Improve attribute handling in opaqueGenericParameters rule (#1713)

Sources/Rules.swift

@@ -6626,9 +6626,7 @@ public struct _FormatRules {
  genericSignatureStartIndex < paramListStartIndex,
  genericSignatureEndIndex < paramListStartIndex,
  let openBraceIndex = formatter.index(of: .startOfScope("{"), after: paramListEndIndex),
- let closeBraceIndex = formatter.endOfScope(at: openBraceIndex),
- // Ignore anything with attributes
- !formatter.modifiersForDeclaration(at: keywordIndex, contains: { $1.hasPrefix("@") })
+ let closeBraceIndex = formatter.endOfScope(at: openBraceIndex)
  else { return }
 
  var genericTypes = [Formatter.GenericType]()
@@ -6700,6 +6698,14 @@ public struct _FormatRules {
  continue
  }
 
+ // If the generic type is referenced in any attributes, then it can't be removed
+ let startOfModifiers = formatter.startOfModifiers(at: keywordIndex, includingAttributes: true)
+ let modifierTokens = formatter.tokens[startOfModifiers ..< keywordIndex]
+ if modifierTokens.contains(where: { $0.string == genericType.name }) {
+ genericType.eligibleToRemove = false
+ continue
+ }
+
  // If the generic type is used in a constraint of any other generic type, then the type
  // can't be removed without breaking that other type
  let otherGenericTypes = genericTypes.filter { $0.name != genericType.name }

Tests/RulesTests+Syntax.swift

@@ -2867,6 +2867,37 @@ class SyntaxTests: RulesTests {
  testFormatting(for: input, rule: FormatRules.opaqueGenericParameters, options: options)
  }
 
+ func testGenericSimplifiedInMethodWithAttributeOrMacro() {
+ let input = """
+ @MyResultBuilder
+ func foo<T: Foo, U: Bar>(foo: T, bar: U) -> MyResult {
+ foo
+ bar
+ }
+
+ @MyFunctionBodyMacro(withArgument: true)
+ func foo<T: Foo, U: Bar>(foo: T, bar: U) {
+ print(foo, bar)
+ }
+ """
+
+ let output = """
+ @MyResultBuilder
+ func foo(foo: some Foo, bar: some Bar) -> MyResult {
+ foo
+ bar
+ }
+
+ @MyFunctionBodyMacro(withArgument: true)
+ func foo(foo: some Foo, bar: some Bar) {
+ print(foo, bar)
+ }
+ """
+
+ let options = FormatOptions(swiftVersion: "5.7")
+ testFormatting(for: input, output, rule: FormatRules.opaqueGenericParameters, options: options)
+ }
+
  // MARK: - genericExtensions
 
  func testGenericExtensionNotModifiedBeforeSwift5_7() {