CL-USER> (trivial-cltl2:define-declaration foo (&rest things)
           (values :declare (cons 'foo things)))
#<FUNCTION (LAMBDA
               (SB-KERNEL:LEXENV SB-CLTL2::SPEC SB-CLTL2::PD-VARS
                SB-CLTL2::PD-FVARS)) {53CFAAFB}>

CL-USER> (locally (declare (foo 42))
           (macrolet 
               ((foo (&environment env)
                  `',(trivial-cltl2:declaration-information 
                      'foo
                      env)))
             (foo)))
((FOO 42) #<NULL-LEXENV>)