https://issues.dlang.org/show_bug.cgi?id=20598

          Issue ID: 20598
           Summary: AssertError@dmd/optimize.d(692): 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

Reduced test:

TemplateInstance[TemplateInstanceBox] instances;

class TemplateInstance
{
    bool equalsx()
    {
    }

    final toHash()
    {
    }
}

struct TemplateInstanceBox
{
    TemplateInstance ti;

    bool opEquals(ref const TemplateInstanceBox s) const
    {
        (cast()s.ti).equalsx;
    }
}

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