Make this unreachable case an error.

diff --git a/src/runtime/dragon4.scm b/src/runtime/dragon4.scm
index eee2dcf6271b4d9d9842bb89ca7fc563455592ed..e10ba149876c0efdf2b2795d0a85b4bf1f753400 100644 (file)
--- a/src/runtime/dragon4.scm
+++ b/src/runtime/dragon4.scm
@@ -103,7 +103,7 @@ not much different to numbers within a few orders of magnitude of 1.
              ((flo:zero? x)
               (if (flo:sign-negative? x) "-0." "0."))
              (else
-              "+nan.0")))))
+              (error "Invalid floating-point value:" x))))))
 
 (define (flonum-printer:normal-output digits k radix)
   (let ((k+1 (+ k 1)))