From: shevegen@...
Date: 2019-07-04T13:06:00+00:00
Subject: [ruby-core:93544] [Ruby master Feature#11460] Unhelpful error message when naming a module with the same name as an existing class

Issue #11460 has been updated by shevegen (Robert A. Heiler).


> I would appreciate feedback on whether this more detailed error message is an improvement.

I think this depends on what the ruby user at hand is doing; and how much expertise that
ruby user may have. Some behaviour in ruby can be confusing to newcomers, such as when 
variables may be assigned to nil, without explicit "x = nil".

I personally do not really need a change either way in the context of this suggestion (I
am fine with the current behaviour), but I think it is not completely unreasonable to
assume that there could be use cases for letting ruby be more verbose in this (or
similar) situation, if it leads to an improvement such as less confusion for newcomers.

In the long run it may be good to sort of have ruby in different "modes"; a bit like
the did-you-mean gem and the -w flag for running ruby code, but with more control over
the messages (as long as they are just warnings, but perhaps also some that relate to
errors, in particular when ruby interacts with the user). But as written before, I am
really mostly neutral either way - not really decidedly adopting any pro or con 
opinion, just commenting to the question by jeremy. :-)

----------------------------------------
Feature #11460: Unhelpful error message when naming a module with the same name as an existing class
https://bugs.ruby-lang.org/issues/11460#change-79108

* Author: iMIchael (Michael Martinez)
* Status: Feedback
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
# Summary
The error message when naming a module with the same name as an existing class causes more trouble then it helps.

# Steps to Reproduce
~~~
class X;end
module X;end
=> TypeError: X is not a module
~~~

# Expected Results
Ruby has this very helpful and explicit error when reassigning a value to an existing constant. 

~~~
A = 1
A = 2
warning: already initialized constant A
warning: previous definition of A was here
~~~

which makes me expect Ruby to keep track of names of global constants and prevent me from colliding names with helpful warnings. This warning however raises a "Type error" which is not very intuitive. When users think of type errors they think of things like "foo" * "foo" => TypeError: no implicit conversion of String into Integer. 

# Actual Results
Confusion about what the actual error is, especially for people learning Ruby.

---Files--------------------------------
mod-reopen-error-message.patch (2.82 KB)
0001-Show-the-previous-definition-location.patch (4.89 KB)


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