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When mentioning lifetimes, put either the trait ref or the self type …
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…closer to the lifetimes

When mentioning lifetimes, only invert wording between the expected trait and the self type when the self type has the vid.
This way, the lifetimes always stay close to the self type or trait ref that actually contains them.
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@lqd
lqd committed Jan 27, 2019
1 parent 1730ad4 commit 489bc4a
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Showing 8 changed files with 81 additions and 44 deletions.
89 changes: 63 additions & 26 deletions src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -251,10 +251,16 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
}
});

let self_ty_has_vid = self
let actual_self_ty_has_vid = self
.tcx()
.any_free_region_meets(&actual_trait_ref.self_ty(), |r| Some(r) == vid);

let expected_self_ty_has_vid = self
.tcx()
.any_free_region_meets(&expected_trait_ref.self_ty(), |r| Some(r) == vid);

let self_ty_has_vid = actual_self_ty_has_vid || expected_self_ty_has_vid;

debug!(
"try_report_placeholders_trait: actual_has_vid={:?}",
actual_has_vid
Expand All @@ -266,8 +272,12 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
debug!("try_report_placeholders_trait: has_sub={:?}", has_sub);
debug!("try_report_placeholders_trait: has_sup={:?}", has_sup);
debug!(
"try_report_placeholders_trait: self_ty_has_vid={:?}",
self_ty_has_vid
"try_report_placeholders_trait: actual_self_ty_has_vid={:?}",
actual_self_ty_has_vid
);
debug!(
"try_report_placeholders_trait: expected_self_ty_has_vid={:?}",
expected_self_ty_has_vid
);

// The weird thing here with the `maybe_highlighting_region` calls and the
Expand All @@ -289,23 +299,43 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
RegionHighlightMode::maybe_highlighting_region(sup_placeholder, has_sup, || {
match (has_sub, has_sup) {
(Some(n1), Some(n2)) => {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for any two lifetimes `'{}` and `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
std::cmp::min(n1, n2),
std::cmp::max(n1, n2),
));
if self_ty_has_vid {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for any two lifetimes `'{}` and `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
std::cmp::min(n1, n2),
std::cmp::max(n1, n2),
));
} else {
err.note(&format!(
"`{}` must implement `{}`, \
for any two lifetimes `'{}` and `'{}`",
expected_trait_ref.self_ty(),
expected_trait_ref,
std::cmp::min(n1, n2),
std::cmp::max(n1, n2),
));
}
}
(Some(n), _) | (_, Some(n)) => {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for any lifetime `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
n,
));
if self_ty_has_vid {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for any lifetime `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
n,
));
} else {
err.note(&format!(
"`{}` must implement `{}`, for any lifetime `'{}`",
expected_trait_ref.self_ty(),
expected_trait_ref,
n,
));
}
}
(None, None) => RegionHighlightMode::maybe_highlighting_region(
vid,
Expand All @@ -320,11 +350,19 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
n,
));
} else {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
));
if self_ty_has_vid {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
));
} else {
err.note(&format!(
"`{}` must implement `{}`",
expected_trait_ref.self_ty(),
expected_trait_ref,
));
}
}
},
),
Expand All @@ -347,10 +385,9 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
));
} else {
err.note(&format!(
"but `{}` is actually implemented for the type `{}`, \
for some lifetime `'{}`",
actual_trait_ref,
"but `{}` actually implements `{}`, for some lifetime `'{}`",
actual_trait_ref.self_ty(),
actual_trait_ref,
n
));
}
Expand Down
12 changes: 6 additions & 6 deletions src/test/ui/associated-types/associated-types-eq-hr.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,8 +41,8 @@ LL | tuple_one::<Tuple>();
| ^^^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `tuple_one`,
= note: `TheTrait<(&'0 isize, &'1 isize)>` would have to be implemented for the type `Tuple`, for any two lifetimes `'0` and `'1`
= note: but `TheTrait<(&'2 isize, &'2 isize)>` is actually implemented for the type `Tuple`, for some lifetime `'2`
= note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>`, for any two lifetimes `'0` and `'1`
= note: but `Tuple` actually implements `TheTrait<(&'2 isize, &'2 isize)>`, for some lifetime `'2`

error: implementation of `TheTrait` is not general enough
--> $DIR/associated-types-eq-hr.rs:96:5
Expand All @@ -51,8 +51,8 @@ LL | tuple_two::<Tuple>();
| ^^^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `tuple_two`,
= note: `TheTrait<(&'0 isize, &'1 isize)>` would have to be implemented for the type `Tuple`, for any two lifetimes `'0` and `'1`
= note: but `TheTrait<(&'2 isize, &'2 isize)>` is actually implemented for the type `Tuple`, for some lifetime `'2`
= note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>`, for any two lifetimes `'0` and `'1`
= note: but `Tuple` actually implements `TheTrait<(&'2 isize, &'2 isize)>`, for some lifetime `'2`

