Enum Shown 

pub enum Shown {
    Reg,
    Const,
    Var,
    Expand,
}

How one operand is shown to the matcher.

Variants

Reg

As a value sitting in a register, which is what (value.iN x) matches.

Const

As a constant the caller has in hand, which is what (iconst.iN k) matches.

Var

As a register that is not a constant, which is what (value.iN x) matches when the operand is anything other than a number.

This is Shown::Reg with the constants refused. A canonicalisation is a rule that moves an operand from one side to the other, and the swapped form it writes matches the rule again the moment the other side is a constant too, which is a term the pass would rewrite until it ran out of fuel. Saying which side is not a number is what stops it, and it has to be said in the plan rather than in a guard, because a guard reads a binding as a number and is false when it is not one.

Expand

As the instruction that computed it, so a rule can be about two instructions at once.

Trait Implementations

impl Clone for Shown

fn clone(&self) -> Shown

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Shown

impl Debug for Shown

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

Formats the value using the given formatter.

impl Eq for Shown

impl PartialEq for Shown

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Shown