const std = @import("std"); const expect = std.testing.expect; test "null literal outside function" { const is_null = here_is_a_null_literal.context == null; try expect(is_null); const is_non_null = here_is_a_null_literal.context != null; try expect(!is_non_null); } const SillyStruct = struct { context: ?i32, }; const here_is_a_null_literal = SillyStruct{ .context = null }; const StructWithOptional = struct { field: ?i32, }; var struct_with_optional: StructWithOptional = undefined; test "unwrap optional which is field of global var" { struct_with_optional.field = null; if (struct_with_optional.field) |payload| { _ = payload; unreachable; } struct_with_optional.field = 1234; if (struct_with_optional.field) |payload| { try expect(payload == 1234); } else { unreachable; } }