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Rollup merge of rust-lang#74168 - JohnTitor:help-for-in-band-lifetime…
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…s, r=petrochenkov

Add a help to use `in_band_lifetimes` in nightly

Fixes rust-lang#73775
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@Manishearth
Manishearth authored Jul 10, 2020
2 parents 6c73e61 + a9b6476 commit 8ba2bfc
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Showing 10 changed files with 78 additions and 0 deletions.
11 changes: 11 additions & 0 deletions src/librustc_resolve/late/diagnostics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1044,6 +1044,7 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
lifetime_ref
);
err.span_label(lifetime_ref.span, "undeclared lifetime");
let mut suggests_in_band = false;
for missing in &self.missing_named_lifetime_spots {
match missing {
MissingLifetimeSpot::Generics(generics) => {
Expand All @@ -1057,6 +1058,7 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
}) {
(param.span.shrink_to_lo(), format!("{}, ", lifetime_ref))
} else {
suggests_in_band = true;
(generics.span, format!("<{}>", lifetime_ref))
};
err.span_suggestion(
Expand Down Expand Up @@ -1084,6 +1086,15 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
}
}
}
if nightly_options::is_nightly_build()
&& !self.tcx.features().in_band_lifetimes
&& suggests_in_band
{
err.help(
"if you want to experiment with in-band lifetime bindings, \
add `#![feature(in_band_lifetimes)]` to the crate attributes",
);
}
err.emit();
}

Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/error-codes/E0261.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ LL | fn foo(x: &'a str) { }
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/E0261.rs:5:9
Expand All @@ -13,6 +15,8 @@ LL | struct Foo {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | x: &'a str,
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 2 previous errors

Expand Down
22 changes: 22 additions & 0 deletions src/test/ui/feature-gates/feature-gate-in_band_lifetimes.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ LL | fn foo(x: &'x u8) -> &'x u8 { x }
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'x` here: `<'x>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'x`
--> $DIR/feature-gate-in_band_lifetimes.rs:3:23
Expand All @@ -13,6 +15,8 @@ LL | fn foo(x: &'x u8) -> &'x u8 { x }
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'x` here: `<'x>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'b`
--> $DIR/feature-gate-in_band_lifetimes.rs:15:12
Expand All @@ -28,6 +32,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn inner_2(&self) -> &'b u8 {
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b, 'a> X<'b> {
Expand All @@ -44,13 +49,16 @@ LL | impl X<'b> {
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'b` here: `<'b>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'b`
--> $DIR/feature-gate-in_band_lifetimes.rs:25:27
|
LL | fn inner_3(&self) -> &'b u8 {
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b> X<'b> {
Expand All @@ -67,13 +75,16 @@ LL | impl Y<&'a u8> {
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/feature-gate-in_band_lifetimes.rs:35:25
|
LL | fn inner(&self) -> &'a u8 {
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'a` here
|
LL | impl<'a> Y<&'a u8> {
Expand All @@ -89,6 +100,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn any_lifetime() -> &'b u8;
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | trait MyTrait<'b, 'a> {
Expand All @@ -104,6 +116,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn borrowed_lifetime(&'b self) -> &'b u8;
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | trait MyTrait<'b, 'a> {
Expand All @@ -119,6 +132,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn borrowed_lifetime(&'b self) -> &'b u8;
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | trait MyTrait<'b, 'a> {
Expand All @@ -135,6 +149,8 @@ LL | impl MyTrait<'a> for Y<&'a u8> {
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/feature-gate-in_band_lifetimes.rs:50:25
Expand All @@ -143,13 +159,16 @@ LL | impl MyTrait<'a> for Y<&'a u8> {
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/feature-gate-in_band_lifetimes.rs:53:31
|
LL | fn my_lifetime(&self) -> &'a u8 { self.0 }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'a` here
|
LL | impl<'a> MyTrait<'a> for Y<&'a u8> {
Expand All @@ -165,6 +184,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn any_lifetime() -> &'b u8 { &0 }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b> MyTrait<'a> for Y<&'a u8> {
Expand All @@ -180,6 +200,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn borrowed_lifetime(&'b self) -> &'b u8 { &*self.0 }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b> MyTrait<'a> for Y<&'a u8> {
Expand All @@ -195,6 +216,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn borrowed_lifetime(&'b self) -> &'b u8 { &*self.0 }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b> MyTrait<'a> for Y<&'a u8> {
Expand Down
2 changes: 2 additions & 0 deletions src/test/ui/generic-associated-types/generic_associated_type_undeclared_lifetimes.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | + Deref<Target = Self::Item<'b>>;
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | trait Iterable<'b> {
Expand All @@ -19,6 +20,7 @@ error[E0261]: use of undeclared lifetime name `'undeclared`
LL | fn iter<'a>(&'a self) -> Self::Iter<'undeclared>;
| ^^^^^^^^^^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'undeclared` here
|
LL | trait Iterable<'undeclared> {
Expand Down
2 changes: 2 additions & 0 deletions src/test/ui/methods/method-call-lifetime-args-unresolved.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ LL | fn main() {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | 0.clone::<'a>();
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to previous error

Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/regions/regions-in-enums.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ LL | enum No0 {
| - help: consider introducing lifetime `'foo` here: `<'foo>`
LL | X5(&'foo usize)
| ^^^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-in-enums.rs:17:9
Expand All @@ -13,6 +15,8 @@ LL | enum No1 {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | X6(&'a usize)
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 2 previous errors

Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/regions/regions-in-structs.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ LL | struct StructDecl {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | a: &'a isize,
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-in-structs.rs:11:9
Expand All @@ -14,6 +16,8 @@ LL | struct StructDecl {
LL | a: &'a isize,
LL | b: &'a isize,
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 2 previous errors

Expand Down
17 changes: 17 additions & 0 deletions src/test/ui/regions/regions-name-undeclared.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn m4(&self, arg: &'b isize) { }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b, 'a> Foo<'a> {
Expand All @@ -19,6 +20,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn m5(&'b self) { }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b, 'a> Foo<'a> {
Expand All @@ -34,6 +36,7 @@ error[E0261]: use of undeclared lifetime name `'b`
LL | fn m6(&self, arg: Foo<'b>) { }
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | impl<'b, 'a> Foo<'a> {
Expand All @@ -50,6 +53,8 @@ LL | type X = Option<&'a isize>;
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-name-undeclared.rs:27:13
Expand All @@ -58,6 +63,8 @@ LL | enum E {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | E1(&'a isize)
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-name-undeclared.rs:30:13
Expand All @@ -66,6 +73,8 @@ LL | struct S {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | f: &'a isize
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-name-undeclared.rs:32:14
Expand All @@ -74,6 +83,8 @@ LL | fn f(a: &'a isize) { }
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-name-undeclared.rs:40:17
Expand All @@ -82,6 +93,8 @@ LL | fn fn_types(a: &'a isize,
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'b`
--> $DIR/regions-name-undeclared.rs:42:36
Expand All @@ -90,6 +103,7 @@ LL | ... &'b isize,
| ^^ undeclared lifetime
|
= note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | fn fn_types<'b>(a: &'a isize,
Expand All @@ -106,6 +120,7 @@ LL | ... &'b isize)>,
| ^^ undeclared lifetime
|
= note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes
help: consider introducing lifetime `'b` here
|
LL | fn fn_types<'b>(a: &'a isize,
Expand All @@ -123,6 +138,8 @@ LL | fn fn_types(a: &'a isize,
...
LL | c: &'a isize)
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 11 previous errors

Expand Down
8 changes: 8 additions & 0 deletions src/test/ui/regions/regions-undeclared.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,8 @@ LL | enum EnumDecl {
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | Foo(&'a isize),
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-undeclared.rs:5:10
Expand All @@ -20,6 +22,8 @@ LL | enum EnumDecl {
LL | Foo(&'a isize),
LL | Bar(&'a isize),
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-undeclared.rs:8:15
Expand All @@ -28,6 +32,8 @@ LL | fn fnDecl(x: &'a isize,
| - ^^ undeclared lifetime
| |
| help: consider introducing lifetime `'a` here: `<'a>`
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'a`
--> $DIR/regions-undeclared.rs:9:15
Expand All @@ -36,6 +42,8 @@ LL | fn fnDecl(x: &'a isize,
| - help: consider introducing lifetime `'a` here: `<'a>`
LL | y: &'a isize)
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 5 previous errors

Expand Down
4 changes: 4 additions & 0 deletions src/test/ui/where-clauses/where-lifetime-resolution.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,8 @@ LL | fn f() where
LL | for<'a> dyn Trait1<'a>: Trait1<'a>, // OK
LL | (dyn for<'a> Trait1<'a>): Trait1<'a>,
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error[E0261]: use of undeclared lifetime name `'b`
--> $DIR/where-lifetime-resolution.rs:8:52
Expand All @@ -15,6 +17,8 @@ LL | fn f() where
...
LL | for<'a> dyn for<'b> Trait2<'a, 'b>: Trait2<'a, 'b>,
| ^^ undeclared lifetime
|
= help: if you want to experiment with in-band lifetime bindings, add `#![feature(in_band_lifetimes)]` to the crate attributes

error: aborting due to 2 previous errors

Expand Down

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