985ae0b55b
Extract attribute name once and match it against symbols that are being validated, instead of using `Session::check_name` for each symbol individually. Assume that all validated attributes are used, instead of marking them as such, since the attribute check should be exhaustive.
The rustc_ast crate contains those things concerned purely with syntax
– that is, the AST ("abstract syntax tree"), parser, pretty-printer,
lexer, macro expander, and utilities for traversing ASTs.
For more information about how these things work in rustc, see the rustc dev guide: