for i, test := range tests {
		arch, ctxt := setArch(goarch)
		tokenizer := lex.NewTokenizer("", strings.NewReader(test.input+"\n"), nil)
		parser := NewParser(ctxt, arch, tokenizer)

		err := tryParse(t, func() {
			parser.Parse()
		})

		switch {
		case err == nil:
			t.Errorf("#%d: %q: want error %q; have none", i, test.input, test.error)
		case !strings.Contains(err.Error(), test.error):

	}
}

func runBadTest(i int, test badExprTest, t *testing.T) (err error) {
	p := NewParser(nil, nil, nil) // Expression evaluation uses none of these fields of the parser.
	p.start(lex.Tokenize(test.input))
	return tryParse(t, func() {
		p.expr()
	})