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rust/tests/ui/structs/default-field-values-failures.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
error: generic parameters may not be used in const operations
--> $DIR/default-field-values-failures.rs:22:23
|
LL | bat: i32 = <Qux<{ C }> as T>::K,
| ^ cannot perform const operation using `C`
|
= help: const parameters may only be used as standalone arguments, i.e. `C`
= help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
Detect `struct S(ty = val);` Emit a specific error for unsupported default field value syntax in tuple structs.
2024-11-26 17:53:00 +00:00
error: default field in tuple struct
--> $DIR/default-field-values-failures.rs:26:22
|
LL | pub struct Rak(i32 = 42);
| ^^ default fields are only supported on structs
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
error[E0277]: the trait bound `S: Default` is not satisfied
--> $DIR/default-field-values-failures.rs:14:5
|
LL | #[derive(Debug, Default)]
| ------- in this derive macro expansion
LL | pub struct Bar {
LL | pub bar: S,
| ^^^^^^^^^^ the trait `Default` is not implemented for `S`
|
= note: this error originates in the derive macro `Default` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider annotating `S` with `#[derive(Default)]`
|
LL + #[derive(Default)]
LL | pub struct S;
|
error: missing mandatory field `bar`
Detect `struct S(ty = val);` Emit a specific error for unsupported default field value syntax in tuple structs.
2024-11-26 17:53:00 +00:00
--> $DIR/default-field-values-failures.rs:47:21
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
|
LL | let _ = Bar { .. };
| ^
error: generic `Self` types are currently not permitted in anonymous constants
--> $DIR/default-field-values-failures.rs:20:14
|
LL | bar: S = Self::S,
| ^^^^
Detect `struct S(ty = val);` Emit a specific error for unsupported default field value syntax in tuple structs.
2024-11-26 17:53:00 +00:00
error: aborting due to 5 previous errors
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
For more information about this error, try `rustc --explain E0277`.
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