// Put it back and read it again.
		if err = r.UnreadRune(); err != nil {
			t.Fatal("unexpected error on UnreadRune:", err)
		}
		r2, _, err := r.ReadRune()
		if err != nil {
			t.Fatal("unexpected error reading after unreading:", err)
		}
		if r1 != r2 {
			t.Fatalf("incorrect rune after unread: got %c, want %c", r1, r2)
		}
	}
	if got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

	// Scan DWARF info for top-level TagVariable entries with AttrName __cgo__i.
	types := make([]dwarf.Type, len(names))
	r := d.Reader()
	for {
		e, err := r.Next()
		if err != nil {
			fatalf("reading DWARF entry: %s", err)
		}
		if e == nil {
			break
		}
		switch e.Tag {
		case dwarf.TagVariable:
			name, _ := e.Val(dwarf.AttrName).(string)
			// As of https://reviews.llvm.org/D123534, clang

		}
	}
	return true
}

func sliceOfString(s [][]byte) []string {
	result := make([]string, len(s))
	for i, v := range s {
		result[i] = string(v)
	}
	return result
}

// For ease of reading, the test cases use strings that are converted to byte
// slices before invoking the functions.

var abcd = "abcd"
var faces = "☺☻☹"
var commas = "1,2,3,4"
var dots = "1....2....3....4"

type BinOpTest struct {

	return r
}

// uaddOvf reports whether unsigned a+b would overflow.
func uaddOvf(a, b int64) bool {
	return uint64(a)+uint64(b) < uint64(a)
}

// loadLSymOffset simulates reading a word at an offset into a
// read-only symbol's runtime memory. If it would read a pointer to
// another symbol, that symbol is returned. Otherwise, it returns nil.
func loadLSymOffset(lsym *obj.LSym, offset int64) *obj.LSym {

	p.errh = errh
	p.mode = mode
	p.pragh = pragh
	p.scanner.init(
		r,
		// Error and directive handler for scanner.
		// Because the (line, col) positions passed to the
		// handler is always at or after the current reading
		// position, it is safe to use the most recent position
		// base to compute the corresponding Pos value.
		func(line, col uint, msg string) {
			if msg[0] != '/' {
				p.errorAt(p.posAt(line, col), msg)
				return