Incorrect error message for invalid use of special-form

[cbaggers]

(glsl-code
 (compile-frag ((a :int)) :450 nil
   (let ((a (if (= a 1)
				(return 1)
				(return 1 2))))
	 a)))

raises

invalid number of arguments: 4
   [Condition of type SB-INT:SIMPLE-PROGRAM-ERROR]

Restarts:
 0: [*ABORT] Return to SLIME's top level.
 1: [ABORT] abort thread (#<THREAD "repl-thread" RUNNING {10025E8003}>)

But this is an error for the function that implements the special form, not a proper varjo error for incorrect number of args