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Diffstat (limited to 'tests/ui/nll/issue-53570.rs')
-rw-r--r-- | tests/ui/nll/issue-53570.rs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/tests/ui/nll/issue-53570.rs b/tests/ui/nll/issue-53570.rs new file mode 100644 index 000000000..35860ba9c --- /dev/null +++ b/tests/ui/nll/issue-53570.rs @@ -0,0 +1,32 @@ +// Regression test for #53570. Here, we need to propagate that `T: 'a` +// but in some versions of NLL we were propagating a stronger +// requirement that `T: 'static`. This arose because we actually had +// to propagate both that `T: 'a` but also `T: 'b` where `'b` is the +// higher-ranked lifetime that appears in the type of the closure +// parameter `x` -- since `'b` cannot be expressed in the caller's +// space, that got promoted th `'static`. +// +// check-pass + +use std::cell::{RefCell, Ref}; + +trait AnyVec<'a> { +} + +trait GenericVec<T> { + fn unwrap<'a, 'b>(vec: &'b dyn AnyVec<'a>) -> &'b [T] where T: 'a; +} + +struct Scratchpad<'a> { + buffers: RefCell<Box<dyn AnyVec<'a>>>, +} + +impl<'a> Scratchpad<'a> { + fn get<T: GenericVec<T>>(&self) -> Ref<[T]> + where T: 'a + { + Ref::map(self.buffers.borrow(), |x| T::unwrap(x.as_ref())) + } +} + +fn main() { } |