diff --git a/src/dorem.c b/src/dorem.c
index a3b4840e..d1f5d755 100644
--- a/src/dorem.c
+++ b/src/dorem.c
@@ -71,6 +71,10 @@ check_trigger_function(char const *fname, char const *type)
         }
         return;
     }
+    if (f->nargs != 1) {
+        Wprint("%s function `%s' defined at %s:%d should take 1 argument but actually takes %d", type, fname, f->filename, f->lineno, f->nargs);
+        return;
+    }
     if (ensure_expr_references_first_local_arg(f->node)) {
         return;
     }
diff --git a/tests/test.cmp b/tests/test.cmp
index d5831afe..423165b5 100644
--- a/tests/test.cmp
+++ b/tests/test.cmp
@@ -5371,10 +5371,48 @@ REM OMITFUNC gg MSG hehe
 hehe
 
 
-FSET gg(x) x-x
+FSET gg(x,y,z) 0
 ../tests/test.rem(1035): Function gg redefined (previously defined at ../tests/test.rem:1030)
 REM WARN gg MSG Wookie
+../tests/test.rem(1036): WARN function `gg' defined at ../tests/test.rem:1035 should take 1 argument but actually takes 3
 ../tests/test.rem(1036): Trig = Saturday, 16 February, 1991
+../tests/test.rem(1036): Undefined WARN function: `gg'
+Wookie
+
+REM AT 11:00 SCHED gg MSG blork
+../tests/test.rem(1037): SCHED function `gg' defined at ../tests/test.rem:1035 should take 1 argument but actually takes 3
+../tests/test.rem(1037): Trig = Saturday, 16 February, 1991 AT 11:00
+blork
+
+REM OMITFUNC gg MSG hehe
+../tests/test.rem(1038): OMITFUNC function `gg' defined at ../tests/test.rem:1035 should take 1 argument but actually takes 3
+../tests/test.rem(1038): Trig = Saturday, 16 February, 1991
+hehe
+
+
+FSET gg() 0
+../tests/test.rem(1040): Function gg redefined (previously defined at ../tests/test.rem:1035)
+REM WARN gg MSG Wookie
+../tests/test.rem(1041): WARN function `gg' defined at ../tests/test.rem:1040 should take 1 argument but actually takes 0
+../tests/test.rem(1041): Trig = Saturday, 16 February, 1991
+../tests/test.rem(1041): Undefined WARN function: `gg'
+Wookie
+
+REM AT 11:00 SCHED gg MSG blork
+../tests/test.rem(1042): SCHED function `gg' defined at ../tests/test.rem:1040 should take 1 argument but actually takes 0
+../tests/test.rem(1042): Trig = Saturday, 16 February, 1991 AT 11:00
+blork
+
+REM OMITFUNC gg MSG hehe
+../tests/test.rem(1043): OMITFUNC function `gg' defined at ../tests/test.rem:1040 should take 1 argument but actually takes 0
+../tests/test.rem(1043): Trig = Saturday, 16 February, 1991
+hehe
+
+
+FSET gg(x) x-x
+../tests/test.rem(1045): Function gg redefined (previously defined at ../tests/test.rem:1040)
+REM WARN gg MSG Wookie
+../tests/test.rem(1046): Trig = Saturday, 16 February, 1991
 Entering UserFN gg(1)
 x => 1
 x => 1
@@ -5383,27 +5421,27 @@ Leaving UserFN gg(1) => 0
 Wookie
 
 REM AT 11:00 SCHED gg MSG blork
-../tests/test.rem(1037): Trig = Saturday, 16 February, 1991 AT 11:00
+../tests/test.rem(1047): Trig = Saturday, 16 February, 1991 AT 11:00
 blork
 
 REM OMITFUNC gg MSG hehe
-../tests/test.rem(1038): Trig = Saturday, 16 February, 1991
+../tests/test.rem(1048): Trig = Saturday, 16 February, 1991
 hehe
 
 
 REM WARN not_defined MSG Wookie
-../tests/test.rem(1040): Trig = Saturday, 16 February, 1991
-../tests/test.rem(1040): Undefined WARN function: `not_defined'
+../tests/test.rem(1050): Trig = Saturday, 16 February, 1991
+../tests/test.rem(1050): Undefined WARN function: `not_defined'
 Wookie
 
 REM AT 11:00 SCHED not_defined MSG blork
-../tests/test.rem(1041): Undefined SCHED function: `not_defined'
-../tests/test.rem(1041): Trig = Saturday, 16 February, 1991 AT 11:00
+../tests/test.rem(1051): Undefined SCHED function: `not_defined'
+../tests/test.rem(1051): Trig = Saturday, 16 February, 1991 AT 11:00
 blork
 
 REM OMITFUNC not_defined MSG hehe
-../tests/test.rem(1042): Undefined OMITFUNC function: `not_defined'
-../tests/test.rem(1042): Trig = Saturday, 16 February, 1991
+../tests/test.rem(1052): Undefined OMITFUNC function: `not_defined'
+../tests/test.rem(1052): Trig = Saturday, 16 February, 1991
 hehe
 
 
diff --git a/tests/test.rem b/tests/test.rem
index 878b0bac..d276de8b 100644
--- a/tests/test.rem
+++ b/tests/test.rem
@@ -1032,6 +1032,16 @@ REM WARN gg MSG Wookie
 REM AT 11:00 SCHED gg MSG blork
 REM OMITFUNC gg MSG hehe
 
+FSET gg(x,y,z) 0
+REM WARN gg MSG Wookie
+REM AT 11:00 SCHED gg MSG blork
+REM OMITFUNC gg MSG hehe
+
+FSET gg() 0
+REM WARN gg MSG Wookie
+REM AT 11:00 SCHED gg MSG blork
+REM OMITFUNC gg MSG hehe
+
 FSET gg(x) x-x
 REM WARN gg MSG Wookie
 REM AT 11:00 SCHED gg MSG blork