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Jun 24, 2025
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Allow #selector to reference async method in non-async code #82426

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96297e6
Make the mangling grammar a little more regular
DougGregor Jun 21, 2025
c34f81e
Allow #selector to reference async method in non-async code
DougGregor Jun 23, 2025
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91 changes: 46 additions & 45 deletions docs/ABI/Mangling.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -66,9 +66,9 @@ part of a symbolic reference.

symbolic-reference ::= [\x01-\x17] .{4} // Relative symbolic reference
#if sizeof(void*) == 8
symbolic-reference ::= [\x18-\x1F] .{8} // Absolute symbolic reference
symbolic-reference ::= [\x18-\x1F] .{8} // Absolute symbolic reference for 64-bit pointers
#elif sizeof(void*) == 4
symbolic-reference ::= [\x18-\x1F] .{4} // Absolute symbolic reference
symbolic-reference ::= [\x18-\x1F] .{4} // Absolute symbolic reference for 32-bit pointers
#endif

Symbolic references are only valid in compiler-emitted metadata structures
Expand Down Expand Up @@ -110,7 +110,7 @@ The following symbolic reference kinds are currently implemented:
#endif

#if SWIFT_RUNTIME_VERSION >= 5.TBD
objective-c-protocol-relative-reference ::= `\x0C` .{4} // Reference points directly to a objective-c protcol reference
objective-c-protocol-relative-reference ::= '\x0C' .{4} // Reference points directly to a objective-c protcol reference
#endif

A mangled name may also include ``\xFF`` bytes, which are only used for
Expand Down Expand Up @@ -151,7 +151,7 @@ Globals
global ::= protocol 'Hr' // protocol descriptor runtime record
global ::= nominal-type 'Hn' // nominal type descriptor runtime record
#if SWIFT_RUNTIME_VERSION >= 5.1
global ::= opaque-type 'Ho' // opaque type descriptor runtime record
global ::= opaque-type-decl-name 'Ho' // opaque type descriptor runtime record
#endif
global ::= protocol-conformance 'Hc' // protocol conformance runtime record
global ::= global 'HF' // accessible function runtime record
Expand Down Expand Up @@ -250,14 +250,11 @@ types where the metadata itself has unknown layout.)
global ::= global specialization // function specialization
global ::= global 'Tm' // merged function
global ::= entity // some identifiable thing
global ::= from-type to-type generic-signature? 'TR' // reabstraction thunk
global ::= impl-function-type type 'Tz' index? // objc-to-swift-async completion handler block implementation
global ::= impl-function-type type 'TZ' index? // objc-to-swift-async completion handler block implementation (predefined by runtime)
global ::= from-type to-type generic-signature? 'TR' // reabstraction thunk
global ::= impl-function-type type generic-signature? 'Tz' // objc-to-swift-async completion handler block implementation
global ::= impl-function-type type generic-signature? 'TZ' // objc-to-swift-async completion handler block implementation (predefined by runtime)
global ::= from-type to-type self-type generic-signature? 'Ty' // reabstraction thunk with dynamic 'Self' capture
global ::= from-type to-type generic-signature? 'Tr' // obsolete mangling for reabstraction thunk
global ::= type type generic-signature? 'TR' // reabstraction thunk
global ::= impl-function-type type generic-signature? 'Tz' index? // objc-to-swift-async completion handler block implementation
global ::= impl-function-type type generic-signature? 'TZ' index? // objc-to-swift-async completion handler block implementation predefined by runtime
global ::= type type type generic-signature? 'Ty' // reabstraction thunk with dynamic 'Self' capture
global ::= type type generic-signature? 'Tr' // obsolete mangling for reabstraction thunk
global ::= entity generic-signature? type type* 'TK' // key path getter
global ::= entity generic-signature? type type* 'Tk' // key path setter
global ::= entity generic-signature? type type* 'Tkmu' // key path unapplied method
Expand All @@ -266,9 +263,9 @@ types where the metadata itself has unknown layout.)
global ::= type generic-signature 'Th' // key path hasher
global ::= global generic-signature? 'TJ' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff function
global ::= global generic-signature? 'TJV' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' // autodiff derivative vtable thunk
global ::= from-type to-type 'TJO' AUTODIFF-FUNCTION-KIND // autodiff self-reordering reabstraction thunk
global ::= from-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff linear map subset parameters thunk
global ::= global to-type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff derivative function subset parameters thunk
global ::= type type 'TJO' AUTODIFF-FUNCTION-KIND // autodiff self-reordering reabstraction thunk
global ::= type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff linear map subset parameters thunk
global ::= global type 'TJS' AUTODIFF-FUNCTION-KIND INDEX-SUBSET 'p' INDEX-SUBSET 'r' INDEX-SUBSET 'P' // autodiff derivative function subset parameters thunk

global ::= protocol 'TL' // protocol requirements base descriptor
global ::= assoc-type-name 'Tl' // associated type descriptor
Expand All @@ -280,9 +277,9 @@ types where the metadata itself has unknown layout.)
REABSTRACT-THUNK-TYPE ::= 'R' // reabstraction thunk
REABSTRACT-THUNK-TYPE ::= 'r' // reabstraction thunk (obsolete)

global ::= reabstraction-thunk type 'TU' // reabstraction thunk with global actor constraint
global ::= global type 'TU' // reabstraction thunk with global actor constraint

