Precedence issue with ":"

[szhorvat]

Describe the bug

x y : z is parsed as Optional[Times[x, y], z], according to the Wolfram Language -> Show FullForm menu item. This is also reflected in how the incremental selection works ("expand selection").

The correct parsing is Times[x, Pattern[y, z]]. There are two problems here: (1) precedence of : vs implicit multiplication (2) confusion between Optional and Pattern.

Let us look at another example:

x y_ : z (notice the _) is parsed as Optional[Times[x, Pattern[y]], z].

The correct parsing is Times[x, Optional[Pattern[y, Blank[]], z]]. Again, two issues: (1) precedence of : vs implicit multiplication (2) Pattern[y] vs Pattern[y, Blank[]]

As far as I can tell, in both cases it is only (1) that affects the functionality of the plugin, and (2) can be ignored. It affects incremental selections.