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Track type member declarations optionally (#6596)

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This commit is contained in:
Danny Mösch
2026-04-15 21:58:40 +02:00
committed by GitHub
parent 949cfe9889
commit ceef663aaa
2 changed files with 78 additions and 144 deletions
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Source/SwiftLintBuiltInRules/Rules/Lint/VariableShadowingRule.swift
+54 -143
View File
@@ -35,8 +35,8 @@ struct VariableShadowingRule: Rule {
for i in 1...10 {
print(i)
}
for j in 1...10 {
print(j)
for i in 1...10 {
print(i)
}
"""),
Example("""
@@ -57,52 +57,6 @@ struct VariableShadowingRule: Rule {
}
"""),
Example("""
var outer: String = "hello"
if let inner = Optional(outer) {
print(inner)
}
"""),
Example("""
var a: String = "outer"
let (b, c) = ("first", "second")
print(a, b, c)
"""),
Example("""
class Test {
var property: String = "class property"
func test() {
var localVar = "local"
print(property, localVar)
}
}
"""),
Example("""
func outer() {
func inner() {
print("no shadowing")
}
}
"""),
Example("""
var result: String?
if let unwrappedResult = result {
print(unwrappedResult)
}
"""),
Example("""
var value: Int? = 10
guard let safeValue = value else {
return
}
print(safeValue)
"""),
Example("""
var data: [Int?] = [1, nil, 3]
for case let item? in data {
print(item)
}
"""),
Example("""
let a: Int?
if let a { print(a) }
"""),
@@ -121,52 +75,24 @@ struct VariableShadowingRule: Rule {
}
"""),
Example("""
func test() {
var a = 1
var b = 2
var a = 1
if let a = self.a {
print(a)
}
"""),
Example("""
struct S {
static let c: Int? = nil
var a: Int?
var b: Int {
if let a = self.a { a }
else if let c = Self.c { c }
else { 0 }
}
}
"""),
],
triggeringExamples: [
Example("""
var outer: String = "hello"
func test() {
let ↓outer = "world"
print(outer)
}
"""),
Example("""
var x = 1
do {
let ↓x = 2
print(x)
}
"""),
Example("""
var counter = 0
func incrementCounter() {
var ↓counter = 1
counter += 1
}
"""),
Example("""
func outer() {
var value = 10
do {
let ↓value = 20
print(value)
}
}
"""),
Example("""
var globalName = "global"
func test() {
for item in [1, 2, 3] {
var ↓globalName = "local"
print(globalName)
}
}
"""),
Example("""
var foo = 1
do {
@@ -174,12 +100,6 @@ struct VariableShadowingRule: Rule {
}
"""),
Example("""
var bar = 1
func test() {
let ↓bar = 2
}
"""),
Example("""
var a = 1
if let ↓a = Optional(2) {
let ↓a = 3
@@ -194,8 +114,8 @@ struct VariableShadowingRule: Rule {
}
"""),
Example("""
var a = 1
func test() {
var a = 1
do {
var ↓a = 2
print(a)
@@ -205,7 +125,7 @@ struct VariableShadowingRule: Rule {
Example("""
func test() {
var a = 1
if true {
if var ↓a = Optional(2) {
var ↓a = 2
print(a)
}
@@ -214,7 +134,7 @@ struct VariableShadowingRule: Rule {
Example("""
func test() {
var a = 1
for _ in 0..<1 {
for ↓a in 0..<1 {
var ↓a = 2
print(a)
}
@@ -230,16 +150,9 @@ struct VariableShadowingRule: Rule {
}
"""),
Example("""
var a = 1
if let ↓a = Optional(2) {}
"""),
Example("""
var i = 1
for ↓i in 1...3 {}
"""),
Example("""
var a: String?
func test(↓a: String?) {
let ↓a = ""
print(a)
}
""", configuration: ["ignore_parameters": false]),
@@ -257,8 +170,8 @@ struct VariableShadowingRule: Rule {
while let ↓a = Optional("hello") {}
"""),
Example("""
var a: String?
guard let ↓a = Optional("hello") else { return }
var a = "outer"
let (↓a, c) = ("first", "second")
"""),
]
)
@@ -266,9 +179,14 @@ struct VariableShadowingRule: Rule {
private extension VariableShadowingRule {
final class Visitor: DeclaredIdentifiersTrackingVisitor<VariableShadowingConfiguration> {
init(configuration: ConfigurationType, file: SwiftLintFile) {
super.init(configuration: configuration, file: file, includeMembers: true)
}
override func visit(_ node: VariableDeclSyntax) -> SyntaxVisitorContinueKind {
if node.parent?.is(MemberBlockItemSyntax.self) == false {
node.bindings.forEach { binding in
let isUnmodifiable = node.bindingSpecifier.tokenKind == .keyword(.let)
for binding in node.bindings where isUnmodifiable || !binding.isIdentity {
checkForShadowing(in: binding.pattern)
}
}
@@ -319,32 +237,15 @@ private extension VariableShadowingRule {
return super.visit(node)
}
override func visit(_ node: MemberBlockSyntax) -> SyntaxVisitorContinueKind {
let result = super.visit(node)
if let parent = node.parent,
[.actorDecl, .classDecl, .enumDecl, .structDecl].contains(parent.kind) {
for member in node.members {
if let varDecl = member.decl.as(VariableDeclSyntax.self) {
for binding in varDecl.bindings {
if let id = binding.pattern.as(IdentifierPatternSyntax.self)?.identifier {
scope.modifyLast { $0.append(.localVariable(name: id)) }
}
}
}
}
}
return result
}
// Checking shadowing in both variable declarations and optional bindings.
