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paldepind merged 2 commits into from
Nov 9, 2026
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Unified, Swift: Translate ignored parameters into ignore patterns #23050

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8559595
Unified: Add Swift corpus tests for anonymous parameters
paldepind Nov 9, 2026
fbef21d
Unified: Translate anonymous Swift parameters as ignore patterns
paldepind Nov 9, 2026
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19 changes: 15 additions & 4 deletions unified/extractor/src/languages/swift/swift.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,17 @@ fn make_or_pattern(
}
}

fn parameter_pattern(
ctx: &mut yeast::build::BuildCtx<'_, SwiftContext>,
name: yeast::Id,
) -> yeast::OutputId {
if ctx.source_text(name) == "_" {
tree!((ignore_pattern #{name}))
} else {
tree!((identifier #{name}))
}
}

/// Translate a multi-part identifier (for example `Foo.Bar.Baz`) into a
/// `member_access_expr` chain rooted at a `name_node` for the first
/// part. Panics on an empty input because the grammar's `_+` quantifier
Expand Down Expand Up @@ -669,7 +680,7 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
=>
(parameter
external_name_node: (identifier #{first})
pattern: (identifier #{second})
pattern: {parameter_pattern(&mut ctx, second)}
type: {ty}
default: {val})
),
Expand All @@ -681,7 +692,7 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
=>
(parameter
external_name_node: (identifier #{first}) // duplicate the parameter name
pattern: (identifier #{first})
pattern: {parameter_pattern(&mut ctx, first)}
type: {ty}
default: {val})
),
Expand Down Expand Up @@ -867,14 +878,14 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
rule!(
(closureParameter firstName: @@name type: _? @ty)
=>
(parameter pattern: (identifier #{name}) type: {ty})
(parameter pattern: {parameter_pattern(&mut ctx, name)} type: {ty})
),
// A shorthand closure parameter (`x` in `{ x, y in … }`): a bare name
// with no parentheses and no type.
rule!(
(closureShorthandParameter name: @@name)
=>
(parameter pattern: (identifier #{name}))
(parameter pattern: {parameter_pattern(&mut ctx, name)})
),
// ---- Control flow ----
// An `if`/`else` expression. Conditions are joined via `and_chain`; the
Expand Down
2 changes: 1 addition & 1 deletion unified/extractor/tests/corpus/swift/expressions/array-type-constructor.output
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Expand Up @@ -181,7 +181,7 @@ top_level source="⟨body⟩"
function_expr source="{ ⟨parameter⟩, ⟨parameter⟩ in\n\t⟨body⟩\n}"
parameter:
parameter source="⟨pattern⟩"
pattern: identifier "_" source="_"
pattern: ignore_pattern "_" source="_"
parameter source="⟨pattern⟩"
pattern: identifier "count" source="count"
body:
Expand Down
251 changes: 251 additions & 0 deletions unified/extractor/tests/corpus/swift/functions/function-with-anonymous-parameters.output
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@@ -0,0 +1,251 @@
func ignore(_: Int, _: String) {
}

func ignore(first _: Int, second _: String) {
}

let ignoreClosure: (Int, String) -> Void = { _, _ in
}

let ignoreTypedClosure = { (_: Int, _: String) in
}

---

sourceFile
endOfFileToken: endOfFile
statements:
codeBlockItem
item:
functionDecl
attributes:
body:
codeBlock
leftBrace: {
rightBrace: }
statements:
modifiers:
name: identifier "ignore"
signature:
functionSignature
parameterClause:
functionParameterClause
leftParen: (
rightParen: )
parameters:
functionParameter
colon: :
attributes:
modifiers:
trailingComma: ,
type:
identifierType
name: identifier "Int"
firstName: _
functionParameter
colon: :
attributes:
modifiers:
type:
identifierType
name: identifier "String"
firstName: _
funcKeyword: func
codeBlockItem
item:
functionDecl
attributes:
body:
codeBlock
leftBrace: {
rightBrace: }
statements:
modifiers:
name: identifier "ignore"
signature:
functionSignature
parameterClause:
functionParameterClause
leftParen: (
rightParen: )
parameters:
functionParameter
colon: :
attributes:
modifiers:
trailingComma: ,
type:
identifierType
name: identifier "Int"
firstName: identifier "first"
secondName: _
functionParameter
colon: :
attributes:
modifiers:
type:
identifierType
name: identifier "String"
firstName: identifier "second"
secondName: _
funcKeyword: func
codeBlockItem
item:
variableDecl
attributes:
modifiers:
bindingSpecifier: let
bindings:
patternBinding
initializer:
initializerClause
equal: =
value:
closureExpr
leftBrace: {
rightBrace: }
signature:
closureSignature
attributes:
inKeyword: in
parameterClause:
closureShorthandParameter
name: _
trailingComma: ,
closureShorthandParameter
name: _
statements:
pattern:
identifierPattern
identifier: identifier "ignoreClosure"
typeAnnotation:
typeAnnotation
colon: :
type:
functionType
leftParen: (
rightParen: )
parameters:
tupleTypeElement
trailingComma: ,
type:
identifierType
name: identifier "Int"
tupleTypeElement
type:
identifierType
name: identifier "String"
returnClause:
returnClause
arrow: ->
type:
identifierType
name: identifier "Void"
codeBlockItem
item:
variableDecl
attributes:
modifiers:
bindingSpecifier: let
bindings:
patternBinding
initializer:
initializerClause
equal: =
value:
closureExpr
leftBrace: {
rightBrace: }
signature:
closureSignature
attributes:
inKeyword: in
parameterClause:
closureParameterClause
leftParen: (
rightParen: )
parameters:
closureParameter
colon: :
attributes:
modifiers:
trailingComma: ,
type:
identifierType
name: identifier "Int"
firstName: _
closureParameter
colon: :
attributes:
modifiers:
type:
identifierType
name: identifier "String"
firstName: _
statements:
pattern:
identifierPattern
identifier: identifier "ignoreTypedClosure"

