# Struct chalk_ir::BoundVar

``````pub struct BoundVar {
pub debruijn: DebruijnIndex,
pub index: usize,
}``````
Expand description

Identifies a particular bound variable within a binder. Variables are identified by the combination of a `DebruijnIndex`, which identifies the binder, and an index within that binder.

Consider this case:

``forall<'a, 'b> { forall<'c, 'd> { ... } }``

Within the `...` term:

• the variable `'a` have a debruijn index of 1 and index 0
• the variable `'b` have a debruijn index of 1 and index 1
• the variable `'c` have a debruijn index of 0 and index 0
• the variable `'d` have a debruijn index of 0 and index 1

The variables `'a` and `'b` both have debruijn index of 1 because, counting out, they are the 2nd binder enclosing `...`. The indices identify the location within that binder.

The variables `'c` and `'d` both have debruijn index of 0 because they appear in the innermost binder enclosing the `...`. The indices identify the location within that binder.

## Fields§

§`debruijn: DebruijnIndex`

Debruijn index, which identifies the binder.

§`index: usize`

Index within the binder.

## Implementations§

Creates a new bound variable.

Casts the bound variable to a type.

Wrap the bound variable in a lifetime.

Wraps the bound variable in a constant.

True if this variable is bound within the `amount` innermost binders.

Adjusts the debruijn index (see `DebruijnIndex::shifted_in`).

Adjusts the debruijn index (see `DebruijnIndex::shifted_in`).

Adjusts the debruijn index (see `DebruijnIndex::shifted_in`).

Adjusts the debruijn index (see `DebruijnIndex::shifted_in`).

Return the index of the bound variable, but only if it is bound at the innermost binder. Otherwise, returns `None`.

Return the index of the bound variable, but only if it is bound at the innermost binder. Otherwise, returns `None`.

## 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

## 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
Cast a value to type `U` using `CastTo`.

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.