fix unnecessary_parens overreporting on records missing commas

Fixes: https://github.com/dart-lang/linter/issues/4876

Change-Id: I171709f15b5341e91726024f387d9f842a524b4e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352104
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/linter/lib/src/rules/unnecessary_parenthesis.dart

@@ -6,6 +6,7 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
 
 import '../analyzer.dart';
 import '../extensions.dart';
@@ -92,6 +93,26 @@ class _Visitor extends SimpleAstVisitor<void> {
     var parent = node.parent;
     // case const (a + b):
     if (parent is ConstantPattern) return;
+
+    // Don't over-report on records missing trailing commas.
+    // (int,) r = (3);
+    if (parent is VariableDeclaration &&
+        parent.declaredElement?.type is RecordType) {
+      if (node.expression is! RecordLiteral) return;
+    }
+    // g((3)); => g((int,) i) { }
+    if (parent is ArgumentList) {
+      var element = node.staticParameterElement;
+      if (element?.type is RecordType && node.expression is! RecordLiteral) {
+        return;
+      }
+    }
+    // g(i: (3)); => g({required (int,) i}) { }
+    if (parent is NamedExpression &&
+        parent.staticParameterElement?.type is RecordType) {
+      if (node.expression is! RecordLiteral) return;
+    }
+
     var expression = node.expression;
     if (expression is SimpleIdentifier ||
         expression.containsNullAwareInvocationInChain()) {

pkg/linter/test/rules/unnecessary_parenthesis_test.dart

@@ -51,6 +51,84 @@ void g(List<int>? list) {
 ''');
   }
 
+  test_record_assignment() async {
+    await assertDiagnostics(r'''
+void f() {
+  (int,) r = ((3,));
+}
+''', [
+      lint(24, 6),
+    ]);
+  }
+
+  test_record_namedParam() async {
+    await assertDiagnostics(r'''
+void f() {
+  g(i: ((3,)));
+}
+g({required (int,) i}) { }
+
+''', [
+      lint(18, 6),
+    ]);
+  }
+
+  test_record_param() async {
+    await assertDiagnostics(r'''
+void f() {
+  g(((3,)));
+}
+g((int,) i) { }
+
+''', [
+      lint(15, 6),
+    ]);
+  }
+
+  test_singleElementRecordWithNoTrailingComma_assignment() async {
+    await assertDiagnostics(r'''
+void f() {
+  (int,) r = (3);
+}
+''', [
+      error(
+          CompileTimeErrorCode.RECORD_LITERAL_ONE_POSITIONAL_NO_TRAILING_COMMA,
+          24,
+          3),
+    ]);
+  }
+
+  test_singleElementRecordWithNoTrailingComma_namedParam() async {
+    await assertDiagnostics(r'''
+f() {
+  g(i: (3));
+}
+
+g({required (int,) i}) { }
+''', [
+      error(
+          CompileTimeErrorCode.RECORD_LITERAL_ONE_POSITIONAL_NO_TRAILING_COMMA,
+          13,
+          3),
+    ]);
+  }
+
+  /// https://github.com/dart-lang/linter/issues/4876
+  test_singleElementRecordWithNoTrailingComma_param() async {
+    await assertDiagnostics(r'''
+f() {    
+  g((3));
+}
+
+g((int,) i) { }
+''', [
+      error(
+          CompileTimeErrorCode.RECORD_LITERAL_ONE_POSITIONAL_NO_TRAILING_COMMA,
+          14,
+          3),
+    ]);
+  }
+
   test_switchExpression_expressionStatement() async {
     await assertNoDiagnostics(r'''
 void f(Object? x) {