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Fix error message with non-tupled bare fn trait

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This commit is contained in:
Michael Goulet 2022-07-30 09:41:19 +00:00
parent 40336865fe
commit 8b64988575
10 changed files with 101 additions and 38 deletions
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1
compiler/rustc_infer/src/infer/error_reporting/mod.rs
View file

@ -1750,6 +1750,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
if let Some(ValuePairs::PolyTraitRefs(exp_found)) = values
&& let ty::Closure(def_id, _) = exp_found.expected.skip_binder().self_ty().kind()
&& let Some(def_id) = def_id.as_local()
&& terr.involves_regions()
{
let span = self.tcx.def_span(def_id);
diag.span_note(span, "this closure does not fulfill the lifetime requirements");

12
compiler/rustc_infer/src/infer/mod.rs
View file

@ -1935,6 +1935,18 @@ impl<'tcx> TypeTrace<'tcx> {
}
}
pub fn poly_trait_refs(
cause: &ObligationCause<'tcx>,
a_is_expected: bool,
a: ty::PolyTraitRef<'tcx>,
b: ty::PolyTraitRef<'tcx>,
) -> TypeTrace<'tcx> {
TypeTrace {
cause: cause.clone(),
values: PolyTraitRefs(ExpectedFound::new(a_is_expected, a.into(), b.into())),
}
}
pub fn consts(
cause: &ObligationCause<'tcx>,
a_is_expected: bool,

12
compiler/rustc_middle/src/ty/error.rs
View file

@ -74,6 +74,18 @@ pub enum TypeError<'tcx> {
TargetFeatureCast(DefId),
}
impl TypeError<'_> {
pub fn involves_regions(self) -> bool {
match self {
TypeError::RegionsDoesNotOutlive(_, _)
| TypeError::RegionsInsufficientlyPolymorphic(_, _)
| TypeError::RegionsOverlyPolymorphic(_, _)
| TypeError::RegionsPlaceholderMismatch => true,
_ => false,
}
}
}
/// Explains the source of a type err in a short, human readable way. This is meant to be placed
/// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
/// afterwards to present additional details, particularly when it comes to lifetime-related

30
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file

@ -22,6 +22,7 @@ use rustc_hir::intravisit::Visitor;
use rustc_hir::GenericParam;
use rustc_hir::Item;
use rustc_hir::Node;
use rustc_infer::infer::TypeTrace;
use rustc_infer::traits::TraitEngine;
use rustc_middle::traits::select::OverflowError;
use rustc_middle::ty::abstract_const::NotConstEvaluatable;
@ -941,9 +942,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
self.reported_closure_mismatch.borrow_mut().insert((span, found_span));
let mut not_tupled = false;
let found = match found_trait_ref.skip_binder().substs.type_at(1).kind() {
ty::Tuple(ref tys) => vec![ArgKind::empty(); tys.len()],
_ => vec![ArgKind::empty()],
_ => {
not_tupled = true;
vec![ArgKind::empty()]
}
};
let expected_ty = expected_trait_ref.skip_binder().substs.type_at(1);
@ -951,10 +957,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
ty::Tuple(ref tys) => {
tys.iter().map(|t| ArgKind::from_expected_ty(t, Some(span))).collect()
}
_ => vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())],
_ => {
not_tupled = true;
vec![ArgKind::Arg("_".to_owned(), expected_ty.to_string())]
}
};
if found.len() == expected.len() {
// If this is a `Fn` family trait and either the expected or found
// is not tupled, then fall back to just a regular mismatch error.
// This shouldn't be common unless manually implementing one of the
// traits manually, but don't make it more confusing when it does
// happen.
if Some(expected_trait_ref.def_id()) != tcx.lang_items().gen_trait() && not_tupled {
self.report_and_explain_type_error(
TypeTrace::poly_trait_refs(
&obligation.cause,
true,
expected_trait_ref,
found_trait_ref,
),
ty::error::TypeError::Mismatch,
)
} else if found.len() == expected.len() {
self.report_closure_arg_mismatch(
span,
found_span,

4
src/test/ui/mismatched_types/E0631.rs
View file

@ -5,7 +5,7 @@ fn bar<F: Fn<usize>>(_: F) {}
fn main() {
fn f(_: u64) {}
foo(|_: isize| {}); //~ ERROR type mismatch
bar(|_: isize| {}); //~ ERROR type mismatch
bar(|_: isize| {}); //~ ERROR mismatched types
foo(f); //~ ERROR type mismatch
bar(f); //~ ERROR type mismatch
bar(f); //~ ERROR mismatched types
}

