From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- .../issue-55748-pat-types-constrain-bindings.rs | 68 ++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 src/test/ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs (limited to 'src/test/ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs') diff --git a/src/test/ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs b/src/test/ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs new file mode 100644 index 000000000..c71937a50 --- /dev/null +++ b/src/test/ui/nll/user-annotations/issue-55748-pat-types-constrain-bindings.rs @@ -0,0 +1,68 @@ +// This test is ensuring that type ascriptions on let bindings +// constrain both: +// +// 1. the input expression on the right-hand side (after any potential +// coercion, and allowing for covariance), *and* +// +// 2. the bindings (if any) nested within the pattern on the left-hand +// side (and here, the type-constraint is *invariant*). + +#![allow(dead_code, unused_mut)] +type PairUncoupled<'a, 'b, T> = (&'a T, &'b T); +type PairCoupledRegions<'a, T> = (&'a T, &'a T); +type PairCoupledTypes = (T, T); + +fn uncoupled_lhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 { + let ((mut y, mut _z),): (PairUncoupled,) = ((s, &_x),); // ok + // Above compiling does *not* imply below would compile. + // ::std::mem::swap(&mut y, &mut _z); + y +} + +fn swap_regions((mut y, mut _z): PairCoupledRegions) { + ::std::mem::swap(&mut y, &mut _z); +} + +fn coupled_regions_lhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 { + let ((y, _z),): (PairCoupledRegions,) = ((s, &_x),); + // If above line compiled, so should line below ... + + // swap_regions((y, _z)); + + // ... but the ascribed type also invalidates this use of `y` + y //~ ERROR lifetime may not live long enough +} + +fn swap_types((mut y, mut _z): PairCoupledTypes<&u32>) { + ::std::mem::swap(&mut y, &mut _z); +} + +fn coupled_types_lhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 { + let ((y, _z),): (PairCoupledTypes<&u32>,) = ((s, &_x),); + // If above line compiled, so should line below ... + + // swap_types((y, _z)); + + // ... but the ascribed type also invalidates this use of `y` + y //~ ERROR lifetime may not live long enough +} + +fn swap_wilds((mut y, mut _z): PairCoupledTypes<&u32>) { + ::std::mem::swap(&mut y, &mut _z); +} + +fn coupled_wilds_lhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 { + let ((y, _z),): (PairCoupledTypes<_>,) = ((s, &_x),); + // If above line compiled, so should line below + // swap_wilds((y, _z)); + + // ... but the ascribed type also invalidates this use of `y` + y //~ ERROR lifetime may not live long enough +} + +fn main() { + uncoupled_lhs(&3, &4); + coupled_regions_lhs(&3, &4); + coupled_types_lhs(&3, &4); + coupled_wilds_lhs(&3, &4); +} -- cgit v1.2.3