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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /compiler/rustc_error_codes/src/error_codes/E0183.md | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_error_codes/src/error_codes/E0183.md')
-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0183.md | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0183.md b/compiler/rustc_error_codes/src/error_codes/E0183.md new file mode 100644 index 000000000..92fa4c7c2 --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0183.md @@ -0,0 +1,39 @@ +Manual implementation of a `Fn*` trait. + +Erroneous code example: + +```compile_fail,E0183 +struct MyClosure { + foo: i32 +} + +impl FnOnce<()> for MyClosure { // error + type Output = (); + extern "rust-call" fn call_once(self, args: ()) -> Self::Output { + println!("{}", self.foo); + } +} +``` + +Manually implementing `Fn`, `FnMut` or `FnOnce` is unstable +and requires `#![feature(fn_traits, unboxed_closures)]`. + +``` +#![feature(fn_traits, unboxed_closures)] + +struct MyClosure { + foo: i32 +} + +impl FnOnce<()> for MyClosure { // ok! + type Output = (); + extern "rust-call" fn call_once(self, args: ()) -> Self::Output { + println!("{}", self.foo); + } +} +``` + +The arguments must be a tuple representing the argument list. +For more info, see the [tracking issue][iss29625]: + +[iss29625]: https://github.com/rust-lang/rust/issues/29625 |