mirror of
https://github.com/rust-lang/rust.git
synced 2025-04-30 12:07:40 +00:00
9ac95c10c0
Initial implementation of `#[feature(default_field_values]`, proposed in https://github.com/rust-lang/rfcs/pull/3681. Support default fields in enum struct variant Allow default values in an enum struct variant definition: ```rust pub enum Bar { Foo { bar: S = S, baz: i32 = 42 + 3, } } ``` Allow using `..` without a base on an enum struct variant ```rust Bar::Foo { .. } ``` `#[derive(Default)]` doesn't account for these as it is still gating `#[default]` only being allowed on unit variants. Support `#[derive(Default)]` on enum struct variants with all defaulted fields ```rust pub enum Bar { #[default] Foo { bar: S = S, baz: i32 = 42 + 3, } } ``` Check for missing fields in typeck instead of mir_build. Expand test with `const` param case (needs `generic_const_exprs` enabled). Properly instantiate MIR const The following works: ```rust struct S<A> { a: Vec<A> = Vec::new(), } S::<i32> { .. } ``` Add lint for default fields that will always fail const-eval We *allow* this to happen for API writers that might want to rely on users' getting a compile error when using the default field, different to the error that they would get when the field isn't default. We could change this to *always* error instead of being a lint, if we wanted. This will *not* catch errors for partially evaluated consts, like when the expression relies on a const parameter. Suggestions when encountering `Foo { .. }` without `#[feature(default_field_values)]`: - Suggest adding a base expression if there are missing fields. - Suggest enabling the feature if all the missing fields have optional values. - Suggest removing `..` if there are no missing fields. |
||
|---|---|---|
| .. | ||
| analyze_source_file | ||
| edit_distance | ||
| source_map | ||
| symbol | ||
| analyze_source_file.rs | ||
| caching_source_map_view.rs | ||
| def_id.rs | ||
| edit_distance.rs | ||
| edition.rs | ||
| fatal_error.rs | ||
| hygiene.rs | ||
| lib.rs | ||
| profiling.rs | ||
| source_map.rs | ||
| span_encoding.rs | ||
| symbol.rs | ||
| tests.rs | ||