some background, this issue came up when I first turned on generator result caching as the default, for dev mode tests (which of ended up testing deRPC)...
http://gwt-code-reviews.appspot.com/1462809/diff/2003/user/src/com/google/gwt/user/rebind/rpc/CachedRpcTypeInformation.java File user/src/com/google/gwt/user/rebind/rpc/CachedRpcTypeInformation.java (right): http://gwt-code-reviews.appspot.com/1462809/diff/2003/user/src/com/google/gwt/user/rebind/rpc/CachedRpcTypeInformation.java#newcode128 user/src/com/google/gwt/user/rebind/rpc/CachedRpcTypeInformation.java:128: private void addCustomSerializerType(JType type) { agreed http://gwt-code-reviews.appspot.com/1462809/ -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
