1. A non-transitory, computer-readable storage medium storing program instructions that when executed on a computing device cause the computing device to perform: passing a generic method and specialization metadata to a specialized method generator, wherein the specialization metadata comprises information identifying one or more program elements of the generic method to be adjusted when specializing the generic method for a particular type parameterization; generating, by the specialized method generator in response to said passing, a specialized method based, at least in part, on the generic method and the specialization metadata, wherein the specialized method is a version of the generic method specialized for the particular type parameterization; and storing, as a result of the specialized method being generated, a handle to the specialized method, such that the handle is usable to invoke the specialized method.