pub(crate) enum ImplTraitContext {
Universal,
ReturnPositionOpaqueTy {
origin: OpaqueTyOrigin,
in_trait: bool,
},
TypeAliasesOpaqueTy,
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,
in_trait: bool
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.
Disallowed(ImplTraitPosition)
impl Trait
is not accepted in this position.
Trait Implementations
sourceimpl Clone for ImplTraitContext
impl Clone for ImplTraitContext
sourcefn clone(&self) -> ImplTraitContext
fn clone(&self) -> ImplTraitContext
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresourceimpl Debug for ImplTraitContext
impl Debug for ImplTraitContext
sourceimpl PartialEq<ImplTraitContext> for ImplTraitContext
impl PartialEq<ImplTraitContext> for ImplTraitContext
sourcefn eq(&self, other: &ImplTraitContext) -> bool
fn eq(&self, other: &ImplTraitContext) -> bool
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
sourceimpl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
T: Copy,
fn allocate_on(self, arena: &'a Arena<'tcx>) -> &'a mut T
fn allocate_from_iter(
arena: &'a Arena<'tcx>,
iter: impl IntoIterator<Item = T>
) -> &'a mut [T]ⓘNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
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
: 12 bytesTypeAliasesOpaqueTy
: 0 bytesDisallowed
: 5 bytes