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Auto merge of #120227 - nnethercote:further-improve-space_between, r=petrochenkov
Further improve `space_between` `space_between` is used by `print_tts` to decide when spaces should be put between tokens. This PR improves it in two ways: - avoid unnecessary spaces before semicolons, and - don't omit some necessary spaces before/after some punctuation symbols. r? `@petrochenkov`
2 parents cb4d9a1 + 1fbabee commit 80deabd

28 files changed

+102
-109
lines changed

‎compiler/rustc_ast_pretty/src/pprust/state.rs‎

Lines changed: 33 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -160,31 +160,46 @@ fn space_between(tt1: &TokenTree, tt2: &TokenTree) -> bool {
160160
use TokenTree::Delimited as Del;
161161
use TokenTree::Token as Tok;
162162

163+
fn is_punct(tt: &TokenTree) -> bool {
164+
matches!(tt, TokenTree::Token(tok, _) if tok.is_punct())
165+
}
166+
163167
// Each match arm has one or more examples in comments. The default is to
164168
// insert space between adjacent tokens, except for the cases listed in
165169
// this match.
166170
match (tt1, tt2) {
167171
// No space after line doc comments.
168172
(Tok(Token { kind: DocComment(CommentKind::Line, ..), .. }, _), _) => false,
169173

170-
// `.` + ANYTHING: `x.y`, `tup.0`
171-
// `$` + ANYTHING: `$e`
172-
(Tok(Token { kind: Dot | Dollar, .. }, _), _) => false,
173-
174-
// ANYTHING + `,`: `foo,`
175-
// ANYTHING + `.`: `x.y`, `tup.0`
176-
// ANYTHING + `!`: `foo! { ... }`
177-
//
178-
// FIXME: Incorrect cases:
179-
// - Logical not: `x =! y`, `if! x { f(); }`
180-
// - Never type: `Fn() ->!`
181-
(_, Tok(Token { kind: Comma | Dot | Not, .. }, _)) => false,
182-
183-
// IDENT + `(`: `f(3)`
184-
//
185-
// FIXME: Incorrect cases:
186-
// - Let: `let(a, b) = (1, 2)`
187-
(Tok(Token { kind: Ident(..), .. }, _), Del(_, _, Parenthesis, _)) => false,
174+
// `.` + NON-PUNCT: `x.y`, `tup.0`
175+
(Tok(Token { kind: Dot, .. }, _), tt2) if !is_punct(tt2) => false,
176+
177+
// `$` + IDENT: `$e`
178+
(Tok(Token { kind: Dollar, .. }, _), Tok(Token { kind: Ident(..), .. }, _)) => false,
179+
180+
// NON-PUNCT + `,`: `foo,`
181+
// NON-PUNCT + `;`: `x = 3;`, `[T; 3]`
182+
// NON-PUNCT + `.`: `x.y`, `tup.0`
183+
(tt1, Tok(Token { kind: Comma | Semi | Dot, .. }, _)) if !is_punct(tt1) => false,
184+
185+
// IDENT + `!`: `println!()`, but `if !x { ... }` needs a space after the `if`
186+
(Tok(Token { kind: Ident(sym, is_raw), span }, _), Tok(Token { kind: Not, .. }, _))
187+
if !Ident::new(*sym, *span).is_reserved() || *is_raw =>
188+
{
189+
false
190+
}
191+
192+
// IDENT|`fn`|`Self`|`pub` + `(`: `f(3)`, `fn(x: u8)`, `Self()`, `pub(crate)`,
193+
// but `let (a, b) = (1, 2)` needs a space after the `let`
194+
(Tok(Token { kind: Ident(sym, is_raw), span }, _), Del(_, _, Parenthesis, _))
195+
if !Ident::new(*sym, *span).is_reserved()
196+
|| *sym == kw::Fn
197+
|| *sym == kw::SelfUpper
198+
|| *sym == kw::Pub
199+
|| *is_raw =>
200+
{
201+
false
202+
}
188203

189204
// `#` + `[`: `#[attr]`
190205
(Tok(Token { kind: Pound, .. }, _), Del(_, _, Bracket, _)) => false,

‎tests/pretty/delimited-token-groups.rs‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@ mac! {
99
{
1010
fn clone() -> S
1111
{
12-
panic! () ;
12+
panic! ();
1313

1414
}
1515
}

‎tests/pretty/macro_rules.rs‎

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,19 +1,19 @@
11
// pp-exact
22

