A misfeature of a system, especially a
programming language or environment, that tends to breed bugs or
mistakes because it both enticingly easy to invoke and completely
unexpected and/or unreasonable in its outcome. For example, a
classic gotcha in C is the fact that if (a=b) {code;}
is syntactically valid and sometimes even correct. It puts the
value of b into a and then executes code if
a is non-zero. What the programmer probably meant was
if (a==b) {code;}, which executes code if a
and b are equal.
