Issue #16506 has been updated by zverok (Victor Shepelev).


@sawa That's an interesting question! I wrote an original doc, and I meant this:

```ruby
# test.rb:
class A
end

class A # reopening
end

Object.const_source_location('A') # => ["test.rb", 1] -- first definition
```

But of course, if we are talking about plain constants (not classes), you are right:

```ruby
# test.rb:
A = 1

A = 2

Object.const_source_location('A') # => ["test.rb", 3] -- LAST definition
```

I'll submit a PR with clarifications to cover both cases.

----------------------------------------
Bug #16506: Documentation for `Module#const_souce_location` is wrong
https://bugs.ruby-lang.org/issues/16506#change-83807

* Author: sawa (Tsuyoshi Sawada)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.7
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
https://ruby-doc.org/core-2.7.0/Module.html#method-i-const_source_location says:

> Returns the Ruby source filename and line number containing **first** definition of constant specified.

It should be:

> Returns the Ruby source filename and line number containing the **last** definition (the effective definition) of the constant specified.

It also has an example line:

```ruby
p Object.const_source_location('A')       # => ["test.rb", 1]  -- note it is first entry, not "continuation"
```

but that may give the impression that the first-ness is due to the nature of this method. The reason `["test.rb", 1]` is returned instead of `["test.rb", 14]` is because the constant is created at line 1, and is only reopened/modified in line 14. Perhaps, this line can be changed to:


```ruby
p Object.const_source_location('A')       # => ["test.rb", 1]  -- note 'A' is created in line 1, and is only reopened/modified in "continuation"
```

Adding something like this may make it clear that it is the last definition that is returned:

```ruby
D = 'D1'
D = 'D2'
D = 'D3'

...

Object.const_source_location('D') # => returns the location that corresponds to 'D3'



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