Issue 16672. Report warning for assignment to a function.

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

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
index beeb47bc8a75e3c805c2bb4826b8a9d35958c02c..0b24eabfebf754fc479ac2c06cce9d58c027ab24 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/error/StaticWarningCode.java
@@ -82,8 +82,16 @@ public enum StaticWarningCode implements ErrorCode {
   ASSIGNMENT_TO_FINAL("'%s' cannot be used as a setter, it is final"),
 
   /**
+   * 12.18 Assignment: It is as static warning if an assignment of the form <i>v = e</i> occurs
+   * inside a top level or static function (be it function, method, getter, or setter) or variable
+   * initializer and there is neither a local variable declaration with name <i>v</i> nor setter
+   * declaration with name <i>v=</i> in the lexical scope enclosing the assignment.
+   */
+  ASSIGNMENT_TO_FUNCTION("Functions cannot be assigned a value"),
+
+  /**
    * 12.18 Assignment: Let <i>T</i> be the static type of <i>e<sub>1</sub></i>. It is a static type
-   * warning if <i>T</i> does not have an accessible instance setter named <i>v =</i>.
+   * warning if <i>T</i> does not have an accessible instance setter named <i>v=</i>.
    */
   ASSIGNMENT_TO_METHOD("Methods cannot be assigned a value"),