plt/racket — pull request #531 by takikawa (2013-12-29 11:19:10+00:00)
Title: Improve TR support of struct-type types

These commits improve the base types for reflective operations on structure types, such as `struct-info`, `struct-type-info`, and so on.

The PR also adds a new `Struct-TypeTop` type that is the supertype of all structure type descriptor value types.