24
src/test/ui/mismatched_types/E0631.stderr
View file

@ -14,16 +14,14 @@ note: required by a bound in `foo`
LL | fn foo<F: Fn(usize)>(_: F) {}
| ^^^^^^^^^ required by this bound in `foo`
error[E0631]: type mismatch in closure arguments
error[E0308]: mismatched types
--> $DIR/E0631.rs:8:5
|
LL | bar(|_: isize| {});
| ^^^ ---------- found signature defined here
| |
| expected due to this
| ^^^ types differ
|
= note: expected closure signature `fn(usize) -> _`
found closure signature `fn(isize) -> _`
= note: expected trait `Fn<usize>`
found trait `Fn<(isize,)>`
note: required by a bound in `bar`
--> $DIR/E0631.rs:4:11
|
@ -49,19 +47,16 @@ note: required by a bound in `foo`
LL | fn foo<F: Fn(usize)>(_: F) {}
| ^^^^^^^^^ required by this bound in `foo`
error[E0631]: type mismatch in function arguments
error[E0308]: mismatched types
--> $DIR/E0631.rs:10:9
|
LL | fn f(_: u64) {}
| ------------ found signature defined here
...
LL | bar(f);
| --- ^ expected due to this
| --- ^ types differ
| |
| required by a bound introduced by this call
|
= note: expected function signature `fn(usize) -> _`
found function signature `fn(u64) -> _`
= note: expected trait `Fn<usize>`
found trait `Fn<(u64,)>`
note: required by a bound in `bar`
--> $DIR/E0631.rs:4:11
|
@ -70,4 +65,5 @@ LL | fn bar<F: Fn<usize>>(_: F) {}
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0631`.
Some errors have detailed explanations: E0308, E0631.
For more information about an error, try `rustc --explain E0308`.

4
src/test/ui/mismatched_types/closure-arg-count.rs
View file

@ -11,9 +11,9 @@ fn main() {
[1, 2, 3].sort_by(|(tuple, tuple2): (usize, _)| panic!());
//~^ ERROR closure is expected to take
f(|| panic!());
//~^ ERROR closure is expected to take
//~^ ERROR mismatched types
f( move || panic!());
//~^ ERROR closure is expected to take
//~^ ERROR mismatched types
let _it = vec![1, 2, 3].into_iter().enumerate().map(|i, x| i);
//~^ ERROR closure is expected to take

27
src/test/ui/mismatched_types/closure-arg-count.stderr
View file

@ -45,41 +45,33 @@ help: change the closure to take multiple arguments instead of a single tuple
LL | [1, 2, 3].sort_by(|tuple, tuple2| panic!());
| ~~~~~~~~~~~~~~~
error[E0593]: closure is expected to take 1 argument, but it takes 0 arguments
error[E0308]: mismatched types
--> $DIR/closure-arg-count.rs:13:5
|
LL | f(|| panic!());
| ^ -- takes 0 arguments
| |
| expected closure that takes 1 argument
| ^ types differ
|
= note: expected trait `Fn<usize>`
found trait `Fn<()>`
note: required by a bound in `f`
--> $DIR/closure-arg-count.rs:3:9
|
LL | fn f<F: Fn<usize>>(_: F) {}
| ^^^^^^^^^ required by this bound in `f`
help: consider changing the closure to take and ignore the expected argument
|
LL | f(|_| panic!());
| ~~~
error[E0593]: closure is expected to take 1 argument, but it takes 0 arguments
error[E0308]: mismatched types
--> $DIR/closure-arg-count.rs:15:5
|
LL | f( move || panic!());
| ^ ---------- takes 0 arguments
| |
| expected closure that takes 1 argument
| ^ types differ
|
= note: expected trait `Fn<usize>`
found trait `Fn<()>`
note: required by a bound in `f`
--> $DIR/closure-arg-count.rs:3:9
|
LL | fn f<F: Fn<usize>>(_: F) {}
| ^^^^^^^^^ required by this bound in `f`
help: consider changing the closure to take and ignore the expected argument
|
LL | f( move |_| panic!());
| ~~~
error[E0593]: closure is expected to take a single 2-tuple as argument, but it takes 2 distinct arguments
--> $DIR/closure-arg-count.rs:18:53
@ -198,4 +190,5 @@ LL | fn call<F, R>(_: F) where F: FnOnce() -> R {}
error: aborting due to 14 previous errors
For more information about this error, try `rustc --explain E0593`.
Some errors have detailed explanations: E0308, E0593.
For more information about an error, try `rustc --explain E0308`.

8
src/test/ui/unboxed-closures/non-tupled-arg-mismatch.rs Normal file
View file

@ -0,0 +1,8 @@
#![feature(unboxed_closures)]
fn a<F: Fn<usize>>(f: F) {}
fn main() {
a(|_: usize| {});
//~^ ERROR mismatched types
}

17
src/test/ui/unboxed-closures/non-tupled-arg-mismatch.stderr Normal file
View file

@ -0,0 +1,17 @@
error[E0308]: mismatched types
--> $DIR/non-tupled-arg-mismatch.rs:6:5
|
LL | a(|_: usize| {});
| ^ types differ
|
= note: expected trait `Fn<usize>`
found trait `Fn<(usize,)>`
note: required by a bound in `a`
--> $DIR/non-tupled-arg-mismatch.rs:3:9
|
LL | fn a<F: Fn<usize>>(f: F) {}
| ^^^^^^^^^ required by this bound in `a`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0308`.