Struct rustc_mir::transform::promote_consts::Validator

pub(in transform::promote_consts) struct Validator<'a, 'tcx> {
    ccx: &'a ConstCx<'a, 'tcx>,
    temps: &'a IndexVec<Local, TempState>,
    explicit: bool,
}

Checks whether locals that appear in a promotion context (Candidate) are actually promotable.

This wraps an Item, and has access to all fields of that Item via Deref coercion.

Fields

ccx: &'a ConstCx<'a, 'tcx>

temps: &'a IndexVec<Local, TempState>

explicit: bool

Explicit promotion happens e.g. for constant arguments declared via rustc_args_required_const. Implicit promotion has almost the same rules, except that disallows const fn except for those marked #[rustc_promotable]. This is to avoid changing a legitimate run-time operation into a failing compile-time operation e.g. due to addresses being compared inside the function.

Implementations

impl<'tcx, '_> Validator<'_, 'tcx>

pub(in transform::promote_consts) fn validate_candidate(
    &self,
    candidate: Candidate
) -> Result<(), Unpromotable>

pub(in transform::promote_consts) fn qualif_local<Q: Qualif>(
    &self,
    local: Local
) -> bool

pub(in transform::promote_consts) fn validate_local(
    &self,
    local: Local
) -> Result<(), Unpromotable>

pub(in transform::promote_consts) fn validate_place(
    &self,
    place: PlaceRef<'tcx>
) -> Result<(), Unpromotable>

pub(in transform::promote_consts) fn validate_operand(
    &self,
    operand: &Operand<'tcx>
) -> Result<(), Unpromotable>

pub(in transform::promote_consts) fn validate_rvalue(
    &self,
    rvalue: &Rvalue<'tcx>
) -> Result<(), Unpromotable>

pub(in transform::promote_consts) fn validate_call(
    &self,
    callee: &Operand<'tcx>,
    args: &[Operand<'tcx>]
) -> Result<(), Unpromotable>

Methods from Deref<Target = ConstCx<'a, 'tcx>>

pub fn def_id(&self) -> LocalDefId

pub fn const_kind(&self) -> ConstContext

Returns the kind of const context this Item represents (const, static, etc.).

Panics if this Item is not const.

pub fn is_const_stable_const_fn(&self) -> bool

pub fn fn_sig(&self) -> Option<&'tcx FnSig<'tcx>>

Returns the function signature of the item being const-checked if it is a fn or const fn.

Trait Implementations

impl<'a, 'tcx> Deref for Validator<'a, 'tcx>

type Target = ConstCx<'a, 'tcx>

The resulting type after dereferencing.

pub fn deref(&self) -> &Self::Target

Dereferences the value.