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| author | bors <bors@rust-lang.org> | 2021-07-30 12:05:48 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2021-07-30 12:05:48 +0000 |
| commit | 87dc8242484110c75596a91ebd2043a476c09839 (patch) | |
| tree | 00eb86f03f25d8707dd1784052d813dcc4cb0803 /compiler/rustc_error_codes/src | |
| parent | 1195bea5a7b73e079fa14b37ac7e375fc77d368a (diff) | |
| parent | c5a29f92450c5d1191754000d37611af5e19f38b (diff) | |
| download | rust-87dc8242484110c75596a91ebd2043a476c09839.tar.gz rust-87dc8242484110c75596a91ebd2043a476c09839.zip | |
Auto merge of #87237 - jonas-schievink:const-for-and-try, r=oli-obk
Add feature gates for `for` and `?` in consts These operations seems *relatively* straightforward to support, and only seem to be blocked on `impl const Trait`. I have included a working test for `const_try`, but `const_for` is currently unusable without reimplementing *every single* defaulted `Iterator` method, so I didn't do that. (both features still need tracking issues before this is merged)
Diffstat (limited to 'compiler/rustc_error_codes/src')
| -rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0744.md | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0744.md b/compiler/rustc_error_codes/src/error_codes/E0744.md index 45804ab266e..9a8ef3b840d 100644 --- a/compiler/rustc_error_codes/src/error_codes/E0744.md +++ b/compiler/rustc_error_codes/src/error_codes/E0744.md @@ -2,25 +2,15 @@ An unsupported expression was used inside a const context. Erroneous code example: -```compile_fail,E0744 +```compile_fail,edition2018,E0744 const _: i32 = { - let mut x = 0; - - for i in 0..4 { // error! - x += i; - } + async { 0 }.await }; ``` -At the moment, `for` loops, `.await`, and the `Try` operator (`?`) are forbidden -inside a `const`, `static`, or `const fn`. +At the moment, `.await` is forbidden inside a `const`, `static`, or `const fn`. This may be allowed at some point in the future, but the implementation is not -yet complete. See the tracking issues for [`async`] and [`?`] in `const fn`, and -(to support `for` loops in `const fn`) the tracking issues for [`impl const -Trait for Ty`] and [`&mut T`] in `const fn`. +yet complete. See the tracking issue for [`async`] in `const fn`. [`async`]: https://github.com/rust-lang/rust/issues/69431 -[`?`]: https://github.com/rust-lang/rust/issues/74935 -[`impl const Trait for Ty`]: https://github.com/rust-lang/rust/issues/67792 -[`&mut T`]: https://github.com/rust-lang/rust/issues/57349 |