#2080. Update assertion texts, add mixin syntax test (#2095)

Author: sgrekhov

Language/Classes/Superinterfaces/no_member_t01.dart

@@ -7,8 +7,8 @@
 /// It is a compile error if the implicit interface of C includes an instance
 /// member m of type F and C does not declare or inherit a corresponding
 /// non-abstract instance member m of type F' such that F' <: F.
-/// @description Checks that it is a compile error if a class does not declare
 ///
+/// @description Checks that it is a compile error if a class does not declare
 /// nor inherit an instance method declared in class' interface.
 /// @author msyabro
 

Language/Classes/Superinterfaces/no_member_t02.dart

@@ -4,22 +4,29 @@
 
 /// @assertion Let C be a concrete class that does not declare its own
 /// noSuchMethod().
-/// It is a compile error if the implicit interface
-/// of C includes an instance member m of type F and C does not declare or
-/// inherit a corresponding instance member m of type F' such that F' <: F.
+/// It is a compile error if the implicit interface of C includes an instance
+/// member m of type F and C does not declare or inherit a corresponding
+/// instance member m of type F' such that F' <: F.
 ///
-/// @description Checks that there are no warnings if the type F' of
-/// declared instance member m is in fact a subtype of F.
+/// @description Checks that there are no errors if the type F' of declared
+/// instance member m is in fact a subtype of F.
 /// @author ilya
 
 abstract class I {
   foo(int x);
 }
 
-class C implements I { 
+mixin M {
   foo(num x) {}
 }
 
+class C1 implements I {
+  foo(num x) {}
+}
+
+class C2 with M {}
+
 main () {
-  new C();
+  C1();
+  C2();
 }

Language/Classes/Superinterfaces/no_member_t03.dart

@@ -4,15 +4,14 @@
 
 /// @assertion Let C be a concrete class that does not declare its own
 /// noSuchMethod().
-/// It is a compile error if the implicit interface
-/// of C includes an instance member m of type F and C does not declare or
-/// inherit a corresponding instance member m of type F' such that F' <: F.
+/// It is a compile error if the implicit interface of C includes an instance
+/// member m of type F and C does not declare or inherit a corresponding
+/// instance member m of type F' such that F' <: F.
 ///
-/// @description Checks that there are no warnings if the type F' of
-/// inherited instance member m is in fact a subtype of F.
+/// @description Checks that there are no errors if the type F' of inherited
+/// instance member m is in fact a subtype of F.
 /// @author ilya
 
-
 abstract class I {
   foo(int x);
 }

Language/Classes/Superinterfaces/no_member_t04.dart

@@ -4,16 +4,15 @@
 
 /// @assertion Let C be a concrete class that does not declare its own
 /// noSuchMethod().
-/// It is a compile error if the implicit interface
-/// of C includes an instance member m of type F and C does not declare or
-/// inherit a corresponding instance member m of type F' such that F' <: F.
+/// It is a compile error if the implicit interface of C includes an instance
+/// member m of type F and C does not declare or inherit a corresponding
+/// instance member m of type F' such that F' <: F.
 ///
-/// @description Checks that there are no warnings if a class declares
-/// its own noSuchMethod() and does not declare nor inherit an instance
-/// method declared in class interface.
+/// @description Checks that there are no errors if a class declares its own
+/// `noSuchMethod()` and does not declare nor inherit an instance method
+/// declared in class interface.
 /// @author ilya
 
-
 abstract class I {
   foo();
 }

Language/Classes/Superinterfaces/no_member_t05.dart

@@ -13,7 +13,6 @@
 /// class.
 /// @author [email protected]
 
-
 class I {
   foo() {}
 }

Language/Classes/Superinterfaces/no_member_t07.dart

@@ -4,12 +4,12 @@
 
 /// @assertion Let C be a concrete class that does not declare its own
 /// noSuchMethod().
-/// It is a compile error if the implicit interface
-/// of C includes an instance member m of type F and C does not declare or
-/// inherit a corresponding instance member m of type F' such that F' <: F.
+/// It is a compile error if the implicit interface of C includes an instance
+/// member m of type F and C does not declare or inherit a corresponding
+/// instance member m of type F' such that F' <: F.
 ///
 /// @description Checks that there are no warnings if a class declares
-/// its own noSuchMethod() and does not declare nor inherit an instance
+/// its own `noSuchMethod()` and does not declare nor inherit an instance
 /// method declared in class interface. Test type alias
 /// @author [email protected]
 

Language/Mixins/Mixin_Application/syntax_t27.dart

@@ -0,0 +1,27 @@
+// Copyright (c) 2023, 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.
+
+/// @assertion Let S be a class, M be a mixin with required superinterfaces
+/// T1, . . . , Tn, combined superinterface MS, implemented interfaces
+/// I1, . . . , Ik and members as mixin member declarations, and let N be a name.
+/// ...
+/// The mixin application of M to S with name N introduces a new class, C,
+/// with name N, superclass S, implemented interface I1, . . . , Ik and members
+/// as instance members.
+///
+/// @description Checks that it is not an error if a class mixes in and
+/// implements the same mixin class
+/// @author [email protected]
+
+mixin class M {
+  num foo(int i) => i;
+}
+
+class C1 with M implements M {}
+class C2 = Object with M implements M;
+
+main() {
+  C1();
+  C2();
+}