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Sema: Check availability of conformance type witnesses.
The type satisfying a protocol requirement must be at least as available as the associated type for the requirement. Resolves rdar://134093006
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7 files changed

+269
-8
lines changed

7 files changed

+269
-8
lines changed

‎include/swift/AST/DiagnosticsCommon.def

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -51,6 +51,10 @@ WARNING(error_in_future_swift_version,none,
5151
"%0; this is an error in the Swift %1 language mode",
5252
(DiagnosticInfo *, unsigned))
5353

54+
WARNING(error_in_a_future_swift_version,none,
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"%0; this will be an error in a future Swift language mode",
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(DiagnosticInfo *))
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5458
// Generic disambiguation
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NOTE(while_parsing_as_left_angle_bracket,none,
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"while parsing this '<' as a type parameter bracket", ())

‎lib/AST/DiagnosticEngine.cpp

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -405,8 +405,13 @@ InFlightDiagnostic::limitBehaviorUntilSwiftVersion(
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// in a message that this will become an error in a later Swift
406406
// version. We do this before limiting the behavior, because
407407
// wrapIn will result in the behavior of the wrapping diagnostic.
408-
if (limit >= DiagnosticBehavior::Warning)
409-
wrapIn(diag::error_in_future_swift_version, majorVersion);
408+
if (limit >= DiagnosticBehavior::Warning) {
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if (majorVersion > 6) {
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wrapIn(diag::error_in_a_future_swift_version);
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} else {
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wrapIn(diag::error_in_future_swift_version, majorVersion);
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}
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}
410415

411416
limitBehavior(limit);
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}

‎lib/Sema/TypeCheckDecl.cpp

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1689,8 +1689,9 @@ SelfAccessKindRequest::evaluate(Evaluator &evaluator, FuncDecl *FD) const {
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}
16901690

16911691
bool TypeChecker::isAvailabilitySafeForConformance(
1692-
ProtocolDecl *proto, ValueDecl *requirement, ValueDecl *witness,
1693-
DeclContext *dc, AvailabilityContext &requirementInfo) {
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const ProtocolDecl *proto, const ValueDecl *requirement,
1693+
const ValueDecl *witness, const DeclContext *dc,
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AvailabilityContext &requirementInfo) {
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// We assume conformances in
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// non-SourceFiles have already been checked for availability.

‎lib/Sema/TypeCheckProtocol.cpp

Lines changed: 61 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4784,6 +4784,63 @@ static void diagnoseInvariantSelfRequirement(
47844784
.warnUntilSwiftVersion(6);
47854785
}
47864786

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static bool diagnoseTypeWitnessAvailability(
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NormalProtocolConformance *conformance, const TypeDecl *witness,
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const AssociatedTypeDecl *assocType, const ExportContext &where) {
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auto dc = conformance->getDeclContext();
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auto &ctx = dc->getASTContext();
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if (ctx.LangOpts.DisableAvailabilityChecking)
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return false;
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// In Swift 6 and earlier type witness availability diagnostics are warnings.
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const unsigned warnBeforeVersion = 7;
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bool shouldError =
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ctx.LangOpts.EffectiveLanguageVersion.isVersionAtLeast(warnBeforeVersion);
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if (auto attr = where.shouldDiagnoseDeclAsUnavailable(witness)) {
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ctx.addDelayedConformanceDiag(
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conformance, shouldError,
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[witness, assocType, attr](NormalProtocolConformance *conformance) {
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SourceLoc loc = getLocForDiagnosingWitness(conformance, witness);
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EncodedDiagnosticMessage encodedMessage(attr->Message);
4806+
auto &ctx = conformance->getDeclContext()->getASTContext();
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ctx.Diags
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.diagnose(loc, diag::witness_unavailable, witness,
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conformance->getProtocol(), encodedMessage.Message)
4810+
.warnUntilSwiftVersion(warnBeforeVersion);
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emitDeclaredHereIfNeeded(ctx.Diags, loc, witness);
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ctx.Diags.diagnose(assocType, diag::kind_declname_declared_here,
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DescriptiveDeclKind::Requirement,
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assocType->getName());
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});
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}
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4819+
auto requiredAvailability = AvailabilityContext::alwaysAvailable();
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if (!TypeChecker::isAvailabilitySafeForConformance(conformance->getProtocol(),
4821+
assocType, witness, dc,
4822+
requiredAvailability)) {
4823+
auto requiredRange = requiredAvailability.getOSVersion();
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ctx.addDelayedConformanceDiag(
4825+
conformance, shouldError,
4826+
[witness, requiredRange](NormalProtocolConformance *conformance) {
4827+
SourceLoc loc = getLocForDiagnosingWitness(conformance, witness);
4828+
auto &ctx = conformance->getDeclContext()->getASTContext();
4829+
ctx.Diags
4830+
.diagnose(loc, diag::availability_protocol_requires_version,
4831+
conformance->getProtocol(), witness,
4832+
prettyPlatformString(targetPlatform(ctx.LangOpts)),
4833+
requiredRange.getLowerEndpoint())
4834+
.warnUntilSwiftVersion(warnBeforeVersion);
4835+
4836+
emitDeclaredHereIfNeeded(ctx.Diags, loc, witness);
4837+
});
4838+
return true;
4839+
}
4840+
4841+
return false;
4842+
}
4843+
47874844
/// Check whether the type witnesses satisfy the protocol's requirement
47884845
/// signature. Also checks access level of type witnesses and availiability
47894846
/// of associated conformances.
@@ -4906,6 +4963,10 @@ static void ensureRequirementsAreSatisfied(ASTContext &ctx,
49064963
}
49074964
}
49084965

