); |
| // If the argument cannot be initialized with a scalar, then it is an |
| // error, so we might as well pass down the expected type, to get a |
| // specific error involving it. |
| if (scalarElt == -1) { |
| // However, if there are default values, we don't actually want to do |
| // this. We don't know if the user just forgot a label on a defaulted |
| // value. |
| if (argTT->hasAnyDefaultValues()) |
| argType = Type(); |
| } else { |
| // If we found the single argument being initialized, use it. |
| auto &arg = argTT->getElement(scalarElt); |
| |
| // If the argument being specified is actually varargs, then we're |
| // just specifying one element of a variadic list. Use the type of |
| // the individual varargs argument, not the overall array type. |
| if (arg.isVararg()) |
| argType = arg.getVarargBaseTy(); |
| else |
| argType = arg.getType(); |
| } |
| } |
| |
| auto CTPurpose = argType ? CTP_CallArgument : CTP_Unused; |
| return typeCheckChildIndependently(argExpr, argType, |
| CTPurpose, options); |
| } |
| |
| // If we know the requested argType to use, use computeTupleShuffle to produce |
| // the shuffle of input arguments to destination values. It requires a |
| // TupleType to compute the mapping from argExpr. Conveniently, it doesn't |
| // care about the actual types though, so we can just use 'void' for them. |
| if (argType && argType->is<TupleType>()) { |
| auto argTypeTT = argType->castTo<TupleType>(); |
| SmallVector<TupleTypeElt, 4> ArgElts; |
| auto voidTy = CS->getASTContext().TheEmptyTupleType; |
| |
| for (unsigned i = 0, e = TE->getNumElements(); i != e; ++i) |
| ArgElts.push_back({ voidTy, TE->getElementName(i) }); |
| SmallVector<int, 4> sources; |
| SmallVector<unsigned, 4> variadicArgs; |
| if (!computeTupleShuffle(ArgElts, argTypeTT->getElements(), |
| sources, variadicArgs)) { |
| SmallVector<Expr*, 4> resultElts(TE->getNumElements(), nullptr); |
| SmallVector<TupleTypeElt, 4> resultEltTys(TE->getNumElements(), voidTy); |
| |
| // If we got a correct shuffle, we can perform the analysis of all of |
| // the input elements, with their expected types. |
| for (unsigned i = 0, e = sources.size(); i != e; ++i) { |
| // If the value is taken from a default argument, ignore it. |
| if (sources[i] == TupleShuffleExpr::DefaultInitialize || |
| sources[i] == TupleShuffleExpr::Variadic || |
| sources[i] == TupleShuffleExpr::CallerDefaultInitialize) |
| continue; |
| |
| assert(sources[i] >= 0 && "Unknown sources index"); |
| |
| // Otherwise, it must match the corresponding expected argument type. |
| unsigned inArgNo = sources[i]; |
| auto actualType = argTypeTT->getElementType(i); |
| |
| TCCOptions options; |
| if (actualType->is<InOutType>()) |
| options |= TCC_AllowLValue; |
| |
| auto exprResult = |
| typeCheckChildIndependently(TE->getElement(inArgNo), actualType, |
| CTP_CallArgument, options); |
| // If there was an error type checking this argument, then we're done. |
| if (!exprResult) |
| return nullptr; |
| |
| // If the caller expected something inout, but we didn't have |
| // something of inout type, diagnose it. |
| if (auto IOE = |
| dyn_cast<InOutExpr>(exprResult->getSemanticsProvidingExpr())) { |
| if (!actualType->is<InOutType>()) { |
| diagnose(exprResult->getLoc(), diag::extra_address_of, |
| exprResult->getType()->getInOutObjectType()) |
| .highlight(exprResult->getSourceRange()) |
| .fixItRemove(IOE->getStartLoc()); |
| return nullptr; |
| } |
| } |
| |
| resultElts[inArgNo] = exprResult; |
| resultEltTys[inArgNo] = { |
| exprResult->getType(), |
| TE->getElementName(inArgNo) |
| }; |
| } |
| |
| if (!variadicArgs.empty()) { |
| auto varargsTy = argTypeTT->getVarArgsBaseType(); |
| for (unsigned i = 0, e = variadicArgs.size(); i != e; ++i) { |
| unsigned inArgNo = variadicArgs[i]; |
| |
| auto expr = |
| typeCheckChildIndependently(TE->getElement(inArgNo), varargsTy, |
| CTP_CallArgument); |
| // If there was an error type checking this argument, then we're done. |
| if (!expr) |
| return nullptr; |
| resultElts[inArgNo] = expr; |
| resultEltTys[inArgNo] = { expr->getType() }; |
| } |
| } |
| |
| auto TT = TupleType::get(resultEltTys, CS->getASTContext()); |
| return TupleExpr::create(CS->getASTContext(), TE->getLParenLoc(), |
| resultElts, TE->getElementNames(), |
| TE->getElementNameLocs(), |
| TE->getRParenLoc(), TE->hasTrailingClosure(), |
| TE->isImplicit(), TT); |
| } |
| } |
| |
| // Get the simplified type of each element and rebuild the aggregate. |
| SmallVector<TupleTypeElt, 4> resultEltTys; |
| SmallVector<Expr*, 4> resultElts; |
| |
| TupleType *exampleInputTuple = nullptr; |
| if (exampleInputType) |
| exampleInputTuple = exampleInputType->getAs<TupleType>(); |
| |
| for (unsigned i = 0, e = TE->getNumElements(); i != e; i++) { |
| TCCOptions options; |
| if (exampleInputTuple && i < exampleInputTuple->getNumElements() && |
| exampleInputTuple->getElementType(i)->is<InOutType>()) |
| options |= TCC_AllowLValue; |
| |
| auto elExpr = typeCheckChildIndependently(TE->getElement(i), options); |
| if (!elExpr) return nullptr; // already diagnosed. |
| |
| resultElts.push_back(elExpr); |
| resultEltTys.push_back({elExpr->getType(), TE->getElementName(i)}); |
| } |
| |
| auto TT = TupleType::get(resultEltTys, CS->getASTContext()); |
| return TupleExpr::create(CS->getASTContext(), TE->getLParenLoc(), |
| resultElts, TE->getElementNames(), |
| TE->getElementNameLocs(), |
| TE->getRParenLoc(), TE->hasTrailingClosure(), |
| TE->isImplicit(), TT); |
| } |
| |
| bool FailureDiagnosis::visitSubscriptExpr(SubscriptExpr *SE) { |
| // FIXME: Why isn't this passing TCC_AllowLValue? It seems that this could |
| // cause problems with subscripts that have mutating getters. |
| auto baseExpr = typeCheckChildIndependently(SE->getBase()); |
| if (!baseExpr) return true; |
| auto baseType = baseExpr->getType(); |
| |
| auto locator = |
| CS->getConstraintLocator(SE, ConstraintLocator::SubscriptMember); |
| |
| auto subscriptName = CS->getASTContext().Id_subscript; |
| |
| MemberLookupResult result = |
| CS->performMemberLookup(ConstraintKind::ValueMember, subscriptName, |
| baseType, locator); |
| |
| |
| switch (result.OverallResult) { |
| case MemberLookupResult::Unsolved: |
| return false; |
| case MemberLookupResult::ErrorAlreadyDiagnosed: |
| // If an error was already emitted, then we're done, don't emit anything |
| // redundant. |
| return true; |
| case MemberLookupResult::HasResults: |
| break; // Interesting case. :-) |
| } |
| |
| // If we have unviable candidates (e.g. because of access control or some |
| // other problem) we should diagnose the problem. |
| if (result.ViableCandidates.empty()) { |
| diagnoseUnviableLookupResults(result, baseType, /*no base expr*/nullptr, |
| subscriptName, SE->getLoc(), |
| SE->getLoc()); |
| return true; |
| } |
| |
| |
| |
| CalleeCandidateInfo calleeInfo(baseType, result.ViableCandidates, 0, |
| /*FIXME: Subscript trailing closures*/ |
| /*hasTrailingClosure*/false, CS); |
| |
| auto indexExpr = typeCheckArgumentChildIndependently(SE->getIndex(), |
| Type(), calleeInfo); |
| if (!indexExpr) return true; |
| |
| auto indexType = indexExpr->getType(); |
| |
| auto decomposedIndexType = decomposeArgParamType(indexType); |
| calleeInfo.filterList([&](UncurriedCandidate cand) -> |
| CalleeCandidateInfo::ClosenessResultTy |
| { |
| // Classify how close this match is. Non-subscript decls don't match. |
| auto *SD = dyn_cast<SubscriptDecl>(cand.decl); |
| if (!SD) return { CC_GeneralMismatch, {}}; |
| |
| // Check to make sure the base expr type is convertible to the expected base |
| // type. We check either the getter, or if it isn't present, the addressor. |
| auto selfConstraint = CC_ExactMatch; |
| auto getter = SD->getGetter(); |
| if (!getter) getter = SD->getAddressor(); |
| |
| auto instanceTy = |
| getter->getImplicitSelfDecl()->getType()->getInOutObjectType(); |
| if (!isUnresolvedOrTypeVarType(baseType) && |
| // TODO: We're not handling archetypes well here. |
| !instanceTy->hasArchetype() && |
| !CS->TC.isConvertibleTo(baseType, instanceTy, CS->DC)) { |
| selfConstraint = CC_SelfMismatch; |
| } |
| |
| // Explode out multi-index subscripts to find the best match. |
| auto indexResult = |
| evaluateCloseness(cand.getArgumentType(), decomposedIndexType, |
