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LifetimeDependence: Disable parameter indices in Swift lifetime dependence annotations #86846

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Merged
aidan-hall merged 1 commit into from
Feb 6, 2026
Merged

LifetimeDependence: Disable parameter indices in Swift lifetime dependence annotations #86846

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4 changes: 2 additions & 2 deletions include/swift/AST/DiagnosticsParse.def
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Original file line number Diff line number Diff line change
Expand Up @@ -2178,8 +2178,8 @@ ERROR(expected_lparen_after_lifetime_dependence, PointsToFirstBadToken,

ERROR(expected_identifier_or_index_or_self_after_lifetime_dependence,
PointsToFirstBadToken,
"expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier",
())
"expected 'copy', 'borrow', or '&' followed by an identifier%select{|, index}0 or 'self' in lifetime dependence specifier",
(bool))

ERROR(expected_rparen_after_lifetime_dependence, PointsToFirstBadToken,
"expected ')' after parameter list in lifetime dependence specifier", ())
Expand Down
3 changes: 2 additions & 1 deletion include/swift/Parse/Parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1158,7 +1158,8 @@ class Parser {

/// Common utility to parse swift @lifetime decl attribute and SIL @lifetime
/// type modifier.
ParserResult<LifetimeEntry> parseLifetimeEntry(SourceLoc loc);
ParserResult<LifetimeEntry> parseLifetimeEntry(SourceLoc loc,
bool allowIndices);

/// Parse a specific attribute.
ParserStatus parseDeclAttribute(DeclAttributes &Attributes, SourceLoc AtLoc,
Expand Down
30 changes: 20 additions & 10 deletions lib/Parse/ParseDecl.cpp
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Expand Up @@ -2545,7 +2545,7 @@ static std::optional<Identifier> parseSingleAttrOptionImpl(
}

static std::optional<LifetimeDescriptor>
parseLifetimeDescriptor(Parser &P,
parseLifetimeDescriptor(Parser &P, bool allowIndices,
ParsedLifetimeDependenceKind lifetimeDependenceKind =
ParsedLifetimeDependenceKind::Default) {
auto token = P.Tok;
Expand Down Expand Up @@ -2577,6 +2577,13 @@ parseLifetimeDescriptor(Parser &P,
case tok::integer_literal: {
SourceLoc loc;
unsigned index;
if (!allowIndices) {
P.diagnose(
token,
diag::expected_identifier_or_index_or_self_after_lifetime_dependence,
/* allow indices */ false);
return std::nullopt;
}
if (P.parseUnsignedInteger(
index, loc, diag::expected_param_index_lifetime_dependence)) {
return std::nullopt;
Expand All @@ -2590,7 +2597,8 @@ parseLifetimeDescriptor(Parser &P,
default: {
P.diagnose(
token,
diag::expected_identifier_or_index_or_self_after_lifetime_dependence);
diag::expected_identifier_or_index_or_self_after_lifetime_dependence,
allowIndices);
return std::nullopt;
}
}
Expand All @@ -2601,7 +2609,7 @@ ParserResult<LifetimeAttr> Parser::parseLifetimeAttribute(StringRef attrName,
SourceLoc loc) {
ParserStatus status;

auto lifetimeEntry = parseLifetimeEntry(loc);
auto lifetimeEntry = parseLifetimeEntry(loc, /*allowIndices=*/false);
if (lifetimeEntry.isNull()) {
status.setIsParseError();
return status;
Expand Down Expand Up @@ -5077,7 +5085,7 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
}

case TypeAttrKind::Lifetime: {
const auto entryResult = parseLifetimeEntry(AtLoc);
const auto entryResult = parseLifetimeEntry(AtLoc, /*allowIndices=*/false);
if (entryResult.isNull()) {
return makeParserError();
}
Expand Down Expand Up @@ -5164,7 +5172,8 @@ ParserStatus Parser::parseTypeAttribute(TypeOrCustomAttr &result,
llvm_unreachable("bad attribute kind");
}

ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc,
bool allowIndices) {
ParserStatus status;

auto getLifetimeDependenceKind =
Expand Down Expand Up @@ -5198,7 +5207,7 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
std::optional<LifetimeDescriptor> targetDescriptor;
if (Tok.isAny(tok::identifier, tok::integer_literal, tok::kw_self) &&
peekToken().is(tok::colon)) {
targetDescriptor = parseLifetimeDescriptor(*this);
targetDescriptor = parseLifetimeDescriptor(*this, allowIndices);
if (!targetDescriptor) {
status.setIsParseError();
return status;
Expand All @@ -5223,8 +5232,8 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
consumeToken();
}

auto sourceDescriptor =
parseLifetimeDescriptor(*this, lifetimeDependenceKind);
auto sourceDescriptor = parseLifetimeDescriptor(*this, allowIndices,
lifetimeDependenceKind);
if (!sourceDescriptor) {
invalidSourceDescriptor = true;
listStatus.setIsParseError();
Expand All @@ -5241,7 +5250,8 @@ ParserResult<LifetimeEntry> Parser::parseLifetimeEntry(SourceLoc loc) {
if (!foundParamId) {
diagnose(
Tok,
diag::expected_identifier_or_index_or_self_after_lifetime_dependence);
diag::expected_identifier_or_index_or_self_after_lifetime_dependence,
/* allow indices */ isInSILMode());
status.setIsParseError();
return status;
}
Expand Down Expand Up @@ -5583,7 +5593,7 @@ ParserStatus Parser::ParsedTypeAttributeList::slowParse(Parser &P) {
}
P.consumeToken(); // consume '@'
auto loc = P.consumeToken(); // consume 'lifetime'
auto result = P.parseLifetimeEntry(loc);
auto result = P.parseLifetimeEntry(loc, /*allowIndices=*/true);
if (result.isNull()) {
status |= result;
continue;
Expand Down
2 changes: 1 addition & 1 deletion test/Parse/lifetime_attr.swift
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Expand Up @@ -24,7 +24,7 @@ func testMissingLParenError(_ ne: NE) -> NE {
ne
}

@_lifetime() // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier}}
@_lifetime() // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}
func testMissingDependence(_ ne: NE) -> NE {
ne
}
Expand Down
7 changes: 6 additions & 1 deletion test/Sema/lifetime_attr.swift
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Expand Up @@ -17,7 +17,12 @@ func invalidAttrOnNonExistingSelf(_ ne: NE) -> NE {
ne
}

@_lifetime(2) // expected-error{{invalid parameter index specified '2'}}
@_lifetime(copy 0) // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}
func invalidAttrOnExistingParamIndex(_ ne: NE) -> NE {
ne
}

@_lifetime(2) // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}
func invalidAttrOnNonExistingParamIndex(_ ne: NE) -> NE {
ne
}
Expand Down
2 changes: 1 addition & 1 deletion test/Sema/lifetime_depend_infer.swift
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Expand Up @@ -849,7 +849,7 @@ struct NoncopyableSelfAccessors: ~Copyable & ~Escapable {

// Invalid keyword for the dependence kind.
//
@_lifetime(a: inout a) // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier, index or 'self' in lifetime dependence specifier}}
@_lifetime(a: inout a) // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}
func f_inout_bad_keyword(a: inout MutableRawSpan) {}

// Don't allow a useless borrow dependency on an inout param--it is misleading.
Expand Down
6 changes: 4 additions & 2 deletions test/Sema/lifetime_dependence_functype.swift
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Expand Up @@ -19,7 +19,7 @@ func transfer(_ ne: NE) -> NE {
}

@_lifetime(copy ne)
func applyAnnotatedTransfer(ne: NE, @_lifetime(0) transfer: (NE) -> NE) -> NE { // expected-error{{'@_lifetime' attribute cannot be applied to this declaration}}
func applyAnnotatedTransfer(ne: NE, @_lifetime(copy ne) transfer: (_ ne: NE) -> NE) -> NE { // expected-error{{'@_lifetime' attribute cannot be applied to this declaration}}
transfer(ne)
}

Expand Down Expand Up @@ -61,7 +61,9 @@ typealias InvalidAttrOnNonExistingParamType = @_lifetime(copy nonexisting) (_ ne

typealias InvalidAttrOnNonExistingSelfType = @_lifetime(copy self) (_ ne: NE) -> NE // expected-error{{invalid lifetime dependence specifier on non-existent self}}

typealias InvalidAttrOnNonExistingParamIndexType = @_lifetime(2) (_ ne: NE) -> NE // expected-error{{invalid parameter index specified '2'}}
typealias InvalidAttrOnExistingParamIndexType = @_lifetime(0) (_ ne: NE) -> NE // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}

typealias InvalidAttrOnNonExistingParamIndexType = @_lifetime(2) (_ ne: NE) -> NE // expected-error{{expected 'copy', 'borrow', or '&' followed by an identifier or 'self' in lifetime dependence specifier}}

typealias InvalidDuplicateLifetimeDependenceType = @_lifetime(copy ne, borrow ne) (_ ne: borrowing NE) -> NE // expected-error{{duplicate lifetime dependence specifier}}

Expand Down