3-
macro_rules! brace { () => {} ; }
3+
macro_rules! brace { () => {}; }
44

5-
macro_rules! bracket[() => {} ;];
5+
macro_rules! bracket[() => {};];
66

7-
macro_rules! paren(() => {} ;);
7+
macro_rules! paren(() => {};);
88

99
macro_rules! matcher_brackets {
10-
(paren) => {} ; (bracket) => {} ; (brace) => {} ;
10+
(paren) => {}; (bracket) => {}; (brace) => {};
1111
}
1212

1313
macro_rules! all_fragments {
1414
($b : block, $e : expr, $i : ident, $it : item, $l : lifetime, $lit :
1515
literal, $m : meta, $p : pat, $pth : path, $s : stmt, $tt : tt, $ty : ty,
16-
$vis : vis) => {} ;
16+
$vis : vis) => {};
1717
}
1818

1919
fn main() {}

‎tests/pretty/stmt_expr_attributes.rs‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -113,7 +113,7 @@ fn _8() {
113113
}
114114

115115
fn _9() {
116-
macro_rules! stmt_mac { () => { let _ = () ; } }
116+
macro_rules! stmt_mac { () => { let _ = (); } }
117117

118118
#[rustc_dummy]
119119
stmt_mac!();

‎tests/ui/macros/stringify.rs‎

Lines changed: 16 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -107,9 +107,9 @@ fn test_expr() {
107107
c1!(expr, [ true || false ], "true || false");
108108
c1!(expr, [ true || false && false ], "true || false && false");
109109
c1!(expr, [ a < 1 && 2 < b && c > 3 && 4 > d ], "a < 1 && 2 < b && c > 3 && 4 > d");
110-
c2!(expr, [ a & b & !c ], "a & b & !c", "a & b &!c"); // FIXME
110+
c1!(expr, [ a & b & !c ], "a & b & !c");
111111
c1!(expr, [ a + b * c - d + -1 * -2 - -3], "a + b * c - d + -1 * -2 - -3");
112-
c2!(expr, [ x = !y ], "x = !y", "x =!y"); // FIXME
112+
c1!(expr, [ x = !y ], "x = !y");
113113

114114
// ExprKind::Unary
115115
c1!(expr, [ *expr ], "*expr");
@@ -141,15 +141,14 @@ fn test_expr() {
141141
"if let _ = (true && false) {}",
142142
"if let _ = true && false {}",
143143
);
144-
c2!(expr,
144+
c1!(expr,
145145
[ match () { _ if let _ = Struct {} => {} } ],
146-
"match () { _ if let _ = Struct {} => {} }",
147-
"match() { _ if let _ = Struct {} => {} }",
146+
"match () { _ if let _ = Struct {} => {} }"
148147
);
149148

150149
// ExprKind::If
151150
c1!(expr, [ if true {} ], "if true {}");
152-
c2!(expr, [ if !true {} ], "if !true {}", "if!true {}"); // FIXME
151+
c1!(expr, [ if !true {} ], "if !true {}");
153152
c1!(expr, [ if ::std::blah() { } else { } ], "if ::std::blah() {} else {}");
154153
c1!(expr, [ if let true = true {} else {} ], "if let true = true {} else {}");
155154
c1!(expr,
@@ -212,7 +211,7 @@ fn test_expr() {
212211
c2_match_arm!(
213212
[ { 1 } - 1 ],
214213
"match () { _ => ({ 1 }) - 1, }",
215-
"match() { _ => { 1 } - 1 }",
214+
"match () { _ => { 1 } - 1 }",
216215
);
217216