| /*FIXME: Subscript trailing closures*/false); |
| if (selfConstraint > indexResult.first) |
| return {selfConstraint, {}}; |
| return indexResult; |
| }); |
| |
| // TODO: Is there any reason to check for CC_NonLValueInOut here? |
| |
| if (calleeInfo.closeness == CC_ExactMatch) { |
| // Otherwise, whatever the result type of the call happened to be must not |
| // have been what we were looking for. Lets diagnose it as a conversion |
| // or ambiguity failure. |
| if (calleeInfo.size() == 1) |
| return false; |
| |
| diagnose(SE->getLoc(), diag::ambiguous_subscript, baseType, indexType) |
| .highlight(indexExpr->getSourceRange()) |
| .highlight(baseExpr->getSourceRange()); |
| |
| // FIXME: suggestPotentialOverloads should do this. |
| //calleeInfo.suggestPotentialOverloads(SE->getLoc()); |
| for (auto candidate : calleeInfo.candidates) |
| diagnose(candidate.decl, diag::found_candidate); |
| |
| return true; |
| } |
| |
| if (calleeInfo.closeness == CC_Unavailable) { |
| if (CS->TC.diagnoseExplicitUnavailability(calleeInfo[0].decl, |
| SE->getLoc(), CS->DC)) |
| return true; |
| return false; |
| } |
| |
| // If the closest matches all mismatch on self, we either have something that |
| // cannot be subscripted, or an ambiguity. |
| if (calleeInfo.closeness == CC_SelfMismatch) { |
| diagnose(SE->getLoc(), diag::cannot_subscript_base, baseType) |
| .highlight(SE->getBase()->getSourceRange()); |
| // FIXME: Should suggest overload set, but we're not ready for that until |
| // it points to candidates and identifies the self type in the diagnostic. |
| //calleeInfo.suggestPotentialOverloads(SE->getLoc()); |
| return true; |
| } |
| |
| diagnose(SE->getLoc(), diag::cannot_subscript_with_index, |
| baseType, indexType); |
| |
| calleeInfo.suggestPotentialOverloads(SE->getLoc()); |
| return true; |
| } |
| |
| |
| namespace { |
| /// Type checking listener for pattern binding initializers. |
| class CalleeListener : public ExprTypeCheckListener { |
| Type contextualType; |
| public: |
| explicit CalleeListener(Type contextualType) |
| : contextualType(contextualType) { } |
| |
| virtual bool builtConstraints(ConstraintSystem &cs, Expr *expr) { |
| // If we have no contextual type, there is nothing to do. |
| if (!contextualType) return false; |
| |
| // If the expression is obviously something that produces a metatype, |
| // then don't put a constraint on it. |
| auto semExpr = expr->getValueProvidingExpr(); |
| if (isa<TypeExpr>(semExpr) ||isa<UnresolvedConstructorExpr>(semExpr)) |
| return false; |
| |
| // We're making the expr have a function type, whose result is the same |
| // as our contextual type. |
| auto inputLocator = |
| cs.getConstraintLocator(expr, ConstraintLocator::FunctionResult); |
| |
| auto tv = cs.createTypeVariable(inputLocator, |
| TVO_CanBindToLValue|TVO_PrefersSubtypeBinding); |
| |
| // In order to make this work, we pick the most general function type and |
| // use a conversion constraint. This gives us: |
| // "$T0 throws -> contextualType" |
| // this allows things that are throws and not throws, and allows escape |
| // and noescape functions. |
| auto extInfo = FunctionType::ExtInfo().withThrows(); |
| auto fTy = FunctionType::get(tv, contextualType, extInfo); |
| |
| auto locator = cs.getConstraintLocator(expr); |
| |
| // Add a conversion constraint between the types. |
| cs.addConstraint(ConstraintKind::Conversion, expr->getType(), |
| fTy, locator, /*isFavored*/true); |
| return false; |
| } |
| }; |
| } |
| |
| /// Return true if the argument of a CallExpr (or related node) has a trailing |
| /// closure. |
| static bool callArgHasTrailingClosure(Expr *E) { |
| if (!E) return false; |
| if (auto *PE = dyn_cast<ParenExpr>(E)) |
| return PE->hasTrailingClosure(); |
| else if (auto *TE = dyn_cast<TupleExpr>(E)) |
| return TE->hasTrailingClosure(); |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitApplyExpr(ApplyExpr *callExpr) { |
| // Type check the function subexpression to resolve a type for it if possible. |
| auto fnExpr = typeCheckChildIndependently(callExpr->getFn()); |
| if (!fnExpr) return true; |
| |
| // If we have a contextual type, and if we have an ambiguously typed function |
| // result from our previous check, we re-type-check it using this contextual |
| // type to inform the result type of the callee. |
| // |
| // We only do this as a second pass because the first pass we just did may |
| // return something of obviously non-function-type. If this happens, we |
| // produce better diagnostics below by diagnosing this here rather than trying |
| // to peel apart the failed conversion to function type. |
| if (CS->getContextualType() && |
| (isUnresolvedOrTypeVarType(fnExpr->getType()) || |
| (fnExpr->getType()->is<AnyFunctionType>() && |
| fnExpr->getType()->hasUnresolvedType()))) { |
| CalleeListener listener(CS->getContextualType()); |
| fnExpr = typeCheckChildIndependently(callExpr->getFn(), Type(), |
| CTP_CalleeResult, TCC_ForceRecheck, |
| &listener); |
| if (!fnExpr) return true; |
| } |
| |
| auto fnType = fnExpr->getType()->getRValueType(); |
| |
| // If we resolved a concrete expression for the callee, and it has |
| // non-function/non-metatype type, then we cannot call it! |
| if (!isUnresolvedOrTypeVarType(fnType) && |
| !fnType->is<AnyFunctionType>() && !fnType->is<MetatypeType>()) { |
| |
| // If the argument is a trailing ClosureExpr (i.e. {....}) and it is on a |
| // different line than the callee, then the "real" issue is that the user |
| // forgot to write "do" before their brace stmt. |
| if (auto *PE = dyn_cast<ParenExpr>(callExpr->getArg())) |
| if (PE->hasTrailingClosure() && isa<ClosureExpr>(PE->getSubExpr())) { |
| auto &SM = CS->getASTContext().SourceMgr; |
| if (SM.getLineNumber(callExpr->getFn()->getEndLoc()) != |
| SM.getLineNumber(PE->getStartLoc())) { |
| diagnose(PE->getStartLoc(), diag::expected_do_in_statement) |
| .fixItInsert(PE->getStartLoc(), "do "); |
| return true; |
| } |
| } |
| |
| diagnose(callExpr->getArg()->getStartLoc(), |
| diag::cannot_call_non_function_value, fnExpr->getType()) |
| .highlight(fnExpr->getSourceRange()); |
| return true; |
| } |
| |
| bool hasTrailingClosure = callArgHasTrailingClosure(callExpr->getArg()); |
| |
| // Collect a full candidate list of callees based on the partially type |
| // checked function. |
| CalleeCandidateInfo calleeInfo(fnExpr, hasTrailingClosure, CS); |
| |
| // Filter the candidate list based on the argument we may or may not have. |
| calleeInfo.filterContextualMemberList(callExpr->getArg()); |
| |
| if (calleeInfo.diagnoseAnyStructuralArgumentError(callExpr->getFn(), |
| callExpr->getArg())) |
| return true; |
| |
| Type argType; // Type of the argument list, if knowable. |
| if (auto FTy = fnType->getAs<AnyFunctionType>()) |
| argType = FTy->getInput(); |
| else if (auto MTT = fnType->getAs<AnyMetatypeType>()) { |
| // If we are constructing a tuple with initializer syntax, the expected |
| // argument list is the tuple type itself - and there is no initdecl. |
| auto instanceTy = MTT->getInstanceType(); |
| if (instanceTy->is<TupleType>()) { |
| argType = instanceTy; |
| } |
| } |
| |
| // Get the expression result of type checking the arguments to the call |
| // independently, so we have some idea of what we're working with. |
| // |
| auto argExpr = typeCheckArgumentChildIndependently(callExpr->getArg(), |
| argType, calleeInfo); |
| if (!argExpr) |
| return true; // already diagnosed. |
| |
| calleeInfo.filterList(argExpr->getType()); |
| |
| if (calleeInfo.diagnoseAnyStructuralArgumentError(callExpr->getFn(), argExpr)) |
| return true; |
| |
| // If we have a failure where the candidate set differs on exactly one |
| // argument, and where we have a consistent mismatch across the candidate set |
| // (often because there is only one candidate in the set), then diagnose this |
| // as a specific problem of passing something of the wrong type into a |
| // parameter. |
| if ((calleeInfo.closeness == CC_OneArgumentMismatch || |
| calleeInfo.closeness == CC_OneArgumentNearMismatch) && |
| calleeInfo.failedArgument.isValid()) { |
| // Map the argument number into an argument expression. |
| TCCOptions options = TCC_ForceRecheck; |
| if (calleeInfo.failedArgument.parameterType->is<InOutType>()) |
| options |= TCC_AllowLValue; |
| |
