18:34:43mfianoThe former is a promise to the compiler, which is allowed to do nothing or anything.
18:35:03mfianoThe latter will allocate a new object
18:35:05lotuseaterhm i thought with THE it's more like a promise "this shall be that type" and with coerce an instruction "transforms this to the new type"
18:38:33lotuseaterhaha yes i had this experience at some point ^^
18:39:31aethWhat I mean is, (prog1 x (check-type x double-float)) in SBCL will let you supply a new x that satisfies double-float, while (the double-float x) will fail the program if it's not a double-float