diff options
Diffstat (limited to 'tests/ui/nll/member-constraints')
6 files changed, 264 insertions, 0 deletions
diff --git a/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.rs b/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.rs new file mode 100644 index 000000000..52ea0f28d --- /dev/null +++ b/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.rs @@ -0,0 +1,43 @@ +// ... continued from ./min-choice.rs + +// check-fail + +trait Cap<'a> {} +impl<T> Cap<'_> for T {} + +fn type_test<'a, T: 'a>() -> &'a u8 { &0 } + +// Make sure we don't pick `'b`. +fn test_b<'a, 'b, 'c, T>() -> impl Cap<'a> + Cap<'b> + Cap<'c> +where + 'a: 'b, + 'a: 'c, + T: 'b, +{ + type_test::<'_, T>() // This should pass if we pick 'b. + //~^ ERROR the parameter type `T` may not live long enough +} + +// Make sure we don't pick `'c`. +fn test_c<'a, 'b, 'c, T>() -> impl Cap<'a> + Cap<'b> + Cap<'c> +where + 'a: 'b, + 'a: 'c, + T: 'c, +{ + type_test::<'_, T>() // This should pass if we pick 'c. + //~^ ERROR the parameter type `T` may not live long enough +} + +// We need to pick min_choice from `['b, 'c]`, but it's ambiguous which one to pick because +// they're incomparable. +fn test_ambiguous<'a, 'b, 'c>(s: &'a u8) -> impl Cap<'b> + Cap<'c> +where + 'a: 'b, + 'a: 'c, +{ + s + //~^ ERROR captures lifetime that does not appear in bounds +} + +fn main() {} diff --git a/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.stderr b/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.stderr new file mode 100644 index 000000000..e0d476a33 --- /dev/null +++ b/tests/ui/nll/member-constraints/min-choice-reject-ambiguous.stderr @@ -0,0 +1,42 @@ +error[E0309]: the parameter type `T` may not live long enough + --> $DIR/min-choice-reject-ambiguous.rs:17:5 + | +LL | type_test::<'_, T>() // This should pass if we pick 'b. + | ^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds + | +help: consider adding an explicit lifetime bound... + | +LL | T: 'b + 'a, + | ++++ + +error[E0309]: the parameter type `T` may not live long enough + --> $DIR/min-choice-reject-ambiguous.rs:28:5 + | +LL | type_test::<'_, T>() // This should pass if we pick 'c. + | ^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds + | +help: consider adding an explicit lifetime bound... + | +LL | T: 'c + 'a, + | ++++ + +error[E0700]: hidden type for `impl Cap<'b> + Cap<'c>` captures lifetime that does not appear in bounds + --> $DIR/min-choice-reject-ambiguous.rs:39:5 + | +LL | fn test_ambiguous<'a, 'b, 'c>(s: &'a u8) -> impl Cap<'b> + Cap<'c> + | -- ---------------------- opaque type defined here + | | + | hidden type `&'a u8` captures the lifetime `'a` as defined here +... +LL | s + | ^ + | +help: to declare that `impl Cap<'b> + Cap<'c>` captures `'a`, you can add an explicit `'a` lifetime bound + | +LL | fn test_ambiguous<'a, 'b, 'c>(s: &'a u8) -> impl Cap<'b> + Cap<'c> + 'a + | ++++ + +error: aborting due to 3 previous errors + +Some errors have detailed explanations: E0309, E0700. +For more information about an error, try `rustc --explain E0309`. diff --git a/tests/ui/nll/member-constraints/min-choice.rs b/tests/ui/nll/member-constraints/min-choice.rs new file mode 100644 index 000000000..14b4dae7a --- /dev/null +++ b/tests/ui/nll/member-constraints/min-choice.rs @@ -0,0 +1,34 @@ +// Assuming that the hidden type in these tests is `&'_#15r u8`, +// we have a member constraint: `'_#15r member ['static, 'a, 'b, 'c]`. +// +// Make sure we pick up the minimum non-ambiguous region among them. +// We will have to exclude `['b, 'c]` because they're incomparable, +// and then we should pick `'a` because we know `'static: 'a`. + +// check-pass + +trait Cap<'a> {} +impl<T> Cap<'_> for T {} + +fn type_test<'a, T: 'a>() -> &'a u8 { &0 } + +// Basic test: make sure we don't bail out because 'b and 'c are incomparable. +fn basic<'a, 'b, 'c>() -> impl Cap<'a> + Cap<'b> + Cap<'c> +where + 'a: 'b, + 'a: 'c, +{ + &0 +} + +// Make sure we don't pick `'static`. +fn test_static<'a, 'b, 'c, T>() -> impl Cap<'a> + Cap<'b> + Cap<'c> +where + 'a: 'b, + 'a: 'c, + T: 'a, +{ + type_test::<'_, T>() // This will fail if we pick 'static +} + +fn main() {} diff --git a/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs b/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs new file mode 100644 index 000000000..66ff828a8 --- /dev/null +++ b/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs @@ -0,0 +1,33 @@ +// Nested impl-traits can impose different