The `from-type` and `to-type` in a reabstraction thunk helper function
All reabstraction thunks have the "from" and "to" types in that order, and
are always non-polymorphic ``<impl-function-type>`` types.

::
Expand Down Expand Up @@ -341,9 +338,9 @@ with a differentiable function used for differentiable programming.
global ::= generic-signature? type 'WOF' // Outlined assignWithCopy, not using value witness
global ::= generic-signature? type 'WOh' // Outlined destroy
global ::= generic-signature? type 'WOH' // Outlined destroy, not using value witness
global ::= generic-signature? type 'WOi` // Outlined store enum tag
global ::= generic-signature? type 'WOj` // Outlined enum destructive project
global ::= generic-signature? type 'WOg` // Outlined enum get tag
global ::= generic-signature? type 'WOi' // Outlined store enum tag
global ::= generic-signature? type 'WOj' // Outlined enum destructive project
global ::= generic-signature? type 'WOg' // Outlined enum get tag

Entities
~~~~~~~~
Expand All @@ -357,8 +354,10 @@ Entities
curry-thunk ::= 'Tc'

label-list ::= empty-list // represents complete absence of parameter labels
label-list ::= ('_' | identifier)* // '_' is inserted as placeholder for empty label,
label-list ::= label* // '_' is inserted as placeholder for empty label,
// since the number of labels should match the number of parameters
label ::= '_' // empty label
label ::= identifier // label

// The leading type is the function type
entity-spec ::= label-list type file-discriminator? 'fC' // allocating constructor
Expand Down Expand Up @@ -602,6 +601,8 @@ Types

any-generic-type ::= standard-substitutions

nominal-type ::= any-generic-type // nominal type

standard-substitutions ::= 'S' KNOWN-TYPE-KIND // known nominal type substitution
standard-substitutions ::= 'S' NATURAL KNOWN-TYPE-KIND // repeated known type substitutions of the same kind

Expand Down Expand Up @@ -724,8 +725,9 @@ Types
type ::= '$' 'n'? INDEX // integer type
#endif

bound-generic-type ::= type 'y' (type* '_')* type* retroactive-conformance* 'G' // one type-list per nesting level of type
bound-generic-type ::= type bound-generic-args 'G' // one type-list per nesting level of type
bound-generic-type ::= substitution
bound-generic-args ::= 'y' (type* '_')* type* retroactive-conformance* // generic arguments

FUNCTION-KIND ::= 'f' // @thin function type
FUNCTION-KIND ::= 'U' // uncurried function type (currently not used)
Expand All @@ -738,7 +740,7 @@ Types
FUNCTION-KIND ::= 'A' // @auto_closure function type (escaping)
FUNCTION-KIND ::= 'E' // function type (noescape)

C-TYPE ::= NATURAL CHAR* // raw Itanium mangling
C-TYPE ::= NATURAL IDENTIFIER-STRING // raw Itanium mangling

function-signature ::= result-type params-type async? sendable? throws? differentiable? function-isolation? sending-result? // results and parameters

Expand Down Expand Up @@ -785,7 +787,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
METATYPE-REPR ::= 'o' // ObjC metatype representation

existential-layout ::= protocol-list 'p' // existential layout
existential-layout ::= protocol-list superclass 'Xc' // existential layout with superclass
existential-layout ::= protocol-list type 'Xc' // existential layout with superclass
existential-layout ::= protocol-list 'Xl' // existential layout with AnyObject

type ::= associated-type
Expand All @@ -801,11 +803,10 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
type ::= assoc-type-name 'Qz' // shortcut for 'Qyz'
type ::= assoc-type-list 'QY' GENERIC-PARAM-INDEX // associated type at depth
type ::= assoc-type-list 'QZ' // shortcut for 'QYz'