218217
// ExprKind::Closure
@@ -655,11 +654,11 @@ fn test_stmt() {
655654
c2!(stmt, [ let _ ], "let _;", "let _");
656655
c2!(stmt, [ let x = true ], "let x = true;", "let x = true");
657656
c2!(stmt, [ let x: bool = true ], "let x: bool = true;", "let x: bool = true");
658-
c2!(stmt, [ let (a, b) = (1, 2) ], "let (a, b) = (1, 2);", "let(a, b) = (1, 2)"); // FIXME
657+
c2!(stmt, [ let (a, b) = (1, 2) ], "let (a, b) = (1, 2);", "let (a, b) = (1, 2)");
659658
c2!(stmt,
660659
[ let (a, b): (u32, u32) = (1, 2) ],
661660
"let (a, b): (u32, u32) = (1, 2);",
662-
"let(a, b): (u32, u32) = (1, 2)" // FIXME
661+
"let (a, b): (u32, u32) = (1, 2)"
663662
);
664663
macro_rules! c2_let_expr_minus_one {
665664
([ $expr:expr ], $stmt_expected:expr, $tokens_expected:expr $(,)?) => {
@@ -776,8 +775,8 @@ fn test_ty() {
776775
c1!(ty, [ Ref<'a> ], "Ref<'a>");
777776
c1!(ty, [ PhantomData<T> ], "PhantomData<T>");
778777
c2!(ty, [ PhantomData::<T> ], "PhantomData<T>", "PhantomData::<T>");
779-
c2!(ty, [ Fn() -> ! ], "Fn() -> !", "Fn() ->!");
780-
c2!(ty, [ Fn(u8) -> ! ], "Fn(u8) -> !", "Fn(u8) ->!"); // FIXME
778+
c1!(ty, [ Fn() -> ! ], "Fn() -> !");
779+
c1!(ty, [ Fn(u8) -> ! ], "Fn(u8) -> !");
781780
c1!(ty, [ <Struct as Trait>::Type ], "<Struct as Trait>::Type");
782781

783782
// TyKind::TraitObject
@@ -857,16 +856,16 @@ fn test_punct() {
857856
// Otherwise, any old proc macro that parses pretty-printed code might glue
858857
// together tokens that shouldn't be glued.
859858
p!([ = = < < <= <= == == != != >= >= > > ], "= = < < <= <= == == != != >= >= > >");
860-
p!([ && && & & || || | | ! ! ], "&& && & & || || | |!!"); // FIXME
859+
p!([ && && & & || || | | ! ! ], "&& && & & || || | | ! !");
861860
p!([ ~ ~ @ @ # # ], "~ ~ @ @ # #");
862-
p!([ . . .. .. ... ... ..= ..=], ".... .. ... ... ..= ..="); // FIXME
863-
p!([ , , ; ; : : :: :: ], ",, ; ; : : :: ::"); // FIXME
861+
p!([ . . .. .. ... ... ..= ..=], ". . .. .. ... ... ..= ..=");
862+
p!([ , , ; ; : : :: :: ], ", , ; ; : : :: ::");
864863
p!([ -> -> <- <- => =>], "-> -> <- <- => =>");
865-
p!([ $ $ ? ? ' ' ], "$$? ? ' '"); // FIXME
864+
p!([ $ $ ? ? ' ' ], "$ $ ? ? ' '");
866865
p!([ + + += += - - -= -= * * *= *= / / /= /= ], "+ + += += - - -= -= * * *= *= / / /= /=");
867866
p!([ % % %= %= ^ ^ ^= ^= << << <<= <<= >> >> >>= >>= ],
868867
"% % %= %= ^ ^ ^= ^= << << <<= <<= >> >> >>= >>=");
869-
p!([ +! ?= |> >>@ --> <-- $$ =====> ], "+! ?= |> >>@ --> <-- $$=====>");
870-
p!([ ,; ;, ** @@ $+$ >< <> ?? +== ], ",; ;, ** @@ $+$>< <> ?? +=="); // FIXME: `$ >` -> `$>`
868+
p!([ +! ?= |> >>@ --> <-- $$ =====> ], "+! ?= |> >>@ --> <-- $$ =====>");
869+
p!([ ,; ;, ** @@ $+$ >< <> ?? +== ], ",; ;, ** @@ $+$ >< <> ?? +==");
871870
p!([ :#!@|$=&*,+;*~? ], ":#!@|$=&*,+;*~?");
872871
}

‎tests/ui/macros/trace_faulty_macros.stderr‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -111,7 +111,7 @@ LL | test!(let x = 1+1);
111111
= note: expanding `test! { let x = 1+1 }`
112112
= note: to `test! ((x, 1 + 1))`
113113
= note: expanding `test! { (x, 1 + 1) }`
114-
= note: to `let x = 1 + 1 ;`
114+
= note: to `let x = 1 + 1;`
115115

