luaur-analysis 0.1.3

Luau type checker and type inference (Rust).
Documentation 
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use crate::functions::follow_type::follow_type_id;
use crate::functions::get_2::get2;
use crate::functions::is_optional_or_free::is_optional_or_free;
use crate::records::property_type::Property;
use crate::records::table_type::TableType;
use crate::type_aliases::type_id::TypeId;
use luaur_common::macros::luau_assert::LUAU_ASSERT;

// Two tables may be compatible even if their shapes aren't exactly the
// same if the extra property is optional, free (and therefore
// potentially optional), or if the right table has an indexer.  Or if
// the right table is free (and therefore potentially has an indexer or
// a compatible property)
unsafe fn missing_prop_is_compatible(left_prop: &Property, right_table: &TableType) -> bool {
    if right_table.state == crate::enums::table_state::TableState::Free
        || right_table.indexer.is_some()
    {
        return true;
    }

    if left_prop.is_read_only() || left_prop.is_shared() {
        if is_optional_or_free(left_prop.read_ty.unwrap()) {
            return true;
        }
    }

    // FIXME: Could this create an issue for write only / divergent properties?
    false
}

pub unsafe fn are_compatible(left: TypeId, right: TypeId) -> bool {
    let p = get2::<TableType, TableType, TypeId>(follow_type_id(left), follow_type_id(right));
    if p.first.is_null() {
        return true;
    }

    let left_table = p.first;
    LUAU_ASSERT!(!left_table.is_null());
    let right_table = p.second;
    LUAU_ASSERT!(!right_table.is_null());

    let left_table = &*left_table;
    let right_table = &*right_table;

    for (_name, left_prop) in left_table.props.iter() {
        let it = right_table.props.get(_name);
        if it.is_none() {
            if !missing_prop_is_compatible(left_prop, right_table) {
                return false;
            }
        }
    }

    for (_name, right_prop) in right_table.props.iter() {
        let it = left_table.props.get(_name);
        if it.is_none() {
            if !missing_prop_is_compatible(right_prop, left_table) {
                return false;
            }
        }
    }

    true
}