[private named parameters] Test constant evaluation in analyzer and CFE.

Change-Id: I3fea84eed754b199f31f96c1e9f0b76182db8152
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/465821
Reviewed-by: Johnni Winther <[email protected]>
Auto-Submit: Bob Nystrom <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: munificent

pkg/analyzer/test/src/dart/constant/evaluation_test.dart

@@ -1316,6 +1316,30 @@ void f(Object? x) {
 ''');
   }
 
+  test_privateNamedParameter() async {
+    await assertNoErrorsInCode('''
+class C {
+  final int _x;
+  final int _y;
+  const C({required this._x, required this._y});
+  int get xy => _x + _y; // Avoid unused field warning.
+}
+const c = C(x: 123, y: 456);
+''');
+    var result = _topLevelVar('c');
+    assertDartObjectText(result, '''
+C
+  _x: int 123
+  _y: int 456
+  constructorInvocation
+    constructor: <testLibrary>::@class::C::@constructor::new
+    namedArguments
+      x: int 123
+      y: int 456
+  variable: <testLibrary>::@topLevelVariable::c
+''');
+  }
+
   test_propertyAccess_nullAware_dynamic_length_notNull() async {
     await assertNoErrorsInCode(r'''
 const dynamic d = 'foo';

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class C {
+  final int _x;
+  final int _y;
+  const C({required this._x, required this._y});
+}
+const c = C(x: 123, y: 456);
+
+main() {}

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.strong.expect

@@ -0,0 +1,25 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class C extends core::Object /*hasConstConstructor*/  {
+  final field core::int _x;
+  final field core::int _y;
+  const constructor •({required core::int x, required core::int y}) → self::C
+    : self::C::_x = x, self::C::_y = y, super core::Object::•()
+    ;
+}
+static const field self::C c = #C3;
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 123
+  #C2 = 456
+  #C3 = self::C {_x:#C1, _y:#C2}
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///constant_evaluation.dart:
+- C. (from org-dartlang-testcase:///constant_evaluation.dart:8:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.strong.modular.expect

@@ -0,0 +1,25 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class C extends core::Object /*hasConstConstructor*/  {
+  final field core::int _x;
+  final field core::int _y;
+  const constructor •({required core::int x, required core::int y}) → self::C
+    : self::C::_x = x, self::C::_y = y, super core::Object::•()
+    ;
+}
+static const field self::C c = #C3;
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 123
+  #C2 = 456
+  #C3 = self::C {_x:#C1, _y:#C2}
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///constant_evaluation.dart:
+- C. (from org-dartlang-testcase:///constant_evaluation.dart:8:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.strong.outline.expect

@@ -0,0 +1,19 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class C extends core::Object /*hasConstConstructor*/  {
+  final field core::int _x;
+  final field core::int _y;
+  const constructor •({required core::int x, required core::int y}) → self::C
+    : self::C::_x = x, self::C::_y = y, super core::Object::•()
+    ;
+}
+static const field self::C c = const self::C::•(x: 123, y: 456);
+static method main() → dynamic
+  ;
+
+
+Extra constant evaluation status:
+Evaluated: ConstructorInvocation @ org-dartlang-testcase:///constant_evaluation.dart:10:11 -> InstanceConstant(const C{C._x: 123, C._y: 456})
+Extra constant evaluation: evaluated: 3, effectively constant: 1

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.strong.transformed.expect

@@ -0,0 +1,25 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+class C extends core::Object /*hasConstConstructor*/  {
+  final field core::int _x;
+  final field core::int _y;
+  const constructor •({required core::int x, required core::int y}) → self::C
+    : self::C::_x = x, self::C::_y = y, super core::Object::•()
+    ;
+}
+static const field self::C c = #C3;
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 123
+  #C2 = 456
+  #C3 = self::C {_x:#C1, _y:#C2}
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///constant_evaluation.dart:
+- C. (from org-dartlang-testcase:///constant_evaluation.dart:8:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart)

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.textual_outline.expect

@@ -0,0 +1,9 @@
+class C {
+  final int _x;
+  final int _y;
+  const C({required this._x, required this._y});
+}
+
+const c = C(x: 123, y: 456);
+
+main() {}

pkg/front_end/testcases/private_named_parameters/constant_evaluation.dart.textual_outline_modelled.expect

@@ -0,0 +1,9 @@
+class C {
+  const C({required this._x, required this._y});
+  final int _x;
+  final int _y;
+}
+
+const c = C(x: 123, y: 456);
+
+main() {}