error: implementation of `TheTrait` is not general enough
--> $DIR/associated-types-eq-hr.rs:105:5
Expand All @@ -61,8 +61,8 @@ LL | tuple_four::<Tuple>();
| ^^^^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `tuple_four`,
= note: `TheTrait<(&'0 isize, &'1 isize)>` would have to be implemented for the type `Tuple`, for any two lifetimes `'0` and `'1`
= note: but `TheTrait<(&'2 isize, &'2 isize)>` is actually implemented for the type `Tuple`, for some lifetime `'2`
= note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>`, for any two lifetimes `'0` and `'1`
= note: but `Tuple` actually implements `TheTrait<(&'2 isize, &'2 isize)>`, for some lifetime `'2`

error: aborting due to 5 previous errors

Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/hrtb/hrtb-cache-issue-54302.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@ error: implementation of `Deserialize` is not general enough
LL | assert_deserialize_owned::<&'static str>(); //~ ERROR
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `Deserialize<'0>` would have to be implemented for the type `&'static str`, for any lifetime `'0`
= note: but `Deserialize<'1>` is actually implemented for the type `&str`, for some lifetime `'1`
= note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`
= note: but `&str` actually implements `Deserialize<'1>`, for some lifetime `'1`

error: aborting due to previous error

4 changes: 2 additions & 2 deletions src/test/ui/hrtb/hrtb-conflate-regions.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@ LL | fn b() { want_foo2::<SomeStruct>(); } //~ ERROR
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `want_foo2`,
= note: `Foo<(&'0 isize, &'1 isize)>` would have to be implemented for the type `SomeStruct`, for any two lifetimes `'0` and `'1`
= note: but `Foo<(&'2 isize, &'2 isize)>` is actually implemented for the type `SomeStruct`, for some lifetime `'2`
= note: `SomeStruct` must implement `Foo<(&'0 isize, &'1 isize)>`, for any two lifetimes `'0` and `'1`
= note: but `SomeStruct` actually implements `Foo<(&'2 isize, &'2 isize)>`, for some lifetime `'2`

error: aborting due to previous error

4 changes: 2 additions & 2 deletions src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@ LL | foo::<()>(); //~ ERROR not general enough
| ^^^^^^^^^
|
= note: Due to a where-clause on `foo`,
= note: `Trait<for<'b> fn(std::cell::Cell<&'b u32>)>` would have to be implemented for the type `()`
= note: but `Trait<fn(std::cell::Cell<&'0 u32>)>` is actually implemented for the type `()`, for some lifetime `'0`
= note: `()` must implement `Trait<for<'b> fn(std::cell::Cell<&'b u32>)>`
= note: but `()` actually implements `Trait<fn(std::cell::Cell<&'0 u32>)>`, for some lifetime `'0`

error: aborting due to previous error

4 changes: 2 additions & 2 deletions src/test/ui/hrtb/hrtb-just-for-static.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@ LL | want_hrtb::<StaticInt>() //~ ERROR
| ^^^^^^^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `want_hrtb`,
= note: `Foo<&'0 isize>` would have to be implemented for the type `StaticInt`, for any lifetime `'0`
= note: but `Foo<&'1 isize>` is actually implemented for the type `StaticInt`, for some lifetime `'1`
= note: `StaticInt` must implement `Foo<&'0 isize>`, for any lifetime `'0`
= note: but `StaticInt` actually implements `Foo<&'1 isize>`, for some lifetime `'1`

error: implementation of `Foo` is not general enough
--> $DIR/hrtb-just-for-static.rs:30:5
Expand Down
4 changes: 2 additions & 2 deletions src/test/ui/hrtb/hrtb-perfect-forwarding.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@ LL | foo_hrtb_bar_not(&mut t); //~ ERROR not general enough
| ^^^^^^^^^^^^^^^^
|
= note: Due to a where-clause on `foo_hrtb_bar_not`,
= note: `Foo<&'0 isize>` would have to be implemented for the type `&mut T`, for any lifetime `'0`
= note: but `Foo<&'1 isize>` is actually implemented for the type `&mut T`, for some lifetime `'1`
= note: `&mut T` must implement `Foo<&'0 isize>`, for any lifetime `'0`
= note: but `&mut T` actually implements `Foo<&'1 isize>`, for some lifetime `'1`

error: aborting due to previous error

4 changes: 2 additions & 2 deletions src/test/ui/issues/issue-54302.stderr
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,8 @@ error: implementation of `Deserialize` is not general enough
LL | assert_deserialize_owned::<&'static str>();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `Deserialize<'0>` would have to be implemented for the type `&'static str`, for any lifetime `'0`
= note: but `Deserialize<'1>` is actually implemented for the type `&str`, for some lifetime `'1`
= note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`
= note: but `&str` actually implements `Deserialize<'1>`, for some lifetime `'1`

error: aborting due to previous error

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