99f5c79d64
From 72 bytes to 12 bytes (on x86-64). There are two parts to this: - Changing various source code offsets from 64-bit to 32-bit. This is not a problem because the rest of rustc also uses 32-bit source code offsets. This means `Token` is no longer `Copy` but this causes no problems. - Removing the `RawStrError` from `LiteralKind`. Raw string literal invalidity is now indicated by a `None` value within `RawStr`/`RawByteStr`, and the new `validate_raw_str` function can be used to re-lex an invalid raw string literal to get the `RawStrError`. There is one very small change in behaviour. Previously, if a raw string literal matched both the `InvalidStarter` and `TooManyHashes` cases, the latter would override the former. This has now changed, because `raw_double_quoted_string` now uses `?` and so returns immediately upon detecting the `InvalidStarter` case. I think this is a slight improvement to report the earlier-detected error, and it explains the change in the `test_too_many_hashes` test. The commit also removes a couple of comments that refer to #77629 and say that the size of these types don't affect performance. These comments are wrong, though the performance effect is small.
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: