[cfe] Make named mixin applications non-constructable and abstract if sealed.

Special syntax for mixin applications should be also abstract if we add the sealed modifier.

Change-Id: I3af3e997734f4bc762dc29bfc3f61f2e691ca41b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/271840
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Kallen Tu <[email protected]>

Author: kallentu

pkg/front_end/lib/src/fasta/source/outline_builder.dart

@@ -2209,6 +2209,9 @@ class OutlineBuilder extends StackListenerImpl {
           }
         }
       }
+      if (sealedToken != null) {
+        modifiers |= abstractMask;
+      }
 
       int startCharOffset = beginToken.charOffset;
       int charEndOffset = endToken.charOffset;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.strong.expect

@@ -9,7 +9,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B = core::Object with self::M /*hasConstConstructor*/  {
+abstract sealed class B = core::Object with self::M /*hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.strong.transformed.expect

@@ -9,7 +9,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B extends core::Object implements self::M /*isEliminatedMixin,hasConstConstructor*/  {
+abstract sealed class B extends core::Object implements self::M /*isEliminatedMixin,hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.weak.expect

@@ -9,7 +9,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B = core::Object with self::M /*hasConstConstructor*/  {
+abstract sealed class B = core::Object with self::M /*hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.weak.modular.expect

@@ -9,7 +9,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B = core::Object with self::M /*hasConstConstructor*/  {
+abstract sealed class B = core::Object with self::M /*hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.weak.outline.expect

@@ -8,7 +8,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B = core::Object with self::M /*hasConstConstructor*/  {
+abstract sealed class B = core::Object with self::M /*hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

pkg/front_end/testcases/sealed_class/sealed_class_declaration.dart.weak.transformed.expect

@@ -9,7 +9,7 @@ abstract sealed class A extends core::Object {
 }
 abstract class M extends core::Object /*isMixinDeclaration*/  {
 }
-sealed class B extends core::Object implements self::M /*isEliminatedMixin,hasConstConstructor*/  {
+abstract sealed class B extends core::Object implements self::M /*isEliminatedMixin,hasConstConstructor*/  {
   const synthetic constructor •() → self::B
     : super core::Object::•()
     ;

tests/language/sealed_class/sealed_class_construct_error_test.dart

@@ -11,6 +11,9 @@ sealed class NotConstructable {}
 
 sealed mixin AlsoNotConstructable {}
 
+mixin M {}
+sealed class NotConstructableWithMixin = Object with M;
+
 main() {
   var error = NotConstructable();
   //          ^
@@ -19,4 +22,7 @@ main() {
   //           ^^^^^^^^^^^^^^^^^^^^
   // [analyzer] COMPILE_TIME_ERROR.MIXIN_INSTANTIATE
   // [cfe] Couldn't find constructor 'AlsoNotConstructable'.
+  var error3 = NotConstructableWithMixin();
+  //           ^
+  // [cfe] The class 'NotConstructableWithMixin' is abstract and can't be instantiated.
 }