rust/tests/ui/issues/issue-5062.rs

fn main() { format!("{:?}", None); }
    //~^ ERROR type annotations needed [E0282]
core: split into fmt::Show and fmt::String fmt::Show is for debugging, and can and should be implemented for all public types. This trait is used with `{:?}` syntax. There still exists #[derive(Show)]. fmt::String is for types that faithfully be represented as a String. Because of this, there is no way to derive fmt::String, all implementations must be purposeful. It is used by the default format syntax, `{}`. This will break most instances of `{}`, since that now requires the type to impl fmt::String. In most cases, replacing `{}` with `{:?}` is the correct fix. Types that were being printed specifically for users should receive a fmt::String implementation to fix this. Part of #20013 [breaking-change] 2014-12-20 00:09:35 -08:00			`fn main() { format!("{:?}", None); }`
Add a new ui test and update existing ones 2017-02-02 21:35:31 +00:00			`//~^ ERROR type annotations needed [E0282]`