| Expr *badArgExpr; |
| if (auto *TE = dyn_cast<TupleExpr>(argExpr)) |
| badArgExpr = TE->getElement(calleeInfo.failedArgument.argumentNumber); |
| else if (auto *PE = dyn_cast<ParenExpr>(argExpr)) { |
| assert(calleeInfo.failedArgument.argumentNumber == 0 && |
| "Unexpected argument #"); |
| badArgExpr = PE->getSubExpr(); |
| } else { |
| assert(calleeInfo.failedArgument.argumentNumber == 0 && |
| "Unexpected argument #"); |
| badArgExpr = argExpr; |
| } |
| |
| // Re-type-check the argument with the expected type of the candidate set. |
| // This should produce a specific and tailored diagnostic saying that the |
| // type mismatches with expectations. |
| if (!typeCheckChildIndependently(badArgExpr, |
| calleeInfo.failedArgument.parameterType, |
| CTP_CallArgument, options)) |
| return true; |
| } |
| |
| |
| // Handle uses of unavailable symbols. |
| if (calleeInfo.closeness == CC_Unavailable) |
| return CS->TC.diagnoseExplicitUnavailability(calleeInfo[0].decl, |
| callExpr->getLoc(), CS->DC); |
| |
| // A common error is to apply an operator that only has inout forms (e.g. +=) |
| // to non-lvalues (e.g. a local let). Produce a nice diagnostic for this |
| // case. |
| if (calleeInfo.closeness == CC_NonLValueInOut) { |
| Diag<StringRef> subElementDiagID; |
| Diag<Type> rvalueDiagID; |
| Expr *diagExpr = nullptr; |
| |
| 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; |
| |
| if (auto argTuple = dyn_cast<TupleExpr>(argExpr)) |
| diagExpr = argTuple->getElement(0); |
| } |
| |
| if (diagExpr) { |
| diagnoseSubElementFailure(diagExpr, callExpr->getFn()->getLoc(), *CS, |
| subElementDiagID, rvalueDiagID); |
| return true; |
| } |
| } |
| |
| // Handle argument label mismatches when we have multiple candidates. |
| if (calleeInfo.closeness == CC_ArgumentLabelMismatch) { |
| auto args = decomposeArgParamType(argExpr->getType()); |
| |
| // If we have multiple candidates that we fail to match, just say we have |
| // the wrong labels and list the candidates out. |
| |
| // TODO: It would be nice to use an analog of getTypeListString that |
| // doesn't include the argument types. |
| diagnose(callExpr->getLoc(), diag::wrong_argument_labels_overload, |
| getParamListAsString(args)) |
| .highlight(argExpr->getSourceRange()); |
| |
| // Did the user intend on invoking a different overload? |
| calleeInfo.suggestPotentialOverloads(fnExpr->getLoc()); |
| return true; |
| } |
| |
| auto overloadName = calleeInfo.declName; |
| |
| // Otherwise, we have a generic failure. Diagnose it with a generic error |
| // message now. |
| if (isa<BinaryExpr>(callExpr) && isa<TupleExpr>(argExpr)) { |
| auto argTuple = cast<TupleExpr>(argExpr); |
| auto lhsExpr = argTuple->getElement(0), rhsExpr = argTuple->getElement(1); |
| auto lhsType = lhsExpr->getType()->getRValueType(); |
| auto rhsType = rhsExpr->getType()->getRValueType(); |
| |
| // If this is a comparison against nil, then we should produce a specific |
| // diagnostic. |
| if (isa<NilLiteralExpr>(rhsExpr->getValueProvidingExpr()) && |
| !isUnresolvedOrTypeVarType(lhsType)) { |
| if (overloadName == "==" || overloadName == "!=" || |
| overloadName == "===" || overloadName == "!==" || |
| overloadName == "<" || overloadName == ">" || |
| overloadName == "<=" || overloadName == ">=") { |
| diagnose(callExpr->getLoc(), diag::comparison_with_nil_illegal, lhsType) |
| .highlight(lhsExpr->getSourceRange()); |
| return true; |
| } |
| } |
| |
| if (callExpr->isImplicit() && overloadName == "~=") { |
| // This binop was synthesized when typechecking an expression pattern. |
| diagnose(lhsExpr->getLoc(), |
| diag::cannot_match_expr_pattern_with_value, lhsType, rhsType) |
| .highlight(lhsExpr->getSourceRange()) |
| .highlight(rhsExpr->getSourceRange()); |
| return true; |
| } |
| |
| // If we found an exact match, this must be a problem with a conversion from |
| // the result of the call to the expected type. Diagnose this as a |
| // conversion failure. |
| if (calleeInfo.closeness == CC_ExactMatch) |
| return false; |
| |
| if (!lhsType->isEqual(rhsType)) { |
| diagnose(callExpr->getLoc(), diag::cannot_apply_binop_to_args, |
| overloadName, lhsType, rhsType) |
| .highlight(lhsExpr->getSourceRange()) |
| .highlight(rhsExpr->getSourceRange()); |
| } else { |
| diagnose(callExpr->getLoc(), diag::cannot_apply_binop_to_same_args, |
| overloadName, lhsType) |
| .highlight(lhsExpr->getSourceRange()) |
| .highlight(rhsExpr->getSourceRange()); |
| } |
| |
| calleeInfo.suggestPotentialOverloads(callExpr->getLoc()); |
| return true; |
| } |
| |
| // If we found an exact match, this must be a problem with a conversion from |
| // the result of the call to the expected type. Diagnose this as a |
| // conversion failure. |
| if (calleeInfo.closeness == CC_ExactMatch) |
| return false; |
| |
| // Generate specific error messages for unary operators. |
| if (isa<PrefixUnaryExpr>(callExpr) || isa<PostfixUnaryExpr>(callExpr)) { |
| assert(!overloadName.empty()); |
| diagnose(argExpr->getLoc(), diag::cannot_apply_unop_to_arg, overloadName, |
| argExpr->getType()); |
| |
| calleeInfo.suggestPotentialOverloads(argExpr->getLoc()); |
| return true; |
| } |
| |
| std::string argString = getTypeListString(argExpr->getType()); |
| |
| // If we couldn't get the name of the callee, then it must be something of a |
| // more complex "value of function type". |
| if (overloadName.empty()) { |
| // If we couldn't infer the result type of the closure expr, then we have |
| // some sort of ambiguity, let the ambiguity diagnostic stuff handle this. |
| if (auto ffty = fnType->getAs<AnyFunctionType>()) |
| if (ffty->getResult()->hasTypeVariable()) { |
| diagnoseAmbiguity(fnExpr); |
| return true; |
| } |
| |
| // The most common unnamed value of closure type is a ClosureExpr, so |
| // special case it. |
| if (isa<ClosureExpr>(fnExpr->getValueProvidingExpr())) { |
| if (fnType->hasTypeVariable()) |
| diagnose(argExpr->getStartLoc(), diag::cannot_invoke_closure, argString) |
| .highlight(fnExpr->getSourceRange()); |
| else |
| diagnose(argExpr->getStartLoc(), diag::cannot_invoke_closure_type, |
| fnType, argString) |
| .highlight(fnExpr->getSourceRange()); |
| |
| } else if (fnType->hasTypeVariable()) { |
| diagnose(argExpr->getStartLoc(), diag::cannot_call_function_value, |
| argString) |
| .highlight(fnExpr->getSourceRange()); |
| } else { |
| diagnose(argExpr->getStartLoc(), diag::cannot_call_value_of_function_type, |
| fnType, argString) |
| .highlight(fnExpr->getSourceRange()); |
| } |
| |
| return true; |
| } |
| |
| // If we have an argument list (i.e., a scalar, or a non-zero-element tuple) |
| // then diagnose with some specificity about the arguments. |
| bool isInitializer = isa<TypeExpr>(fnExpr); |
| if (isa<TupleExpr>(argExpr) && |
| cast<TupleExpr>(argExpr)->getNumElements() == 0) { |
| // Emit diagnostics that say "no arguments". |
| diagnose(fnExpr->getLoc(), diag::cannot_call_with_no_params, |
| overloadName, isInitializer); |
| } else { |
| diagnose(fnExpr->getLoc(), diag::cannot_call_with_params, |
| overloadName, argString, isInitializer); |
| } |
| |
| // Did the user intend on invoking a different overload? |
| calleeInfo.suggestPotentialOverloads(fnExpr->getLoc()); |
| return true; |
| } |
| |
| bool FailureDiagnosis::visitAssignExpr(AssignExpr *assignExpr) { |
| // Diagnose obvious assignments to literals. |
| if (isa<LiteralExpr>(assignExpr->getDest()->getValueProvidingExpr())) { |
| diagnose(assignExpr->getLoc(), diag::cannot_assign_to_literal); |
| return true; |
| } |
| |
| // Type check the destination first, so we can coerce the source to it. |
| auto destExpr = typeCheckChildIndependently(assignExpr->getDest(), |
| TCC_AllowLValue); |
| if (!destExpr) return true; |
| |
| auto destType = destExpr->getType(); |
| if (destType->is<UnresolvedType>() || destType->hasTypeVariable()) { |
| // If we have no useful type information from the destination, just type |
| // check the source without contextual information. If it succeeds, then we |
| // win, but if it fails, we'll have to diagnose this another way. |
| return !typeCheckChildIndependently(assignExpr->getSrc()); |
| } |
| |
| |
| // If the result type is a non-lvalue, then we are failing because it is |
| // immutable and that's not a great thing to assign to. |
| if (!destType->isLValueType()) { |
