Also, the "hot loop hypothesis" still tends to hold in CL; you only end up needing to annotate the crap out of the small number of functions that end up being m

Also, the "hot loop hypothesis" still tends to hold in CL; you only end up needing to annotate the crap out of the small number of functions that end up being most of your runtime. (It can sometimes be worth it to declare types for other functions, but that's as much for error checking as performance.) Being able to set the compiler flags on a per-function level is also really helpful for this, since these hot functions can be compiled for run-time speed rather than safety, debuggability, or compile-time speed (once one's sure they're correct, of course!).