8000 Add information to higher-ranked lifetimes conflicts error messages by lqd · Pull Request #57901 · rust-lang/rust · GitHub
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Merged
merged 16 commits into from
Jan 29, 2019
Merged

Add information to higher-ranked lifetimes conflicts error messages #57901

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c1437c9
Make NiceRegionError use the `InferCtxt` instead of its `TyCtxt`
lqd Jan 25, 2019
a602826
Handle higher-ranked lifetime conflict errors where the subtype is th…
lqd Jan 25, 2019
823c888
Try to resolve type vars in the placeholder errors trait refs
lqd Jan 25, 2019
55389f9
Try to reword placeholder error messages to make them clearer
lqd Jan 25, 2019
ce61b1b
Update two E308 tests to the new placeholder error
lqd Jan 25, 2019
a79f135
Update test expectations for new placeholder error messages
lqd Jan 25, 2019
f5a74d4
Test new placeholder error messages in previously untested combinations
lqd Jan 25, 2019
c5dea57
break apart tests
nikomatsakis Jan 25, 2019
ab80162
add a lot more `debug!` to `try_report_placeholders_trait`
nikomatsakis Jan 25, 2019
ec6405b
identify when implemented for "some specific lifetime"
nikomatsakis Jan 25, 2019
790ed91
comment the pattern
nikomatsakis Jan 25, 2019
1730ad4
Fix issue-57362-1.rs attributes
lqd Jan 25, 2019
489bc4a
When mentioning lifetimes, put either the trait ref or the self type …
lqd Jan 26, 2019
43c0518
Extract the notes explaining the placeholder region errors to a helpe…
lqd Jan 26, 2019
e077501
Fix stray typo
lqd Jan 26, 2019
c97d135
Refer to synthetically named lifetimes as "some specific lifetime" ra…
lqd Jan 28, 2019
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identify when implemented for "some specific lifetime"
  • Loading branch information
@nikomatsakis @lqd
nikomatsakis authored and lqd committed Jan 27, 2019
commit ec6405bccd8b1f0933a3604bdd86c43707350275
247 changes: 120 additions & 127 deletions src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
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2D0F
Original file line number Diff line number Diff line change
Expand Up @@ -34,19 +34,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
sub_placeholder @ ty::RePlaceholder(_),
_,
sup_placeholder @ ty::RePlaceholder(_),
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
Some(sub_placeholder),
Some(sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
Some(sub_placeholder),
Some(sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::SubSupConflict(
vid,
Expand All @@ -58,19 +54,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
sub_placeholder @ ty::RePlaceholder(_),
_,
_,
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
Some(sub_placeholder),
None,
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
Some(sub_placeholder),
None,
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::SubSupConflict(
vid,
Expand All @@ -82,19 +74,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
_,
_,
sup_placeholder @ ty::RePlaceholder(_),
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
None,
Some(*sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
None,
Some(*sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::SubSupConflict(
vid,
Expand All @@ -106,19 +94,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
values: ValuePairs::TraitRefs(ExpectedFound { expected, found }),
}),
sup_placeholder @ ty::RePlaceholder(_),
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
None,
Some(*sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(self.tcx().mk_region(ty::ReVar(*vid))),
cause,
None,
Some(*sup_placeholder),
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::ConcreteFailure(
SubregionOrigin::Subtype(TypeTrace {
Expand All @@ -127,19 +111,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
}),
sub_region @ ty::RePlaceholder(_),
sup_region @ ty::RePlaceholder(_),
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
None,
cause,
Some(*sub_region),
Some(*sup_region),
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
None,
cause,
Some(*sub_region),
Some(*sup_region),
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::ConcreteFailure(
SubregionOrigin::Subtype(TypeTrace {
Expand All @@ -148,19 +128,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
}),
sub_region @ ty::RePlaceholder(_),
sup_region,
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(sup_region),
cause,
Some(*sub_region),
None,
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(sup_region),
cause,
Some(*sub_region),
None,
expected.def_id,
expected.substs,
found.substs,
)),

Some(RegionResolutionError::ConcreteFailure(
SubregionOrigin::Subtype(TypeTrace {
Expand All @@ -169,19 +145,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
}),
sub_region,
sup_region @ ty::RePlaceholder(_),
))
if expected.def_id == found.def_id =>
{
Some(self.try_report_placeholders_trait(
Some(sub_region),
cause,
None,
Some(*sup_region),
expected.def_id,
expected.substs,
found.substs,
))
}
)) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
Some(sub_region),
cause,
None,
Some(*sup_region),
expected.def_id,
expected.substs,
found.substs,
)),

