From: "nobu (Nobuyoshi Nakada) via ruby-core" <ruby-core@...>
Date: 2025-01-20T05:01:49+00:00
Subject: [ruby-core:120741] [Ruby master Bug#21048] [Prism] rescue in modifier form with condition behaves differently

Issue #21048 has been updated by nobu (Nobuyoshi Nakada).


Earlopain (Earlopain _) wrote:
> Prism interprets it as `(foo rescue nil) if false`, not calling the method. `parse.y` does `foo rescue (nil if false)` since at least Ruby 2.0

Inverse?

> ```sh
> $ ruby -v
> ruby 3.5.0dev (2025-01-19T12:44:20Z master f27ed98eff) +PRISM [x86_64-linux]
> 
> $ ruby code.rb
> Called: true
> 
> $ ruby --parser=parse.y code.rb
> Called: false
> ```



----------------------------------------
Bug #21048: [Prism] rescue in modifier form with condition behaves differently
https://bugs.ruby-lang.org/issues/21048#change-111572

* Author: Earlopain (Earlopain _)
* Status: Open
* ruby -v: ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux]
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
With the following code there is a discrepancy in how prism and parse.y consider precedence:

```rb
$called = false
def foo
  $called = true
end

foo rescue nil if false

puts "Called: #{$called}"
```

Prism interprets it as `(foo rescue nil) if false`, not calling the method. `parse.y` does `foo rescue (nil if false)` since at least Ruby 2.0

```sh
$ ruby -v
ruby 3.5.0dev (2025-01-19T12:44:20Z master f27ed98eff) +PRISM [x86_64-linux]

$ ruby code.rb
Called: true

$ ruby --parser=parse.y code.rb
Called: false
```



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