diff options
| -rw-r--r-- | src/libcore/default.rs | 44 | ||||
| -rw-r--r-- | src/test/ui/resolve/issue-2356.stderr | 11 |
2 files changed, 54 insertions, 1 deletions
diff --git a/src/libcore/default.rs b/src/libcore/default.rs index 06402a05d26..9a8d65cd4e0 100644 --- a/src/libcore/default.rs +++ b/src/libcore/default.rs @@ -115,6 +115,50 @@ pub trait Default: Sized { fn default() -> Self; } +/// Return the default value of a type according to the `Default` trait. +/// +/// The type to return is inferred from context; this is equivalent to +/// `Default::default()` but shorter to type. +/// +/// For example: +/// ``` +/// #![feature(default_free_fn)] +/// +/// use std::default::default; +/// +/// #[derive(Default)] +/// struct AppConfig { +/// foo: FooConfig, +/// bar: BarConfig, +/// } +/// +/// #[derive(Default)] +/// struct FooConfig { +/// foo: i32, +/// } +/// +/// #[derive(Default)] +/// struct BarConfig { +/// bar: f32, +/// baz: u8, +/// } +/// +/// fn main() { +/// let options = AppConfig { +/// foo: default(), +/// bar: BarConfig { +/// bar: 10.1, +/// ..default() +/// }, +/// }; +/// } +/// ``` +#[unstable(feature = "default_free_fn", issue = "73014")] +#[inline] +pub fn default<T: Default>() -> T { + Default::default() +} + /// Derive macro generating an impl of the trait `Default`. #[rustc_builtin_macro] #[stable(feature = "builtin_macro_prelude", since = "1.38.0")] diff --git a/src/test/ui/resolve/issue-2356.stderr b/src/test/ui/resolve/issue-2356.stderr index 329543114a6..b687f0b0af0 100644 --- a/src/test/ui/resolve/issue-2356.stderr +++ b/src/test/ui/resolve/issue-2356.stderr @@ -14,7 +14,16 @@ error[E0425]: cannot find function `default` in this scope --> $DIR/issue-2356.rs:31:5 | LL | default(); - | ^^^^^^^ help: try: `Self::default` + | ^^^^^^^ + | +help: try + | +LL | Self::default(); + | ^^^^^^^^^^^^^ +help: consider importing this function + | +LL | use std::default::default; + | error[E0425]: cannot find value `whiskers` in this scope --> $DIR/issue-2356.rs:39:5 |