Fix Style/MethodCallParentheses failed on or assign to instance vaiable's accessor

[yuroyoro]

Style/MethodCallParentheses failed on following code.

@foo.bar ||= puts()

This is a backtrace log that reported with running rubocop -d --only Style/MethodCallParentheses.

$ rubocop --only Style/MethodCallParentheses sample.rb -d
Inspecting 1 file
Scanning /home/ozaki/dev/rubocop_sample/sample.rb
For /home/ozaki/dev/rubocop_sample: configuration from /home/ozaki/dev/rubocop_sample/.rubocop.yml
Default configuration from /home/ozaki/dev/rubocop_sample/vendor/bundle/ruby/2.1.0/gems/rubocop-0.34.2/config/default.yml
Inheriting configuration from /home/ozaki/dev/rubocop_sample/vendor/bundle/ruby/2.1.0/gems/rubocop-0.34.2/config/enabled.yml
Inheriting configuration from /home/ozaki/dev/rubocop_sample/vendor/bundle/ruby/2.1.0/gems/rubocop-0.34.2/config/disabled.yml
.

1 file inspected, no offenses detected
Finished in 0.04518964 seconds

I corrected lib/rubocop/cop/style/method_call_parentheses.rb to check the asgn_node.loc respond to name.
(I wonder this is right way to fix this bug...)

[alexdowad]

Thanks for reporting this issue! But the "fix" doesn't go to the root of the bug.

Your code produces the following AST:

(or-asgn
  (send (ivar :@foo) :bar)
  (send nil :puts))

The problem is that asgn_node.loc is returning the Parser::Source::Map of its first child, (send (ivar :foo) :bar). Why? I don't know yet.

Until you know exactly what is causing the problem, you can't know what the correct fix is.

[alexdowad]

OK, I was wrong. It's normal for asgn_node.loc to return that value in this case.

[alexdowad]

I've found the problem.