[−][src]Module rustc_mir::transform::check_consts::qualifs

Structural const qualification.

See the Qualif trait for more info.

Structs

CustomEq	A constant that cannot be used as part of a pattern in a `match` expression.
HasMutInterior	Constant containing interior mutability (`UnsafeCell<T>`). This must be ruled out to make sure that evaluating the constant at compile-time and at any point during the run-time would produce the same result. In particular, promotion of temporaries must not change program behavior; if the promoted could be written to, that would be a problem.
NeedsDrop	Constant containing an ADT that implements `Drop`. This must be ruled out (a) because we cannot run `Drop` during compile-time as that might not be a `const fn`, and (b) because implicit promotion would remove side-effects that occur as part of dropping that value.

Traits

Qualif

A "qualif"(-ication) is a way to look for something "bad" in the MIR that would disqualify some code for promotion or prevent it from evaluating at compile time.

Functions

in_any_value_of_ty
in_operand	Returns `true` if this `Operand` contains qualif `Q`.
in_place	Returns `true` if this `Place` contains qualif `Q`.
in_rvalue	Returns `true` if this `Rvalue` contains qualif `Q`.