List of warnings that the byte-compiler should issue (t for all).
Elements of the list may be:
free-vars references to variables not in the current lexical scope.
unresolved calls to unknown functions.
callargs function calls with args that don't match the definition.
redefine function name redefined from a macro to ordinary function or vice
versa, or redefined to take a different number of arguments.
obsolete obsolete variables and functions.
noruntime functions that may not be defined at runtime (typically
defined only under `eval-when-compile').
cl-functions calls to runtime functions from the CL package (as
distinguished from macros and aliases).
commands that normally shouldn't be called from Lisp code.
make-local calls to make-variable-buffer-local that may be incorrect.
mapcar mapcar called for effect.
constants let-binding of, or assignment to, constants/nonvariables.
suspicious constructs that usually don't do what the coder wanted.
If the list begins with `not', then the remaining elements specify warnings to suppress. For example, (not mapcar) will suppress warnings about mapcar.