pub(crate) enum ImplTraitContext {
Universal,
ReturnPositionOpaqueTy {
origin: OpaqueTyOrigin,
fn_kind: FnDeclKind,
},
TypeAliasesOpaqueTy {
in_assoc_ty: bool,
},
FeatureGated(ImplTraitPosition, Symbol),
Disallowed(ImplTraitPosition),
}
Expand description
Context of impl Trait
in code, which determines whether it is allowed in an HIR subtree,
and if so, what meaning it has.
Variants§
Universal
Treat impl Trait
as shorthand for a new universal generic parameter.
Example: fn foo(x: impl Debug)
, where impl Debug
is conceptually
equivalent to a fresh universal parameter like fn foo<T: Debug>(x: T)
.
Newly generated parameters should be inserted into the given Vec
.
ReturnPositionOpaqueTy
Fields
origin: OpaqueTyOrigin
Origin: Either OpaqueTyOrigin::FnReturn or OpaqueTyOrigin::AsyncFn,
fn_kind: FnDeclKind
Treat impl Trait
as shorthand for a new opaque type.
Example: fn foo() -> impl Debug
, where impl Debug
is conceptually
equivalent to a new opaque type like type T = impl Debug; fn foo() -> T
.
TypeAliasesOpaqueTy
Impl trait in type aliases.
FeatureGated(ImplTraitPosition, Symbol)
impl Trait
is unstably accepted in this position.
Disallowed(ImplTraitPosition)
impl Trait
is not accepted in this position.
Trait Implementations§
source§impl Clone for ImplTraitContext
impl Clone for ImplTraitContext
source§fn clone(&self) -> ImplTraitContext
fn clone(&self) -> ImplTraitContext
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ImplTraitContext
impl Debug for ImplTraitContext
source§impl PartialEq<ImplTraitContext> for ImplTraitContext
impl PartialEq<ImplTraitContext> for ImplTraitContext
source§fn eq(&self, other: &ImplTraitContext) -> bool
fn eq(&self, other: &ImplTraitContext) -> bool
self
and other
values to be equal, and is used
by ==
.impl Copy for ImplTraitContext
impl Eq for ImplTraitContext
impl StructuralEq for ImplTraitContext
impl StructuralPartialEq for ImplTraitContext
Auto Trait Implementations§
impl RefUnwindSafe for ImplTraitContext
impl Send for ImplTraitContext
impl Sync for ImplTraitContext
impl Unpin for ImplTraitContext
impl UnwindSafe for ImplTraitContext
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Layout§
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.
Size: 12 bytes
Size for each variant:
Universal
: 0 bytesReturnPositionOpaqueTy
: 11 bytesTypeAliasesOpaqueTy
: 1 byteFeatureGated
: 7 bytesDisallowed
: 1 byte