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| author | Dylan DPC <dylan.dpc@gmail.com> | 2020-03-01 17:23:36 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-03-01 17:23:36 +0100 |
| commit | d3a5a5d20bb128dd08ac37717f6415baf80d5039 (patch) | |
| tree | d1d11d9401394a1739e96bbd54bca5aec78fea25 /src | |
| parent | 22a03913f4ebd9d190c2037411301783f9178946 (diff) | |
| parent | dd142b1dc43f0e9a9b860003816b1a91b4e1a52d (diff) | |
| download | rust-d3a5a5d20bb128dd08ac37717f6415baf80d5039.tar.gz rust-d3a5a5d20bb128dd08ac37717f6415baf80d5039.zip | |
Rollup merge of #69607 - GuillaumeGomez:cleanup-e0376, r=Dylan-DPC
Clean up E0376 explanation r? @Dylan-DPC
Diffstat (limited to 'src')
| -rw-r--r-- | src/librustc_error_codes/error_codes/E0376.md | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/src/librustc_error_codes/error_codes/E0376.md b/src/librustc_error_codes/error_codes/E0376.md index b028aab4583..50de15bd30f 100644 --- a/src/librustc_error_codes/error_codes/E0376.md +++ b/src/librustc_error_codes/error_codes/E0376.md @@ -1,14 +1,6 @@ -The type you are trying to impl `CoerceUnsized` for is not a struct. -`CoerceUnsized` can only be implemented for a struct. Unsized types are -already able to be coerced without an implementation of `CoerceUnsized` -whereas a struct containing an unsized type needs to know the unsized type -field it's containing is able to be coerced. An [unsized type][1] -is any type that the compiler doesn't know the length or alignment of at -compile time. Any struct containing an unsized type is also unsized. - -[1]: https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait +`CoerceUnsized` was implemented on something that isn't a struct. -Example of erroneous code: +Erroneous code example: ```compile_fail,E0376 #![feature(coerce_unsized)] @@ -22,6 +14,15 @@ struct Foo<T: ?Sized> { impl<T, U> CoerceUnsized<U> for Foo<T> {} ``` +`CoerceUnsized` can only be implemented for a struct. Unsized types are +already able to be coerced without an implementation of `CoerceUnsized` +whereas a struct containing an unsized type needs to know the unsized type +field it's containing is able to be coerced. An [unsized type][1] +is any type that the compiler doesn't know the length or alignment of at +compile time. Any struct containing an unsized type is also unsized. + +[1]: https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait + The `CoerceUnsized` trait takes a struct type. Make sure the type you are providing to `CoerceUnsized` is a struct with only the last field containing an unsized type. |
