diff options
| -rw-r--r-- | src/doc/unstable-book/src/language-features/explicit-generic-args-with-impl-trait.md | 53 |
1 files changed, 0 insertions, 53 deletions
diff --git a/src/doc/unstable-book/src/language-features/explicit-generic-args-with-impl-trait.md b/src/doc/unstable-book/src/language-features/explicit-generic-args-with-impl-trait.md deleted file mode 100644 index 479571d85fe..00000000000 --- a/src/doc/unstable-book/src/language-features/explicit-generic-args-with-impl-trait.md +++ /dev/null @@ -1,53 +0,0 @@ -# `explicit_generic_args_with_impl_trait` - -The tracking issue for this feature is: [#83701] - -[#83701]: https://github.com/rust-lang/rust/issues/83701 - ------------------------- - -The `explicit_generic_args_with_impl_trait` feature gate lets you specify generic arguments even -when `impl Trait` is used in argument position. - -A simple example is: - -```rust -#![feature(explicit_generic_args_with_impl_trait)] - -fn foo<T: ?Sized>(_f: impl AsRef<T>) {} - -fn main() { - foo::<str>("".to_string()); -} -``` - -This is currently rejected: - -```text -error[E0632]: cannot provide explicit generic arguments when `impl Trait` is used in argument position - --> src/main.rs:6:11 - | -6 | foo::<str>("".to_string()); - | ^^^ explicit generic argument not allowed - -``` - -However it would compile if `explicit_generic_args_with_impl_trait` is enabled. - -Note that the synthetic type parameters from `impl Trait` are still implicit and you -cannot explicitly specify these: - -```rust,compile_fail -#![feature(explicit_generic_args_with_impl_trait)] - -fn foo<T: ?Sized>(_f: impl AsRef<T>) {} -fn bar<T: ?Sized, F: AsRef<T>>(_f: F) {} - -fn main() { - bar::<str, _>("".to_string()); // Okay - bar::<str, String>("".to_string()); // Okay - - foo::<str>("".to_string()); // Okay - foo::<str, String>("".to_string()); // Error, you cannot specify `impl Trait` explicitly -} -``` |