| CS->diagnoseAssignmentFailure(destExpr, destType, assignExpr->getLoc()); |
| return true; |
| } |
| |
| // If the source type is already an error type, we've already posted an error. |
| auto srcExpr = typeCheckChildIndependently(assignExpr->getSrc(), |
| destType->getRValueType(), |
| CTP_AssignSource); |
| if (!srcExpr) return true; |
| return false; |
| } |
| |
| |
| /// Return true if this type is known to be an ArrayType. |
| static bool isKnownToBeArrayType(Type ty) { |
| if (!ty) return false; |
| |
| auto bgt = ty->getAs<BoundGenericType>(); |
| if (!bgt) return false; |
| |
| auto &ctx = bgt->getASTContext(); |
| return bgt->getDecl() == ctx.getArrayDecl(); |
| } |
| |
| /// If the specific type is UnsafePointer<T>, UnsafeMutablePointer<T>, or |
| /// AutoreleasingUnsafeMutablePointer<T>, return the BoundGenericType for it. |
| static BoundGenericType *getKnownUnsafePointerType(Type ty) { |
| // Must be a generic type. |
| auto bgt = ty->getAs<BoundGenericType>(); |
| if (!bgt) return nullptr; |
| |
| // Must be UnsafeMutablePointer or UnsafePointer. |
| auto &ctx = bgt->getASTContext(); |
| if (bgt->getDecl() != ctx.getUnsafeMutablePointerDecl() && |
| bgt->getDecl() != ctx.getUnsafePointerDecl() && |
| bgt->getDecl() != ctx.getAutoreleasingUnsafeMutablePointerDecl()) |
| return nullptr; |
| |
| return bgt; |
| } |
| |
| bool FailureDiagnosis::visitInOutExpr(InOutExpr *IOE) { |
| // If we have a contextual type, it must be an inout type. |
| auto contextualType = CS->getContextualType(); |
| if (contextualType) { |
| // If the contextual type is one of the UnsafePointer<T> types, then the |
| // contextual type of the subexpression must be T. |
| if (auto pointerType = getKnownUnsafePointerType(contextualType)) { |
| auto pointerEltType = pointerType->getGenericArgs()[0]; |
| |
| // If the element type is Void, then we allow any input type, since |
| // everything is convertible to UnsafePointer<Void> |
| if (pointerEltType->isVoid()) |
| contextualType = Type(); |
| else |
| contextualType = pointerEltType; |
| |
| // Furthermore, if the subexpr type is already known to be an array type, |
| // then we must have an attempt at an array to pointer conversion. |
| if (isKnownToBeArrayType(IOE->getSubExpr()->getType())) { |
| // If we're converting to an UnsafeMutablePointer, then the pointer to |
| // the first element is being passed in. The array is ok, so long as |
| // it is mutable. |
| if (pointerType->getDecl() == |
| CS->getASTContext().getUnsafeMutablePointerDecl()) { |
| if (contextualType) |
| contextualType = ArraySliceType::get(contextualType); |
| } else if (pointerType->getDecl() == |
| CS->getASTContext().getUnsafePointerDecl()) { |
| // If we're converting to an UnsafePointer, then the programmer |
| // specified an & unnecessarily. Produce a fixit hint to remove it. |
| diagnose(IOE->getLoc(), diag::extra_address_of_unsafepointer, |
| pointerType) |
| .highlight(IOE->getSourceRange()) |
| .fixItRemove(IOE->getStartLoc()); |
| return true; |
| } |
| } |
| |
| |
| } else if (contextualType->is<InOutType>()) { |
| contextualType = contextualType->getInOutObjectType(); |
| } else { |
| // If the caller expected something inout, but we didn't have |
| // something of inout type, diagnose it. |
| diagnose(IOE->getLoc(), diag::extra_address_of, contextualType) |
| .highlight(IOE->getSourceRange()) |
| .fixItRemove(IOE->getStartLoc()); |
| return true; |
| } |
| } |
| |
| auto subExpr = typeCheckChildIndependently(IOE->getSubExpr(), contextualType, |
| CS->getContextualTypePurpose(), |
| TCC_AllowLValue); |
| if (!subExpr) return true; |
| |
| auto subExprType = subExpr->getType(); |
| |
| // The common cause is that the operand is not an lvalue. |
| if (!subExprType->isLValueType()) { |
| diagnoseSubElementFailure(subExpr, IOE->getLoc(), *CS, |
| diag::cannot_pass_rvalue_inout_subelement, |
| diag::cannot_pass_rvalue_inout); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitCoerceExpr(CoerceExpr *CE) { |
| // Coerce the input to whatever type is specified by the CoerceExpr. |
| if (!typeCheckChildIndependently(CE->getSubExpr(), |
| CE->getCastTypeLoc().getType(), |
| CTP_CoerceOperand)) |
| return true; |
| |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitForceValueExpr(ForceValueExpr *FVE) { |
| auto argExpr = typeCheckChildIndependently(FVE->getSubExpr()); |
| if (!argExpr) return true; |
| auto argType = argExpr->getType(); |
| |
| // If the subexpression type checks as a non-optional type, then that is the |
| // error. Produce a specific diagnostic about this. |
| if (!isUnresolvedOrTypeVarType(argType) && |
| argType->getAnyOptionalObjectType().isNull()) { |
| diagnose(FVE->getLoc(), diag::invalid_force_unwrap, argType) |
| .fixItRemove(FVE->getExclaimLoc()) |
| .highlight(FVE->getSourceRange()); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitBindOptionalExpr(BindOptionalExpr *BOE) { |
| auto argExpr = typeCheckChildIndependently(BOE->getSubExpr()); |
| if (!argExpr) return true; |
| auto argType = argExpr->getType(); |
| |
| // If the subexpression type checks as a non-optional type, then that is the |
| // error. Produce a specific diagnostic about this. |
| if (!isUnresolvedOrTypeVarType(argType) && |
| argType->getAnyOptionalObjectType().isNull()) { |
| diagnose(BOE->getQuestionLoc(), diag::invalid_optional_chain, argType) |
| .highlight(BOE->getSourceRange()) |
| .fixItRemove(BOE->getQuestionLoc()); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitIfExpr(IfExpr *IE) { |
| // Check all of the subexpressions independently. |
| auto condExpr = typeCheckChildIndependently(IE->getCondExpr()); |
| if (!condExpr) return true; |
| auto trueExpr = typeCheckChildIndependently(IE->getThenExpr()); |
| if (!trueExpr) return true; |
| |
| auto falseExpr = typeCheckChildIndependently(IE->getElseExpr()); |
| if (!falseExpr) return true; |
| |
| // Check for "=" converting to BooleanType. The user probably meant ==. |
| if (auto *AE = dyn_cast<AssignExpr>(condExpr->getValueProvidingExpr())) { |
| diagnose(AE->getEqualLoc(), diag::use_of_equal_instead_of_equality) |
| .fixItReplace(AE->getEqualLoc(), "==") |
| .highlight(AE->getDest()->getLoc()) |
| .highlight(AE->getSrc()->getLoc()); |
| return true; |
| } |
| |
| // If the condition wasn't of boolean type, diagnose the problem. |
| auto booleanType = CS->TC.getProtocol(IE->getQuestionLoc(), |
| KnownProtocolKind::BooleanType); |
| if (!booleanType) return true; |
| |
| if (!CS->TC.conformsToProtocol(condExpr->getType(), booleanType, CS->DC, |
| ConformanceCheckFlags::InExpression, |
| nullptr, condExpr->getLoc())) |
| return true; |
| |
| // If the true/false values already match, it must be a contextual problem. |
| if (trueExpr->getType()->isEqual(falseExpr->getType())) |
| return false; |
| |
| // Otherwise, the true/false result types must not be matching. |
| diagnose(IE->getColonLoc(), diag::if_expr_cases_mismatch, |
| trueExpr->getType(), falseExpr->getType()) |
| .highlight(trueExpr->getSourceRange()) |
| .highlight(falseExpr->getSourceRange()); |
| return true; |
| } |
| |
| |
| bool FailureDiagnosis:: |
| visitRebindSelfInConstructorExpr(RebindSelfInConstructorExpr *E) { |
| // Don't walk the children for this node, it leads to multiple diagnostics |
| // because of how sema injects this node into the type checker. |
| return false; |
| } |
| |
| |
| bool FailureDiagnosis::visitClosureExpr(ClosureExpr *CE) { |
| Type expectedResultType; |
| |
| // If we have a contextual type available for this closure, apply it to the |
| // ParamDecls in our parameter list. This ensures that any uses of them get |
| // appropriate types. |
| if (CS->getContextualType() && |
| CS->getContextualType()->is<AnyFunctionType>()) { |
| |
| auto fnType = CS->getContextualType()->castTo<AnyFunctionType>(); |
| auto *params = CE->getParameters(); |
| Type inferredArgType = fnType->getInput(); |
| |
| // It is very common for a contextual type to disagree with the argument |
| // list built into the closure expr. This can be because the closure expr |
| // had an explicitly specified pattern, a la: |
| // { a,b in ... } |
| // or could be because the closure has an implicitly generated one: |
| // { $0 + $1 } |
| // in either case, we want to produce nice and clear diagnostics. |
