Enum rustc_middle::ty::InferTy

pub enum InferTy {
    TyVar(TyVid),
    IntVar(IntVid),
    FloatVar(FloatVid),
    FreshTy(u32),
    FreshIntTy(u32),
    FreshFloatTy(u32),
}

A placeholder for a type that hasn’t been inferred yet.

E.g., if we have an empty array ([]), then we create a fresh type variable for the element type since we won’t know until it’s used what the element type is supposed to be.

Variants

TyVar(TyVid)

A type variable.

IntVar(IntVid)

An integral type variable ({integer}).

These are created when the compiler sees an integer literal like 1 that could be several different types (u8, i32, u32, etc.). We don’t know until it’s used what type it’s supposed to be, so we create a fresh type variable.

FloatVar(FloatVid)

A floating-point type variable ({float}).

These are created when the compiler sees an float literal like 1.0 that could be either an f32 or an f64. We don’t know until it’s used what type it’s supposed to be, so we create a fresh type variable.

FreshTy(u32)

A FreshTy is one that is generated as a replacement for an unbound type variable. This is convenient for caching etc. See rustc_infer::infer::freshen for more details.

Compare with TyVar.

FreshIntTy(u32)

Like FreshTy, but as a replacement for IntVar.

FreshFloatTy(u32)

Like FreshTy, but as a replacement for FloatVar.

Trait Implementations

impl<'tcx> Lift<'tcx> for InferTy

type Lifted = InferTy

fn lift_to_tcx(self, _: TyCtxt<'tcx>) -> Option<Self>

impl<'tcx> TypeFoldable<'tcx> for InferTy

fn try_fold_with<F: FallibleTypeFolder<'tcx>>(
    self,
    _: &mut F
) -> Result<Self, F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f).

fn fold_with<F: TypeFolder<'tcx>>(self, _: &mut F) -> Self

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.

impl<'tcx> TypeVisitable<'tcx> for InferTy

fn visit_with<F: TypeVisitor<'tcx>>(&self, _: &mut F) -> ControlFlow<F::BreakTy>

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v).

fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool

Returns true if self has any late-bound regions that are either bound by binder or bound by some binder outside of binder. If binder is ty::INNERMOST, this indicates whether there are any late-bound regions that appear free.

fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool

Returns true if this type has any regions that escape binder (and hence are not bound by it).

fn has_escaping_bound_vars(&self) -> bool

Return true if this type has regions that are not a part of the type. For example, for<'a> fn(&'a i32) return false, while fn(&'a i32) would return true. The latter can occur when traversing through the former.

fn has_type_flags(&self, flags: TypeFlags) -> bool

fn has_projections(&self) -> bool

fn has_opaque_types(&self) -> bool

fn references_error(&self) -> bool

fn error_reported(&self) -> Result<(), ErrorGuaranteed>

fn has_non_region_param(&self) -> bool

fn has_infer_regions(&self) -> bool

fn has_infer_types(&self) -> bool

fn has_non_region_infer(&self) -> bool

fn needs_infer(&self) -> bool

fn has_placeholders(&self) -> bool

fn needs_subst(&self) -> bool

fn has_free_regions(&self) -> bool

“Free” regions in this context means that it has any region that is not (a) erased or (b) late-bound.

fn has_erased_regions(&self) -> bool

fn has_erasable_regions(&self) -> bool

True if there are any un-erased free regions.

fn is_global(&self) -> bool

Indicates whether this value references only ‘global’ generic parameters that are the same regardless of what fn we are in. This is used for caching.

fn has_late_bound_regions(&self) -> bool

True if there are any late-bound regions

fn still_further_specializable(&self) -> bool

Indicates whether this value still has parameters/placeholders/inference variables which could be replaced later, in a way that would change the results of impl specialization.

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: 8 bytes

Size for each variant:

• TyVar: 4 bytes
• IntVar: 4 bytes
• FloatVar: 4 bytes
• FreshTy: 4 bytes
• FreshIntTy: 4 bytes
• FreshFloatTy: 4 bytes