It depends on a couple of factors. Personally I always write subtraction as &quot;x - y&quot;, so I never have any issues. Also, if undeclared variables are a compile-time error, the compiler will (probably) complain loudly about &quot;x-y&quot;. So you can fix that quickly and easily, it&#x27;s not too bad.<p>The one error that might be problematic depending on the language&#x27;s semantics is if you write something like &quot;x.y-z&quot; intending to subtract &quot;z&quot; from &quot;x.y&quot;, but in fact you are going to get the &quot;y-z&quot; property of &quot;x&quot;. I must say that in Earl Grey you&#x27;ll unfortunately end up with &quot;undefined&quot; as the result of that expression (saner languages would raise an exception on a missing property). I have never had that issue in practice, but then again, I always space subtraction.