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From "Tomas Rokicki (JIRA)" <j...@apache.org>
Subject [jira] [Created] (GROOVY-8077) double comparison (apparently) uses .equals and not ==
Date Tue, 07 Feb 2017 19:29:41 GMT
Tomas Rokicki created GROOVY-8077:
-------------------------------------

             Summary: double comparison (apparently) uses .equals and not ==
                 Key: GROOVY-8077
                 URL: https://issues.apache.org/jira/browse/GROOVY-8077
             Project: Groovy
          Issue Type: Bug
          Components: Compiler
    Affects Versions: 2.4.8
         Environment: Windows (but probably generic)
            Reporter: Tomas Rokicki


groovy:000> f1 = new Double(-1)
===> -1.0
groovy:000> f2 = new Double(0)
===> 0.0
groovy:000> f3 = new Double(1)
===> 1.0
groovy:000> (f1 * f2) == (f2 * f3)
===> false

This should return true.  It appears (f1*f2)==(f2*f3) is being compiled to Double#equals(Double)
where it should be compiled to unboxed float comparisons.  IEEE874 requires -0.0 be equal
to 0.0 when using a normal arithmetic comparison.  Note that Java does the correct thing with
==.  Double#equals(Double) (and #compareTo and #hashCode) are defined to distinguish negative
zero from zero so hash tables "work properly".



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