Struct VariantDecl 

pub struct VariantDecl {
    pub name: String,
    pub params: usize,
    pub ctors: Vec<(String, Option<MonoType>)>,
    pub param_vars: Vec<TyVarRef>,
}

A user (or built-in) variant type declaration.

param_vars names the declaration’s type parameters as concrete placeholder TyVarRefs that appear (via MonoType::Var) inside ctors’ payload types; they are never meant to be unified against anything directly. VariantDecl::instantiate_ctor is the only sanctioned way to use a declaration: given concrete argument types for the variant’s params type parameters, it substitutes them for the placeholders (matched by pointer identity, the same mechanism types::instantiate uses for quantified variables — see types::substitute) throughout the chosen constructor’s payload type, and returns both that payload type and the resulting MonoType::Variant(name, args).

This mirrors v0.0.6’s Typeenv.Raw.register_type/add_constructor (primitives.cppo.ml:154-217), which pairs a TypeID.t with a Typeenv.Data(arity) and each constructor with a Poly(...) scheme quantified over the same bid/typaram placeholders declared once for the whole type — the same shape, just spelled with this port’s TyVarRef/substitute machinery instead of v0.0.6’s BoundID/ PolyBound.

Fields

name: String

params: usize

ctors: Vec<(String, Option<MonoType>)>

param_vars: Vec<TyVarRef>

Trait Implementations

impl Clone for VariantDecl

fn clone(&self) -> VariantDecl

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VariantDecl

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

Formats the value using the given formatter.