116116
error: aborting due to 5 previous errors
117117

‎tests/ui/proc-macro/allowed-attr-stmt-expr.stdout‎

Lines changed: 2 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,4 @@
11
PRINT-ATTR INPUT (DISPLAY): struct ItemWithSemi;
2-
PRINT-ATTR RE-COLLECTED (DISPLAY): struct ItemWithSemi ;
32
PRINT-ATTR INPUT (DEBUG): TokenStream [
43
Ident {
54
ident: "struct",
@@ -47,7 +46,6 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
4746
},
4847
]
4948
PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!";
50-
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_let] let string = "Hello, world!" ;
5149
PRINT-ATTR INPUT (DEBUG): TokenStream [
5250
Punct {
5351
ch: '#',
@@ -90,7 +88,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
9088
},
9189
]
9290
PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro!("{}", string);
93-
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string) ;
91+
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string);
9492
PRINT-ATTR INPUT (DEBUG): TokenStream [
9593
Punct {
9694
ch: '#',
@@ -144,7 +142,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
144142
},
145143
]
146144
PRINT-ATTR INPUT (DISPLAY): second_make_stmt!(#[allow(dead_code)] struct Bar {});
147-
PRINT-ATTR RE-COLLECTED (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {}) ;
145+
PRINT-ATTR RE-COLLECTED (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {});
148146
PRINT-ATTR INPUT (DEBUG): TokenStream [
149147
Ident {
150148
ident: "second_make_stmt",
@@ -293,7 +291,6 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
293291
},
294292
]
295293
PRINT-ATTR INPUT (DISPLAY): #[rustc_dummy] struct NonBracedStruct;
296-
PRINT-ATTR RE-COLLECTED (DISPLAY): #[rustc_dummy] struct NonBracedStruct ;
297294
PRINT-ATTR INPUT (DEBUG): TokenStream [
298295
Punct {
299296
ch: '#',

‎tests/ui/proc-macro/attr-stmt-expr.stdout‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -30,7 +30,6 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
3030
},
3131
]
3232
PRINT-ATTR INPUT (DISPLAY): #[expect_let] let string = "Hello, world!";
33-
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_let] let string = "Hello, world!" ;
3433
PRINT-ATTR INPUT (DEBUG): TokenStream [
3534
Punct {
3635
ch: '#',
@@ -73,7 +72,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
7372
},
7473
]
7574
PRINT-ATTR INPUT (DISPLAY): #[expect_my_macro_stmt] my_macro!("{}", string);
76-
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string) ;
75+
PRINT-ATTR RE-COLLECTED (DISPLAY): #[expect_my_macro_stmt] my_macro! ("{}", string);
7776
PRINT-ATTR INPUT (DEBUG): TokenStream [
7877
Punct {
7978
ch: '#',
@@ -127,7 +126,7 @@ PRINT-ATTR INPUT (DEBUG): TokenStream [
127126
},
128127
]
129128
PRINT-ATTR INPUT (DISPLAY): second_make_stmt!(#[allow(dead_code)] struct Bar {});
130-
PRINT-ATTR RE-COLLECTED (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {}) ;
129+
PRINT-ATTR RE-COLLECTED (DISPLAY): second_make_stmt! (#[allow(dead_code)] struct Bar {});
131130
PRINT-ATTR INPUT (DEBUG): TokenStream [
132131
Ident {
133132
ident: "second_make_stmt",

‎tests/ui/proc-macro/attribute-spans-preserved.stdout‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1 +1 @@
1-
fn main() { let y : u32 = "z" ; { let x: u32 = "y"; } }
1+
fn main() { let y : u32 = "z"; { let x: u32 = "y"; } }

‎tests/ui/proc-macro/auxiliary/attr-stmt-expr.rs‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,14 +10,14 @@ use proc_macro::TokenStream;
1010
#[proc_macro_attribute]
1111
pub fn expect_let(attr: TokenStream, item: TokenStream) -> TokenStream {
1212
assert!(attr.to_string().is_empty());
13-
assert_eq!(item.to_string(), "let string = \"Hello, world!\" ;");
13+
assert_eq!(item.to_string(), "let string = \"Hello, world!\";");
1414
item
1515
}
1616

1717
#[proc_macro_attribute]
1818
pub fn expect_my_macro_stmt(attr: TokenStream, item: TokenStream) -> TokenStream {
1919
assert!(attr.to_string().is_empty());
20-
assert_eq!(item.to_string(), "my_macro! (\"{}\", string) ;");
20+
assert_eq!(item.to_string(), "my_macro! (\"{}\", string);");
2121
item
2222
}
2323

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