| unsigned actualArgCount = params->size(); |
| unsigned inferredArgCount = 1; |
| if (auto *argTupleTy = inferredArgType->getAs<TupleType>()) |
| inferredArgCount = argTupleTy->getNumElements(); |
| |
| // If the actual argument count is 1, it can match a tuple as a whole. |
| if (actualArgCount != 1 && actualArgCount != inferredArgCount) { |
| // 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 (actualArgCount == 0 && CE->getInLoc().isInvalid()) { |
| auto diag = |
| diagnose(CE->getStartLoc(), diag::closure_argument_list_missing, |
| inferredArgCount); |
| StringRef fixText; // We only handle the most common cases. |
| if (inferredArgCount == 1) |
| fixText = " _ in "; |
| else if (inferredArgCount == 2) |
| fixText = " _,_ in "; |
| else if (inferredArgCount == 3) |
| 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 = CE->getStartLoc().getAdvancedLoc(1); |
| auto text = CS->TC.Context.SourceMgr.extractText({afterBrace, 1}); |
| if (text.size() == 1 && text == " ") |
| fixText = fixText.drop_back(); |
| else |
| fixText = fixText.drop_front(); |
| diag.fixItInsertAfter(CE->getStartLoc(), fixText); |
| } |
| return true; |
| } |
| |
| // Okay, the wrong number of arguments was used, complain about that. |
| // Before doing so, strip attributes off the function type so that they |
| // don't confuse the issue. |
| fnType = FunctionType::get(fnType->getInput(), fnType->getResult()); |
| diagnose(params->getStartLoc(), diag::closure_argument_list_tuple, |
| fnType, inferredArgCount, actualArgCount); |
| return true; |
| } |
| |
| if (CS->TC.coerceParameterListToType(params, CE, inferredArgType)) |
| return true; |
| |
| expectedResultType = fnType->getResult(); |
| } else { |
| |
| // Defend against type variables from our constraint system leaking into |
| // recursive constraints systems formed when checking the body of the |
| // closure. These typevars come into them when the body does name |
| // lookups against the parameter decls. |
| // |
| // Handle this by rewriting the arguments to UnresolvedType(). |
| for (auto VD : *CE->getParameters()) { |
| if (VD->getType()->hasTypeVariable() || VD->getType()->is<ErrorType>()) |
| VD->overwriteType(CS->getASTContext().TheUnresolvedType); |
| } |
| } |
| |
| // If this is a complex leaf closure, there is nothing more we can do. |
| if (!CE->hasSingleExpressionBody()) |
| return false; |
| |
| // If the closure had an expected result type, use it. |
| if (CE->hasExplicitResultType()) |
| expectedResultType = CE->getExplicitResultTypeLoc().getType(); |
| |
| // When we're type checking a single-expression closure, we need to reset the |
| // DeclContext to this closure for the recursive type checking. Otherwise, |
| // if there is a closure in the subexpression, we can violate invariants. |
| { |
| llvm::SaveAndRestore<DeclContext*> SavedDC(CS->DC, CE); |
| |
| auto CTP = expectedResultType ? CTP_ClosureResult : CTP_Unused; |
| |
| if (!typeCheckChildIndependently(CE->getSingleExpressionBody(), |
| expectedResultType, CTP)) |
| return true; |
| } |
| |
| // If the body of the closure looked ok, then look for a contextual type |
| // error. This is necessary because FailureDiagnosis::diagnoseExprFailure |
| // doesn't do this for closures. |
| if (CS->getContextualType() && |
| !CS->getContextualType()->isEqual(CE->getType())) { |
| |
| auto fnType = CS->getContextualType()->getAs<AnyFunctionType>(); |
| |
| // If the closure had an explicitly written return type incompatible with |
| // the contextual type, diagnose that. |
| if (CE->hasExplicitResultType() && |
| CE->getExplicitResultTypeLoc().getTypeRepr()) { |
| auto explicitResultTy = CE->getExplicitResultTypeLoc().getType(); |
| if (fnType && !explicitResultTy->isEqual(fnType->getResult())) { |
| auto repr = CE->getExplicitResultTypeLoc().getTypeRepr(); |
| diagnose(repr->getStartLoc(), diag::incorrect_explicit_closure_result, |
| explicitResultTy, fnType->getResult()) |
| .fixItReplace(repr->getSourceRange(),fnType->getResult().getString()); |
| return true; |
| } |
| } |
| } |
| |
| // Otherwise, we can't produce a specific diagnostic. |
| return false; |
| } |
| |
| static bool isDictionaryLiteralCompatible(Type ty, ConstraintSystem *CS, |
| SourceLoc loc) { |
| auto DLC = CS->TC.getProtocol(loc, |
| KnownProtocolKind::DictionaryLiteralConvertible); |
| if (!DLC) return false; |
| return CS->TC.conformsToProtocol(ty, DLC, CS->DC, |
| ConformanceCheckFlags::InExpression); |
| } |
| |
| bool FailureDiagnosis::visitArrayExpr(ArrayExpr *E) { |
| Type contextualElementType; |
| auto elementTypePurpose = CTP_Unused; |
| |
| // If we had a contextual type, then it either conforms to |
| // ArrayLiteralConvertible or it is an invalid contextual type. |
| if (auto contextualType = CS->getContextualType()) { |
| // If our contextual type is an optional, look through them, because we're |
| // surely initializing whatever is inside. |
| contextualType = contextualType->lookThroughAllAnyOptionalTypes(); |
| |
| // Validate that the contextual type conforms to ArrayLiteralConvertible and |
| // figure out what the contextual element type is in place. |
| auto ALC = CS->TC.getProtocol(E->getLoc(), |
| KnownProtocolKind::ArrayLiteralConvertible); |
| ProtocolConformance *Conformance = nullptr; |
| if (!ALC) |
| return visitExpr(E); |
| |
| // Check to see if the contextual type conforms. |
| bool foundConformance = |
| CS->TC.conformsToProtocol(contextualType, ALC, CS->DC, |
| ConformanceCheckFlags::InExpression, |
| &Conformance); |
| |
| // If not, we may have an implicit conversion going on. If the contextual |
| // type is an UnsafePointer or UnsafeMutablePointer, then that is probably |
| // what is happening. |
| if (!foundConformance) { |
| // TODO: Not handling various string conversions or void conversions. |
| auto cBGT = contextualType->getAs<BoundGenericType>(); |
| if (cBGT && cBGT->getDecl() == CS->TC.Context.getUnsafePointerDecl()) { |
| auto arrayTy = ArraySliceType::get(cBGT->getGenericArgs()[0]); |
| foundConformance = |
| CS->TC.conformsToProtocol(arrayTy, ALC, CS->DC, |
| ConformanceCheckFlags::InExpression, |
| &Conformance); |
| if (foundConformance) |
| contextualType = arrayTy; |
| } |
| } |
| |
| if (!foundConformance) { |
| // If the contextual type conforms to DictionaryLiteralConvertible and |
| // this is an empty array, then they meant "[:]". |
| if (E->getNumElements() == 0 && |
| isDictionaryLiteralCompatible(contextualType, CS, E->getLoc())) { |
| diagnose(E->getStartLoc(), diag::should_use_empty_dictionary_literal) |
| .fixItInsert(E->getEndLoc(), ":"); |
| return true; |
| } |
| |
| |
| diagnose(E->getStartLoc(), diag::type_is_not_array, contextualType) |
| .highlight(E->getSourceRange()); |
| |
| // If the contextual type conforms to DictionaryLiteralConvertible, then |
| // they wrote "x = [1,2]" but probably meant "x = [1:2]". |
| if ((E->getElements().size() & 1) == 0 && !E->getElements().empty() && |
| isDictionaryLiteralCompatible(contextualType, CS, E->getLoc())) { |
| auto diag = diagnose(E->getStartLoc(), diag::meant_dictionary_lit); |
| |
| // Change every other comma into a colon. |
| for (unsigned i = 0, e = E->getElements().size()/2; i != e; ++i) |
| diag.fixItReplace(E->getCommaLocs()[i*2], ":"); |
| } |
| |
| return true; |
| } |
| |
| Conformance->forEachTypeWitness(&CS->TC, |
| [&](AssociatedTypeDecl *ATD, |
| const Substitution &subst, TypeDecl *d)->bool |
| { |
| if (ATD->getName().str() == "Element") |
| contextualElementType = subst.getReplacement()->getDesugaredType(); |
| return false; |
| }); |
| assert(contextualElementType && |
| "Could not find 'Element' ArrayLiteral associated types from" |
| " contextual type conformance"); |
| |
| elementTypePurpose = CTP_ArrayElement; |
| } |
| |
| // Type check each of the subexpressions in place, passing down the contextual |
| // type information if we have it. |
| for (auto elt : E->getElements()) { |
| if (typeCheckChildIndependently(elt, contextualElementType, |
| elementTypePurpose) == nullptr) |
| return true; |
| } |
| |
| // If that didn't turn up an issue, then we don't know what to do. |
| // TODO: When a contextual type is missing, we could try to diagnose cases |
| // where the element types mismatch... but theoretically they should type |
