weird shell behaviour with case pattern

[Han Boetes]

I ran into weird behaviour which was triggered by a recent version of
the emacs build system. This small scriplet is the minimal case which
triggers it as well. You can replace the 5 with any other letter or
number. The funny thing is the -~ which I wouldn't expect to match.

#!/bin/sh                                                                       
                                                                                
             
case "foobar" in
  *[5~-]*) echo "Of course I don't match." ;;
esac

case "foobar" in
  *[5-~]*) echo "Why do I match now?" ;;
esac

What is going on here?


# Han