member constraints on the same region variable. + +// check-fail + +trait Cap<'a> {} +impl<T> Cap<'_> for T {} + +// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints: +// - '_#15r member ['static, 'a, 'b] // from outer impl-trait +// - '_#15r member ['static, 'a, 'b] // from inner impl-trait +// To satisfy both we can choose 'a or 'b, so it's a failure due to ambiguity. +fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> +where + 's: 'a, + 's: 'b, +{ + [a] + //~^ E0700 + //~| E0700 +} + +// Same as the above but with late-bound regions. +fn fail_late_bound<'s, 'a, 'b>( + a: &'s u8, + _: &'a &'s u8, + _: &'b &'s u8, +) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> { + [a] + //~^ E0700 + //~| E0700 +} + +fn main() {} diff --git a/tests/ui/nll/member-constraints/nested-impl-trait-fail.stderr b/tests/ui/nll/member-constraints/nested-impl-trait-fail.stderr new file mode 100644 index 000000000..483b5822b --- /dev/null +++ b/tests/ui/nll/member-constraints/nested-impl-trait-fail.stderr @@ -0,0 +1,83 @@ +error[E0700]: hidden type for `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures lifetime that does not appear in bounds + --> $DIR/nested-impl-trait-fail.rs:17:5 + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + | -- ------------------------------------------------ opaque type defined here + | | + | hidden type `[&'s u8; 1]` captures the lifetime `'s` as defined here +... +LL | [a] + | ^^^ + | +help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's + | ++++ +help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> + | ++++ + +error[E0700]: hidden type for `impl Cap<'a> + Cap<'b>` captures lifetime that does not appear in bounds + --> $DIR/nested-impl-trait-fail.rs:17:5 + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + | -- ---------------------- opaque type defined here + | | + | hidden type `&'s u8` captures the lifetime `'s` as defined here +... +LL | [a] + | ^^^ + | +help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's + | ++++ +help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> + | ++++ + +error[E0700]: hidden type for `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures lifetime that does not appear in bounds + --> $DIR/nested-impl-trait-fail.rs:28:5 + | +LL | fn fail_late_bound<'s, 'a, 'b>( + | -- hidden type `[&'s u8; 1]` captures the lifetime `'s` as defined here +... +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> { + | ------------------------------------------------ opaque type defined here +LL | [a] + | ^^^ + | +help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's { + | ++++ +help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> { + | ++++ + +error[E0700]: hidden type for `impl Cap<'a> + Cap<'b>` captures lifetime that does not appear in bounds + --> $DIR/nested-impl-trait-fail.rs:28:5 + | +LL | fn fail_late_bound<'s, 'a, 'b>( + | -- hidden type `&'s u8` captures the lifetime `'s` as defined here +... +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> { + | ---------------------- opaque type defined here +LL | [a] + | ^^^ + | +help: to declare that `impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> + 's { + | ++++ +help: to declare that `impl Cap<'a> + Cap<'b>` captures `'s`, you can add an explicit `'s` lifetime bound + | +LL | ) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b> + 's> { + | ++++ + +error: aborting due to 4 previous errors + +For more information about this error, try `rustc --explain E0700`. diff --git a/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs b/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs new file mode 100644 index 000000000..15540cb46 --- /dev/null +++ b/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs @@ -0,0 +1,29 @@ +// Nested impl-traits can impose different member constraints on the same region variable. + +// check-pass + +trait Cap<'a> {} +impl<T> Cap<'_> for T {} + +// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints: +// - '_#15r member ['static, 'a, 'b] // from outer impl-trait +// - '_#15r member ['static, 'a] // from inner impl-trait +// To satisfy both we can only choose 'a. +fn pass_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a>> + Cap<'b> +where + 's: 'a, + 's: 'b, +{ + [a] +} + +// Same as the above but with late-bound regions. +fn pass_late_bound<'s, 'a, 'b>( + a: &'s u8, + _: &'a &'s u8, + _: &'b &'s u8, +) -> impl IntoIterator<Item = impl Cap<'a>> + Cap<'b> { + [a] +} + +fn main() {} |