Generic data and methods

class Cell[T]:
    value: T

    def read(self) -> T:
        self.value

enum Choice[T]:
    Value(T)

Cell[u8](7) constructs a Cell[u8] directly using the ordinary class rules. Class constructor parameters can be inferred from generated field order or an explicit initializer’s signature: Cell(7u8) selects u8, while Cell(7) selects i64. Output-only or phantom parameters need explicit arguments; a result annotation does not influence argument inference.

A constructor’s enum qualifier requires explicit arguments: Choice[u8].Value(7) constructs a concrete instance. A pattern takes none, because the matched value supplies them: case Choice.Value(value): matches it. Aliases can name complete instances. Different arguments produce different nominal identities even when a parameter is absent from every payload. This includes value parameters: Tag[3] and Tag[4] are distinct instances.

Bare self uses the current concrete class or enum; an explicit mutable receiver is self: &mut Cell[T] or self: &mut Choice[T]. A by-value receiver is self: Cell[T] or self: Choice[T] (the current-owner spellings Cell and Choice also infer their declared parameters). Ordinary methods may declare their own parameters and integer, protocol, or callable constraints. Data parameters are already fixed by the receiver; method parameters cannot shadow them. Lifecycle methods cannot add parameters.

Explicit method calls use receiver.method[Types](arguments). Supply every method parameter without repeating data parameters. Inferred method arguments follow ordinary inference. Fields and temporary owned receivers support generic method calls; returned references retain their ordinary named-receiver and lifetime restrictions. Brackets beginning with a local binding index a callable field instead, as in table.callbacks[index](argument).

Data parameters accept IntType, FloatType, CopyType, KeyType, Callable, and OnceCallable constraints; protocol bounds on data are unsupported. Callable signatures may mention other data parameters and contribute constructor inference evidence. Explicit instances and aliases are checked too; unused declaration bounds still require valid signature shapes.

Data type arguments cannot be unit, references, or generators. Resolved owned closures can be arguments; see stored callables. Generic fields, construction, moves, and destruction keep their ordinary data semantics, including recursive storage.

Public instances must expose public concrete arguments, including phantom parameters and types named only in callback constraints. Declaration and member visibility apply normally. A generic method does not currently satisfy a protocol’s monomorphic method requirement.