diff options
Diffstat (limited to 'tests/ui/nll/issue-54556-stephaneyfx.rs')
-rw-r--r-- | tests/ui/nll/issue-54556-stephaneyfx.rs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/tests/ui/nll/issue-54556-stephaneyfx.rs b/tests/ui/nll/issue-54556-stephaneyfx.rs new file mode 100644 index 000000000..b758228e4 --- /dev/null +++ b/tests/ui/nll/issue-54556-stephaneyfx.rs @@ -0,0 +1,35 @@ +// This is a reduction of a concrete test illustrating a case that was +// annoying to Rust developer stephaneyfx (see issue #46413). +// +// With resolving issue #54556, pnkfelix hopes that the new diagnostic +// output produced by NLL helps to *explain* the semantic significance +// of temp drop order, and thus why storing the result in `x` and then +// returning `x` works. + +pub struct Statement; + +pub struct Rows<'stmt>(&'stmt Statement); + +impl<'stmt> Drop for Rows<'stmt> { + fn drop(&mut self) {} +} + +impl<'stmt> Iterator for Rows<'stmt> { + type Item = String; + + fn next(&mut self) -> Option<Self::Item> { + None + } +} + +fn get_names() -> Option<String> { + let stmt = Statement; + let rows = Rows(&stmt); //~ ERROR does not live long enough + rows.map(|row| row).next() + // let x = rows.map(|row| row).next(); + // x + // + // Removing the map works too as does removing the Drop impl. +} + +fn main() {} |