case err := <-c:
		if err == nil {
			t.Error("error expected")
		} else if err != io.ErrNoProgress {
			t.Error("unexpected error:", err)
		}
	case <-time.After(time.Second):
		t.Error("test timed out (endless loop in ReadByte?)")
	}
}

// A StringReader delivers its data one string segment at a time via Read.
type StringReader struct {
	data []string
	step int
}

	// See issue https://golang.org/issue/31891
	key := parent + " > " + dtype.String()

	if checkCache {
		if t, ok := c.m[key]; ok {
			if t.Go == nil {
				fatalf("%s: type conversion loop at %s", lineno(pos), dtype)
			}
			return t
		}
	}

	t := new(Type)
	t.Size = dtype.Size() // note: wrong for array of pointers, corrected below
	t.Align = -1