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Diffstat (limited to 'compiler/rustc_error_codes/src/error_codes/E0232.md')
-rw-r--r-- | compiler/rustc_error_codes/src/error_codes/E0232.md | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/compiler/rustc_error_codes/src/error_codes/E0232.md b/compiler/rustc_error_codes/src/error_codes/E0232.md new file mode 100644 index 000000000..b310caefa --- /dev/null +++ b/compiler/rustc_error_codes/src/error_codes/E0232.md @@ -0,0 +1,18 @@ +The `#[rustc_on_unimplemented]` attribute lets you specify a custom error +message for when a particular trait isn't implemented on a type placed in a +position that needs that trait. For example, when the following code is +compiled: + +```compile_fail,E0232 +#![feature(rustc_attrs)] + +#[rustc_on_unimplemented(lorem="")] // error! +trait BadAnnotation {} +``` + +there will be an error about `bool` not implementing `Index<u8>`, followed by a +note saying "the type `bool` cannot be indexed by `u8`". + +For this to work, some note must be specified. An empty attribute will not do +anything, please remove the attribute or add some helpful note for users of the +trait. |