Github various const parameter defaults improvements by lcnr · Pull Request #842...
source link: https://github.com/rust-lang/rust/pull/84299
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Actually resolve names in const parameter defaults, fixing struct Foo<const N: usize = { usize::MAX }>.
Split generic parameter ban rib for types and consts, allowing
#![feature(const_generics_defaults)] struct Q; struct Foo<T = Q, const Q: usize = 3>(T);
Remove the type/const ordering restriction if const_generics_defaults is active, even if const_generics is not. allowing us to stabilize and test const param defaults separately.
Check well formedness of const parameter defaults, eagerly emitting an error for struct Foo<const N: usize = { 0 - 1 }>
Do not forbid const parameters in param defaults, allowing struct Foo<const N: usize, T = [u8; N]>(T) and struct Foo<const N: usize, const M: usize = N>. Note that this should not change anything which is stabilized, as on stable, type parameters must be in front of const parameters, which means that type parameter defaults are only allowed if no const parameters exist.
We still forbid generic parameters inside of const param types.
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