In a .webidl file that just includes this: callback interface Foo { TestInterface receiveSelf(); }; The resulting .cpp file fails to build with this error: /Users/amccreight/mz/cent/obj-dbg/dom/bindings/JSImplBinding.cpp:6:10: fatal error: 'TestBindingHeader.h' file not found #include "TestBindingHeader.h" If |TestInterface| is replaced with |long|, then the resulting file compiles just fine. ^ 1 error generated.

TestInterface is not an external interface. Where is this .webidl file located?

This is just because TestInterface is listed in Bindings.conf as having that header file, and the .webidl file isn't with the test stuff. Oops. When I change TestInterface to TestInterfaceFooFoo, then it throws an exception while generating the file: WebIDL.WebIDLError: error: Unresolved type '<unresolved scope>::TestInterfaceFooFoo'., JSImpl.webidl line 8:2 TestInterfaceFooFoo receiveSelf(); ^