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nnethercotennethercote
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Show invisible delimeters (within comments) when pretty printing.
1 parent baaa3b6 commit 5022d76

17 files changed

+110
-68
lines changed

‎compiler/rustc_ast/src/token.rs

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -50,11 +50,12 @@ pub enum Delimiter {
5050
Brace,
5151
/// `[ ... ]`
5252
Bracket,
53-
/// `Ø ... Ø`
53+
/// `/*«*/ ... /*»*/`
5454
/// An invisible delimiter, that may, for example, appear around tokens coming from a
5555
/// "macro variable" `$var`. It is important to preserve operator priorities in cases like
5656
/// `$var * 3` where `$var` is `1 + 2`.
57-
/// Invisible delimiters might not survive roundtrip of a token stream through a string.
57+
/// Invisible delimiters are not directly writable in normal Rust code except as comments.
58+
/// Therefore, they might not survive a roundtrip of a token stream through a string.
5859
Invisible,
5960
}
6061

‎compiler/rustc_ast_pretty/src/pprust/state.rs

Lines changed: 18 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -582,15 +582,29 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
582582
self.nbsp();
583583
}
584584
self.word("{");
585-
if !tts.is_empty() {
585+
let empty = tts.is_empty();
586+
if !empty {
586587
self.space();
587588
}
588589
self.ibox(0);
589590
self.print_tts(tts, convert_dollar_crate);
590591
self.end();
591-
let empty = tts.is_empty();
592592
self.bclose(span, empty);
593593
}
594+
Some(Delimiter::Invisible) => {
595+
self.word("/*«*/");
596+
let empty = tts.is_empty();
597+
if !empty {
598+
self.space();
599+
}
600+
self.ibox(0);
601+
self.print_tts(tts, convert_dollar_crate);
602+
self.end();
603+
if !empty {
604+
self.space();
605+
}
606+
self.word("/*»*/");
607+
}
594608
Some(delim) => {
595609
let token_str = self.token_kind_to_string(&token::OpenDelim(delim));
596610
self.word(token_str);
@@ -764,9 +778,8 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
764778
token::CloseDelim(Delimiter::Bracket) => "]".into(),
765779
token::OpenDelim(Delimiter::Brace) => "{".into(),
766780
token::CloseDelim(Delimiter::Brace) => "}".into(),
767-
token::OpenDelim(Delimiter::Invisible) | token::CloseDelim(Delimiter::Invisible) => {
768-
"".into()
769-
}
781+
token::OpenDelim(Delimiter::Invisible) => "/*«*/".into(),
782+
token::CloseDelim(Delimiter::Invisible) => "/*»*/".into(),
770783
token::Pound => "#".into(),
771784
token::Dollar => "$".into(),
772785
token::Question => "?".into(),

‎library/proc_macro/src/lib.rs

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -703,11 +703,12 @@ pub enum Delimiter {
703703
/// `[ ... ]`
704704
#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
705705
Bracket,
706-
/// `Ø ... Ø`
706+
/// `/*«*/ ... /*»*/`
707707
/// An invisible delimiter, that may, for example, appear around tokens coming from a
708708
/// "macro variable" `$var`. It is important to preserve operator priorities in cases like
709709
/// `$var * 3` where `$var` is `1 + 2`.
710-
/// Invisible delimiters might not survive roundtrip of a token stream through a string.
710+
/// Invisible delimiters are not directly writable in normal Rust code except as comments.
711+
/// Therefore, they might not survive a roundtrip of a token stream through a string.
711712
#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
712713
None,
713714
}

‎src/test/ui/proc-macro/auxiliary/expand-expr.rs

Lines changed: 21 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -12,6 +12,15 @@ use std::str::FromStr;
1212

1313
#[proc_macro]
1414
pub fn expand_expr_is(input: TokenStream) -> TokenStream {
15+
expand_expr_is_inner(input, false)
16+
}
17+
18+
#[proc_macro]
19+
pub fn expand_expr_is_trim(input: TokenStream) -> TokenStream {
20+
expand_expr_is_inner(input, true)
21+
}
22+
23+
fn expand_expr_is_inner(input: TokenStream, trim_invisible: bool) -> TokenStream {
1524
let mut iter = input.into_iter();
1625
let mut expected_tts = Vec::new();
1726
loop {
@@ -22,14 +31,18 @@ pub fn expand_expr_is(input: TokenStream) -> TokenStream {
2231
}
2332
}
2433

