Enum rustc_middle::ty::adjustment::AllowTwoPhase

pub enum AllowTwoPhase {
    Yes,
    No,
}

At least for initial deployment, we want to limit two-phase borrows to only a few specific cases. Right now, those are mostly “things that desugar” into method calls:

• using x.some_method() syntax, where some_method takes &mut self,
• using Foo::some_method(&mut x, ...) syntax,
• binary assignment operators (+=, -=, *=, etc.). Anything else should be rejected until generalized two-phase borrow support is implemented. Right now, dataflow can’t handle the general case where there is more than one use of a mutable borrow, and we don’t want to accept too much new code via two-phase borrows, so we try to limit where we create two-phase capable mutable borrows. See #49434 for tracking.

Variants

Yes

No

Trait Implementations

impl Clone for AllowTwoPhase

fn clone(&self) -> AllowTwoPhase

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AllowTwoPhase

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'tcx, __D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<__D> for AllowTwoPhase

fn decode(__decoder: &mut __D) -> Self

impl<'tcx, __E: TyEncoder<I = TyCtxt<'tcx>>> Encodable<__E> for AllowTwoPhase

fn encode(&self, __encoder: &mut __E)

impl<'__ctx> HashStable<StableHashingContext<'__ctx>> for AllowTwoPhase

fn hash_stable( &self, __hcx: &mut StableHashingContext<'__ctx>, __hasher: &mut StableHasher )

impl PartialEq<AllowTwoPhase> for AllowTwoPhase

fn eq(&self, other: &AllowTwoPhase) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for AllowTwoPhase

impl StructuralPartialEq for AllowTwoPhase

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: 1 byte

Size for each variant:

• Yes: 0 bytes
• No: 0 bytes