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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/test/ui/nll/ty-outlives/projection-one-region-closure.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/test/ui/nll/ty-outlives/projection-one-region-closure.rs')
-rw-r--r-- | src/test/ui/nll/ty-outlives/projection-one-region-closure.rs | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs b/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs new file mode 100644 index 000000000..af361e990 --- /dev/null +++ b/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs @@ -0,0 +1,83 @@ +// Test cases where we constrain `<T as Anything<'b>>::AssocType` to +// outlive `'a` and there are no bounds in the trait definition of +// `Anything`. This means that the constraint can only be satisfied in two +// ways: +// +// - by ensuring that `T: 'a` and `'b: 'a`, or +// - by something in the where clauses. +// +// As of this writing, the where clause option does not work because +// of limitations in our region inferencing system (this is true both +// with and without NLL). See `projection_outlives`. +// +// Ensuring that both `T: 'a` and `'b: 'a` holds does work (`elements_outlive`). + +// compile-flags:-Zverbose + +#![allow(warnings)] +#![feature(rustc_attrs)] + +use std::cell::Cell; + +trait Anything<'a> { + type AssocType; +} + +fn with_signature<'a, T, F>(cell: Cell<&'a ()>, t: T, op: F) +where + F: FnOnce(Cell<&'a ()>, T), +{ + op(cell, t) +} + +fn require<'a, 'b, T>(_cell: Cell<&'a ()>, _t: T) +where + T: Anything<'b>, + T::AssocType: 'a, +{ +} + +#[rustc_regions] +fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T) +where + T: Anything<'b>, +{ + with_signature(cell, t, |cell, t| require(cell, t)); + //~^ ERROR the parameter type `T` may not live long enough + //~| ERROR +} + +#[rustc_regions] +fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T) +where + T: Anything<'b>, + 'a: 'a, +{ + with_signature(cell, t, |cell, t| require(cell, t)); + //~^ ERROR the parameter type `T` may not live long enough + //~| ERROR +} + +#[rustc_regions] +fn projection_outlives<'a, 'b, T>(cell: Cell<&'a ()>, t: T) +where + T: Anything<'b>, + T::AssocType: 'a, +{ + // We are projecting `<T as Anything<'b>>::AssocType`, and we know + // that this outlives `'a` because of the where-clause. + + with_signature(cell, t, |cell, t| require(cell, t)); +} + +#[rustc_regions] +fn elements_outlive<'a, 'b, T>(cell: Cell<&'a ()>, t: T) +where + T: Anything<'b>, + T: 'a, + 'b: 'a, +{ + with_signature(cell, t, |cell, t| require(cell, t)); +} + +fn main() {} |