Struct kailua_types::ty::NoTypeContext

pub struct NoTypeContext;

An implementation of TypeContext that raises an error for most methods.

Useful for ensuring that no operations involve type variables or row variables.

Trait Implementations

impl TypeContext for NoTypeContext

fn gen_report(&self) -> TypeReport

Generates a new, empty type report.

fn last_tvar(&self) -> Option<TVar>

Returns the latest type variable generated, if any.

fn gen_tvar(&mut self) -> TVar

Generates a new fresh type variable.

fn copy_tvar(&mut self, tvar: TVar) -> TVar

Copies a type variable so that a new variable has the same constraints to the original but is no longer connected to the original.

fn assert_tvar_sub(&mut self, lhs: TVar, rhs: &Ty) -> TypeResult<()>

Asserts that the type variable has given upper bound.

fn assert_tvar_sup(&mut self, lhs: TVar, rhs: &Ty) -> TypeResult<()>

Asserts that the type variable has given lower bound.

fn assert_tvar_eq(&mut self, lhs: TVar, rhs: &Ty) -> TypeResult<()>

Asserts that the type variable has given tight bound.

fn assert_tvar_sub_tvar(&mut self, lhs: TVar, rhs: TVar) -> TypeResult<()>

Asserts that the first type variable is a subtype of the second.

fn assert_tvar_eq_tvar(&mut self, lhs: TVar, rhs: TVar) -> TypeResult<()>

Asserts that the first type variable is equal to the second.

fn get_tvar_bounds(&self, tvar: TVar) -> (Flags, Flags)

Returns lower and upper bounds of given type variable as type flags.

fn get_tvar_exact_type(&self, tvar: TVar) -> Option<Ty>

Resolves a given type variable if there is a tight bound.

fn gen_rvar(&mut self) -> RVar

Generates a new fresh row variable.

fn copy_rvar(&mut self, rvar: RVar) -> RVar

Copies a row variable so that a new variable has the same fields to the original but is no longer connected to the original.

fn assert_rvar_sub(&mut self, lhs: RVar, rhs: RVar) -> TypeResult<()>

Asserts that the first row variable is a subtype of the second.

fn assert_rvar_eq(&mut self, lhs: RVar, rhs: RVar) -> TypeResult<()>

Asserts that the first row variable is equal to the second.

fn assert_rvar_includes(
    &mut self,
    lhs: RVar,
    rhs: &[(Key, Slot)]
) -> TypeResult<()>

Asserts that the row variable contains given fields. If there is a matching field, the types should be equal to each other.

fn assert_rvar_closed(&mut self, rvar: RVar) -> TypeResult<()>

Asserts that the row variable is no longer extensible.

fn list_rvar_fields(
    &self,
    rvar: RVar,
    _f: &mut FnMut(&Key, &Slot) -> Result<(), ()>
) -> Result<RVar, ()>

Iterates over a list of field keys and corresponding types. The closure can stop the iteration by returning Err. The iteration order is unspecified but all keys will be unique (guaranteed by type system).

fn fmt_class_name(
    &self,
    cid: ClassId,
    _f: &mut Formatter,
    _st: &DisplayState
) -> Result

Prints a type name for given nominal identifier to the formatter.

fn fmt_class_system_name(
    &self,
    csid: ClassSystemId,
    _f: &mut Formatter,
    _st: &DisplayState
) -> Result

Prints a type name for given nominal set identifier to the formatter.

fn is_subclass_of(&self, lhs: ClassId, rhs: ClassId) -> bool

Returns true if given nominal instance type is a subtype of another nominal instance type.

fn get_rvar_fields(&self, rvar: RVar) -> Vec<(Key, Slot)>

Collects and returns a list of all known fields in the row variable.

fn get_type_bounds(&self, ty: &Ty) -> (Flags, Flags)

Returns a pair of type flags that is an exact lower and upper bound for that type.

fn resolve_exact_type(&self, ty: &Ty) -> Option<Ty>

Exactly resolves the type variable inside ty if possible.