_ => None,
}
Expand All @@ -206,14 +178,16 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
expected_substs: &'tcx Substs<'tcx>,
actual_substs: &'tcx Substs<'tcx>,
) -> ErrorReported {
debug!("try_report_placeholders_trait(\
vid={:?}, \
sub_placeholder={:?}, \
sup_placeholder={:?}, \
trait_def_id={:?}, \
expected_substs={:?}, \
actual_substs={:?})",
vid, sub_placeholder, sup_placeholder, trait_def_id, expected_substs, actual_substs);
debug!(
"try_report_placeholders_trait(\
vid={:?}, \
sub_placeholder={:?}, \
sup_placeholder={:?}, \
trait_def_id={:?}, \
expected_substs={:?}, \
actual_substs={:?})",
vid, sub_placeholder, sup_placeholder, trait_def_id, expected_substs, actual_substs
);

let mut err = self.tcx().sess.struct_span_err(
cause.span(&self.tcx()),
Expand All @@ -233,18 +207,14 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
_ => (),
}

let expected_trait_ref = self.infcx.resolve_type_vars_if_possible(
&ty::TraitRef {
def_id: trait_def_id,
substs: expected_substs,
}
);
let actual_trait_ref = self.infcx.resolve_type_vars_if_possible(
&ty::TraitRef {
def_id: trait_def_id,
substs: actual_substs,
}
);
let expected_trait_ref = self.infcx.resolve_type_vars_if_possible(&ty::TraitRef {
def_id: trait_def_id,
substs: expected_substs,
});
let actual_trait_ref = self.infcx.resolve_type_vars_if_possible(&ty::TraitRef {
def_id: trait_def_id,
substs: actual_substs,
});

// Search the expected and actual trait references to see (a)
// whether the sub/sup placeholders appear in them (sometimes
Expand Down Expand Up @@ -285,19 +255,28 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
.tcx()
.any_free_region_meets(&actual_trait_ref.self_ty(), |r| Some(r) == vid);

debug!("try_report_placeholders_trait: actual_has_vid={:?}", actual_has_vid);
debug!("try_report_placeholders_trait: expected_has_vid={:?}", expected_has_vid);
debug!(
"try_report_placeholders_trait: actual_has_vid={:?}",
actual_has_vid
);
debug!(
"try_report_placeholders_trait: expected_has_vid={:?}",
expected_has_vid
);
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);
debug!(
"try_report_placeholders_trait: self_ty_has_vid={:?}",
self_ty_has_vid
);

RegionHighlightMode::maybe_highlighting_region(sub_placeholder, has_sub, || {
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 `'{}`",
for any two lifetimes `'{}` and `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
std::cmp::min(n1, n2),
Expand All @@ -307,40 +286,54 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
(Some(n), _) | (_, Some(n)) => {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for any lifetime `'{}`",
for any lifetime `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
n,
));
}
(None, None) => {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
));
}
(None, None) => RegionHighlightMode::maybe_highlighting_region(
vid,
expected_has_vid,
|| {
if let Some(n) = expected_has_vid {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`, \
for some specific lifetime `'{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
n,
));
} else {
err.note(&format!(
"`{}` would have to be implemented for the type `{}`",
expected_trait_ref,
expected_trait_ref.self_ty(),
));
}
},
),
}
})
});

RegionHighlightMode::maybe_highlighting_region(
vid,
actual_has_vid.or(expected_has_vid),
actual_has_vid,
|| match actual_has_vid {
Some(n) => {
if self_ty_has_vid {
err.note(&format!(
"but `{}` is actually implemented for the type `{}`, \
for the specific lifetime `'{}`",
for the specific lifetime `'{}`",
actual_trait_ref,
actual_trait_ref.self_ty(),
n
));
} else {
err.note(&format!(
"but `{}` is actually implemented for the type `{}`, \
for some lifetime `'{}`",
for some lifetime `'{}`",
actual_trait_ref,
actual_trait_ref.self_ty(),
n
Expand All @@ -355,7 +348,7 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
actual_trait_ref.self_ty(),
));
}
}
},
);

err.emit();
Expand Down
15 changes: 3 additions & 12 deletions src/test/ui/issues/issue-57362-1.stderr
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Original file line number Diff line number Diff line change
@@ -1,20 +1,11 @@
error: implementation of `Trait` is not general enough
--> $DIR/issue-57362.rs:20:7
--> $DIR/issue-57362-1.rs:20:7
|
LL | a.f(); //~ ERROR not general enough
| ^
|
= note: `Trait` would have to be implemented for the type `fn(&u8)`
= note: `Trait` would have to be implemented for the type `fn(&'0 u8)`, for some specific lifetime `'0`
= note: but `Trait` is actually implemented for the type `for<'r> fn(&'r u8)`

error: implementation of `X` is not general enough
--> $DIR/issue-57362.rs:38:13
|
LL | let x = <fn (&())>::make_g(); //~ ERROR not general enough
| ^^^^^^^^^^^^^^^^^^
|
= note: `X` would have to be implemented for the type `for<'r> fn(&'r ())`
= note: but `X` is actually implemented for the type `fn(&'0 ())`, for the specific lifetime `'0`

error: aborting due to 2 previous errors
error: aborting due to previous error

11 changes: 11 additions & 0 deletions src/test/ui/issues/issue-57362-2.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
error: implementation of `X` is not general enough
--> $DIR/issue-57362-2.rs:22:13
|
LL | let x = <fn (&())>::make_g(); //~ ERROR not general enough
| ^^^^^^^^^^^^^^^^^^
|
= note: `X` would have to be implemented for the type `for<'r> fn(&'r ())`
= note: but `X` is actually implemented for the type `fn(&'0 ())`, for the specific lifetime `'0`

error: aborting due to previous error

0