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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import SwiftSyntax
/// Overloads with only a closure argument should not be disambiguated by parameter labels.
///
/// Lint: If two overloaded functions with one closure parameter appear in the same scope, a lint
/// error is raised.
@_spi(Rules)
public final class AmbiguousTrailingClosureOverload: SyntaxLintRule {
private func diagnoseBadOverloads(_ overloads: [String: [FunctionDeclSyntax]]) {
for (_, decls) in overloads where decls.count > 1 {
let decl = decls[0]
diagnose(
.ambiguousTrailingClosureOverload(decl.fullDeclName),
on: decl.name,
notes: decls.dropFirst().map { decl in
Finding.Note(
message: .otherAmbiguousOverloadHere(decl.fullDeclName),
location: Finding.Location(
decl.name.startLocation(converter: self.context.sourceLocationConverter)
)
)
}
)
}
}
private func discoverAndDiagnoseOverloads(_ functions: [FunctionDeclSyntax]) {
var overloads = [String: [FunctionDeclSyntax]]()
var staticOverloads = [String: [FunctionDeclSyntax]]()
for fn in functions {
let params = fn.signature.parameterClause.parameters
guard let firstParam = params.firstAndOnly else { continue }
guard firstParam.type.is(FunctionTypeSyntax.self) else { continue }
if fn.modifiers.contains(anyOf: [.class, .static]) {
staticOverloads[fn.name.text, default: []].append(fn)
} else {
overloads[fn.name.text, default: []].append(fn)
}
}
diagnoseBadOverloads(overloads)
diagnoseBadOverloads(staticOverloads)
}
public override func visit(_ node: SourceFileSyntax) -> SyntaxVisitorContinueKind {
let functions = node.statements.compactMap { $0.item.as(FunctionDeclSyntax.self) }
discoverAndDiagnoseOverloads(functions)
return .visitChildren
}
public override func visit(_ node: CodeBlockSyntax) -> SyntaxVisitorContinueKind {
let functions = node.statements.compactMap { $0.item.as(FunctionDeclSyntax.self) }
discoverAndDiagnoseOverloads(functions)
return .visitChildren
}
public override func visit(_ decls: MemberBlockSyntax) -> SyntaxVisitorContinueKind {
let functions = decls.members.compactMap { $0.decl.as(FunctionDeclSyntax.self) }
discoverAndDiagnoseOverloads(functions)
return .visitChildren
}
}
extension Finding.Message {
fileprivate static func ambiguousTrailingClosureOverload(_ decl: String) -> Finding.Message {
"rename '\(decl)' so it is no longer ambiguous when called with a trailing closure"
}
fileprivate static func otherAmbiguousOverloadHere(_ decl: String) -> Finding.Message {
"ambiguous overload '\(decl)' is here"
}
}
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