Don't export unnamed mixins.

pkg/front_end/testcases/rasta/super_mixin.dart.outline.expect

 library;
 import self as self;
 import "dart:core" as core;
 import "./mixin_library.dart" as mix;
 
 class Super<S extends core::Object> extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     ;
   method foo() → dynamic
     ;
   method f() → dynamic
     ;
 }
-class C<V extends core::Object> extends self::Super+Mixin#3<self::C::V, self::C::V> {
-  constructor •() → void
+abstract class _Super&Mixin^#T0^#T0<#T0 extends core::Object> = self::Super<self::_Super&Mixin^#T0^#T0::#T0> with mix::Mixin<self::_Super&Mixin^#T0^#T0::#T0> {
+}
+class C<V extends core::Object> extends self::_Super&Mixin^#T0^#T0<self::C::V> {
+  default constructor •() → void
     ;
 }
-class D extends self::Super+Mixin#2<dynamic> {
-  constructor •() → void
+abstract class _Super&Mixin = self::Super<dynamic> with mix::Mixin<dynamic> {
+}
+class D extends self::_Super&Mixin {
+  default constructor •() → void
     ;
 }
-class C2<V extends core::Object> extends self::Super+Mixin#1<self::C2::V, self::C2::V> {
+class C2<V extends core::Object> = self::Super<self::C2::V> with mix::Mixin<self::C2::V> {
   constructor •() → void
+    : super self::Super::•()
     ;
 }
-class D2 extends self::Super+Mixin#0<dynamic> {
+class D2 = self::Super<dynamic> with mix::Mixin<dynamic> {
   constructor •() → void
-    ;
-}
-abstract class Super+Mixin#0<T extends core::Object> extends self::Super<dynamic> implements mix::Mixin<dynamic> {
-  field self::Super+Mixin#0::T t;
-  field dynamic z;
-  field dynamic y;
-  field dynamic x;
-  constructor •() → void
-    ;
-  method publicMethod() → dynamic
-    ;
-  method _privateMethod() → dynamic
-    ;
-  method l() → dynamic
-    ;
-  method h() → dynamic
-    ;
-  method g(self::Super+Mixin#0::T a) → self::Super+Mixin#0::T
-    ;
-  method foo() → dynamic
-    ;
-}
-abstract class Super+Mixin#1<T extends core::Object, V extends core::Object> extends self::Super<self::Super+Mixin#1::V> implements mix::Mixin<self::Super+Mixin#1::V> {
-  field self::Super+Mixin#1::T t;
-  field dynamic z;
-  field dynamic y;
-  field dynamic x;
-  constructor •() → void
-    ;
-  method publicMethod() → dynamic
-    ;
-  method _privateMethod() → dynamic
-    ;
-  method l() → dynamic
-    ;
-  method h() → dynamic
-    ;
-  method g(self::Super+Mixin#1::T a) → self::Super+Mixin#1::T
-    ;
-  method foo() → dynamic
-    ;
-}
-abstract class Super+Mixin#2<T extends core::Object> extends self::Super<dynamic> implements mix::Mixin<dynamic> {
-  field self::Super+Mixin#2::T t;
-  field dynamic z;
-  field dynamic y;
-  field dynamic x;
-  constructor •() → void
-    ;
-  method publicMethod() → dynamic
-    ;
-  method _privateMethod() → dynamic
-    ;
-  method l() → dynamic
-    ;
-  method h() → dynamic
-    ;
-  method g(self::Super+Mixin#2::T a) → self::Super+Mixin#2::T
-    ;
-  method foo() → dynamic
-    ;
-}
-abstract class Super+Mixin#3<T extends core::Object, V extends core::Object> extends self::Super<self::Super+Mixin#3::V> implements mix::Mixin<self::Super+Mixin#3::V> {
-  field self::Super+Mixin#3::T t;
-  field dynamic z;
-  field dynamic y;
-  field dynamic x;
-  constructor •() → void
-    ;
-  method publicMethod() → dynamic
-    ;
-  method _privateMethod() → dynamic
-    ;
-  method l() → dynamic
-    ;
-  method h() → dynamic
-    ;
-  method g(self::Super+Mixin#3::T a) → self::Super+Mixin#3::T
-    ;
-  method foo() → dynamic
+    : super self::Super::•()
     ;
 }
 static method main() → dynamic
   ;