Struct TypeUnion 

pub struct TypeUnion { /* private fields */ }

A set of types representing the possible result types of a match expression.

TypeUnion enforces the set invariant: inserting a type that is already present is a no-op. Order is not significant; two TypeUnion values are equal if they contain the same types regardless of insertion order.

Implementations

impl TypeUnion

pub fn new() -> TypeUnion

Creates an empty type union.

Examples

let u = TypeUnion::new();
assert!(u.is_empty());

pub fn insert(&mut self, ty: Type) -> bool

Insert ty if it is not already present. Returns whether it was inserted.

Type::Unknown is skipped — it carries no type information and should not widen the union (e.g. an Expr::Error branch in a Match).

pub fn contains(&self, ty: &Type) -> bool

Returns true if this union contains ty.

pub fn len(&self) -> usize

Returns the number of types in the union.

pub fn is_empty(&self) -> bool

Returns true if the union contains no types.

pub fn iter(&self) -> impl Iterator<Item = &Type>

Returns an iterator over the types in the union.

pub fn simplify(self) -> Type

Collapse the union into a single Type.

• 0 members → Type::Null (no type information)
• 1 member → that type directly (no union needed)
• 2+ members → Type::Union(self)

Trait Implementations

impl Clone for TypeUnion

fn clone(&self) -> TypeUnion

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TypeUnion

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

Formats the value using the given formatter.

impl Default for TypeUnion

fn default() -> TypeUnion

Returns the “default value” for a type.

impl From<TypeUnion> for Type

fn from(value: TypeUnion) -> Type

Converts to this type from the input type.

impl<'a> IntoIterator for &'a TypeUnion

type Item = &'a Type

The type of the elements being iterated over.

type IntoIter = Iter<'a, Type>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <&'a TypeUnion as IntoIterator>::IntoIter

Creates an iterator from a value.

impl IntoIterator for TypeUnion

type Item = Type

The type of the elements being iterated over.

type IntoIter = IntoIter<Type>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <TypeUnion as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for TypeUnion

Set equality: two unions are equal iff they contain the same types, regardless of insertion order.

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for TypeUnion