getOrPutTypeNoExtraAssumeCapacity

fn getOrPutTypeNoExtraAssumeCapacity(self: *Builder, item: Type.Item) struct { new: bool, type: Type } {
    const Adapter = struct {
        builder: *const Builder,
        pub fn hash(_: @This(), key: Type.Item) u32 {
            return @truncate(std.hash.Wyhash.hash(
                comptime std.hash.int(@backingInt(Type.Tag.simple)),
                std.mem.asBytes(&key),
            ));
        }
        pub fn eql(ctx: @This(), lhs_key: Type.Item, _: void, rhs_index: usize) bool {
            const lhs_bits: u32 = @bitCast(lhs_key);
            const rhs_bits: u32 = @bitCast(ctx.builder.type_items.items[rhs_index]);
            return lhs_bits == rhs_bits;
        }
    };
    const gop = self.type_map.getOrPutAssumeCapacityAdapted(item, Adapter{ .builder = self });
    if (!gop.found_existing) {
        gop.key_ptr.* = {};
        gop.value_ptr.* = {};
        self.type_items.appendAssumeCapacity(item);
    }
    return .{ .new = !gop.found_existing, .type = @fromBackingInt(@intCast(gop.index)) };
}