| // unify to Any, so that could never happen? |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitDictionaryExpr(DictionaryExpr *E) { |
| Type contextualKeyType, contextualValueType; |
| auto keyTypePurpose = CTP_Unused, valueTypePurpose = CTP_Unused; |
| |
| // If we had a contextual type, then it either conforms to |
| // DictionaryLiteralConvertible or it is an invalid contextual type. |
| if (auto contextualType = CS->getContextualType()) { |
| // If our contextual type is an optional, look through them, because we're |
| // surely initializing whatever is inside. |
| contextualType = contextualType->lookThroughAllAnyOptionalTypes(); |
| |
| auto DLC = CS->TC.getProtocol(E->getLoc(), |
| KnownProtocolKind::DictionaryLiteralConvertible); |
| if (!DLC) return visitExpr(E); |
| |
| // Validate the contextual type conforms to DictionaryLiteralConvertible |
| // and figure out what the contextual Key/Value types are in place. |
| ProtocolConformance *Conformance = nullptr; |
| if (!CS->TC.conformsToProtocol(contextualType, DLC, CS->DC, |
| ConformanceCheckFlags::InExpression, |
| &Conformance)) { |
| diagnose(E->getStartLoc(), diag::type_is_not_dictionary, contextualType) |
| .highlight(E->getSourceRange()); |
| return true; |
| } |
| |
| Conformance->forEachTypeWitness(&CS->TC, |
| [&](AssociatedTypeDecl *ATD, |
| const Substitution &subst, TypeDecl *d)->bool |
| { |
| if (ATD->getName().str() == "Key") |
| contextualKeyType = subst.getReplacement()->getDesugaredType(); |
| else if (ATD->getName().str() == "Value") |
| contextualValueType = subst.getReplacement()->getDesugaredType(); |
| return false; |
| }); |
| assert(contextualKeyType && contextualValueType && |
| "Could not find Key/Value DictionaryLiteral associated types from" |
| " contextual type conformance"); |
| |
| keyTypePurpose = CTP_DictionaryKey; |
| valueTypePurpose = CTP_DictionaryValue; |
| } |
| |
| // Type check each of the subexpressions in place, passing down the contextual |
| // type information if we have it. |
| for (auto elt : E->getElements()) { |
| auto TE = dyn_cast<TupleExpr>(elt); |
| if (!TE || TE->getNumElements() != 2) continue; |
| |
| if (!typeCheckChildIndependently(TE->getElement(0), |
| contextualKeyType, keyTypePurpose)) |
| return true; |
| if (!typeCheckChildIndependently(TE->getElement(1), |
| contextualValueType, valueTypePurpose)) |
| return true; |
| } |
| |
| // If that didn't turn up an issue, then we don't know what to do. |
| // TODO: When a contextual type is missing, we could try to diagnose cases |
| // where the element types mismatch. There is no Any equivalent since they |
| // keys need to be hashable. |
| return false; |
| } |
| |
| /// When an object literal fails to typecheck because its protocol's |
| /// corresponding default type has not been set in the global namespace (e.g. |
| /// _ColorLiteralType), suggest that the user import the appropriate module for |
| /// the target. |
| bool FailureDiagnosis::visitObjectLiteralExpr(ObjectLiteralExpr *E) { |
| auto &TC = CS->getTypeChecker(); |
| |
| // Type check the argument first. |
| auto protocol = TC.getLiteralProtocol(E); |
| if (!protocol) |
| return false; |
| DeclName constrName = TC.getObjectLiteralConstructorName(E); |
| assert(constrName); |
| ArrayRef<ValueDecl *> constrs = protocol->lookupDirect(constrName); |
| if (constrs.size() != 1 || !isa<ConstructorDecl>(constrs.front())) |
| return false; |
| auto *constr = cast<ConstructorDecl>(constrs.front()); |
| if (!typeCheckChildIndependently( |
| E->getArg(), constr->getArgumentType(), CTP_CallArgument)) |
| return true; |
| |
| // Conditions for showing this diagnostic: |
| // * The object literal protocol's default type is unimplemented |
| if (TC.getDefaultType(protocol, CS->DC)) |
| return false; |
| // * The object literal has no contextual type |
| if (CS->getContextualType()) |
| return false; |
| |
| // Figure out what import to suggest. |
| auto &Ctx = CS->getASTContext(); |
| const auto &target = Ctx.LangOpts.Target; |
| StringRef plainName = E->getName().str(); |
| StringRef importModule; |
| StringRef importDefaultTypeName; |
| if (protocol == Ctx.getProtocol(KnownProtocolKind::ColorLiteralConvertible)) { |
| plainName = "color"; |
| if (target.isMacOSX()) { |
| importModule = "AppKit"; |
| importDefaultTypeName = "NSColor"; |
| } else if (target.isiOS() || target.isTvOS()) { |
| importModule = "UIKit"; |
| importDefaultTypeName = "UIColor"; |
| } |
| } else if (protocol == Ctx.getProtocol( |
| KnownProtocolKind::ImageLiteralConvertible)) { |
| plainName = "image"; |
| if (target.isMacOSX()) { |
| importModule = "AppKit"; |
| importDefaultTypeName = "NSImage"; |
| } else if (target.isiOS() || target.isTvOS()) { |
| importModule = "UIKit"; |
| importDefaultTypeName = "UIImage"; |
| } |
| } else if (protocol == Ctx.getProtocol( |
| KnownProtocolKind::FileReferenceLiteralConvertible)) { |
| plainName = "file reference"; |
| importModule = "Foundation"; |
| importDefaultTypeName = "NSURL"; |
| } |
| |
| // Emit the diagnostic. |
| TC.diagnose(E->getLoc(), diag::object_literal_default_type_missing, |
| plainName); |
| if (!importModule.empty()) { |
| TC.diagnose(E->getLoc(), diag::object_literal_resolve_import, |
| importModule, importDefaultTypeName, plainName); |
| } |
| return true; |
| } |
| |
| bool FailureDiagnosis::visitUnresolvedMemberExpr(UnresolvedMemberExpr *E) { |
| // If we have no contextual type, there is no way to resolve this. Just |
| // diagnose this as an ambiguity. |
| if (!CS->getContextualType()) |
| return false; |
| |
| // OTOH, if we do have a contextual type, we can provide a more specific |
| // error. Dig out the UnresolvedValueMember constraint for this expr node. |
| Constraint *memberConstraint = nullptr; |
| auto checkConstraint = [&](Constraint *C) { |
| if (C->getKind() == ConstraintKind::UnresolvedValueMember && |
| simplifyLocatorToAnchor(*CS, C->getLocator()) == E) |
| memberConstraint = C; |
| }; |
| |
| if (CS->failedConstraint) |
| checkConstraint(CS->failedConstraint); |
| for (auto &C : CS->getConstraints()) { |
| if (memberConstraint) break; |
| checkConstraint(&C); |
| } |
| |
| // If we can't find the member constraint in question, then we failed. |
| if (!memberConstraint) |
| return false; |
| |
| // If we succeeded, get ready to do the member lookup. |
| auto baseObjTy = CS->getContextualType()->getRValueType(); |
| |
| // If the base object is already a metatype type, then something weird is |
| // going on. For now, just generate a generic error. |
| if (baseObjTy->is<MetatypeType>()) |
| return false; |
| |
| // Otherwise, we'll perform a lookup against the metatype of our contextual |
| // type. |
| baseObjTy = MetatypeType::get(baseObjTy); |
| MemberLookupResult result = |
| CS->performMemberLookup(memberConstraint->getKind(), |
| memberConstraint->getMember(), |
| baseObjTy, memberConstraint->getLocator()); |
| |
| switch (result.OverallResult) { |
| case MemberLookupResult::Unsolved: |
| llvm_unreachable("base expr type should be resolved at this point"); |
| case MemberLookupResult::ErrorAlreadyDiagnosed: |
| // If an error was already emitted, then we're done, don't emit anything |
| // redundant. |
| return true; |
| case MemberLookupResult::HasResults: |
| break; // Interesting case. :-) |
| } |
| |
| // If we have unviable candidates (e.g. because of access control or some |
| // other problem) we should diagnose the problem. Note that we diagnose this |
| // here instead of letting diagnoseGeneralMemberFailure handle it, because it |
| // doesn't know how to handle lookup into a contextual type for an URME. |
| if (result.ViableCandidates.empty()) { |
| diagnoseUnviableLookupResults(result, baseObjTy, /*no base expr*/nullptr, |
| E->getName(), E->getNameLoc(), |
| E->getLoc()); |
| return true; |
| } |
| |
| bool hasTrailingClosure = callArgHasTrailingClosure(E->getArgument()); |
| |
| // Dump all of our viable candidates into a CalleeCandidateInfo (with an |
| // uncurry level of 1 to represent the contextual type) and sort it out. |
| CalleeCandidateInfo candidateInfo(baseObjTy, result.ViableCandidates, 1, |
| hasTrailingClosure, CS); |
| |
| // Filter the candidate list based on the argument we may or may not have. |
| candidateInfo.filterContextualMemberList(E->getArgument()); |
| |
| // If we have multiple candidates, then we have an ambiguity. |