25-
let expected = expected_tts.into_iter().collect::<TokenStream>();
26-
let expanded = iter.collect::<TokenStream>().expand_expr().expect("expand_expr failed");
27-
assert!(
28-
expected.to_string() == expanded.to_string(),
29-
"assert failed\nexpected: `{}`\nexpanded: `{}`",
30-
expected.to_string(),
31-
expanded.to_string()
32-
);
34+
// If requested, trim the "invisible" delimiters at the start and end.
35+
let expected = expected_tts.into_iter().collect::<TokenStream>().to_string();
36+
let expected = if trim_invisible {
37+
let len1 = "/*«*/ ".len();
38+
let len2 = " /*»*/".len();
39+
&expected[len1..expected.len() - len2]
40+
} else {
41+
&expected[..]
42+
};
43+
let expanded = iter.collect::<TokenStream>().expand_expr().unwrap().to_string();
44+
45+
assert_eq!(expected, expanded);
3346

3447
TokenStream::new()
3548
}

‎src/test/ui/proc-macro/capture-macro-rules-invoke.stdout

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
PRINT-BANG INPUT (DISPLAY): self
2+
PRINT-BANG RE-COLLECTED (DISPLAY): /*«*/ self /*»*/
23
PRINT-BANG INPUT (DEBUG): TokenStream [
34
Group {
45
delimiter: None,
@@ -13,8 +14,10 @@ PRINT-BANG INPUT (DEBUG): TokenStream [
1314
]
1415
PRINT-BANG INPUT (DISPLAY): 1 + 1, { "a" }, let a = 1;, String, my_name, 'a, my_val = 30,
1516
std::option::Option, pub(in some::path) , [a b c], -30
16-
PRINT-BANG RE-COLLECTED (DISPLAY): 1 + 1, { "a" }, let a = 1, String, my_name, 'a, my_val = 30,
17-
std :: option :: Option, pub(in some :: path), [a b c], - 30
17+
PRINT-BANG RE-COLLECTED (DISPLAY): /*«*/ 1 + 1 /*»*/, /*«*/ { "a" } /*»*/, /*«*/ let a = 1 /*»*/, /*«*/
18+
String /*»*/, my_name, /*«*/ 'a /*»*/, /*«*/ my_val = 30 /*»*/, /*«*/
19+
std :: option :: Option /*»*/, /*«*/ pub(in some :: path) /*»*/, [a b c],
20+
/*«*/ - 30 /*»*/
1821
PRINT-BANG INPUT (DEBUG): TokenStream [
1922
Group {
2023
delimiter: None,
@@ -295,6 +298,7 @@ PRINT-BANG INPUT (DEBUG): TokenStream [
295298
},
296299
]
297300
PRINT-BANG INPUT (DISPLAY): (a, b)
301+
PRINT-BANG RE-COLLECTED (DISPLAY): /*«*/ (a, b) /*»*/
298302
PRINT-BANG INPUT (DEBUG): TokenStream [
299303
Group {
300304
delimiter: None,

‎src/test/ui/proc-macro/capture-unglued-token.stdout

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
PRINT-BANG INPUT (DISPLAY): Vec<u8>
2-
PRINT-BANG RE-COLLECTED (DISPLAY): Vec < u8 >
2+
PRINT-BANG RE-COLLECTED (DISPLAY): /*«*/ Vec < u8 > /*»*/
33
PRINT-BANG INPUT (DEBUG): TokenStream [
44
Group {
55
delimiter: None,

‎src/test/ui/proc-macro/expand-expr.rs

Lines changed: 12 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -2,9 +2,9 @@
22

33
extern crate expand_expr;
44

5-
use expand_expr::{
6-
check_expand_expr_file, echo_pm, expand_expr_fail, expand_expr_is, recursive_expand,
7-
};
5+
use expand_expr::{check_expand_expr_file, echo_pm, expand_expr_fail, expand_expr_is};
6+
use expand_expr::{expand_expr_is_trim, recursive_expand};
7+
88

