Issue #13872 has been updated by matsuda (Akira Matsuda).


This is not a bug. The warning you see is a result of an improvement of "unused variable" detection at r59585.
Now it simply checks whether each variable is actually "used" or not. Please also take a look at #13809 to see what was solved here.
`var = var = "foo"` warns now because `var = var = "foo"` doesn't really "use" the variable `var`.

Please upgrade your code to actually "use" all the assigned local variables, in this case, to `var = "foo"; var = var`.


----------------------------------------
Bug #13872: Duplicate assignment no longer silences "assigned but unused variable" warning
https://bugs.ruby-lang.org/issues/13872#change-67263

* Author: segiddins (Samuel Giddins)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.5.0dev (2017-09-04 trunk 59742) [x86_64-darwin16]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
On ruby 2.4.1:

`ruby -W -e 'def a; var = var = "foo"; end'`

prints no warning

On ruby 2.5.0dev (2017-09-04 trunk 59742) [x86_64-darwin16]

`ruby -W -e 'def a; var = var = "foo"; end'`

prints warning `-e:1: warning: assigned but unused variable - var`

This feature was useful when the local binding would be passed to another scope (like to ERB), and those variables were only accessed via the binding



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>