Issue #13939 has been updated by nobu (Nobuyoshi Nakada).


It's a bug in 2.4.0 and 2.4.1 only.
Braces just after a literal has caused a syntax error before, like as:

danielpclark (Daniel P. Clark) wrote:
> I apologize I wrote that earlier with a different error message.  Here's what importing 'read_source' does in Ruby 2.4.2 (but will work for any other version of Ruby).
> 
> ~~~
> /usr/share/rvm/rubies/ruby-2.3.5/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- read_source (LoadError)

A brace block has higher precedence and is bound to the previous expression, and a literal cannot be a method call and have a block.

shevegen (Robert A. Heiler) wrote:
> I guess ruby core prefers short messages when possible (aka "syntax error, unexpected '}'")
> but this is indeed not always extremely helpful. 

Unfortunately, this message is generated by bison, not us.

----------------------------------------
Bug #13939: Ruby 2.4.2 has issue supporting Seattle.rb style for define_method
https://bugs.ruby-lang.org/issues/13939#change-66920

* Author: danielpclark (Daniel P. Clark)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
In Ruby 2.3 & 2.4.0 you can do this

~~~ruby
define_method :some_method_name { "asdf" }
~~~

As of my trying 2.4.2 this is no longer supported.  Anyone who tries to load my 'read_source' gem will get a failure message in require without explaining the specific area of code.

~~~
SyntaxError: /home/danielpclark/dev/read_source/test/support/example.rb:18: syntax error, unexpected '{', expecting keyword_end
ethod :also_attr_method_name { "asdf" }
                              ^
/home/danielpclark/dev/read_source/test/support/example.rb:18: syntax error, unexpected '}', expecting keyword_end
so_attr_method_name { "asdf" }
                              ^
	from (irb):2:in `require_relative'
	from (irb):2
	from /usr/share/rvm/rubies/ruby-2.4.2/bin/irb:11:in `<main>'
~~~

To fix my gem for Ruby 2.4.2 I now have to wrap the method name in parenthesis `()`

~~~ruby
define_method(:some_method_name) { "asdf" }
~~~

And that will work.  But I find this odd as the following will still work in 2.4.2:

~~~ruby
define_method :johny, instance_method(:apple)
~~~

Which is still Seattle.rb style.



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