3cf2bc0e51
Extract `rustc_ast_lowering` crate from `rustc` Working towards https://github.com/rust-lang/rust/issues/65031. This PR moves `src/librustc/hir/lowering{/, .rs}` to its own crate (`librustc_ast_lowering`) which is very self-contained (only `fn lower_crate` and `trait Resolver` are exposed). r? @Mark-Simulacrum