https://issues.dlang.org/show_bug.cgi?id=21424

          Issue ID: 21424
           Summary: Variable is incremented twice
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: tim.dlang@t-online.de

The following code fails with dmd v2.094.1 under Linux x86_64:

int main()
{
        ubyte[10] buf;
        size_t pos = 0;
        size_t num = 5;
        buf[pos++] += num;
        assert(pos == 1);
        assert(buf[0] == 5);
        assert(buf[1] == 0);
        return 0;
}

Instead pos == 2, buf[0] == 0 and buf[1] == 5.

The same code works as expected with ldc and gdc.

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