type ::= opaque-type-decl-name bound-generic-args 'Qo' INDEX // opaque type

type ::= pack-type 'Qe' INDEX // pack element type

type ::= type 'Qe' INDEX // pack element type

type ::= pattern-type count-type 'Qp' // pack expansion type
type ::= type type 'Qp' // pack expansion type (pattern, count)
type ::= pack-element-list 'QP' // pack type
type ::= pack-element-list 'QS' DIRECTNESS // SIL pack type

Expand All @@ -814,7 +815,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when

#if SWIFT_RUNTIME_VERSION >= 5.2
type ::= type assoc-type-name 'Qx' // associated type relative to base `type`
type ::= type assoc-type-list 'QX' // associated type relative to base `type`
type ::= type assoc-type-list 'QX' // associated type relative to base `type` list
#endif

#if SWIFT_RUNTIME_VERSION >= 5.7
Expand All @@ -830,7 +831,7 @@ The 6.0 Swift runtime supports demangling ``sending-result``, but has a bug when
associated-type ::= type identifier 'Qa' // associated type

assoc-type-name ::= identifier // associated type name without protocol
assoc-type-name ::= identifier protocol 'P' //
assoc-type-name ::= identifier protocol 'P' // associated type name with protocol

empty-list ::= 'y'

Expand All @@ -845,7 +846,7 @@ mangled in to disambiguate.
impl-function-type ::= type* 'I' FUNC-ATTRIBUTES '_'
impl-function-type ::= type* generic-signature 'I' FUNC-ATTRIBUTES '_'

FUNC-ATTRIBUTES ::= PATTERN-SUBS? INVOCATION-SUBS? PSEUDO-GENERIC? CALLEE-ESCAPE? ISOLATION? DIFFERENTIABILITY-KIND? CALLEE-CONVENTION FUNC-REPRESENTATION? COROUTINE-KIND? SENDABLE? ASYNC? SENDING-RESULT? (PARAM-CONVENTION PARAM-DIFFERENTIABILITY?)* RESULT-CONVENTION* ('Y' PARAM-CONVENTION)* ('z' RESULT-CONVENTION RESULT-DIFFERENTIABILITY?)?
FUNC-ATTRIBUTES ::= PATTERN-SUBS? INVOCATION-SUB? PSEUDO-GENERIC? CALLEE-ESCAPE? ISOLATION? DIFFERENTIABILITY-KIND? CALLEE-CONVENTION FUNC-REPRESENTATION? COROUTINE-KIND? SENDABLE? ASYNC? SENDING-RESULT? (PARAM-CONVENTION PARAM-DIFFERENTIABILITY?)* RESULT-CONVENTION* ('Y' PARAM-CONVENTION)* ('z' RESULT-CONVENTION RESULT-DIFFERENTIABILITY?)?

PATTERN-SUBS ::= 's' // has pattern substitutions
INVOCATION-SUB ::= 'I' // has invocation substitutions
Expand Down Expand Up @@ -953,10 +954,10 @@ productions:
::

any-generic-type ::= context decl-name 'a' // typealias type
type ::= base-type "XSq" // sugared Optional type
type ::= base-type "XSa" // sugared Array type
type ::= key-type value-type "XSD" // sugared Dictionary type
type ::= count-type element-type "XSA" // sugared InlineArray type
type ::= type 'XSq' // sugared Optional type
type ::= type 'XSa' // sugared Array type
type ::= type type 'XSD' // sugared Dictionary type (key, value)
type ::= type type 'XSA' // sugared InlineArray type (count, element)

Generics
~~~~~~~~
Expand Down Expand Up @@ -1005,7 +1006,7 @@ Property behaviors are implemented using private protocol conformances.
dependent-associated-conformance 'HA' DEPENDENT-CONFORMANCE-INDEX

dependent-associated-conformance ::= type protocol
dependent-protocol-conformance ::= dependent-protocol-conformance opaque-type 'HO'
dependent-protocol-conformance ::= dependent-protocol-conformance type 'HO'

pack-protocol-conformance ::= any-protocol-conformance-list 'HX'

Expand Down Expand Up @@ -1041,7 +1042,7 @@ now codified into the ABI; the index 0 is therefore reserved.
generic-param-marker ::= generic-param-pack-marker
generic-param-marker ::= generic-param-value-marker

generic-param-pack-marker ::= 'Rv' GENERIC_PARAM-INDEX // generic parameter pack marker
generic-param-pack-marker ::= 'Rv' GENERIC-PARAM-INDEX // generic parameter pack marker

