c896f06bdb
Use the same precedence for all macro-like exprs No need to make these have a different precedence since they're all written like `whatever!(expr)`, and it makes it simpler when adding new macro-based built-in operators in the future.
The rustc_ast crate contains those things concerned purely with syntax
– that is, the AST ("abstract syntax tree"), along with some definitions for tokens and token streams, data structures/traits for mutating ASTs, and shared definitions for other AST-related parts of the compiler (like the lexer and macro-expansion).
For more information about how these things work in rustc, see the rustc dev guide: