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aliemjaylcnr
aliemjay
authored and
lcnr
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borrowck: wf-check fn item args
1 parent f9c2421 commit a3fe3bb

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17 files changed

+269
-49
lines changed

17 files changed

+269
-49
lines changed

‎compiler/rustc_borrowck/src/type_check/mod.rs

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Original file line numberDiff line numberDiff line change
@@ -406,6 +406,16 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
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instantiated_predicates,
407407
locations,
408408
);
409+
410+
assert!(!matches!(
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tcx.impl_of_method(def_id).map(|imp| tcx.def_kind(imp)),
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Some(DefKind::Impl { of_trait: true })
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));
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self.cx.prove_predicates(
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args.types().map(|ty| ty::ClauseKind::WellFormed(ty.into())),
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locations,
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ConstraintCategory::Boring,
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);
409419
}
410420
}
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}

‎library/std/src/collections/hash/map.rs

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -3049,8 +3049,9 @@ where
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#[stable(feature = "hash_extend_copy", since = "1.4.0")]
30503050
impl<'a, K, V, S> Extend<(&'a K, &'a V)> for HashMap<K, V, S>
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where
3052-
K: Eq + Hash + Copy,
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V: Copy,
3052+
// FIXME(aliemjay): the bound `+ 'a` should not be necessary.
3053+
K: Eq + Hash + Copy + 'a,
3054+
V: Copy + 'a,
30543055
S: BuildHasher,
30553056
{
30563057
#[inline]

‎tests/ui/borrowck/fn-item-check-trait-ref.rs

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
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// The method `assert_static` should be callable only for static values,
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// because the impl has an implied bound `where T: 'static`.
3+
4+
// check-fail
5+
6+
trait AnyStatic<Witness>: Sized {
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fn assert_static(self) {}
8+
}
9+
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impl<T> AnyStatic<&'static T> for T {}
11+
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fn main() {
13+
(&String::new()).assert_static();
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//~^ ERROR temporary value dropped while borrowed
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}

‎tests/ui/borrowck/fn-item-check-trait-ref.stderr

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
error[E0716]: temporary value dropped while borrowed
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--> $DIR/fn-item-check-trait-ref.rs:13:7
3+
|
4+
LL | (&String::new()).assert_static();
5+
| --^^^^^^^^^^^^^------------------ temporary value is freed at the end of this statement
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| | |
7+
| | creates a temporary value which is freed while still in use
8+
| argument requires that borrow lasts for `'static`
9+
10+
error: aborting due to 1 previous error
11+
12+
For more information about this error, try `rustc --explain E0716`.

‎tests/ui/borrowck/fn-item-check-type-params.rs

Lines changed: 57 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,57 @@
1+
// Regression test for #104005.
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//
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// Previously, different borrowck implementations used to disagree here.
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// The status of each is documented on `fn test_*`.
5+
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// check-fail
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8+
use std::fmt::Display;
9+
10+
trait Displayable {
11+
fn display(self) -> Box<dyn Display>;
12+
}
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impl<T: Display> Displayable for (T, Option<&'static T>) {
15+
fn display(self) -> Box<dyn Display> {
16+
Box::new(self.0)
17+
}
18+
}
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fn extend_lt<T, U>(val: T) -> Box<dyn Display>
21+
where
22+
(T, Option<U>): Displayable,
23+
{
24+
Displayable::display((val, None))
25+
}
26+
27+
// AST: fail
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// HIR: pass
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// MIR: pass
30+
pub fn test_call<'a>(val: &'a str) {
31+
extend_lt(val);
32+
//~^ ERROR borrowed data escapes outside of function
33+
}
34+
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// AST: fail
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// HIR: fail
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// MIR: pass
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pub fn test_coercion<'a>() {
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let _: fn(&'a str) -> _ = extend_lt;
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//~^ ERROR lifetime may not live long enough
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}
42+
43+
// AST: fail
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// HIR: fail
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// MIR: fail
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pub fn test_arg() {
47+
fn want<I, O>(_: I, _: impl Fn(I) -> O) {}
48+
want(&String::new(), extend_lt);
49+
//~^ ERROR temporary value dropped while borrowed
50+
}
51+
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// An exploit of the unsoundness.
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fn main() {
54+
let val = extend_lt(&String::from("blah blah blah"));
55+
//~^ ERROR temporary value dropped while borrowed
56+
println!("{}", val);
57+
}

