UselessSetterCall bug?

[lenntt]

Hi,
Im getting the following error:

1 error occurred:
An error occurred while UselessSetterCall cop was inspecting        .../...._controller_decorator.rb.
Errors are usually caused by RuboCop bugs.
Please, report your problems to RuboCop's issue tracker.
Mention the following information in the issue report:
0.14.1 (using Parser 2.0.0, running on ruby 2.0.0 x86_64-linux)

Removing the following line from my code, removes the error:

some_name = @some_object.some_list.last

even changing the name 'some_name', seems to 'fix' the error,
while 'some_name' is being used a local variable, not an explicit method or accessor. So its hard to tell what is going on.

[bbatsov]

I guess @yujinakayama will have a look at this soon.

[yujinakayama]

Sure, I'll take a look.

[Confusion]

Partial stacktrace:

An error occurred while UselessSetterCall cop was inspecting something.rb.
undefined local variable or method `table' for #<Rubocop::Cop::Lint::UselessSetterCall::MethodVariableTracker:0x000000033525c0>
vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:122:in `block in process_multiple_assignment'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:113:in `each'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:113:in `each_with_index'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:113:in `process_multiple_assignment'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:85:in `block in contain_object_passed_as_argument?'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:101:in `block in scan'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:100:in `catch'
vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:100:in `scan'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:105:in `block (2 levels) in scan'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:103:in `each'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:103:in `block in scan'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:100:in `catch'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:100:in `scan'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:82:in `contain_object_passed_as_argument?'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:49:in `check_for_useless_assignment'
/vendor/bundle/ruby/2.0.0/gems/rubocop-0.14.1/lib/rubocop/cop/lint/useless_setter_call.rb:22:in `on_def'

[yujinakayama]

@SirLenz0rlot Can you share all lines of the method? I cannot reproduce the issue only with the snippet some_name = @some_object.some_list.last.

[sullerandras]

I have the same error message and stack trace for one of my classes. I'm not allowed to share the problematic code.
0.14.1 (using Parser 2.0.0, running on ruby 2.0.0 x86_64-darwin11.4.2)

However, it seems easy to fix, just a missing @ in cop/lint/useless_setter_call.rb:122
table[lhs_variable_name] = false
should be
@table[lhs_variable_name] = false

[yujinakayama]

@sullerandras Yeah, I've reproduced the error reported by @Confusion and already fixed in my local environment.
It occurs with multiple-assignement with non-array right hand side (e.g. a, b = do_something).

However I guess the issue reported by @SirLenz0rlot seems to be another one, since the report and the workaround are not related to multiple-assignment.

[lenntt]

@yujinakayama
Sorry I couldnt pick an example to exactly to reproduce the error. Unfortunately, I cannot share all the lines of the method.
The error-causing line does not contain multiple-assignment, but I'm getting the exact same stacktrace as @Confusion