4966+
// The type witness must be as available as the associated type.
4967+
if (auto witness = type->getAnyNominal())
4968+
diagnoseTypeWitnessAvailability(conformance, witness, assocType, where);
4969+
49094970
// Make sure any associated type witnesses don't make reference to a
49104971
// type we can't emit metadata for, or we're going to have trouble at
49114972
// runtime.

‎lib/Sema/TypeChecker.h

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -990,10 +990,10 @@ bool diagnoseConformanceExportability(SourceLoc loc,
990990
/// is sufficient to safely conform to the requirement in the context
991991
/// the provided conformance. On return, requiredAvailability holds th
992992
/// availability levels required for conformance.
993-
bool
994-
isAvailabilitySafeForConformance(ProtocolDecl *proto, ValueDecl *requirement,
995-
ValueDecl *witness, DeclContext *dc,
996-
AvailabilityContext &requiredAvailability);
993+
bool isAvailabilitySafeForConformance(
994+
const ProtocolDecl *proto, const ValueDecl *requirement,
995+
const ValueDecl *witness, const DeclContext *dc,
996+
AvailabilityContext &requiredAvailability);
997997

998998
/// Returns an over-approximation of the range of operating system versions
999999
/// that could the passed-in location could be executing upon for

‎test/decl/protocol/associated_type_witness_availability.swift

Lines changed: 168 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,168 @@
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// RUN: %swift -typecheck -verify -target %target-cpu-apple-macosx12 %s
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// REQUIRES: OS=macosx
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4+
protocol ProtoWithAssocType {
5+
associatedtype A // expected-note * {{requirement 'A' declared here}}
6+
}
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struct ConformsToProtoWithAssocType_WitnessOld: ProtoWithAssocType {
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@available(macOS 11, *)
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struct A {} // Ok, A is less available than its parent but more available than the deployment target
11+
}
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struct ConformsToProtoWithAssocType_WitnessSame: ProtoWithAssocType {
14+
@available(macOS 12, *)
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struct A {} // Ok, A is less available than its parent but available at the deployment target
16+
}
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struct ConformsToProtoWithAssocType_WitnessTooNew: ProtoWithAssocType {
19+
@available(macOS 13, *)
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struct A {} // expected-warning {{protocol 'ProtoWithAssocType' requires 'A' to be available in macOS 12 and newer; this will be an error in a future Swift language mode}}
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}
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struct ConformsToProtoWithAssocTypeInExtension_WitnessOld {}
24+
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extension ConformsToProtoWithAssocTypeInExtension_WitnessOld: ProtoWithAssocType {
26+
@available(macOS 11, *)
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struct A {} // Ok, A is less available than its parent but more available than the deployment target
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}
29+
30+
struct ConformsToProtoWithAssocTypeInExtension_WitnessSame {}
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extension ConformsToProtoWithAssocTypeInExtension_WitnessSame: ProtoWithAssocType {
33+
@available(macOS 12, *)
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struct A {} // Ok, A is less available than its parent but available at the deployment target
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}
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struct ConformsToProtoWithAssocTypeInExtension_WitnessTooNew {}
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extension ConformsToProtoWithAssocTypeInExtension_WitnessTooNew: ProtoWithAssocType {
40+
@available(macOS 13, *)
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struct A {} // expected-warning {{protocol 'ProtoWithAssocType' requires 'A' to be available in macOS 12 and newer; this will be an error in a future Swift language mode}}
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}
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@available(macOS 13, *)
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struct ConformsToProtoWithAssocType_NewerConformance: ProtoWithAssocType {
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struct A {} // Ok, A is as available as the conformance
47+
}
48+
49+
struct ConformsToProtoWithAssocTypeInExtension_NewerConformance {}
50+
51+
@available(macOS 13, *)
52+
extension ConformsToProtoWithAssocTypeInExtension_NewerConformance: ProtoWithAssocType {
53+
struct A {} // Ok, A is as available as the conformance
54+
}
55+
56+