---

top_level source="⟨body⟩"
body:
block source="⟨stmt⟩\n\n⟨stmt⟩\n\n⟨stmt⟩\n\n⟨stmt⟩"
stmt:
function_declaration source="func ⟨name_node⟩(⟨parameter⟩, ⟨parameter⟩) ⟨body⟩"
name_node: identifier "ignore" source="ignore"
parameter:
parameter source="⟨external_name_node⟩⟨pattern⟩: ⟨type⟩"
external_name_node: identifier "_" source="_"
type: identifier "Int" source="Int"
pattern: ignore_pattern "_" source="_"
parameter source="⟨external_name_node⟩⟨pattern⟩: ⟨type⟩"
external_name_node: identifier "_" source="_"
type: identifier "String" source="String"
pattern: ignore_pattern "_" source="_"
body: block "{\n}" source="{\n}"
function_declaration source="func ⟨name_node⟩(⟨parameter⟩, ⟨parameter⟩) ⟨body⟩"
name_node: identifier "ignore" source="ignore"
parameter:
parameter source="⟨external_name_node⟩ ⟨pattern⟩: ⟨type⟩"
external_name_node: identifier "first" source="first"
type: identifier "Int" source="Int"
pattern: ignore_pattern "_" source="_"
parameter source="⟨external_name_node⟩ ⟨pattern⟩: ⟨type⟩"
external_name_node: identifier "second" source="second"
type: identifier "String" source="String"
pattern: ignore_pattern "_" source="_"
body: block "{\n}" source="{\n}"
variable_declaration source="⟨modifier⟩ ⟨pattern⟩: ⟨type⟩ = ⟨value⟩"
modifier: modifier "let" source="let"
pattern: identifier "ignoreClosure" source="ignoreClosure"
type:
function_expr source="(⟨parameter⟩, ⟨parameter⟩) -> ⟨return_type⟩"
parameter:
parameter source="⟨type⟩"
type: identifier "Int" source="Int"
parameter source="⟨type⟩"
type: identifier "String" source="String"
return_type: identifier "Void" source="Void"
value:
function_expr source="{ ⟨parameter⟩, ⟨parameter⟩ in\n}"
parameter:
parameter source="⟨pattern⟩"
pattern: ignore_pattern "_" source="_"
parameter source="⟨pattern⟩"
pattern: ignore_pattern "_" source="_"
body: block source=""
variable_declaration source="⟨modifier⟩ ⟨pattern⟩ = ⟨value⟩"
modifier: modifier "let" source="let"
pattern: identifier "ignoreTypedClosure" source="ignoreTypedClosure"
value:
function_expr source="{ (⟨parameter⟩, ⟨parameter⟩) in\n}"
parameter:
parameter source="⟨pattern⟩: ⟨type⟩"
type: identifier "Int" source="Int"
pattern: ignore_pattern "_" source="_"
parameter source="⟨pattern⟩: ⟨type⟩"
type: identifier "String" source="String"
pattern: ignore_pattern "_" source="_"
body: block source=""
11 changes: 11 additions & 0 deletions unified/extractor/tests/corpus/swift/functions/function-with-anonymous-parameters.swift
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
func ignore(_: Int, _: String) {
}

func ignore(first _: Int, second _: String) {
}

let ignoreClosure: (Int, String) -> Void = { _, _ in
}

let ignoreTypedClosure = { (_: Int, _: String) in
}
2 changes: 1 addition & 1 deletion unified/extractor/tests/corpus/swift/types/function-type-with-inout-parameter.output
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Original file line number Diff line number Diff line change
Expand Up @@ -79,5 +79,5 @@ top_level source="⟨body⟩"
function_expr source="{ ⟨parameter⟩ in }"
parameter:
parameter source="⟨pattern⟩"
pattern: identifier "_" source="_"
pattern: ignore_pattern "_" source="_"
body: block source=""
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