clap/tests/derive_ui/default_value_wo_value_removed.stderr

error: `#[clap(default_value)` attribute (without a value) has been replaced by `#[clap(default_value_t)]`.

  = help: Change the attribute to `#[clap(default_value_t)]`

  --> $DIR/default_value_wo_value_removed.rs:14:12
   |
14 |     #[clap(default_value)]
   |            ^^^^^^^^^^^^^
feat(derive): Specify defaults by native expressions Right now - `default_value="something"` is a raw method - `default_value` uses native types This commit splits the meanings - `default_value="something"` is a raw method - `default_value_t` uses `T::default()` - `default_value_t=expr` uses an expression that evaluates to `T` This is meant to mirror the `value_of` / `value_of_t` API. At the moment, this is limited to `T: Display` to work with clap's default system. Something we can look at in the future is a way to loosen that restriction. One quick win is to specialize when `arg_enum` is set. The main downside is complicating the processing of attributes because it then means we need some processed before others. Since this builds on `clap`s existing default system, this also means users do not get any performance gains out of using `default_value_t`, since we still need to parse it but we also need to convert it to a string. Fixes #1694 2021-07-28 13:53:32 +00:00			error: `#[clap(default_value)` attribute (without a value) has been replaced by `#[clap(default_value_t)]`.

			= help: Change the attribute to `#[clap(default_value_t)]`

			`--> $DIR/default_value_wo_value_removed.rs:14:12`
			`\|`
			`14 \| #[clap(default_value)]`
			`\| ^^^^^^^^^^^^^`