From: duerst@...
Date: 2019-07-04T01:15:57+00:00
Subject: [ruby-core:93525] [Ruby master Bug#11460] Unhelpful error message when naming a module with the same name as an existing class

Issue #11460 has been updated by duerst (Martin D�rst).


jeremyevans0 (Jeremy Evans) wrote:
> So I don't think there is a bug here.  It is possible to change the format the error message, though.  Attached is a patch that changes the error message to the include the current class of the object:
> 
> ```ruby
> class X;end
> module X;end
> # TypeError (X is not a module, it is a Class)
> module Y;end
> class Y;end
> # TypeError (Y is not a class, it is a Module)
> ```
> 
> I would appreciate feedback on whether this more detailed error message is an improvement.

I think it is.

----------------------------------------
Bug #11460: Unhelpful error message when naming a module with the same name as an existing class
https://bugs.ruby-lang.org/issues/11460#change-79088

* Author: iMIchael (Michael Martinez)
* Status: Feedback
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.2.0p0
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
# 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)


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