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davidtwcodavidtwco
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Suggestion moving types before associated types.
This commit extends existing suggestions to move lifetimes before types in generic arguments to also suggest moving types behind associated type bindings.
1 parent 095b44c commit 463e623

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4 files changed

+147
-15
lines changed

4 files changed

+147
-15
lines changed

‎src/libsyntax/parse/parser.rs

+52-15
Original file line numberDiff line numberDiff line change
@@ -5530,22 +5530,31 @@ impl<'a> Parser<'a> {
55305530
fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
55315531
let mut args = Vec::new();
55325532
let mut bindings = Vec::new();
5533+
55335534
let mut seen_type = false;
55345535
let mut seen_binding = false;
5536+
5537+
let mut last_comma_span = None;
55355538
let mut first_type_or_binding_span: Option<Span> = None;
5539+
let mut first_binding_span: Option<Span> = None;
5540+
55365541
let mut bad_lifetime_pos = vec![];
5537-
let mut last_comma_span = None;
5538-
let mut suggestions = vec![];
5542+
let mut bad_type_pos = vec![];
5543+
5544+
let mut lifetime_suggestions = vec![];
5545+
let mut type_suggestions = vec![];
55395546
loop {
55405547
if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
55415548
// Parse lifetime argument.
55425549
args.push(GenericArg::Lifetime(self.expect_lifetime()));
5550+
55435551
if seen_type || seen_binding {
55445552
let remove_sp = last_comma_span.unwrap_or(self.prev_span).to(self.prev_span);
55455553
bad_lifetime_pos.push(self.prev_span);
5554+
55465555
if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.prev_span) {
5547-
suggestions.push((remove_sp, String::new()));
5548-
suggestions.push((
5556+
lifetime_suggestions.push((remove_sp, String::new()));
5557+
lifetime_suggestions.push((
55495558
first_type_or_binding_span.unwrap().shrink_to_lo(),
55505559
format!("{}, ", snippet)));
55515560
}
@@ -5563,24 +5572,29 @@ impl<'a> Parser<'a> {
55635572
ty,
55645573
span,
55655574
});
5575+
55665576
seen_binding = true;
55675577
if first_type_or_binding_span.is_none() {
55685578
first_type_or_binding_span = Some(span);
55695579
}
5580+
if first_binding_span.is_none() {
5581+
first_binding_span = Some(span);
5582+
}
55705583
} else if self.check_type() {
55715584
// Parse type argument.
55725585
let ty_param = self.parse_ty()?;
55735586
if seen_binding {
5574-
self.struct_span_err(
5575-
ty_param.span,
5576-
"type parameters must be declared prior to associated type bindings"
5577-
)
5578-
.span_label(
5579-
ty_param.span,
5580-
"must be declared prior to associated type bindings",
5581-
)
5582-
.emit();
5587+
let remove_sp = last_comma_span.unwrap_or(self.prev_span).to(self.prev_span);
5588+
bad_type_pos.push(self.prev_span);
5589+
5590+
if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.prev_span) {
5591+
type_suggestions.push((remove_sp, String::new()));
5592+
type_suggestions.push((
5593+
first_binding_span.unwrap().shrink_to_lo(),
5594+
format!("{}, ", snippet)));
5595+
}
55835596
}
5597+
55845598
if first_type_or_binding_span.is_none() {
55855599
first_type_or_binding_span = Some(ty_param.span);
55865600
}
@@ -5596,6 +5610,7 @@ impl<'a> Parser<'a> {
55965610
last_comma_span = Some(self.prev_span);
55975611
}
55985612
}
5613+
55995614
if !bad_lifetime_pos.is_empty() {
56005615
let mut err = self.struct_span_err(
56015616
bad_lifetime_pos.clone(),
@@ -5604,18 +5619,40 @@ impl<'a> Parser<'a> {
56045619
for sp in &bad_lifetime_pos {
56055620
err.span_label(*sp, "must be declared prior to type parameters");
56065621
}
5607-
if !suggestions.is_empty() {
5622+
if !lifetime_suggestions.is_empty() {
56085623
err.multipart_suggestion_with_applicability(
56095624
&format!(
56105625
"move the lifetime parameter{} prior to the first type parameter",
56115626
if bad_lifetime_pos.len() > 1 { "s" } else { "" },
56125627
),
5613-
suggestions,
5628+
lifetime_suggestions,
56145629
Applicability::MachineApplicable,
56155630
);
56165631
}
56175632
err.emit();
56185633
}
5634+
5635+
if !bad_type_pos.is_empty() {
5636+
let mut err = self.struct_span_err(
5637+
bad_type_pos.clone(),
5638+
"type parameters must be declared prior to associated type bindings"
5639+
);
5640+
for sp in &bad_type_pos {
5641+
err.span_label(*sp, "must be declared prior to associated type bindings");
5642+
}
5643+
if !type_suggestions.is_empty() {
5644+
err.multipart_suggestion_with_applicability(
5645+
&format!(
5646+
"move the type parameter{} prior to the first associated type binding",
5647+
if bad_type_pos.len() > 1 { "s" } else { "" },
5648+
),
5649+
type_suggestions,
5650+
Applicability::MachineApplicable,
5651+
);
5652+
}
5653+
err.emit();
5654+
}
5655+
56195656
Ok((args, bindings))
56205657
}
56215658

