Fix false positive in RedundantParentheses cop with multiple expression

[pocke]

Style/RedundantParentheses cop has a false positive.

For example.

 # test.rb
x ||= (
  foo
  bar
)

$ rubocop --only Style/RedundantParentheses test.rb
Inspecting 1 file
C

Offenses:

test.rb:2:7: C: Don't use parentheses around a method call.
x ||= ( ...
      ^

1 file inspected, 1 offense detected

However, the parentheses can't be omitted.

---

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• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Used the same coding conventions as the rest of the project.
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• All tests are passing.
• The new code doesn't generate RuboCop offenses.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
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[bbatsov]

Are those examples good? The parentheses look redundant to me here, as those could be two independent expressions that happen to be wrapped in parens...

[bbatsov]

I mean - don't you need an assignment operator preceding those expressions to be sure the parens are needed?

[pocke]

don't you need an assignment operator preceding those expressions to be sure the parens are needed?

Yes, however, I need to consider other cases as well.

x = (
  foo
  bar
)


x + (
  foo
  bar
)


x((
  foo
  bar
))

If the parens is removed, the above code changes its meaning(and syntax error).
However, RuboCop adds offences to the code currently.

I'll update the cop. Thank you for your comment!

[pocke]

I fixed the behavior.

When parens's evaluated value is used, parens can not be omitted. As an exception, when the value is used as method/block's last value,

The implementation is referred to Lint/Void cop.

For example

# can't omit
x = (
  foo
  bar
)

# can omit
def x
  (
    foo
    bar
  )
end

# can omit
x do
  (
    foo
    bar
  )
end