#if SWIFT_RUNTIME_VERSION >= 6.TBD
generic-param-value-marker ::= type 'RV' GENERIC-PARAM-INDEX // generic parameter value marker
Expand Down Expand Up @@ -1085,9 +1086,9 @@ now codified into the ABI; the index 0 is therefore reserved.
LAYOUT-CONSTRAINT ::= 'T' // Trivial
LAYOUT-CONSTRAINT ::= 'C' // Class
LAYOUT-CONSTRAINT ::= 'D' // NativeClass
LAYOUT-CONSTRAINT ::= 'E' LAYOUT-SIZE-AND-ALIGNMENT // Trivial of exact size
LAYOUT-CONSTRAINT ::= 'E' LAYOUT-SIZE-AND-ALIGNMENT // Trivial of exact size and alignment
LAYOUT-CONSTRAINT ::= 'e' LAYOUT-SIZE // Trivial of exact size
LAYOUT-CONSTRAINT ::= 'M' LAYOUT-SIZE-AND-ALIGNMENT // Trivial of size at most N bits
LAYOUT-CONSTRAINT ::= 'M' LAYOUT-SIZE-AND-ALIGNMENT // Trivial of size and alignment at most N bits
LAYOUT-CONSTRAINT ::= 'm' LAYOUT-SIZE // Trivial of size at most N bits
LAYOUT-CONSTRAINT ::= 'U' // Unknown layout
LAYOUT-CONSTRAINT ::= 'B' // BridgeObject
Expand Down Expand Up @@ -1231,7 +1232,7 @@ Substitutions
::

substitution ::= 'A' INDEX // substitution of N+26
substitution ::= 'A' SUBST_IDX* LAST-SUBST-IDX // One or more consecutive substitutions of N < 26
substitution ::= 'A' SUBST-IDX* LAST-SUBST-IDX // One or more consecutive substitutions of N < 26
SUBST-IDX ::= [a-z]
SUBST-IDX ::= NATURAL [a-z]
LAST-SUBST-IDX ::= [A-Z]
Expand Down Expand Up @@ -1282,14 +1283,14 @@ Numbers and Indexes
INDEX ::= '_' // 0
INDEX ::= NATURAL '_' // N+1
NATURAL ::= [1-9] [0-9]*
NATURAL_ZERO ::= [0-9]+
NATURAL-ZERO ::= [0-9]+

``<INDEX>`` is a production for encoding numbers in contexts that can't
end in a digit; it's optimized for encoding smaller numbers.

::

INDEX-SUBSET ::= ('S' | 'U')+
INDEX-SUBSET ::= [SU]+

``<INDEX-SUBSET>`` is encoded like a bit vector and is optimized for encoding
indices with a small upper bound.
Expand Down Expand Up @@ -1359,14 +1360,14 @@ Some kinds need arguments, which precede ``Tf``.

CONST-PROP ::= 'f' // Consumes one identifier argument which is a function symbol name
CONST-PROP ::= 'g' // Consumes one identifier argument which is a global symbol name
CONST-PROP ::= 'i' NATURAL_ZERO // 64-bit-integer
CONST-PROP ::= 'd' NATURAL_ZERO // float-as-64-bit-integer
CONST-PROP ::= 'i' NATURAL-ZERO // 64-bit-integer
CONST-PROP ::= 'd' NATURAL-ZERO // float-as-64-bit-integer
CONST-PROP ::= 's' ENCODING // string literal. Consumes one identifier argument.
CONST-PROP ::= 'k' // keypath. Consumes one identifier - the SHA1 of the keypath and two types (root and value).

ENCODING ::= 'b' // utf8
ENCODING ::= 'w' // utf16
ENCODING ::= 'c' // utf16
ENCODING ::= 'c' // objc

If the first character of the string literal is a digit ``[0-9]`` or an
underscore ``_``, the identifier for the string literal is prefixed with an
Expand Down
9 changes: 8 additions & 1 deletion lib/Sema/TypeCheckEffects.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3061,6 +3061,13 @@ class Context {
return copy;
}

/// Form a subcontext that handles all async calls.
Context withHandlesAsync() const {
Context copy = *this;
copy.HandlesAsync = true;
return copy;
}

Kind getKind() const { return TheKind; }

DeclContext *getDeclContext() const { return DC; }
Expand Down Expand Up @@ -4068,7 +4075,7 @@ class CheckEffectsCoverage : public EffectsHandlingWalker<CheckEffectsCoverage>

ShouldRecurse_t checkObjCSelector(ObjCSelectorExpr *E) {
// Walk the operand.
ContextScope scope(*this, std::nullopt);
ContextScope scope(*this, CurContext.withHandlesAsync());
scope.enterNonExecuting();

E->getSubExpr()->walk(*this);
Expand Down
10 changes: 10 additions & 0 deletions test/expr/primary/selector/selector.swift
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Expand Up @@ -180,3 +180,13 @@ func test() -> Selector {
func testWithThrowing(obj: AnyObject) {
_ = #selector(HasThrows.doSomething(to:))
}

@available(SwiftStdlib 5.1, *)
@objc protocol HasAsync {
@objc optional func doSomething(to object: AnyObject) async -> Void
}

@available(SwiftStdlib 5.1, *)
func testWithAsync(obj: AnyObject) {
_ = #selector(HasAsync.doSomething(to:))
}