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Bug #17017

Updated by sambostock (Sam Bostock) 10 months ago

While continuing to add edge cases to [`Range#minmax` specs](https://github.com/ruby/spec/pull/777), I discovered the following bug: 

 ```ruby 
 (1..3.1).to_a.max      == 3        # As expected 
 (1..3.1).to_a.minmax == [1, 3] # As expected 

 (1..3.1).max      == 3.1           # Should be 3, as above 3 
 (1..3.1).minmax == [1, 3.1]      # Should be [1, 3], as above 3] 
 ``` 

 One way to detect this scenario might be to do (whatever the C equivalent is of) 

 ```ruby 
 range_end.is_a?(Numeric)                        // Is this a numeric range? 
   && (range_end - range_begin).modulo(1) == 0 // Can we reach the range_end using the standard step size (1) 
 ``` 

 As for how to handle it, a couple options come to mind: 

 - We could error out and do something similar to what we do for exclusive ranges 

 ```ruby 
 raise TypeError, 'cannot exclude non Integer end value' 
 ``` 

 - We might be able to calculate the range end by doing something like 

 ```ruby 
 num_steps = (range_end / range_beg).to_i - 1 # one fewer steps than would exceed the range_end 
 max = range_beg + num_steps                    # take that many steps all at once 
 ``` 

 - We could delegate to `super` and enumerate the range to find the max 

 ```ruby 
 super 
 ```

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