@available(macOS 13, *)
57+
struct ConformsToProtoWithAssocType_NewerAndWitnessTooNew: ProtoWithAssocType {
58+
@available(macOS 14, *)
59+
struct A {} // expected-warning {{protocol 'ProtoWithAssocType' requires 'A' to be available in macOS 13 and newer; this will be an error in a future Swift language mode}}
60+
}
61+
62+
struct ConformsToProtoWithAssocType_WitnessUnavailable: ProtoWithAssocType {
63+
@available(macOS, unavailable)
64+
struct A {} // expected-warning {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'; this will be an error in a future Swift language mode}}
65+
}
66+
67+
struct ConformsToProtoWithAssocType_WitnessUnavailableInExtension: ProtoWithAssocType {
68+
// expected-warning@-1 {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'; this will be an error in a future Swift language mode}}
69+
}
70+
71+
extension ConformsToProtoWithAssocType_WitnessUnavailableInExtension {
72+
@available(macOS, unavailable)
73+
struct A {} // expected-note {{'A' declared here}}
74+
}
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76+
struct ConformsToProtoWithAssocType_WitnessInUnavailableExtension: ProtoWithAssocType {
77+
// expected-warning@-1 {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'; this will be an error in a future Swift language mode}}
78+
}
79+
80+
@available(macOS, unavailable)
81+
extension ConformsToProtoWithAssocType_WitnessInUnavailableExtension {
82+
struct A {} // expected-note {{'A' declared here}}
83+
}
84+
85+
struct ConformsToProtoWithAssocType_WitnessUnavailableMessage: ProtoWithAssocType {
86+
@available(*, unavailable, message: "Just don't")
87+
struct A {} // expected-warning {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType': Just don't; this will be an error in a future Swift language mode}}
88+
}
89+
90+
struct ConformsToProtoWithAssocType_WitnessObsoleted: ProtoWithAssocType {
91+
@available(macOS, obsoleted: 11)
92+
struct A {} // expected-warning {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'; this will be an error in a future Swift language mode}}
93+
}
94+
95+
struct ConformsToProtoWithAssocType_WitnessIntroInSwift99: ProtoWithAssocType {
96+
@available(swift, introduced: 99)
97+
struct A {} // expected-warning {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'; this will be an error in a future Swift language mode}}
98+
}
99+
100+
@available(macOS, unavailable)
101+
struct ConformsToProtoWithAssocType_Unavailable: ProtoWithAssocType {
102+
struct A {} // Ok, the conformance is unavailable too.
103+
}
104+
105+
@available(macOS, unavailable)
106+
struct ConformsToProtoWithAssocType_WitnessAndConformanceUnavailable: ProtoWithAssocType {
107+
@available(macOS, unavailable)
108+
struct A {} // Ok, the conformance is unavailable too.
109+
}
110+
111+
protocol ProtoWithNewAssocType {
112+
@available(macOS 13, *)
113+
associatedtype A
114+
}
115+
116+
struct ConformsToProtoWithNewAssocType_WitnessOld: ProtoWithNewAssocType {
117+
struct A {} // Ok, A has always been available
118+
}
119+
120+
struct ConformsToProtoWithNewAssocType_WitnessSame: ProtoWithNewAssocType {
121+
@available(macOS 13, *)
122+
struct A {} // Ok, A is as available as the associated type requirement
123+
}
124+
125+
struct ConformsToProtoWithNewAssocType_WitnessTooNew: ProtoWithNewAssocType {
126+
@available(macOS 14, *)
127+
struct A {} // expected-warning {{protocol 'ProtoWithNewAssocType' requires 'A' to be available in macOS 13 and newer; this will be an error in a future Swift language mode}}
128+
}
129+
130+
protocol ProtoWithAssocTypeAndReq {
131+
associatedtype A
132+
133+
@available(macOS 13, *)
134+
func req(_ a: A)
135+
}
136+
137+
@available(macOS 11, *)
138+
struct InferredOld {} // Ok, InferredOld is less available than its parent but more available than the deployment target
139+
140+
struct ConformsToProtoWithAssocTypeAndReq_InferredWitnessOld: ProtoWithAssocTypeAndReq {
141+
142+
func req(_ a: InferredOld) {}
143+
}
144+
145+
@available(macOS 12, *)
146+
struct InferredSame {} // Ok, InferredSame is less available than its parent but available at the deployment target
147+
148+
struct ConformsToProtoWithAssocTypeAndReq_InferredWitnessSame: ProtoWithAssocTypeAndReq {
149+
func req(_ a: InferredSame) {}
150+
}
151+
152+
@available(macOS 13, *)
153+
struct InferredTooNew {} // expected-note {{'InferredTooNew' declared here}}
154+
155+
struct ConformsToProtoWithAssocTypeAndReq_InferredWitnessTooNew: ProtoWithAssocTypeAndReq {
156+
// expected-warning@-1 {{protocol 'ProtoWithAssocTypeAndReq' requires 'InferredTooNew' to be available in macOS 12 and newer; this will be an error in a future Swift language mode}}
157+
158+
@available(macOS 13, *)
159+
func req(_ a: InferredTooNew) {}
160+
}
161+
162+
@available(macOS, unavailable)
163+
struct ConformsToProtoWithAssocTypeAndReq_InferredUnavailable: ProtoWithAssocTypeAndReq {
164+
@available(macOS, unavailable)
165+
struct InferredUnavailable {}
166+
167+
func req(_ a: InferredUnavailable) {}
168+
}

