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Auto merge of #87235 - poliorcetics:issue-87217-fn-quali-order, r=nagisa
Improve diagnostics for wrongly ordered keywords in function declaration Fix #87217 `@rustbot` label A-diagnostics T-compiler
2 parents ad981d5 + 690cbb7 commit 74a11c6

13 files changed

+184
-4
lines changed

‎compiler/rustc_parse/src/parser/item.rs

Lines changed: 34 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1768,8 +1768,14 @@ impl<'a> Parser<'a> {
17681768
pub(super) fn parse_fn_front_matter(&mut self) -> PResult<'a, FnHeader> {
17691769
let sp_start = self.token.span;
17701770
let constness = self.parse_constness();
1771+
1772+
let async_start_sp = self.token.span;
17711773
let asyncness = self.parse_asyncness();
1774+
1775+
let unsafe_start_sp = self.token.span;
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let unsafety = self.parse_unsafety();
1777+
1778+
let ext_start_sp = self.token.span;
17731779
let ext = self.parse_extern();
17741780

17751781
if let Async::Yes { span, .. } = asyncness {
@@ -1784,8 +1790,35 @@ impl<'a> Parser<'a> {
17841790
Ok(true) => {}
17851791
Ok(false) => unreachable!(),
17861792
Err(mut err) => {
1793+
// Qualifier keywords ordering check
1794+
1795+
// This will allow the machine fix to directly place the keyword in the correct place
1796+
let current_qual_sp = if self.check_keyword(kw::Const) {
1797+
Some(async_start_sp)
1798+
} else if self.check_keyword(kw::Async) {
1799+
Some(unsafe_start_sp)
1800+
} else if self.check_keyword(kw::Unsafe) {
1801+
Some(ext_start_sp)
1802+
} else {
1803+
None
1804+
};
1805+
1806+
if let Some(current_qual_sp) = current_qual_sp {
1807+
let current_qual_sp = current_qual_sp.to(self.prev_token.span);
1808+
if let Ok(current_qual) = self.span_to_snippet(current_qual_sp) {
1809+
let invalid_qual_sp = self.token.uninterpolated_span();
1810+
let invalid_qual = self.span_to_snippet(invalid_qual_sp).unwrap();
1811+
1812+
err.span_suggestion(
1813+
current_qual_sp.to(invalid_qual_sp),
1814+
&format!("`{}` must come before `{}`", invalid_qual, current_qual),
1815+
format!("{} {}", invalid_qual, current_qual),
1816+
Applicability::MachineApplicable,
1817+
).note("keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`");
1818+
}
1819+
}
17871820
// Recover incorrect visibility order such as `async pub`.
1788-
if self.check_keyword(kw::Pub) {
1821+
else if self.check_keyword(kw::Pub) {
17891822
let sp = sp_start.to(self.prev_token.span);
17901823
if let Ok(snippet) = self.span_to_snippet(sp) {
17911824
let vis = match self.parse_visibility(FollowedByType::No) {

‎src/test/ui/async-await/no-async-const.stderr

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,12 @@ error: expected one of `extern`, `fn`, or `unsafe`, found keyword `const`
22
--> $DIR/no-async-const.rs:4:11
33
|
44
LL | pub async const fn x() {}
5-
| ^^^^^ expected one of `extern`, `fn`, or `unsafe`
5+
| ------^^^^^
6+
| | |
7+
| | expected one of `extern`, `fn`, or `unsafe`
8+
| help: `const` must come before `async`: `const async`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
611

712
error: aborting due to previous error
813

‎src/test/ui/async-await/no-unsafe-async.stderr

Lines changed: 12 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -5,15 +5,25 @@ LL | impl S {
55
| - while parsing this item list starting here
66
LL | #[cfg(FALSE)]
77
LL | unsafe async fn g() {}
8-
| ^^^^^ expected one of `extern` or `fn`
8+
| -------^^^^^
9+
| | |
10+
| | expected one of `extern` or `fn`
11+
| help: `async` must come before `unsafe`: `async unsafe`
912
LL | }
1013
| - the item list ends here
14+
|
15+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
1116

1217
error: expected one of `extern` or `fn`, found keyword `async`
1318
--> $DIR/no-unsafe-async.rs:11:8
1419
|
1520
LL | unsafe async fn f() {}
16-
| ^^^^^ expected one of `extern` or `fn`
21+
| -------^^^^^
22+
| | |
23+
| | expected one of `extern` or `fn`
24+
| help: `async` must come before `unsafe`: `async unsafe`
25+
|
26+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
1727

1828
error: aborting due to 2 previous errors
1929

‎src/test/ui/parser/issue-87217-keyword-order/const-async-const.rs

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,11 @@
1+
// edition:2018
2+
3+
// Test that even when `const` is already present, the proposed fix is `const const async`,
4+
// like for `pub pub`.
5+
6+
const async const fn test() {}
7+
//~^ ERROR expected one of `extern`, `fn`, or `unsafe`, found keyword `const`
8+
//~| NOTE expected one of `extern`, `fn`, or `unsafe`
9+
//~| HELP `const` must come before `async`
10+
//~| SUGGESTION const async
11+
//~| NOTE keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`