| if (candidateInfo.size() != 1) { |
| SourceRange argRange; |
| if (auto arg = E->getArgument()) argRange = arg->getSourceRange(); |
| diagnose(E->getNameLoc(), diag::ambiguous_member_overload_set, |
| E->getName().str()) |
| .highlight(argRange); |
| candidateInfo.suggestPotentialOverloads(E->getNameLoc()); |
| return true; |
| } |
| |
| auto argumentTy = candidateInfo[0].getArgumentType(); |
| |
| // Depending on how we matched, produce tailored diagnostics. |
| switch (candidateInfo.closeness) { |
| case CC_NonLValueInOut: // First argument is inout but no lvalue present. |
| case CC_OneArgumentMismatch: // All arguments except one match. |
| case CC_OneArgumentNearMismatch: |
| case CC_SelfMismatch: // Self argument mismatches. |
| case CC_ArgumentNearMismatch:// Argument list mismatch. |
| case CC_ArgumentMismatch: // Argument list mismatch. |
| assert(0 && "These aren't produced by filterContextualMemberList"); |
| return false; |
| |
| case CC_ExactMatch: { // This is a perfect match for the arguments. |
| // If we have an exact match, then we must have an argument list. |
| // If we didn't have an argument or an arg type, the expr would be valid. |
| if (!argumentTy) { |
| assert(!E->getArgument() && "Not an exact match"); |
| // If this is an exact match, return false to diagnose this as an |
| // ambiguity. It must be some other problem, such as failing to infer a |
| // generic argument on the enum type. |
| return false; |
| } |
| |
| assert(E->getArgument() && argumentTy && "Exact match without argument?"); |
| return !typeCheckArgumentChildIndependently(E->getArgument(), argumentTy, |
| candidateInfo); |
| } |
| |
| case CC_Unavailable: |
| if (CS->TC.diagnoseExplicitUnavailability(candidateInfo[0].decl, |
| E->getLoc(), CS->DC)) |
| return true; |
| return false; |
| |
| case CC_ArgumentLabelMismatch: { // Argument labels are not correct. |
| auto argExpr = typeCheckArgumentChildIndependently(E->getArgument(), |
| argumentTy, |
| candidateInfo); |
| if (!argExpr) return true; |
| |
| // Construct the actual expected argument labels that our candidate |
| // expected. |
| assert(argumentTy && |
| "Candidate must expect an argument to have a label mismatch"); |
| auto arguments = decomposeArgParamType(argumentTy); |
| |
| // TODO: This is probably wrong for varargs, e.g. calling "print" with the |
| // wrong label. |
| SmallVector<Identifier, 4> expectedNames; |
| for (auto &arg : arguments) |
| expectedNames.push_back(arg.Label); |
| |
| return CS->diagnoseArgumentLabelError(argExpr, expectedNames, |
| /*isSubscript*/false); |
| } |
| |
| case CC_GeneralMismatch: // Something else is wrong. |
| case CC_ArgumentCountMismatch: // This candidate has wrong # arguments. |
| // If we have no argument, the candidates must have expected one. |
| if (!E->getArgument()) { |
| if (!argumentTy) |
| return false; // Candidate must be incorrect for some other reason. |
| |
| // Pick one of the arguments that are expected as an exemplar. |
| diagnose(E->getNameLoc(), diag::expected_argument_in_contextual_member, |
| E->getName(), argumentTy); |
| return true; |
| } |
| |
| // If an argument value was specified, but this is a simple enumerator, then |
| // we fail with a nice error message. |
| auto argTy = candidateInfo[0].getArgumentType(); |
| if (!argTy) { |
| diagnose(E->getNameLoc(), diag::unexpected_argument_in_contextual_member, |
| E->getName()); |
| return true; |
| } |
| |
| assert(E->getArgument() && argTy && "Exact match without an argument?"); |
| return !typeCheckArgumentChildIndependently(E->getArgument(), argTy, |
| candidateInfo); |
| } |
| |
| llvm_unreachable("all cases should be handled"); |
| } |
| |
| /// A TupleExpr propagate contextual type information down to its children and |
| /// can be erroneous when there is a label mismatch etc. |
| bool FailureDiagnosis::visitTupleExpr(TupleExpr *TE) { |
| // If we know the requested argType to use, use computeTupleShuffle to produce |
| // the shuffle of input arguments to destination values. It requires a |
| // TupleType to compute the mapping from argExpr. Conveniently, it doesn't |
| // care about the actual types though, so we can just use 'void' for them. |
| if (!CS->getContextualType() || !CS->getContextualType()->is<TupleType>()) |
| return visitExpr(TE); |
| |
| auto contextualTT = CS->getContextualType()->castTo<TupleType>(); |
| |
| SmallVector<TupleTypeElt, 4> ArgElts; |
| auto voidTy = CS->getASTContext().TheEmptyTupleType; |
| |
| for (unsigned i = 0, e = TE->getNumElements(); i != e; ++i) |
| ArgElts.push_back({ voidTy, TE->getElementName(i) }); |
| auto TEType = TupleType::get(ArgElts, CS->getASTContext()); |
| |
| if (!TEType->is<TupleType>()) |
| return visitExpr(TE); |
| |
| SmallVector<int, 4> sources; |
| SmallVector<unsigned, 4> variadicArgs; |
| |
| // If the shuffle is invalid, then there is a type error. We could diagnose |
| // it specifically here, but the general logic does a fine job so we let it |
| // do it. |
| if (computeTupleShuffle(TEType->castTo<TupleType>()->getElements(), |
| contextualTT->getElements(), sources, variadicArgs)) |
| return visitExpr(TE); |
| |
| // If we got a correct shuffle, we can perform the analysis of all of |
| // the input elements, with their expected types. |
| for (unsigned i = 0, e = sources.size(); i != e; ++i) { |
| // If the value is taken from a default argument, ignore it. |
| if (sources[i] == TupleShuffleExpr::DefaultInitialize || |
| sources[i] == TupleShuffleExpr::Variadic || |
| sources[i] == TupleShuffleExpr::CallerDefaultInitialize) |
| continue; |
| |
| assert(sources[i] >= 0 && "Unknown sources index"); |
| |
| // Otherwise, it must match the corresponding expected argument type. |
| unsigned inArgNo = sources[i]; |
| auto actualType = contextualTT->getElementType(i); |
| |
| TCCOptions options; |
| if (actualType->is<InOutType>()) |
| options |= TCC_AllowLValue; |
| |
| auto exprResult = |
| typeCheckChildIndependently(TE->getElement(inArgNo), actualType, |
| CS->getContextualTypePurpose(), options); |
| // If there was an error type checking this argument, then we're done. |
| if (!exprResult) return true; |
| |
| // If the caller expected something inout, but we didn't have |
| // something of inout type, diagnose it. |
| if (auto IOE = |
| dyn_cast<InOutExpr>(exprResult->getSemanticsProvidingExpr())) { |
| if (!actualType->is<InOutType>()) { |
| diagnose(exprResult->getLoc(), diag::extra_address_of, |
| exprResult->getType()->getInOutObjectType()) |
| .highlight(exprResult->getSourceRange()) |
| .fixItRemove(IOE->getStartLoc()); |
| return true; |
| } |
| } |
| } |
| |
| if (!variadicArgs.empty()) { |
| auto varargsTy = contextualTT->getVarArgsBaseType(); |
| for (unsigned i = 0, e = variadicArgs.size(); i != e; ++i) { |
| unsigned inArgNo = variadicArgs[i]; |
| |
| auto expr = |
| typeCheckChildIndependently(TE->getElement(inArgNo), varargsTy, |
| CS->getContextualTypePurpose()); |
| // If there was an error type checking this argument, then we're done. |
| if (!expr) return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /// An IdentityExpr doesn't change its argument, but it *can* propagate its |
| /// contextual type information down. |
| bool FailureDiagnosis::visitIdentityExpr(IdentityExpr *E) { |
| auto contextualType = CS->getContextualType(); |
| |
| // If we have a paren expr and our contextual type is a ParenType, remove the |
| // paren expr sugar. |
| if (isa<ParenExpr>(E) && contextualType) |
| if (auto *PT = dyn_cast<ParenType>(contextualType.getPointer())) |
| contextualType = PT->getUnderlyingType(); |
| |
| if (!typeCheckChildIndependently(E->getSubExpr(), contextualType, |
| CS->getContextualTypePurpose())) |
| return true; |
| return false; |
| } |
| |
| bool FailureDiagnosis::visitExpr(Expr *E) { |
| // Check each of our immediate children to see if any of them are |
| // independently invalid. |
| bool errorInSubExpr = false; |
| |
| E->forEachImmediateChildExpr([&](Expr *Child) -> Expr* { |
| // If we already found an error, stop checking. |
| if (errorInSubExpr) return Child; |
| |
| // Otherwise just type check the subexpression independently. If that |
| // succeeds, then we stitch the result back into our expression. |
| if (typeCheckChildIndependently(Child, TCC_AllowLValue)) |
