[ruby-core:92653] [Ruby trunk Feature#15848] Silence warning when conditional assignments are wrapped in parentheses

Issue #15848 has been updated by sos4nt (Stefan Sch館ler).


nobu (Nobuyoshi Nakada) wrote:
> No, it doesn't.
> That warning is only when the RHS is a literal, but a method call doesn't cause the warning.

It didn't occur to me the warning is aware of that. I should have tested with the actual example code. Thanks for the clarification nobu!

And thanks for closing it as a duplicate, I searched for one before posting but couldn't find any. (probably because it was already closed)


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Feature #15848: Silence warning when conditional assignments are wrapped in parentheses
https://bugs.ruby-lang.org/issues/15848#change-78016

* Author: sos4nt (Stefan Sch館ler)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
Sometime it's convenient to have an assignment in an `if`-condition. The Ruby documentation even contains an example showing this *"most common use of side-effect"* practice:

http://ruby-doc.org/core-2.6.3/doc/syntax/control_expressions_rdoc.html#label-if+Expression
```ruby
if a = object.some_value
  # do something to a
end
```

Running that code however results in a warning:

> warning: found = in conditional, should be ==

It's very unfortunate that the Ruby docs contain example code that the parser complains about. And it's unfortunate that we can't make use of conditional assignments without getting warnings or turning off warnings.

I propose an obvious change to the current warning mechanism:

**Don't show the warning when the assignment is wrapped in parentheses.**

```ruby
if a = object.some_value
  # warning
end

if (a = object.some_value)
  # no warning
end
```

This is the way RoboCop already works and it's also a known workaround from other languages.

It would also allow the documentation to contain a warning-free example.



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