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Auto merge of #44918 - michaelwoerister:backport-44215, r=alexcrichton
Backport of #44215 Backport of #44215. r? @alexcrichton cc @nikomatsakis
2 parents fdfafb5 + 99b9ffb commit 07f5ea8

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5 files changed

+74
-32
lines changed

5 files changed

+74
-32
lines changed

src/librustc_resolve/lib.rs

+41-19
Original file line numberDiff line numberDiff line change
@@ -605,7 +605,7 @@ impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
605605
ItemKind::Use(..) => {
606606
// don't suggest placing a use before the prelude
607607
// import or other generated ones
608-
if item.span == DUMMY_SP {
608+
if item.span.ctxt.outer().expn_info().is_none() {
609609
let mut span = item.span;
610610
span.hi = span.lo;
611611
self.span = Some(span);
@@ -617,13 +617,26 @@ impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
617617
ItemKind::ExternCrate(_) => {}
618618
// but place them before the first other item
619619
_ => if self.span.map_or(true, |span| item.span < span ) {
620-
let mut span = item.span;
621-
span.hi = span.lo;
622-
self.span = Some(span);
620+
if item.span.ctxt.outer().expn_info().is_none() {
621+
// don't insert between attributes and an item
622+
if item.attrs.is_empty() {
623+
let mut span = item.span;
624+
span.hi = span.lo;
625+
self.span = Some(span);
626+
} else {
627+
// find the first attribute on the item
628+
for attr in &item.attrs {
629+
if self.span.map_or(true, |span| attr.span < span) {
630+
let mut span = attr.span;
631+
span.hi = span.lo;
632+
self.span = Some(span);
633+
}
634+
}
635+
}
636+
}
623637
},
624638
}
625639
}
626-
assert!(self.span.is_some(), "a file can't have no items and emit suggestions");
627640
}
628641
}
629642

@@ -3554,8 +3567,7 @@ impl<'a> Resolver<'a> {
35543567
};
35553568
visit::walk_crate(&mut finder, krate);
35563569
if !candidates.is_empty() {
3557-
let span = finder.span.expect("did not find module");
3558-
show_candidates(&mut err, span, &candidates, better, finder.found_use);
3570+
show_candidates(&mut err, finder.span, &candidates, better, finder.found_use);
35593571
}
35603572
err.emit();
35613573
}
@@ -3749,7 +3761,8 @@ fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, St
37493761
/// entities with that name in all crates. This method allows outputting the
37503762
/// results of this search in a programmer-friendly way
37513763
fn show_candidates(err: &mut DiagnosticBuilder,
3752-
span: Span,
3764+
// This is `None` if all placement locations are inside expansions
3765+
span: Option<Span>,
37533766
candidates: &[ImportSuggestion],
37543767
better: bool,
37553768
found_use: bool) {
@@ -3767,18 +3780,27 @@ fn show_candidates(err: &mut DiagnosticBuilder,
37673780
};
37683781
let msg = format!("possible {}candidate{} into scope", better, msg_diff);
37693782

3770-
for candidate in &mut path_strings {
3771-
// produce an additional newline to separate the new use statement
3772-
// from the directly following item.
3773-
let additional_newline = if found_use {
3774-
""
3775-
} else {
3776-
"\n"
3777-
};
3778-
*candidate = format!("use {};\n{}", candidate, additional_newline);
3779-
}
3783+
if let Some(span) = span {
3784+
for candidate in &mut path_strings {
3785+
// produce an additional newline to separate the new use statement
3786+
// from the directly following item.
3787+
let additional_newline = if found_use {
3788+
""
3789+
} else {
3790+
"\n"
3791+
};
3792+
*candidate = format!("use {};\n{}", candidate, additional_newline);
3793+
}
37803794

3781-
err.span_suggestions(span, &msg, path_strings);
3795+
err.span_suggestions(span, &msg, path_strings);
3796+
} else {
3797+
let mut msg = msg;
3798+
msg.push(':');
3799+
for candidate in path_strings {
3800+
msg.push('\n');
3801+
msg.push_str(&candidate);
3802+
}
3803+
}
37823804
}
37833805

37843806
/// A somewhat inefficient routine to obtain the name of a module.