// For optional bindings, skips idiomatic patterns (if let a / if let a = a).
private func checkForShadowing(in pattern: PatternSyntax, binding: OptionalBindingConditionSyntax? = nil) {
if let identifier = pattern.as(IdentifierPatternSyntax.self) {
let identifierText = identifier.identifier.text
if let binding, isIdiomatic(pattern: identifier, binding: binding) {
let name = identifier.identifier.text
if let binding, binding.initializer?.isBindingFor(name: name) != false {
return
}
if hasSeenDeclaration(for: identifierText) {
if hasSeenDeclaration(for: name) {
violations.append(identifier.identifier.positionAfterSkippingLeadingTrivia)
}
} else if let tuple = pattern.as(TuplePatternSyntax.self) {
@@ -355,18 +256,28 @@ private extension VariableShadowingRule {
checkForShadowing(in: valueBinding.pattern, binding: binding)
}
}
// Idiomatic: shorthand (if let a) or identity (if let a = a)
private func isIdiomatic(
pattern: IdentifierPatternSyntax,
binding: OptionalBindingConditionSyntax
) -> Bool {
let patternName = pattern.identifier.text
guard let initializer = binding.initializer else { return true }
if let identifierExpr = initializer.value.as(DeclReferenceExprSyntax.self) {
return identifierExpr.baseName.text == patternName
}
return false
}
}
}
private extension PatternBindingSyntax {
var isIdentity: Bool {
guard let initializer, let identifierPattern = pattern.as(IdentifierPatternSyntax.self) else {
return false
}
return initializer.isBindingFor(name: identifierPattern.identifier.text)
}
}
private extension InitializerClauseSyntax {
func isBindingFor(name: String) -> Bool {
if let identifierExpr = value.as(DeclReferenceExprSyntax.self) {
return identifierExpr.baseName.text == name
}
if let memberAccessExpr = value.as(MemberAccessExprSyntax.self),
let baseName = memberAccessExpr.base?.as(DeclReferenceExprSyntax.self)?.baseName.text,
["self", "Self"].contains(baseName) {
return memberAccessExpr.declName.baseName.text == name
}
return false
}
}
Source/SwiftLintCore/Visitors/DeclaredIdentifiersTrackingVisitor.swift
+24 -1
View File
@@ -7,6 +7,8 @@ public enum IdentifierDeclaration: Hashable {
case parameter(name: TokenSyntax)
/// Local variable declaration with a name token.
case localVariable(name: TokenSyntax)
/// A member variable declaration with a name token.
case memberVariable(name: TokenSyntax)
/// A variable that is implicitly added by the compiler (e.g. `error` in `catch` clauses).
case implicitVariable(name: String)
/// A variable hidden from scope because its name is a wildcard `_`.
@@ -19,6 +21,7 @@ public enum IdentifierDeclaration: Hashable {
switch self {
case let .parameter(name): name.text
case let .localVariable(name): name.text
case let .memberVariable(name): name.text
case let .implicitVariable(name): name
case .wildcard: "_"
case .lookupBoundary: ""
@@ -50,6 +53,10 @@ open class DeclaredIdentifiersTrackingVisitor<Configuration: RuleConfiguration>:
/// A type that remembers the declared identifiers (in order) up to the current position in the code.
public typealias Scope = Stack<[IdentifierDeclaration]>
/// Whether to include class/struct/actor/enum member declarations in the scope. If `false`, only function-local
/// scopes are tracked.
public let includeMembers: Bool
/// The hierarchical stack of identifiers declared up to the current position in the code.
public var scope: Scope
@@ -58,9 +65,14 @@ open class DeclaredIdentifiersTrackingVisitor<Configuration: RuleConfiguration>:
/// - Parameters:
/// - configuration: Configuration of a rule.
/// - file: File from which the syntax tree stems from.
/// - includeMembers: Whether to include class/struct/actor/enum member declarations in the scope.
/// - scope: A (potentially already pre-filled) scope to collect identifiers into.
@inlinable
public init(configuration: Configuration, file: SwiftLintFile, scope: Scope = Scope()) {
public init(configuration: Configuration,
file: SwiftLintFile,
includeMembers: Bool = false,
scope: Scope = Scope()) {
self.includeMembers = includeMembers
self.scope = scope
super.init(configuration: configuration, file: file)
}
@@ -123,6 +135,14 @@ open class DeclaredIdentifiersTrackingVisitor<Configuration: RuleConfiguration>:
if node.belongsToTypeDefinableInFunction {
scope.push([.lookupBoundary])
}
if includeMembers {
scope.openChildScope()
for binding in node.members.compactMap({ $0.decl.as(VariableDeclSyntax.self) }).flatMap(\.bindings) {
if let id = binding.pattern.as(IdentifierPatternSyntax.self)?.identifier {
scope.addToCurrentScope(.memberVariable(name: id))
}
}
}
return .visitChildren
}
@@ -130,6 +150,9 @@ open class DeclaredIdentifiersTrackingVisitor<Configuration: RuleConfiguration>:
if node.belongsToTypeDefinableInFunction {
scope.pop()
}
if includeMembers {
scope.pop()
}
}
override open func visit(_ node: FunctionDeclSyntax) -> SyntaxVisitorContinueKind {