diff options
Diffstat (limited to 'src/test/ui/borrowck/return-local-binding-from-desugaring.rs')
-rw-r--r-- | src/test/ui/borrowck/return-local-binding-from-desugaring.rs | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/test/ui/borrowck/return-local-binding-from-desugaring.rs b/src/test/ui/borrowck/return-local-binding-from-desugaring.rs new file mode 100644 index 000000000..c6643edf5 --- /dev/null +++ b/src/test/ui/borrowck/return-local-binding-from-desugaring.rs @@ -0,0 +1,33 @@ +// To avoid leaking the names of local bindings from expressions like for loops, #60984 +// explicitly ignored them, but an assertion that `LocalKind::Var` *must* have a name would +// trigger an ICE. Before this change, this file's output would be: +// ``` +// error[E0515]: cannot return value referencing local variable `__next` +// --> return-local-binding-from-desugaring.rs:LL:CC +// | +// LL | for ref x in xs { +// | ----- `__next` is borrowed here +// ... +// LL | result +// | ^^^^^^ returns a value referencing data owned by the current function +// ``` +// FIXME: ideally `LocalKind` would carry more information to more accurately explain the problem. + +use std::collections::HashMap; +use std::hash::Hash; + +fn group_by<I, F, T>(xs: &mut I, f: F) -> HashMap<T, Vec<&I::Item>> +where + I: Iterator, + F: Fn(&I::Item) -> T, + T: Eq + Hash, +{ + let mut result = HashMap::new(); + for ref x in xs { + let key = f(x); + result.entry(key).or_insert(Vec::new()).push(x); + } + result //~ ERROR cannot return value referencing temporary value +} + +fn main() {} |