// The subtype is a nominal, the supertype could be anything.
static bool is_nominal_subtype(ast_t* sub, ast_t* super)
{
// Special case Pointer[A]. It can only be a subtype of itself, because
// in the code generator, a pointer has no vtable.
if(is_pointer(sub))
return is_pointer_subtype(sub, super);
switch(ast_id(super))
{
case TK_NOMINAL:
return is_nominal_sub_nominal(sub, super);
case TK_TYPEPARAMREF:
return is_nominal_sub_typeparam(sub, super);
case TK_UNIONTYPE:
return is_subtype_union(sub, super);
case TK_ISECTTYPE:
return is_subtype_isect(sub, super);
case TK_ARROW:
return is_subtype_arrow(sub, super);
default: {}
}
return false;
}
static bool is_nominal_sub_x(ast_t* sub, ast_t* super, errorframe_t* errors)
{
// N k <: T
switch(ast_id(super))
{
case TK_UNIONTYPE:
return is_x_sub_union(sub, super, errors);
case TK_ISECTTYPE:
return is_x_sub_isect(sub, super, errors);
case TK_TUPLETYPE:
return is_single_sub_tuple(sub, super, errors);
case TK_NOMINAL:
return is_nominal_sub_nominal(sub, super, errors);
case TK_TYPEPARAMREF:
return is_nominal_sub_typeparam(sub, super, errors);
case TK_ARROW:
return is_nominal_sub_arrow(sub, super, errors);
default: {}
}
assert(0);
return false;
}