Issue #16677 has been updated by zpd (Zheng Piaodan).


As far as I know there is no strictly correct math rule for evaluating `-2 ** 2.2` to `-(2 ** 2.2)` or `(-2) ** 2.2`. I expect the current behavior `-(2 ** 2.2)` since I think exponentiation takes higher precedence than unary minus operation.

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Bug #16677: Negative integer powered (**) to a float number results in a complex 
https://bugs.ruby-lang.org/issues/16677#change-84604

* Author: CamilleDrapier (Camille Drapier)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* ruby -v: 2.5.7, 2.6.5, 2.7.0
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
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Not sure if this is an unexpected behavior.

This works as I expect:

```
-2 ** 2.2 # => -4.59479341998814
```

But when I change the code a bit, it gives me a complex:

```ruby
-2.to_i ** 2.2 # => (3.717265962412589+2.7007518095995273i)

a = -2; a ** 2.2 # => (3.717265962412589+2.7007518095995273i)
```

This seems to happen only with negative numbers and float powers. I think it might be related to how `Fixnum` is treated differently from other classes by the power function.



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