a:3; a

[tavmem]

I'm guessing that this must be a regression. In kona:

$ rlwrap ~/kona/k
K Console - Enter \ for help
  a:3; a

In k2.8

$ rlwrap ~/k2.8/k
K 2.8 2000-10-10 Copyright (C) 1993-2000 Kx Systems
Evaluation. Not for commercial use. 
\ for help. \\ to exit.
  a:3; a
3

[tavmem]

This regression was caused by commit 0e6351523ba28def719fe44f1c994764ea57ac02 made on Aug 10, 2017.

[tavmem]

$ rlwrap -n ~/kona/k
K Console - Enter \ for help
  a:3;a
3
  a:3+2;a
5
  a:3+2;a;
  a:7
  a
7
  a;