\[~ann.campbell.2]I am updating example and message for Java as a switch with twice the same case won't compile cf \http://docs.oracle.com/javase/specs/jls/se8/html/jls-14.html#jls-14.11
"No two of the case constants associated with the switch statement have the same value."
\[~ann.campbell.2] same for C-Family as for Java, in fact I suppose that majority of languages forbids duplicate "cases" and minority allows, so might be better to do opposite - generalize "if" and specialize "switch"
Just a note: for Go compiler may disallow some trivial duplicated conditions in ``++case++`` clauses, but it is possible in general. \https://golang.org/ref/spec#Switch_statements