False positive of IfUnlessModifier for array elements

[AlexWayfer]

Hello. I've found a false positive of IfUnlessModifier for array elements with conditions.

You can write an array element with multi-line condition, and with one-line condition, but only with parentheses, without them there is a syntax error:

unexpected `if' modifier, expecting ']'

But IfUnlessModifier doesn't count this specific condition (for conditions), and offenses a multi-line condition, which can be placed into one line with syntax error, but with parentheses it already exceeds LineLength.

---

Expected behavior

No offenses for multi-line condition in array, which can't be placed into one line without LineLength offense.

Actual behavior

There is a "fork" with offenses in any case.

Steps to reproduce the problem

Layout/LineLength:
  Max: 12
Style/FrozenStringLiteralComment:
  Enabled: false

[
  if foo
    bar
  end
]

rubocop/test.rb:2:3: C: Style/IfUnlessModifier: Favor modifier if usage when having a single-line body. Another good alternative is the usage of control flow &&/||.
  if foo
  ^^

[
  (bar if foo)
]

rubocop/test.rb:2:8: C: Style/IfUnlessModifier: Modifier form of if makes the line too long.
  (bar if foo)
       ^^
rubocop/test.rb:2:13: C: Layout/LineLength: Line is too long. [14/12]
  (bar if foo)
            ^^

RuboCop version

Include the output of rubocop -V or bundle exec rubocop -V if using Bundler. Here's an example:

0.86.0 (using Parser 2.7.1.4, rubocop-ast 0.1.0, running on ruby 2.7.1 x86_64-linux)