rust-lang/rust — pull request #16153 by kballard (2014-08-01 02:10:13+00:00)
Title: Stop using the Show impl for ast::Name in our symbols

When generating a unique symbol for things like closures or glue_drop,
we call token::gensym() to create a crate-unique Name. Recently, Name
changed its Show impl so it no longer prints as a number. This caused
symbols like glue_drop:1542 to become glue_drop:"glue_drop"(1542), or in
mangled form, glue_drop.$x22glue_drop$x22$LP$1542$RP$.