Issue 18653. Report error for a const constructor in a class with a mixin.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java
index 506bde1a82f6ec5d78a70c373d7431a0e2ab92b7..c33a3a56e15d3d01cf133ddfbdb3632bdce6eb89 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/CompileTimeErrorCode.java
@@ -139,9 +139,19 @@ public enum CompileTimeErrorCode implements ErrorCode {
    * 7.6.3 Constant Constructors: The superinitializer that appears, explicitly or implicitly, in
    * the initializer list of a constant constructor must specify a constant constructor of the
    * superclass of the immediately enclosing class or a compile-time error occurs.
+   * <p>
+   * 9 Mixins: For each generative constructor named ... an implicitly declared constructor named
+   * ... is declared.
+   */
+  CONST_CONSTRUCTOR_WITH_MIXIN("Constant constructor cannot be declared for a class with a mixin"),
+
+  /**
+   * 7.6.3 Constant Constructors: The superinitializer that appears, explicitly or implicitly, in
+   * the initializer list of a constant constructor must specify a constant constructor of the
+   * superclass of the immediately enclosing class or a compile-time error occurs.
    */
   CONST_CONSTRUCTOR_WITH_NON_CONST_SUPER(
-      "Constant constructor cannot call non-constant super constructor"),
+      "Constant constructor cannot call non-constant super constructor of '%s'"),
 
   /**
    * 7.6.3 Constant Constructors: It is a compile-time error if a constant constructor is declared