Enum Type 

pub enum Type {
    Var(TypeVar),
    Int,
    Bool,
    String,
    Unit,
    Float,
    Tuple(Vec<Type>),
    List(Box<Type>),
    Array(Box<Type>),
    Function(Box<Type>, Box<Type>),
    Record(HashMap<String, Type>),
    Variant(String, Vec<Type>),
}

Core type representation.

Represents all types in the Fusabi type system, including:

• Primitive types (int, bool, string, unit)
• Composite types (tuples, lists, arrays, records)
• Function types
• Type variables (for inference)
• Discriminated unions

Variants

Var(TypeVar)

Type variable (e.g., ’a, ’b)

Int

Integer type

Bool

Boolean type

String

String type

Unit

Unit type ()

Float

Float type

Tuple(Vec<Type>)

Tuple type (e.g., int * string * bool)

List(Box<Type>)

List type (e.g., int list, ’a list)

Array(Box<Type>)

Array type (e.g., int[], ’a[])

Function(Box<Type>, Box<Type>)

Function type (e.g., int -> int, ’a -> ’b)

Record(HashMap<String, Type>)

Record type with named fields

Variant(String, Vec<Type>)

Discriminated union variant (type name, type parameters)

Implementations

impl Type

pub fn free_vars(&self) -> HashSet<TypeVar>

Get all free type variables in this type.

A free type variable is one that is not bound by any quantifier. Used for generalization and substitution.

pub fn apply(&self, subst: &Substitution) -> Type

Apply a substitution to this type.

Replaces all occurrences of type variables according to the substitution.

pub fn occurs_check(&self, var: &TypeVar) -> bool

Occurs check: does this type variable occur in this type?

Used to prevent infinite types during unification. Returns true if the variable appears anywhere in the type structure.

pub fn function_multi(args: &[Type], ret: Type) -> Type

Helper to create a function type with multiple arguments.

Creates a right-associative chain of function types. Example: function_multi(&[int, bool], string) creates int -> bool -> string

Trait Implementations

impl Clone for Type

fn clone(&self) -> Type

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Type

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

Formats the value using the given formatter.

impl Display for Type

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

Formats the value using the given formatter.

impl PartialEq for Type

fn eq(&self, other: &Type) -> 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 StructuralPartialEq for Type