‎src/test/ui/parser/issue-87217-keyword-order/const-async-const.stderr

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
error: expected one of `extern`, `fn`, or `unsafe`, found keyword `const`
2+
--> $DIR/const-async-const.rs:6:13
3+
|
4+
LL | const async const fn test() {}
5+
| ------^^^^^
6+
| | |
7+
| | expected one of `extern`, `fn`, or `unsafe`
8+
| help: `const` must come before `async`: `const async`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
11+
12+
error: aborting due to previous error
13+

‎src/test/ui/parser/issue-87217-keyword-order/several-kw-jump.rs

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// edition:2018
2+
3+
// There is an order to respect for keywords before a function:
4+
// `<visibility>, const, async, unsafe, extern, "<ABI>"`
5+
//
6+
// This test ensures the compiler is helpful about them being misplaced.
7+
// Visibilities are tested elsewhere.
8+
9+
async unsafe const fn test() {}
10+
//~^ ERROR expected one of `extern` or `fn`, found keyword `const`
11+
//~| NOTE expected one of `extern` or `fn`
12+
//~| HELP `const` must come before `async unsafe`
13+
//~| SUGGESTION const async unsafe
14+
//~| NOTE keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`

‎src/test/ui/parser/issue-87217-keyword-order/several-kw-jump.stderr

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
error: expected one of `extern` or `fn`, found keyword `const`
2+
--> $DIR/several-kw-jump.rs:9:14
3+
|
4+
LL | async unsafe const fn test() {}
5+
| -------------^^^^^
6+
| | |
7+
| | expected one of `extern` or `fn`
8+
| help: `const` must come before `async unsafe`: `const async unsafe`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
11+
12+
error: aborting due to previous error
13+

‎src/test/ui/parser/issue-87217-keyword-order/wrong-async.rs

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// edition:2018
2+
3+
// There is an order to respect for keywords before a function:
4+
// `<visibility>, const, async, unsafe, extern, "<ABI>"`
5+
//
6+
// This test ensures the compiler is helpful about them being misplaced.
7+
// Visibilities are tested elsewhere.
8+
9+
unsafe async fn test() {}
10+
//~^ ERROR expected one of `extern` or `fn`, found keyword `async`
11+
//~| NOTE expected one of `extern` or `fn`
12+
//~| HELP `async` must come before `unsafe`
13+
//~| SUGGESTION async unsafe
14+
//~| NOTE keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`

‎src/test/ui/parser/issue-87217-keyword-order/wrong-async.stderr

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
error: expected one of `extern` or `fn`, found keyword `async`
2+
--> $DIR/wrong-async.rs:9:8
3+
|
4+
LL | unsafe async fn test() {}
5+
| -------^^^^^
6+
| | |
7+
| | expected one of `extern` or `fn`
8+
| help: `async` must come before `unsafe`: `async unsafe`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
11+
12+
error: aborting due to previous error
13+

‎src/test/ui/parser/issue-87217-keyword-order/wrong-const.rs

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// edition:2018
2+
3+
// There is an order to respect for keywords before a function:
4+
// `<visibility>, const, async, unsafe, extern, "<ABI>"`
5+
//
6+
// This test ensures the compiler is helpful about them being misplaced.
7+
// Visibilities are tested elsewhere.
8+
9+
unsafe const fn test() {}
10+
//~^ ERROR expected one of `extern` or `fn`, found keyword `const`
11+
//~| NOTE expected one of `extern` or `fn`
12+
//~| HELP `const` must come before `unsafe`
13+
//~| SUGGESTION const unsafe
14+
//~| NOTE keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`

‎src/test/ui/parser/issue-87217-keyword-order/wrong-const.stderr

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
error: expected one of `extern` or `fn`, found keyword `const`
2+
--> $DIR/wrong-const.rs:9:8
3+
|
4+
LL | unsafe const fn test() {}
5+
| -------^^^^^
6+
| | |
7+
| | expected one of `extern` or `fn`
8+
| help: `const` must come before `unsafe`: `const unsafe`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
11+
12+
error: aborting due to previous error
13+

‎src/test/ui/parser/issue-87217-keyword-order/wrong-unsafe.rs

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// edition:2018
2+
3+
// There is an order to respect for keywords before a function:
4+
// `<visibility>, const, async, unsafe, extern, "<ABI>"`
5+
//
6+
// This test ensures the compiler is helpful about them being misplaced.
7+
// Visibilities are tested elsewhere.
8+
9+
extern unsafe fn test() {}
10+
//~^ ERROR expected `fn`, found keyword `unsafe`
11+
//~| NOTE expected `fn`
12+
//~| HELP `unsafe` must come before `extern`
13+
//~| SUGGESTION unsafe extern
14+
//~| NOTE keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`

‎src/test/ui/parser/issue-87217-keyword-order/wrong-unsafe.stderr

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,13 @@
1+
error: expected `fn`, found keyword `unsafe`
2+
--> $DIR/wrong-unsafe.rs:9:8
3+
|
4+
LL | extern unsafe fn test() {}
5+
| -------^^^^^^
6+
| | |
7+
| | expected `fn`
8+
| help: `unsafe` must come before `extern`: `unsafe extern`
9+
|
10+
= note: keyword order for functions declaration is `default`, `pub`, `const`, `async`, `unsafe`, `extern`
11+
12+
error: aborting due to previous error
13+

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