diff options
Diffstat (limited to 'src/test/ui/impl-trait/impl_fn_associativity.rs')
-rw-r--r-- | src/test/ui/impl-trait/impl_fn_associativity.rs | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/impl_fn_associativity.rs b/src/test/ui/impl-trait/impl_fn_associativity.rs new file mode 100644 index 000000000..71a8f9c77 --- /dev/null +++ b/src/test/ui/impl-trait/impl_fn_associativity.rs @@ -0,0 +1,26 @@ +// run-pass +#![feature(impl_trait_in_fn_trait_return)] +use std::fmt::Debug; + +fn f_debug() -> impl Fn() -> impl Debug { + || () +} + +fn ff_debug() -> impl Fn() -> impl Fn() -> impl Debug { + || f_debug() +} + +fn multi() -> impl Fn() -> (impl Debug + Send) { + || () +} + +fn main() { + // Check that `ff_debug` is `() -> (() -> Debug)` and not `(() -> ()) -> Debug` + let debug = ff_debug()()(); + assert_eq!(format!("{:?}", debug), "()"); + + let x = multi()(); + assert_eq!(format!("{:?}", x), "()"); + fn assert_send(_: &impl Send) {} + assert_send(&x); +} |