Enum erg_compiler::ty::free::Constraint

pub enum Constraint {
    Sandwiched {
        sub: Type,
        sup: Type,
    },
    TypeOf(Type),
    Uninited,
}

Represents constraints on type variables and type parameters.

Note that constraints can have circular references. However, type variable (FreeTyVar) is defined with various operations avoiding infinite recursion.

NOTE: you should use Free::get_type/get_subsup instead of deconstructing the constraint by match. Constraints may contain cycles, in which case using match to get the contents will cause memory destructions.

Variants

Sandwiched

:> Sub, <: Sup

Fields

sub: Type

sup: Type

TypeOf(Type)

Uninited

Implementations

impl Constraint

pub const fn new_sandwiched(sub: Type, sup: Type) -> Self

:> Sub, <: Sup

pub fn named_fmt(&self, f: &mut impl Write, name: &str, limit: isize) -> Result

pub fn new_type_of(t: Type) -> Self

pub const fn new_subtype_of(sup: Type) -> Self

pub const fn new_supertype_of(sub: Type) -> Self

pub const fn is_uninited(&self) -> bool

pub fn lift(&self)

pub fn get_type(&self) -> Option<&Type>

pub fn get_sub(&self) -> Option<&Type>

:> Sub

pub fn get_super(&self) -> Option<&Type>

<: Sup

pub fn get_sub_sup(&self) -> Option<(&Type, &Type)>

:> Sub, <: Sup

pub fn get_super_mut(&mut self) -> Option<&mut Type>

pub fn eliminate_recursion(self, target: &Type) -> Self

e.g.

old_sub: ?T, constraint: (:> ?T or NoneType, <: Obj)
-> constraint: (:> NoneType, <: Obj)

pub fn to_type_constraint(self) -> Constraint

Trait Implementations

impl Clone for Constraint

fn clone(&self) -> Constraint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Constraint

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

Formats the value using the given formatter.

impl Display for Constraint

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

Formats the value using the given formatter.

impl Hash for Constraint

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl LimitedDisplay for Constraint

fn limited_fmt<W: Write>(&self, f: &mut W, limit: isize) -> Result

If limit was set to a negative value, it will be displayed without abbreviation. FIXME:

fn to_string_unabbreviated(&self) -> String

impl PartialEq for Constraint

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for Constraint

impl StructuralPartialEq for Constraint