‎src/test/ui/parser/issue-32214.stderr

+4
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,10 @@ error: type parameters must be declared prior to associated type bindings
33
|
44
LL | pub fn test<W, I: Trait<Item=(), W> >() {}
55
| ^ must be declared prior to associated type bindings
6+
help: move the type parameter prior to the first associated type binding
7+
|
8+
LL | pub fn test<W, I: Trait<W, Item=()> >() {}
9+
| ^^ --
610

711
error: aborting due to previous error
812

‎src/test/ui/suggestions/suggest-move-types.rs

+42
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,42 @@
1+
#![allow(warnings)]
2+
3+
// This test verifies that the suggestion to move types before associated type bindings
4+
// is correct.
5+
6+
trait One<T> {
7+
type A;
8+
}
9+
10+
trait Three<T, U, V> {
11+
type A;
12+
type B;
13+
type C;
14+
}
15+
16+
struct A<T, M: One<A=(), T>> { //~ ERROR type parameters must be declared
17+
m: M,
18+
t: T,
19+
}
20+
21+
struct B<T, U, V, M: Three<A=(), B=(), C=(), T, U, V>> { //~ ERROR type parameters must be declared
22+
m: M,
23+
t: T,
24+
u: U,
25+
v: V,
26+
}
27+
28+
struct C<T, U, V, M: Three<T, A=(), B=(), C=(), U, V>> { //~ ERROR type parameters must be declared
29+
m: M,
30+
t: T,
31+
u: U,
32+
v: V,
33+
}
34+
35+
struct D<T, U, V, M: Three<T, A=(), B=(), U, C=(), V>> { //~ ERROR type parameters must be declared
36+
m: M,
37+
t: T,
38+
u: U,
39+
v: V,
40+
}
41+
42+
fn main() {}

‎src/test/ui/suggestions/suggest-move-types.stderr

+49
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
1+
error: type parameters must be declared prior to associated type bindings
2+
--> $DIR/suggest-move-types.rs:16:26
3+
|
4+
LL | struct A<T, M: One<A=(), T>> { //~ ERROR type parameters must be declared
5+
| ^ must be declared prior to associated type bindings
6+
help: move the type parameter prior to the first associated type binding
7+
|
8+
LL | struct A<T, M: One<T, A=()>> { //~ ERROR type parameters must be declared
9+
| ^^ --
10+
11+
error: type parameters must be declared prior to associated type bindings
12+
--> $DIR/suggest-move-types.rs:21:46
13+
|
14+
LL | struct B<T, U, V, M: Three<A=(), B=(), C=(), T, U, V>> { //~ ERROR type parameters must be declared
15+
| ^ ^ ^ must be declared prior to associated type bindings
16+
| | |
17+
| | must be declared prior to associated type bindings
18+
| must be declared prior to associated type bindings
19+
help: move the type parameters prior to the first associated type binding
20+
|
21+
LL | struct B<T, U, V, M: Three<T, U, V, A=(), B=(), C=()>> { //~ ERROR type parameters must be declared
22+
| ^^ ^^ ^^ --
23+
24+
error: type parameters must be declared prior to associated type bindings
25+
--> $DIR/suggest-move-types.rs:28:49
26+
|
27+
LL | struct C<T, U, V, M: Three<T, A=(), B=(), C=(), U, V>> { //~ ERROR type parameters must be declared
28+
| ^ ^ must be declared prior to associated type bindings
29+
| |
30+
| must be declared prior to associated type bindings
31+
help: move the type parameters prior to the first associated type binding
32+
|
33+
LL | struct C<T, U, V, M: Three<T, U, V, A=(), B=(), C=()>> { //~ ERROR type parameters must be declared
34+
| ^^ ^^ --
35+
36+
error: type parameters must be declared prior to associated type bindings
37+
--> $DIR/suggest-move-types.rs:35:43
38+
|
39+
LL | struct D<T, U, V, M: Three<T, A=(), B=(), U, C=(), V>> { //~ ERROR type parameters must be declared
40+
| ^ ^ must be declared prior to associated type bindings
41+
| |
42+
| must be declared prior to associated type bindings
43+
help: move the type parameters prior to the first associated type binding
44+
|
45+
LL | struct D<T, U, V, M: Three<T, U, V, A=(), B=(), C=()>> { //~ ERROR type parameters must be declared
46+
| ^^ ^^ -- --
47+
48+
error: aborting due to 4 previous errors
49+

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