rust/tests/ui/proc-macro/attribute-after-derive.stdout
Nicholas Nethercote 925f7fad57 Improve print_tts by changing tokenstream::Spacing.
`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<u32> = vec![];)
```
currently produces this string:
```
let a : Vec < u32 > = vec! [] ;
```
With this PR, it now produces this string:
```
let a: Vec<u32> = 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.
2023-12-11 09:19:09 +11:00

195 lines
6.4 KiB
Plaintext

PRINT-ATTR INPUT (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field: u8, }
PRINT-ATTR DEEP-RE-COLLECTED (DISPLAY): #[derive(Print)] struct AttributeDerive { #[cfg(FALSE)] field : u8, }
PRINT-ATTR INPUT (DEBUG): TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:15:1: 15:2 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "derive",
span: $DIR/attribute-after-derive.rs:15:3: 15:9 (#0),
},
Group {
delimiter: Parenthesis,
stream: TokenStream [
Ident {
ident: "Print",
span: $DIR/attribute-after-derive.rs:15:10: 15:15 (#0),
},
],
span: $DIR/attribute-after-derive.rs:15:9: 15:16 (#0),
},
],
span: $DIR/attribute-after-derive.rs:15:2: 15:17 (#0),
},
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
},
Ident {
ident: "AttributeDerive",
span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:17:5: 17:6 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "cfg",
span: $DIR/attribute-after-derive.rs:17:7: 17:10 (#0),
},
Group {
delimiter: Parenthesis,
stream: TokenStream [
Ident {
ident: "FALSE",
span: $DIR/attribute-after-derive.rs:17:11: 17:16 (#0),
},
],
span: $DIR/attribute-after-derive.rs:17:10: 17:17 (#0),
},
],
span: $DIR/attribute-after-derive.rs:17:6: 17:18 (#0),
},
Ident {
ident: "field",
span: $DIR/attribute-after-derive.rs:18:5: 18:10 (#0),
},
Punct {
ch: ':',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:18:10: 18:11 (#0),
},
Ident {
ident: "u8",
span: $DIR/attribute-after-derive.rs:18:12: 18:14 (#0),
},
Punct {
ch: ',',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:18:14: 18:15 (#0),
},
],
span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
},
]
PRINT-DERIVE INPUT (DISPLAY): struct AttributeDerive {}
PRINT-DERIVE INPUT (DEBUG): TokenStream [
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:16:1: 16:7 (#0),
},
Ident {
ident: "AttributeDerive",
span: $DIR/attribute-after-derive.rs:16:8: 16:23 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [],
span: $DIR/attribute-after-derive.rs:16:24: 19:2 (#0),
},
]
PRINT-DERIVE INPUT (DISPLAY): #[print_attr] struct DeriveAttribute {}
PRINT-DERIVE INPUT (DEBUG): TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:22:1: 22:2 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "print_attr",
span: $DIR/attribute-after-derive.rs:22:3: 22:13 (#0),
},
],
span: $DIR/attribute-after-derive.rs:22:2: 22:14 (#0),
},
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:23:1: 23:7 (#0),
},
Ident {
ident: "DeriveAttribute",
span: $DIR/attribute-after-derive.rs:23:8: 23:23 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [],
span: $DIR/attribute-after-derive.rs:23:24: 26:2 (#0),
},
]
PRINT-ATTR INPUT (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field: u8, }
PRINT-ATTR DEEP-RE-COLLECTED (DISPLAY): struct DeriveAttribute { #[cfg(FALSE)] field : u8, }
PRINT-ATTR INPUT (DEBUG): TokenStream [
Ident {
ident: "struct",
span: $DIR/attribute-after-derive.rs:23:1: 23:7 (#0),
},
Ident {
ident: "DeriveAttribute",
span: $DIR/attribute-after-derive.rs:23:8: 23:23 (#0),
},
Group {
delimiter: Brace,
stream: TokenStream [
Punct {
ch: '#',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:24:5: 24:6 (#0),
},
Group {
delimiter: Bracket,
stream: TokenStream [
Ident {
ident: "cfg",
span: $DIR/attribute-after-derive.rs:24:7: 24:10 (#0),
},
Group {
delimiter: Parenthesis,
stream: TokenStream [
Ident {
ident: "FALSE",
span: $DIR/attribute-after-derive.rs:24:11: 24:16 (#0),
},
],
span: $DIR/attribute-after-derive.rs:24:10: 24:17 (#0),
},
],
span: $DIR/attribute-after-derive.rs:24:6: 24:18 (#0),
},
Ident {
ident: "field",
span: $DIR/attribute-after-derive.rs:25:5: 25:10 (#0),
},
Punct {
ch: ':',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:25:10: 25:11 (#0),
},
Ident {
ident: "u8",
span: $DIR/attribute-after-derive.rs:25:12: 25:14 (#0),
},
Punct {
ch: ',',
spacing: Alone,
span: $DIR/attribute-after-derive.rs:25:14: 25:15 (#0),
},
],
span: $DIR/attribute-after-derive.rs:23:24: 26:2 (#0),
},
]