‎test/decl/protocol/associated_type_witness_availability_swift7.swift

Lines changed: 22 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,22 @@
1+
// RUN: %swift -typecheck -verify -target %target-cpu-apple-macosx12 %s -swift-version 7
2+
// REQUIRES: OS=macosx
3+
// REQUIRES: swift7
4+
5+
protocol ProtoWithAssocType {
6+
associatedtype A // expected-note {{requirement 'A' declared here}}
7+
}
8+
9+
struct WitnessSame: ProtoWithAssocType {
10+
@available(macOS 12, *)
11+
struct A {} // Ok, A is less available than its parent but available at the deployment target
12+
}
13+
14+
struct WitnessTooNew: ProtoWithAssocType { // expected-error {{type 'WitnessTooNew' does not conform to protocol 'ProtoWithAssocType'}}
15+
@available(macOS 13, *)
16+
struct A {} // expected-error {{protocol 'ProtoWithAssocType' requires 'A' to be available in macOS 12 and newer}}
17+
}
18+
19+
struct WitnessUnavailable: ProtoWithAssocType { // expected-error {{type 'WitnessUnavailable' does not conform to protocol 'ProtoWithAssocType'}}
20+
@available(macOS, unavailable)
21+
struct A {} // expected-error {{unavailable struct 'A' was used to satisfy a requirement of protocol 'ProtoWithAssocType'}}
22+
}

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