This reverts commit 059b68dd677808e14e560802d235ad40beeba71e. Note that this was manually adjusted to retain some of the refactoring introduced by commit 059b68dd677808e14e560802d235ad40beeba71e, so that it could likewise retain the correction introduced in commit 5b4bc05fa57be19bb5962f4b7c0f165e194e3151
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: