But: Unknown properties of string literals / void 0 handling

[loilo]

Found by trying to squash minified asciidoctor.js.

This case is really edgy and kinda weird (because I have no idea what the original code was supposed to do semantically), however it is valid JavaScript and thus should pass the squashing.

The code below actually exposes a few problems:

• Butternut seems to have an ongoing tendency to eating meaningful whitespace. :)
• Expressions replaced with void 0 may no longer be called as functions.
• As bad of a habit as this is: The String prototype might have been manipulated. Calling uncommon properties on string literals should not be removed.

Input:

function fn () {
  return "a"[ "b" ]( c ) ? any_value_1 : any_value_2
}

Output Butternut:

function fn(){returnvoid 0(c)?any_value_1:any_value_2}

Output UglifyJS:

function fn(){return"a".b(c)?any_value_1:any_value_2}