Selector arguments without required argument key are treated as invalid

The bug

In the past you could use some arguments in selectors without providing the argument key, for example @a[0,0,0] would select players at x=0, y=0, z=0. Because of the fix of MC-106842 these arguments are now treated as invalid.

How to reproduce

Use the following command when you are not at 0, 0, 0:

/say @a[0,0,0,r=1]

In previous versions (pre 16w38a) it would only target players at 0, 0, 0 in a radius of 1. In 16w38a+ it targets players who are in a 1 block radius of the command block / entity running the command.