| return Child; |
| |
| // Otherwise, it failed, which emitted a diagnostic. Keep track of this |
| // so that we don't emit multiple diagnostics. |
| errorInSubExpr = true; |
| return Child; |
| }); |
| |
| // If any of the children were errors, we're done. |
| if (errorInSubExpr) |
| return true; |
| |
| // Otherwise, produce a more generic error. |
| return false; |
| } |
| |
| |
| bool FailureDiagnosis::diagnoseExprFailure() { |
| assert(CS && expr); |
| |
| // Our general approach is to do a depth first traversal of the broken |
| // expression tree, type checking as we go. If we find a subtree that cannot |
| // be type checked on its own (even to an incomplete type) then that is where |
| // we focus our attention. If we do find a type, we use it to check for |
| // contextual type mismatches. |
| return visit(expr); |
| } |
| |
| |
| /// Given a specific expression and the remnants of the failed constraint |
| /// system, produce a specific diagnostic. |
| /// |
| /// This is guaranteed to always emit an error message. |
| /// |
| void ConstraintSystem::diagnoseFailureForExpr(Expr *expr) { |
| // Continue simplifying any active constraints left in the system. We can end |
| // up with them because the solver bails out as soon as it sees a Failure. We |
| // don't want to leave them around in the system because later diagnostics |
| // will assume they are unsolvable and may otherwise leave the system in an |
| // inconsistent state. |
| simplify(/*ContinueAfterFailures*/true); |
| |
| // Look through RebindSelfInConstructorExpr to avoid weird sema issues. |
| if (auto *RB = dyn_cast<RebindSelfInConstructorExpr>(expr)) |
| expr = RB->getSubExpr(); |
| |
| FailureDiagnosis diagnosis(expr, this); |
| |
| // Now, attempt to diagnose the failure from the info we've collected. |
| if (diagnosis.diagnoseExprFailure()) |
| return; |
| |
| // If this is a contextual conversion problem, dig out some information. |
| if (diagnosis.diagnoseContextualConversionError()) |
| return; |
| |
| // If we can diagnose a problem based on the constraints left laying around in |
| // the system, do so now. |
| if (diagnosis.diagnoseConstraintFailure()) |
| return; |
| |
| // If the expression-order diagnostics didn't find any diagnosable problems, |
| // try the unavoidable failures list again, with locator substitutions in |
| // place. To make sure we emit the error if we have a failure recorded. |
| for (auto failure : unavoidableFailures) { |
| if (diagnoseFailure(*this, *failure, expr, true)) |
| return; |
| } |
| |
| // If no one could find a problem with this expression or constraint system, |
| // then it must be well-formed... but is ambiguous. Handle this by diagnosic |
| // various cases that come up. |
| diagnosis.diagnoseAmbiguity(expr); |
| } |
| |
| /// Emit an ambiguity diagnostic about the specified expression. |
| void FailureDiagnosis::diagnoseAmbiguity(Expr *E) { |
| |
| // Check out all of the type variables lurking in the system. If any are |
| // unbound archetypes, then the problem is that it couldn't be resolved. |
| for (auto tv : CS->getTypeVariables()) { |
| if (tv->getImpl().hasRepresentativeOrFixed()) |
| continue; |
| |
| |
| // If this is a conversion to a type variable used to form an archetype, |
| // Then diagnose this as a generic parameter that could not be resolved. |
| auto archetype = tv->getImpl().getArchetype(); |
| |
| // Only diagnose archetypes that don't have a parent, i.e., ones |
| // that correspond to generic parameters. |
| if (archetype && !archetype->getParent()) { |
| diagnose(expr->getLoc(), diag::unbound_generic_parameter, archetype); |
| |
| // Emit a "note, archetype declared here" sort of thing. |
| noteTargetOfDiagnostic(*CS, nullptr, tv->getImpl().getLocator()); |
| return; |
| } |
| continue; |
| } |
| |
| // Unresolved/Anonymous ClosureExprs are common enough that we should give |
| // them tailored diagnostics. |
| if (auto CE = dyn_cast<ClosureExpr>(E->getValueProvidingExpr())) { |
| auto CFTy = CE->getType()->getAs<AnyFunctionType>(); |
| |
| // If this is a multi-statement closure with no explicit result type, emit |
| // a note to clue the developer in. |
| if (!CE->hasExplicitResultType() && CFTy && |
| isUnresolvedOrTypeVarType(CFTy->getResult())) { |
| diagnose(CE->getLoc(), diag::cannot_infer_closure_result_type); |
| return; |
| } |
| |
| diagnose(E->getLoc(), diag::cannot_infer_closure_type) |
| .highlight(E->getSourceRange()); |
| return; |
| } |
| |
| // A DiscardAssignmentExpr (spelled "_") needs contextual type information to |
| // infer its type. If we see one at top level, diagnose that it must be part |
| // of an assignment so we don't get a generic "expression is ambiguous" error. |
| if (isa<DiscardAssignmentExpr>(E)) { |
| diagnose(E->getLoc(), diag::discard_expr_outside_of_assignment) |
| .highlight(E->getSourceRange()); |
| return; |
| } |
| |
| |
| // Attempt to re-type-check the entire expression, while allowing ambiguity. |
| auto exprType = getTypeOfTypeCheckedChildIndependently(expr); |
| // If it failed and diagnosed something, then we're done. |
| if (!exprType) return; |
| |
| // If we were able to find something more specific than "unknown" (perhaps |
| // something like "[_:_]" for a dictionary literal), include it in the |
| // diagnostic. |
| if (!isUnresolvedOrTypeVarType(exprType)) { |
| diagnose(E->getLoc(), diag::specific_type_of_expression_is_ambiguous, |
| exprType) |
| .highlight(E->getSourceRange()); |
| return; |
| } |
| |
| // If there are no posted constraints or failures, then there was |
| // not enough contextual information available to infer a type for the |
| // expression. |
| diagnose(E->getLoc(), diag::type_of_expression_is_ambiguous) |
| .highlight(E->getSourceRange()); |
| } |
| |
| bool ConstraintSystem::salvage(SmallVectorImpl<Solution> &viable, Expr *expr) { |
| // If there were any unavoidable failures, emit the first one we can. |
| if (!unavoidableFailures.empty()) { |
| for (auto failure : unavoidableFailures) { |
| if (diagnoseFailure(*this, *failure, expr, false)) |
| return true; |
| } |
| } |
| |
| // There were no unavoidable failures, so attempt to solve again, capturing |
| // any failures that come from our attempts to select overloads or bind |
| // type variables. |
| { |
| viable.clear(); |
| |
| // Set up solver state. |
| SolverState state(*this); |
| state.recordFailures = true; |
| this->solverState = &state; |
| |
| // Solve the system. |
| solveRec(viable, FreeTypeVariableBinding::Disallow); |
| |
| // Check whether we have a best solution; this can happen if we found |
| // a series of fixes that worked. |
| if (auto best = findBestSolution(viable, /*minimize=*/true)) { |
| if (*best != 0) |
| viable[0] = std::move(viable[*best]); |
| viable.erase(viable.begin() + 1, viable.end()); |
| return false; |
| } |
| |
| // FIXME: If we were able to actually fix things along the way, |
| // we may have to hunt for the best solution. For now, we don't care. |
| |
| // Remove solutions that require fixes; the fixes in those systems should |
| // be diagnosed rather than any ambiguity. |
| auto hasFixes = [](const Solution &sol) { return !sol.Fixes.empty(); }; |
| auto newEnd = std::remove_if(viable.begin(), viable.end(), hasFixes); |
| viable.erase(newEnd, viable.end()); |
| |
| // If there are multiple solutions, try to diagnose an ambiguity. |
| if (viable.size() > 1) { |
| if (getASTContext().LangOpts.DebugConstraintSolver) { |
| auto &log = getASTContext().TypeCheckerDebug->getStream(); |
| log << "---Ambiguity error: " |
| << viable.size() << " solutions found---\n"; |
| int i = 0; |
| for (auto &solution : viable) { |
| log << "---Ambiguous solution #" << i++ << "---\n"; |
| solution.dump(log); |
| log << "\n"; |
| } |
| } |
| |
| if (diagnoseAmbiguity(*this, viable, expr)) { |
| return true; |
| } |
| } |
| |
| // Remove the solver state. |
| this->solverState = nullptr; |
| |
| // Fall through to produce diagnostics. |
| } |
| |
| if (getExpressionTooComplex()) { |
| TC.diagnose(expr->getLoc(), diag::expression_too_complex). |
| highlight(expr->getSourceRange()); |
| return true; |
| } |
| |
| // If all else fails, diagnose the failure by looking through the system's |
| // constraints. |
| diagnoseFailureForExpr(expr); |
| return true; |
| } |