src/frontend.lisp: Report an error if no output types are requested.

Silently not doing anything is sort of unhelpful.

diff --git a/src/frontend.lisp b/src/frontend.lisp
index 0336d1ade577b3f5433beb35d14afb32067ba19c..f1694ab9891d760dcdd6541e80571feb8c1d80fc 100644 (file)
--- a/src/frontend.lisp
+++ b/src/frontend.lisp
@@ -169,6 +169,10 @@     (define-program
                                             reason))
                           nil)))))
 
+             ;; If there are no output types then there's nothing to do.
+             (unless output-reasons
+               (error "No output types given: nothing to do"))
+
              ;; If we're writing the builtin module then now seems like a
              ;; good time to do that.
              (when builtinsp