(declaim (safety 3) (ftype (function ({argument types}) {return types}) {function name})) It checks both at compile time and at run time. I find it great for b

(declaim (safety 3) (ftype (function ({argument types}) {return types}) {function name})) It checks both at compile time and at run time. I find it great for bug squashing. See http://www.sbcl.org/manual/index.html#Declarations-as-Assertions http://www.sbcl.org/manual/index.html#Declarations-as-Assert...