src/test/ui/resolve/privacy-struct-ctor.stderr

+3-3
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@ error[E0423]: expected value, found struct `Z`
1010
|
1111
help: possible better candidate is found in another module, you can import it into scope
1212
|
13-
16 | use m::n::Z;
13+
22 | use m::n::Z;
1414
|
1515

1616
error[E0423]: expected value, found struct `S`
@@ -24,7 +24,7 @@ error[E0423]: expected value, found struct `S`
2424
|
2525
help: possible better candidate is found in another module, you can import it into scope
2626
|
27-
15 | use m::S;
27+
32 | use m::S;
2828
|
2929

3030
error[E0423]: expected value, found struct `xcrate::S`
@@ -38,7 +38,7 @@ error[E0423]: expected value, found struct `xcrate::S`
3838
|
3939
help: possible better candidate is found in another module, you can import it into scope
4040
|
41-
15 | use m::S;
41+
32 | use m::S;
4242
|
4343

4444
error[E0603]: tuple struct `Z` is private

src/test/ui/resolve/use_suggestion_placement.rs

+9
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,15 @@ mod m {
1616
pub const A: i32 = 0;
1717
}
1818

19+
mod foo {
20+
#[derive(Debug)]
21+
pub struct Foo;
22+
23+
// test whether the use suggestion isn't
24+
// placed into the expansion of `#[derive(Debug)]
25+
type Bar = Path;
26+
}
27+
1928
fn main() {
2029
y!();
2130
let _ = A;
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,18 @@
1+
error[E0412]: cannot find type `Path` in this scope
2+
--> $DIR/use_suggestion_placement.rs:25:16
3+
|
4+
25 | type Bar = Path;
5+
| ^^^^ not found in this scope
6+
|
7+
help: possible candidate is found in another module, you can import it into scope
8+
|
9+
21 | use std::path::Path;
10+
|
11+
112
error[E0425]: cannot find value `A` in this scope
2-
--> $DIR/use_suggestion_placement.rs:21:13
13+
--> $DIR/use_suggestion_placement.rs:30:13
314
|
4-
21 | let _ = A;
15+
30 | let _ = A;
516
| ^ not found in this scope
617
|
718
help: possible candidate is found in another module, you can import it into scope
@@ -10,9 +21,9 @@ help: possible candidate is found in another module, you can import it into scop
1021
|
1122

1223
error[E0412]: cannot find type `HashMap` in this scope
13-
--> $DIR/use_suggestion_placement.rs:26:23
24+
--> $DIR/use_suggestion_placement.rs:35:23
1425
|
15-
26 | type Dict<K, V> = HashMap<K, V>;
26+
35 | type Dict<K, V> = HashMap<K, V>;
1627
| ^^^^^^^ not found in this scope
1728
|
1829
help: possible candidates are found in other modules, you can import them into scope
@@ -23,16 +34,16 @@ help: possible candidates are found in other modules, you can import them into s
2334
|
2435

2536
error[E0091]: type parameter `K` is unused
26-
--> $DIR/use_suggestion_placement.rs:26:15
37+
--> $DIR/use_suggestion_placement.rs:35:15
2738
|
28-
26 | type Dict<K, V> = HashMap<K, V>;
39+
35 | type Dict<K, V> = HashMap<K, V>;
2940
| ^ unused type parameter
3041

3142
error[E0091]: type parameter `V` is unused
32-
--> $DIR/use_suggestion_placement.rs:26:18
43+
--> $DIR/use_suggestion_placement.rs:35:18
3344
|
34-
26 | type Dict<K, V> = HashMap<K, V>;
45+
35 | type Dict<K, V> = HashMap<K, V>;
3546
| ^ unused type parameter
3647

37-
error: aborting due to 4 previous errors
48+
error: aborting due to 5 previous errors
3849

src/test/ui/span/issue-35987.stderr

+1-1
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@ error[E0404]: expected trait, found type parameter `Add`
66
|
77
help: possible better candidate is found in another module, you can import it into scope
88
|
9-
11 | use std::ops::Add;
9+
13 | use std::ops::Add;
1010
|
1111

1212
error[E0601]: main function not found

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