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Rollup merge of #102273 - woppopo:relax_const_bound, r=fee1-dead 

Allow `~const` bounds on non-const functions

Makes the behavior of bound of trait-associated functions and non-associated functions consistent.
This commit is contained in:
Matthias Krüger 2022-09-26 19:19:21 +02:00 committed by GitHub
parent 0857ddeed6 e4b08ab241
commit e9bec2fdd4
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 43 additions and 32 deletions
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7
compiler/rustc_ast_passes/src/ast_validation.rs
View File

@ -1415,7 +1415,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
if !self.is_tilde_const_allowed {
self.err_handler()
.struct_span_err(bound.span(), "`~const` is not allowed here")
.note("only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions")
.note("only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions")
.emit();
}
}
@ -1523,9 +1523,8 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
});
}
let tilde_const_allowed =
matches!(fk.header(), Some(FnHeader { constness: Const::Yes(_), .. }))
|| matches!(fk.ctxt(), Some(FnCtxt::Assoc(_)));
let tilde_const_allowed = matches!(fk.header(), Some(FnHeader { .. }))
|| matches!(fk.ctxt(), Some(FnCtxt::Assoc(_)));
self.with_tilde_const(tilde_const_allowed, |this| visit::walk_fn(this, fk));
}

34
src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs Normal file
View File

@ -0,0 +1,34 @@
// check-pass
#![feature(const_trait_impl)]
#![feature(generic_arg_infer)]
#![feature(generic_const_exprs)]
#![allow(incomplete_features)]
struct Foo<const N: usize>;
impl<const N: usize> Foo<N> {
fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
Foo
}
}
#[const_trait]
trait Add42 {
fn add(a: usize) -> usize;
}
impl const Add42 for () {
fn add(a: usize) -> usize {
a + 42
}
}
fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
Foo
}
fn main() {
let foo = Foo::<0>;
let foo = bar::<(), _>(foo);
let _foo = bar::<(), _>(foo);
}

6
src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
View File

@ -17,12 +17,6 @@ fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
//~^ ERROR `~const` is not allowed
fn generic<P: ~const T>() {}
//~^ ERROR `~const` is not allowed
fn where_clause<P>() where P: ~const T {}
//~^ ERROR `~const` is not allowed
struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
//~^ ERROR `~const` and `?` are mutually exclusive

28
src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
View File

@ -4,7 +4,7 @@ error: `~const` is not allowed here
LL | fn rpit() -> impl ~const T { S }
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
= note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
error: `~const` is not allowed here
--> $DIR/tilde-const-invalid-places.rs:11:17
@ -12,7 +12,7 @@ error: `~const` is not allowed here
LL | fn apit(_: impl ~const T) {}
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
= note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
error: `~const` is not allowed here
--> $DIR/tilde-const-invalid-places.rs:14:50
@ -20,7 +20,7 @@ error: `~const` is not allowed here
LL | fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
= note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
error: `~const` is not allowed here
--> $DIR/tilde-const-invalid-places.rs:17:48
@ -28,29 +28,13 @@ error: `~const` is not allowed here
LL | fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
error: `~const` is not allowed here
--> $DIR/tilde-const-invalid-places.rs:20:15
|
LL | fn generic<P: ~const T>() {}
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
error: `~const` is not allowed here
--> $DIR/tilde-const-invalid-places.rs:23:31
|
LL | fn where_clause<P>() where P: ~const T {}
| ^^^^^^^^
|
= note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
= note: only allowed on bounds on functions, traits' associated types and functions, const impls and its associated functions
error: `~const` and `?` are mutually exclusive
--> $DIR/tilde-const-invalid-places.rs:26:25
--> $DIR/tilde-const-invalid-places.rs:20:25
|
LL | struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
| ^^^^^^^^^^^^^
error: aborting due to 7 previous errors
error: aborting due to 5 previous errors