From: "nobu (Nobuyoshi Nakada) via ruby-core" <ruby-core@ml.ruby-lang.org>
To: ruby-core@ml.ruby-lang.org
Cc: "nobu (Nobuyoshi Nakada)" <noreply@ruby-lang.org>
Subject: [ruby-core:117844] [Ruby master Bug#20482] nil variables in a guard clause of a standalone => or in expression
Date: Sun, 12 May 2024 07:05:52 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-108249.20240512070552.7613@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-20482.20240511164529.7613@ruby-lang.org
Issue #20482 has been updated by nobu (Nobuyoshi Nakada).
Soilent (Konstantin x) wrote in #note-2:
> Thank you, nobu! That explains it.
>
> Just to clarify, is this how the expression is parsed?
>
> ```ruby
> ( [1, 2] in a, b ) if b == 2*a
> ```
Yes, you can confirm the AST by `ruby --dump=parsetree -e '1 in a if a'` (the code is simplified).
> And since this is a modifier `if`, the parser creates variables a and b first, which is why they are defined in the test expression?
Yes, `a` and `b` are created by `[1, 2] in a, b` and available in the `if` condition.
----------------------------------------
Bug #20482: nil variables in a guard clause of a standalone => or in expression
https://bugs.ruby-lang.org/issues/20482#change-108249
* Author: Soilent (Konstantin x)
* Status: Open
* ruby -v: ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [arm64-darwin23]
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following expression produces a TypeError, which is quite unexpected:
```ruby
[1, 2] in a, b if b == 2*a
```
```
x.rb:1:in `*': nil can't be coerced into Integer (TypeError)
[1, 2] in a, b if b == 2*a
^
from x.rb:1:in `<main>'
```
The expression above should be equivalent to the following one, which works as expected:
```ruby
case [1, 2]
in a, b if b == 2*a
true
else
false
end
# => true
```
Apologies in advance if this is intentional or has been reported before.
--
https://bugs.ruby-lang.org/
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prev parent reply other threads:[~2024-05-12 7:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 16:45 [ruby-core:117833] [Ruby master Bug#20482] nil variables in a guard clause of a standalone => or in expression Soilent (Konstantin x) via ruby-core
2024-05-12 0:05 ` [ruby-core:117836] " nobu (Nobuyoshi Nakada) via ruby-core
2024-05-12 6:08 ` [ruby-core:117841] " Soilent (Konstantin x) via ruby-core
2024-05-12 7:05 ` nobu (Nobuyoshi Nakada) via ruby-core [this message]
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