99
// Check builtin macros can be expanded.
1010

@@ -47,21 +47,21 @@ macro_rules! echo_expr {
4747

4848
macro_rules! simple_lit {
4949
($l:literal) => {
50-
expand_expr_is!($l, $l);
51-
expand_expr_is!($l, echo_lit!($l));
52-
expand_expr_is!($l, echo_expr!($l));
53-
expand_expr_is!($l, echo_tts!($l));
54-
expand_expr_is!($l, echo_pm!($l));
50+
expand_expr_is_trim!($l, $l);
51+
expand_expr_is_trim!($l, echo_lit!($l));
52+
expand_expr_is_trim!($l, echo_expr!($l));
53+
expand_expr_is_trim!($l, echo_tts!($l));
54+
expand_expr_is_trim!($l, echo_pm!($l));
5555
const _: () = {
5656
macro_rules! mac {
5757
() => {
5858
$l
5959
};
6060
}
61-
expand_expr_is!($l, mac!());
62-
expand_expr_is!($l, echo_expr!(mac!()));
63-
expand_expr_is!($l, echo_tts!(mac!()));
64-
expand_expr_is!($l, echo_pm!(mac!()));
61+
expand_expr_is_trim!($l, mac!());
62+
expand_expr_is_trim!($l, echo_expr!(mac!()));
63+
expand_expr_is_trim!($l, echo_tts!(mac!()));
64+
expand_expr_is_trim!($l, echo_pm!(mac!()));
6565
};
6666
};
6767
}

‎src/test/ui/proc-macro/expr-stmt-nonterminal-tokens.stdout

Lines changed: 7 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
11
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = #[allow(warnings)] 0 ; 0 }, }
2-
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = #[allow(warnings)] #[allow(warnings)] 0 ; 0 }, }
2+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E
3+
{ V = { let _ = /*«*/ #[allow(warnings)] #[allow(warnings)] 0 /*»*/ ; 0 }, }
34
PRINT-DERIVE INPUT (DEBUG): TokenStream [
45
Ident {
56
ident: "enum",
@@ -123,7 +124,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
123124
},
124125
]
125126
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = { 0; } ; 0 }, }
126-
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { 0 } ; 0 }, }
127+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { /*«*/ 0 /*»*/ } ; 0 }, }
127128
PRINT-DERIVE INPUT (DEBUG): TokenStream [
128129
Ident {
129130
ident: "enum",
@@ -203,6 +204,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
203204
},
204205
]
205206
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = { {} } ; 0 }, }
207+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { /*«*/ {} /*»*/ } ; 0 }, }
206208
PRINT-DERIVE INPUT (DEBUG): TokenStream [
207209
Ident {
208210
ident: "enum",
@@ -281,7 +283,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
281283
},
282284
]
283285
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = { PATH; } ; 0 }, }
284-
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { PATH } ; 0 }, }
286+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { /*«*/ PATH /*»*/ } ; 0 }, }
285287
PRINT-DERIVE INPUT (DEBUG): TokenStream [
286288
Ident {
287289
ident: "enum",
@@ -359,7 +361,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
359361
},
360362
]
361363
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = { 0 + 1; } ; 0 }, }
362-
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { 0 + 1 } ; 0 }, }
364+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { /*«*/ 0 + 1 /*»*/ } ; 0 }, }
363365
PRINT-DERIVE INPUT (DEBUG): TokenStream [
364366
Ident {
365367
ident: "enum",
@@ -450,7 +452,7 @@ PRINT-DERIVE INPUT (DEBUG): TokenStream [
450452
},
451453
]
452454
PRINT-DERIVE INPUT (DISPLAY): enum E { V = { let _ = { PATH + 1; } ; 0 }, }
453-
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { PATH + 1 } ; 0 }, }
455+
PRINT-DERIVE DEEP-RE-COLLECTED (DISPLAY): enum E { V = { let _ = { /*«*/ PATH + 1 /*»*/ } ; 0 }, }
454456
PRINT-DERIVE INPUT (DEBUG): TokenStream [
455457
Ident {
456458
ident: "enum",

‎src/test/ui/proc-macro/issue-75734-pp-paren.stdout

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -96,6 +96,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
9696
},
9797
]
9898
PRINT-BANG INPUT (DISPLAY): 1 + 1 * 2
99+
PRINT-BANG RE-COLLECTED (DISPLAY): /*«*/ 1 + 1 /*»*/ * 2
99100
PRINT-BANG INPUT (DEBUG): TokenStream [
100101
Group {
101102
delimiter: None,

‎src/test/ui/proc-macro/issue-78675-captured-inner-attrs.stdout

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
PRINT-BANG INPUT (DISPLAY): foo! { #[fake_attr] mod bar {
22
#![doc = r" Foo"]
33
} }
4-
PRINT-BANG DEEP-RE-COLLECTED (DISPLAY): foo! { #[fake_attr] mod bar { #! [doc = r" Foo"] } }
4+
PRINT-BANG DEEP-RE-COLLECTED (DISPLAY): foo! { #[fake_attr] /*«*/ mod bar { #! [doc = r" Foo"] } /*»*/ }
55
PRINT-BANG INPUT (DEBUG): TokenStream [
66
Ident {
77
ident: "foo",

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