https://issues.dlang.org/show_bug.cgi?id=21095

          Issue ID: 21095
           Summary: [ICE] AssertError@dmd/expressionsem.d(5015): Assertion
                    failure
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: critical
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: ibuclaw@gdcproject.org

Release binaries will segfault:

class Mutex
{
    this(Object obj) {
        this(obj, true);
    }
    this()(Object, bool) in { }
}

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