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rust/tests/ui/structs/default-field-values-invalid-const.stderr

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Introduce `default_field_values` feature 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.
2024-08-24 17:22:48 +00:00
warning: lint `default_field_always_invalid_const` can't be warned on
--> $DIR/default-field-values-invalid-const.rs:4:8
|
LL | #[warn(default_field_always_invalid_const)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ either `deny` or `allow`, no other lint level is supported for this lint
error[E0080]: evaluation of constant value failed
--> $DIR/default-field-values-invalid-const.rs:6:19
|
LL | pub bax: u8 = panic!("asdf"),
| ^^^^^^^^^^^^^^ the evaluated program panicked at 'asdf', $DIR/default-field-values-invalid-const.rs:6:19
|
= note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: default field fails const-evaluation
--> $DIR/default-field-values-invalid-const.rs:6:5
|
LL | pub bax: u8 = panic!("asdf"),
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this field's constant fails const-evaluation, as seen in the previous error
|
= help: you can skip const-evaluation of default fields by enabling this lint
note: the lint level is defined here
--> $DIR/default-field-values-invalid-const.rs:4:8
|
LL | #[warn(default_field_always_invalid_const)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0080]: evaluation of `Baz::<C>::bat::{constant#0}` failed
--> $DIR/default-field-values-invalid-const.rs:13:19
|
LL | pub bat: u8 = 130 + 130,
| ^^^^^^^^^ attempt to compute `130_u8 + 130_u8`, which would overflow
error: default field fails const-evaluation
--> $DIR/default-field-values-invalid-const.rs:13:5
|
LL | pub bat: u8 = 130 + 130,
| ^^^^^^^^^^^^^^^^^^^^^^^ this field's constant fails const-evaluation, as seen in the previous error
|
= help: you can skip const-evaluation of default fields by enabling this lint
= note: `#[deny(default_field_always_invalid_const)]` on by default
error: aborting due to 3 previous errors; 2 warnings emitted
For more information about this error, try `rustc --explain E0080`.
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