Don't insert spaces before most semicolons in `print_tts`.

2024-01-22T09:14:59+00:00

This gives better output for code produced by proc macros.

Add spacing information to delimiters.

2023-12-10T22:36:40+00:00

This is an extension of the previous commit. It means the output of something like this: ``` stringify!(let a: Vec = vec![];) ``` goes from this: ``` let a: Vec = vec![] ; ``` With this PR, it now produces this string: ``` let a: Vec = vec![]; ```

Improve `print_tts` by changing `tokenstream::Spacing`.

2023-12-10T22:19:09+00:00

`tokenstream::Spacing` appears on all `TokenTree::Token` instances, both punct and non-punct. Its current usage: - `Joint` means "can join with the next token *and* that token is a punct". - `Alone` means "cannot join with the next token *or* can join with the next token but that token is not a punct". The fact that `Alone` is used for two different cases is awkward. This commit augments `tokenstream::Spacing` with a new variant `JointHidden`, resulting in: - `Joint` means "can join with the next token *and* that token is a punct". - `JointHidden` means "can join with the next token *and* that token is a not a punct". - `Alone` means "cannot join with the next token". This *drastically* improves the output of `print_tts`. For example, this: ``` stringify!(let a: Vec = vec![];) ``` currently produces this string: ``` let a : Vec < u32 > = vec! [] ; ``` With this PR, it now produces this string: ``` let a: Vec = vec![] ; ``` (The space after the `]` is because `TokenTree::Delimited` currently doesn't have spacing information. The subsequent commit fixes this.) The new `print_tts` doesn't replicate original code perfectly. E.g. multiple space characters will be condensed into a single space character. But it's much improved. `print_tts` still produces the old, uglier output for code produced by proc macros. Because we have to translate the generated code from `proc_macro::Spacing` to the more expressive `token::Spacing`, which results in too much `proc_macro::Along` usage and no `proc_macro::JointHidden` usage. So `space_between` still exists and is used by `print_tts` in conjunction with the `Spacing` field. This change will also help with the removal of `Token::Interpolated`. Currently interpolated tokens are pretty-printed nicely via AST pretty printing. `Token::Interpolated` removal will mean they get printed with `print_tts`. Without this change, that would result in much uglier output for code produced by decl macro expansions. With this change, AST pretty printing and `print_tts` produce similar results. The commit also tweaks the comments on `proc_macro::Spacing`. In particular, it refers to "compound tokens" rather than "multi-char operators" because lifetimes aren't operators.

Hide `compiler_builtins` in the prelude

2023-07-14T15:53:36+00:00

This crate is a private implementation detail. We only need to insert it into the crate graph for linking and should not expose any of its public API. Fixes #113533

Move /src/test to /tests

2023-01-11T09:32:08+00:00

rust/tests/ui/proc-macro/allowed-attr-stmt-expr.stdout, branch 1.78.0

Don't insert spaces before most semicolons in `print_tts`.

Add spacing information to delimiters.

Improve `print_tts` by changing `tokenstream::Spacing`.

Hide `compiler_builtins` in the prelude

Move /src/test to /tests