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Allow "protocol P : class, AnyObject..." for Swift 4 compatibility. #11987

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Merged
merged 2 commits into from
Sep 18, 2017
Merged

Allow "protocol P : class, AnyObject..." for Swift 4 compatibility. #11987

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Allow "protocol P : class, AnyObject..." for Swift 4 compatibility.
DougGregor Sep 18, 2017
6d9e921
Restrict the ability to specify "protocol P : class, AnyObject" to Sw…
DougGregor Sep 18, 2017
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2 changes: 2 additions & 0 deletions include/swift/AST/DiagnosticsSema.def
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Original file line number Diff line number Diff line change
Expand Up @@ -1936,6 +1936,8 @@ WARNING(override_swift3_objc_inference,none,
// Inheritance
ERROR(duplicate_inheritance,none,
"duplicate inheritance from %0", (Type))
WARNING(duplicate_anyobject_class_inheritance,none,
"redundant inheritance from 'AnyObject' and Swift 3 'class' keyword", ())
ERROR(multiple_inheritance,none,
"multiple inheritance from classes %0 and %1", (Type, Type))
ERROR(non_class_inheritance,none,
Expand Down
24 changes: 21 additions & 3 deletions lib/Sema/TypeCheckDecl.cpp
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Expand Up @@ -440,7 +440,7 @@ void TypeChecker::checkInheritanceClause(Decl *decl,
Type superclassTy;
SourceRange superclassRange;
llvm::SmallSetVector<ProtocolDecl *, 4> allProtocols;
llvm::SmallDenseMap<CanType, SourceRange> inheritedTypes;
llvm::SmallDenseMap<CanType, std::pair<unsigned, SourceRange>> inheritedTypes;
addImplicitConformances(*this, decl, allProtocols);
for (unsigned i = 0, n = inheritedClause.size(); i != n; ++i) {
auto &inherited = inheritedClause[i];
Expand Down Expand Up @@ -475,15 +475,33 @@ void TypeChecker::checkInheritanceClause(Decl *decl,
CanType inheritedCanTy = inheritedTy->getCanonicalType();
auto knownType = inheritedTypes.find(inheritedCanTy);
if (knownType != inheritedTypes.end()) {
// If the duplicated type is 'AnyObject', check whether the first was
// written as 'class'. Downgrade the error to a warning in such cases
// for backward compatibility with Swift <= 4.
if (!Context.LangOpts.isSwiftVersionAtLeast(5) &&
inheritedTy->isAnyObject() &&
(isa<ProtocolDecl>(decl) || isa<AbstractTypeParamDecl>(decl)) &&
Lexer::getTokenAtLocation(Context.SourceMgr,
knownType->second.second.Start)
.is(tok::kw_class)) {
SourceLoc classLoc = knownType->second.second.Start;
SourceRange removeRange = getRemovalRange(knownType->second.first);

diagnose(classLoc, diag::duplicate_anyobject_class_inheritance)
.fixItRemoveChars(removeRange.Start, removeRange.End);
inherited.setInvalidType(Context);
continue;
}

auto removeRange = getRemovalRange(i);
diagnose(inherited.getSourceRange().Start,
diag::duplicate_inheritance, inheritedTy)
.fixItRemoveChars(removeRange.Start, removeRange.End)
.highlight(knownType->second);
.highlight(knownType->second.second);
inherited.setInvalidType(Context);
continue;
}
inheritedTypes[inheritedCanTy] = inherited.getSourceRange();
inheritedTypes[inheritedCanTy] = { i, inherited.getSourceRange() };

// If this is a protocol or protocol composition type, record the
// protocols.
Expand Down
7 changes: 7 additions & 0 deletions test/Compatibility/anyobject_class.swift
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@@ -0,0 +1,7 @@
// RUN: %target-typecheck-verify-swift -swift-version 3
// RUN: %target-typecheck-verify-swift -swift-version 4
// RUN: not %target-swift-frontend -tyepcheck -swift-version 5

protocol P : class, AnyObject { } // expected-warning{{redundant inheritance from 'AnyObject' and Swift 3 'class' keyword}}{{14-21=}}
// expected-warning@-1{{redundant layout constraint 'Self' : 'AnyObject'}}
// expected-note@-2{{layout constraint constraint 'Self' : 'AnyObject' written here}}