func TestDecoderIssue3577(t *testing.T) {
	next := make(chan nextRead, 10)
	wantErr := errors.New("my error")
	next <- nextRead{5, nil}
	next <- nextRead{10, wantErr}
	next <- nextRead{0, wantErr}
	d := NewDecoder(StdEncoding, &faultInjectReader{
		source: "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==", // twas brillig...
		nextc:  next,
	})
	errc := make(chan error, 1)
	go func() {

	ready := new(uint32)
	for i := 0; i < iters; i++ {
		*ready = 0
		next0 := (i & 1) == 0
		next1 := (i & 2) == 0
		runqput(p, &gs[0], next0)
		go func() {
			for atomic.Xadd(ready, 1); atomic.Load(ready) != 2; {
			}
			if runqempty(p) {
				println("next:", next0, next1)
				throw("queue is empty")
			}
			done <- true
		}()

      items[takeIndex] = null;
      takeIndex = inc(takeIndex);
    } else {
      // slide over all others up through putIndex.
      for (; ; ) {
        int nexti = inc(i);
        if (nexti != putIndex) {
          items[i] = items[nexti];
          i = nexti;
        } else {
          items[i] = null;
          putIndex = i;
          break;
        }
      }
    }
    --count;
  }

  /**

      items[takeIndex] = null;
      takeIndex = inc(takeIndex);
    } else {
      // slide over all others up through putIndex.
      for (; ; ) {
        int nexti = inc(i);
        if (nexti != putIndex) {
          items[i] = items[nexti];
          i = nexti;
        } else {
          items[i] = null;
          putIndex = i;
          break;
        }
      }
    }
    --count;
  }

  /**

// is simultaneously being destroyed.
func (tl traceLocker) GoSwitch(nextg *g, destroy bool) {
	// Emit a GoWaiting status if necessary for the unblocked goroutine.
	w := tl.eventWriter(traceGoRunning, traceProcRunning)
	// Careful: don't use the event writer. We never want status or in-progress events
	// to trigger more in-progress events.
	w.w = emitUnblockStatus(w.w, nextg, tl.gen)
	ev := traceEvGoSwitch
	if destroy {

	x := sgp.prev
	y := sgp.next
	if x != nil {
		if y != nil {
			// middle of queue
			x.next = y
			y.prev = x
			sgp.next = nil
			sgp.prev = nil
			return
		}
		// end of queue
		x.next = nil
		q.last = x
		sgp.prev = nil
		return
	}
	if y != nil {
		// start of queue
		y.prev = nil
		q.first = y
		sgp.next = nil
		return
	}

	case token.ADD, token.SUB, token.NOT, token.XOR, token.AND, token.RANGE:
		pos, op := p.pos, p.tok
		p.next()
		x := p.parseUnaryExpr(false)
		return &ast.UnaryExpr{pos, op, p.checkExpr(x)}

	case token.ARROW:
		// channel type or receive expression
		pos := p.pos
		p.next()
		if p.tok == token.CHAN {
			p.next()
			value := p.parseType()
			return &ast.ChanType{pos, ast.RECV, value}
		}

	}
	// Update the state of the next goroutine.
	nextGState.status = go122.GoRunning
	nextGState.seq = seq
	newCtx := curCtx
	newCtx.G = nextg

	// Queue an event for the next goroutine starting to run.
	startCtx := curCtx
	startCtx.G = NoGoroutine
	o.queue.push(makeEvent(evt, startCtx, go122.EvGoStart, ev.time, uint64(nextg), ev.args[1]))
	return newCtx, true, nil
}

				typ = p.parseType()
			}
		}
	case token.MUL:
		star := p.pos
		p.next()
		if p.tok == token.LPAREN {
			// *(T)
			p.error(p.pos, "cannot parenthesize embedded type")
			p.next()
			typ = p.parseQualifiedIdent(nil)
			// expect closing ')' but no need to complain if missing
			if p.tok == token.RPAREN {
				p.next()
			}
		} else {
			// *T
			typ = p.parseQualifiedIdent(nil)
		}

index2to16loop:

#ifdef GOPPC64_power10
	LXVLL  R7, R14, V8          // Load next 16 bytes of string  from Base
	LXVLL  R10, R14, V9         // Load next 16 bytes of string from Base+1
	LXVLL  R8, R14, V11         // Load next 16 bytes of string from Base+2
	LXVLL  R17,R14, V12         // Load next 16 bytes of string  from Base+3
#else
	LXVB16X  (R7)(R0), V1       // Load next 16 bytes of string into V1 from R7