pub enum Constraint {
    Variant {
        ty: TypeId,
        variant: VariantId,
        fields: TupleIndex,
    },
    ConstInt {
        val: i128,
        ty: TypeId,
    },
    ConstPrim {
        val: Sym,
    },
    Some,
}
Expand description

Pattern matches which can fail. Some binding sites are the result of successfully matching a constraint. A rule applies constraints to binding sites to determine whether the rule matches.

Variants§

§

Variant

Fields

§ty: TypeId

Which enum type is being matched? This is implied by the binding where the constraint is applied, but recorded here for convenience.

§variant: VariantId

Which enum variant must this binding site match to satisfy the rule?

§fields: TupleIndex

Number of fields in this variant of this enum. This is recorded in the constraint for convenience, to avoid needing to look up the variant in a sema::TypeEnv.

The value must match this enum variant.

§

ConstInt

Fields

§val: i128

The constant value.

§ty: TypeId

The constant’s type. Unsigned types preserve the representation of val, not its value.

The value must equal this integer literal.

§

ConstPrim

Fields

§val: Sym

The constant value.

The value must equal this Rust primitive value.

§

Some

The value must be an Option::Some, from a fallible extractor.

Implementations§

Return the nested Bindings from matching the given Constraint against the given BindingId.

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.