Update ReturnVoidInsteadOfEmptyTuple Rule

The new parser will attach the unexpected text here as trailing trivia. Update this rule to account for that.

The new parser also fixes a regression in this test and diagnoses

() -> (\u{feff})

without replacing it

Author: CodaFi

Sources/SwiftFormatRules/ReturnVoidInsteadOfEmptyTuple.swift

@@ -34,7 +34,8 @@ public final class ReturnVoidInsteadOfEmptyTuple: SyntaxFormatRule {
     // If the user has put non-whitespace trivia inside the empty tuple, like a comment, then we
     // still diagnose it as a lint error but we don't replace it because it's not obvious where the
     // comment should go.
-    if hasNonWhitespaceLeadingTrivia(returnType.rightParen) {
+    if hasNonWhitespaceTrivia(returnType.leftParen, at: .trailing)
+        || hasNonWhitespaceTrivia(returnType.rightParen, at: .leading) {
       return super.visit(node)
     }
 
@@ -58,7 +59,8 @@ public final class ReturnVoidInsteadOfEmptyTuple: SyntaxFormatRule {
     // If the user has put non-whitespace trivia inside the empty tuple, like a comment, then we
     // still diagnose it as a lint error but we don't replace it because it's not obvious where the
     // comment should go.
-    if hasNonWhitespaceLeadingTrivia(returnType.rightParen) {
+    if hasNonWhitespaceTrivia(returnType.leftParen, at: .trailing)
+        || hasNonWhitespaceTrivia(returnType.rightParen, at: .leading) {
       return super.visit(node)
     }
 
@@ -79,8 +81,8 @@ public final class ReturnVoidInsteadOfEmptyTuple: SyntaxFormatRule {
 
   /// Returns a value indicating whether the leading trivia of the given token contained any
   /// non-whitespace pieces.
-  private func hasNonWhitespaceLeadingTrivia(_ token: TokenSyntax) -> Bool {
-    for piece in token.leadingTrivia {
+  private func hasNonWhitespaceTrivia(_ token: TokenSyntax, at position: TriviaPosition) -> Bool {
+    for piece in position == .leading ? token.leadingTrivia : token.trailingTrivia {
       switch piece {
       case .blockComment, .docBlockComment, .docLineComment, .unexpectedText, .lineComment,
         .shebang:

Tests/SwiftFormatRulesTests/ReturnVoidInsteadOfEmptyTupleTests.swift

@@ -153,6 +153,7 @@ final class ReturnVoidInsteadOfEmptyTupleTests: LintOrFormatRuleTestCase {
     XCTAssertDiagnosed(.returnVoid, line: 6, column: 21)
     XCTAssertDiagnosed(.returnVoid, line: 7, column: 21)
     XCTAssertDiagnosed(.returnVoid, line: 10, column: 21)
+    XCTAssertDiagnosed(.returnVoid, line: 13, column: 21)
     XCTAssertDiagnosed(.returnVoid, line: 15, column: 22)
     XCTAssertDiagnosed(.returnVoid, line: 15, column: 29)
     XCTAssertDiagnosed(.returnVoid, line: 16, column: 44)