‎tests/ui/borrowck/fn-item-check-type-params.stderr

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,43 @@
1+
error[E0521]: borrowed data escapes outside of function
2+
--> $DIR/fn-item-check-type-params.rs:31:5
3+
|
4+
LL | pub fn test_call<'a>(val: &'a str) {
5+
| -- --- `val` is a reference that is only valid in the function body
6+
| |
7+
| lifetime `'a` defined here
8+
LL | extend_lt(val);
9+
| ^^^^^^^^^^^^^^
10+
| |
11+
| `val` escapes the function body here
12+
| argument requires that `'a` must outlive `'static`
13+
14+
error: lifetime may not live long enough
15+
--> $DIR/fn-item-check-type-params.rs:39:12
16+
|
17+
LL | pub fn test_coercion<'a>() {
18+
| -- lifetime `'a` defined here
19+
LL | let _: fn(&'a str) -> _ = extend_lt;
20+
| ^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
21+
22+
error[E0716]: temporary value dropped while borrowed
23+
--> $DIR/fn-item-check-type-params.rs:48:11
24+
|
25+
LL | want(&String::new(), extend_lt);
26+
| ------^^^^^^^^^^^^^------------- temporary value is freed at the end of this statement
27+
| | |
28+
| | creates a temporary value which is freed while still in use
29+
| argument requires that borrow lasts for `'static`
30+
31+
error[E0716]: temporary value dropped while borrowed
32+
--> $DIR/fn-item-check-type-params.rs:54:26
33+
|
34+
LL | let val = extend_lt(&String::from("blah blah blah"));
35+
| -----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-- temporary value is freed at the end of this statement
36+
| | |
37+
| | creates a temporary value which is freed while still in use
38+
| argument requires that borrow lasts for `'static`
39+
40+
error: aborting due to 4 previous errors
41+
42+
Some errors have detailed explanations: E0521, E0716.
43+
For more information about an error, try `rustc --explain E0521`.

‎tests/ui/higher-ranked/trait-bounds/issue-59311.rs

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Original file line numberDiff line numberDiff line change
@@ -17,6 +17,7 @@ where
1717
v.t(|| {});
1818
//~^ ERROR: higher-ranked lifetime error
1919
//~| ERROR: higher-ranked lifetime error
20+
//~| ERROR: higher-ranked lifetime error
2021
}
2122

2223
fn main() {}

‎tests/ui/higher-ranked/trait-bounds/issue-59311.stderr

Lines changed: 10 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -6,6 +6,15 @@ LL | v.t(|| {});
66
|
77
= note: could not prove `{closure@$DIR/issue-59311.rs:17:9: 17:11} well-formed`
88

9+
error: higher-ranked lifetime error
10+
--> $DIR/issue-59311.rs:17:5
11+
|
12+
LL | v.t(|| {});
13+
| ^^^^^^^^^^
14+
|
15+
= note: could not prove `{closure@$DIR/issue-59311.rs:17:9: 17:11} well-formed`
16+
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
17+
918
error: higher-ranked lifetime error
1019
--> $DIR/issue-59311.rs:17:9
1120
|
@@ -14,5 +23,5 @@ LL | v.t(|| {});
1423
|
1524
= note: could not prove `for<'a> &'a V: 'b`
1625

17-
error: aborting due to 2 previous errors
26+
error: aborting due to 3 previous errors
1827

‎tests/ui/implied-bounds/implied-bounds-on-trait-hierarchy.rs renamed to ‎tests/ui/implied-bounds/implied-bounds-on-trait-hierarchy-1.rs

Lines changed: 4 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,9 +1,7 @@
1-
// check-pass
2-
// known-bug: #84591
1+
// issue: #84591
32

4-
// Should fail. Subtrait can incorrectly extend supertrait lifetimes even when
5-
// supertrait has weaker implied bounds than subtrait. Strongly related to
6-
// issue #25860.
3+
// Subtrait was able to incorrectly extend supertrait lifetimes even when
4+
// supertrait had weaker implied bounds than subtrait.
75

86
trait Subtrait<T>: Supertrait {}
97
trait Supertrait {
@@ -34,6 +32,7 @@ fn main() {
3432
{
3533
let x = "Hello World".to_string();
3634
subs_to_soup((x.as_str(), &mut d));
35+
//~^ does not live long enough
3736
}
3837
println!("{}", d);
3938
}

‎tests/ui/implied-bounds/implied-bounds-on-trait-hierarchy-1.stderr

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,16 @@
1+
error[E0597]: `x` does not live long enough
2+
--> $DIR/implied-bounds-on-trait-hierarchy-1.rs:34:23
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|
4+
LL | let x = "Hello World".to_string();
5+
| - binding `x` declared here
6+
LL | subs_to_soup((x.as_str(), &mut d));
7+
| ^ borrowed value does not live long enough
8+
LL |
9+
LL | }
10+
| - `x` dropped here while still borrowed
11+
LL | println!("{}", d);
12+
| - borrow later used here
13+
14+
error: aborting due to 1 previous error
15+
16+
For more information about this error, try `rustc --explain E0597`.

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