Function enrich_single_parameter

src/inheritance.rs:268–288

Enrich a single child parameter from an ancestor parameter. Copies the ancestor's `type_hint` when the child lacks a docblock override, the ancestor has a richer type, **and** the child's native type is not a specific concrete type. PHP allows contravariant parameter types: a concrete class may declare `?int` where the interface says `int`, or Carbon's `setTimezone(DateTimeZone|string|int)` may

(existing_param: &mut ParameterInfo, ancestor_param: &ParameterInfo)

/// `@implements` tag substitutes the template to a concrete type),
/// the ancestor's enriched type should flow through.
fn enrich_single_parameter(existing_param: &mut ParameterInfo, ancestor_param: &ParameterInfo) {
    // Type hint enrichment — the child must lack a docblock override
    // AND the ancestor must have a richer type (docblock that goes
    // beyond its native hint).  Additionally, skip enrichment when
    // the child has a specific native type (not `object`/`mixed`)
    // because the child's declaration is intentional and may be
    // wider than the ancestor's (contravariant parameters).
    let child_has_specific_native = existing_param.native_type_hint.as_ref().is_some_and(|nt| {
        !nt.is_object() && !nt.is_mixed() && !nt.is_array_like() && !nt.is_iterable()
    });
    if !child_has_specific_native
        && lacks_docblock_override(&existing_param.type_hint, &existing_param.native_type_hint)
        && ancestor_has_richer_type(&ancestor_param.type_hint, &ancestor_param.native_type_hint)
    {
        existing_param.type_hint = ancestor_param.type_hint.clone();
    }
    // Description enrichment
    if existing_param.description.is_none() && ancestor_param.description.is_some() {
        existing_param.description = ancestor_param.description.clone();
    }
}

/// Enrich a child property with docblock information from an ancestor
/// property.