Namespace

    const Namespace = struct {
        const base_tag: Tag = .namespace;
        base: Scope = Scope{ .tag = base_tag },

        /// Parents can be: `LocalVal`, `LocalPtr`, `GenZir`, `Defer`, `Namespace`.
        parent: *Scope,
        /// Maps string table index to the source location of declaration,
        /// for the purposes of reporting name shadowing compile errors.
        decls: std.AutoHashMapUnmanaged(Zir.NullTerminatedString, Ast.Node.Index) = .empty,
        node: Ast.Node.Index,
        inst: Zir.Inst.Index,
        maybe_generic: bool,

        /// The astgen scope containing this namespace.
        /// Only valid during astgen.
        declaring_gz: ?*GenZir,

        /// Set of captures used by this namespace.
        captures: std.array_hash_map.Auto(Zir.Inst.Capture, Zir.NullTerminatedString) = .empty,

        fn deinit(self: *Namespace, gpa: Allocator) void {
            self.decls.deinit(gpa);
            self.captures.deinit(gpa);
            self.* = undefined;
        }
    }