rustdoc doesn't document reexports of implementations

[brson]

http://doc.rust-lang.org/doc/core/index.html

This page should list vec_len, reexported from core::vec

[brson]

@marijnh As far as I can tell reexported impls don't go in the exp_map. How do I find reexported impls so that I can document them?

[marijnh]

@brson See the code in metadata::encoder::encode_info_for_mod. The impl_map (maps everwhere!) is used for two things -- recording impls-in-scope for functions and method calls, and recording exported impls visible for mods. That's why it contains a linked list of scopes, but the entries for modules always contain a list of length 1 (I guess an enum would have made sense there).

[brson]

Fixed by 651aeea. Thanks marijn.