Push(wr http2FrameWriteRequest)

	// Pop dequeues the next frame to write. Returns false if no frames can
	// be written. Frames with a given wr.StreamID() are Pop'd in the same
	// order they are Push'd, except RST_STREAM frames. No frames should be
	// discarded except by CloseStream.
	Pop() (wr http2FrameWriteRequest, ok bool)
}

		line = s.peekPos()
		if base.Flag.K != 0 {
			base.Warn("buildssa: unknown position (line 0)")
		}
	} else {
		s.lastPos = line
	}

	s.line = append(s.line, line)
}

// popLine pops the top of the line number stack.
func (s *state) popLine() {
	s.line = s.line[:len(s.line)-1]
}

// peekPos peeks the top of the line number stack.
func (s *state) peekPos() src.XPos {