Implemented support for generalized void in analyzer.

pkg/analyzer/lib/src/error/codes.dart

Index: pkg/analyzer/lib/src/error/codes.dart
diff --git a/pkg/analyzer/lib/src/error/codes.dart b/pkg/analyzer/lib/src/error/codes.dart
index baad8320645b41792e96db373f91258c656e98fd..d687703c61bc802168f2ba61dc82862b3361589b 100644
--- a/pkg/analyzer/lib/src/error/codes.dart
+++ b/pkg/analyzer/lib/src/error/codes.dart
@@ -4723,16 +4723,6 @@ class StaticWarningCode extends ErrorCode {
           "Try correcting the name to an existing setter, or "
           "defining the setter in a superclass of '{1}'.");
 
-  /**
-   * 7.2 Getters: It is a static warning if the return type of a getter is void.
-   */
-  static const StaticWarningCode VOID_RETURN_FOR_GETTER =
-      const StaticWarningCode(
-          'VOID_RETURN_FOR_GETTER',
-          "The return type of a getter can't be 'void'.",
-          "Try providing a return type for the getter.",
-          false);
-
   /**
    * A flag indicating whether this warning is an error when running with strong
    * mode enabled.