Index: generic/nsf.c
===================================================================
diff -u -re75f57c39bdc5455b65317013ed58d2db8d22dbd -r6b039871ad08a490bb975e3ddd713177f6dd9ea9
--- generic/nsf.c	(.../nsf.c)	(revision e75f57c39bdc5455b65317013ed58d2db8d22dbd)
+++ generic/nsf.c	(.../nsf.c)	(revision 6b039871ad08a490bb975e3ddd713177f6dd9ea9)
@@ -13925,17 +13925,30 @@
       /*fprintf(stderr, "MethodProperty, ParamDefsGet cmd %p paramDefs %p returns %p\n",
 	cmd, paramDefs, paramDefs?paramDefs->returns:NULL);*/
 
-      if (paramDefs == NULL) {
-	paramDefs = ParamDefsNew();
-	ParamDefsStore(interp, cmd, paramDefs);
-	/*fprintf(stderr, "new param defs %p for cmd %p %s\n", paramDefs, cmd, methodName);*/
-      }
-      objPtr = methodproperty == MethodpropertySlotobjIdx ? &paramDefs->slotObj : &paramDefs->returns;
       if (valueObj == NULL) {
-	/* must be a returns query */
-	Tcl_SetObjResult(interp, *objPtr ? *objPtr : NsfGlobalObjs[NSF_EMPTY]);
+	/* a query for "returns" or "slotobj" */
+	Tcl_Obj *resultObj;
+
+	if (paramDefs == NULL) {
+	  resultObj = NsfGlobalObjs[NSF_EMPTY];
+	} else {
+	  objPtr = methodproperty == MethodpropertySlotobjIdx ? &paramDefs->slotObj : &paramDefs->returns;
+	  resultObj = *objPtr ? *objPtr : NsfGlobalObjs[NSF_EMPTY];
+	}
+	Tcl_SetObjResult(interp, resultObj);
+
       } else {
+	/* setting "returns" or "slotobj" */
 	const char *valueString = ObjStr(valueObj);
+
+	if (paramDefs == NULL) {
+	  /* acquire new paramDefs */
+	  paramDefs = ParamDefsNew();
+	  ParamDefsStore(interp, cmd, paramDefs);
+	  /*fprintf(stderr, "new param defs %p for cmd %p %s\n", paramDefs, cmd, methodName);*/
+	}
+	objPtr = methodproperty == MethodpropertySlotobjIdx ? &paramDefs->slotObj : &paramDefs->returns;
+
 	/* Set a new value; if there is already a value, free it */
 	if (*objPtr) {
 	  DECR_REF_COUNT(*objPtr);
Index: tests/returns.test
===================================================================
diff -u -re75f57c39bdc5455b65317013ed58d2db8d22dbd -r6b039871ad08a490bb975e3ddd713177f6dd9ea9
--- tests/returns.test	(.../returns.test)	(revision e75f57c39bdc5455b65317013ed58d2db8d22dbd)
+++ tests/returns.test	(.../returns.test)	(revision 6b039871ad08a490bb975e3ddd713177f6dd9ea9)
@@ -354,14 +354,21 @@
 
 Test case empty-paramdefs-robustedness {
   ::nx::Object create ku {
-    # Condition 1: An empty or checker-free parameter spec!
+    # 1: Create an empty or checker-free parameter spec
     :method foo {} {;}
-    # Condition 2: A call to ::nsf::methodproperty which acquires a
-    # NsfParamDefs
-    ::nsf::methodproperty [::nx::current] foo returns; # a returns query
-    # At this point, we find a NsfParamDefs structure with an empty set
-    # of params! Subsequent references to paramDefs->paramsPtr in
-    # e.g. ListCmdParams() would crash ... if not trapped appropriately.
-    ? [list [::nx::current] info method parameter foo] ""; # boom!
+    ? [:info method parameter foo] ""
+    # 2: A call to ::nsf::methodproperty which might require NsfParamDefs
+    ? [list ::nsf::methodproperty [::nx::current] foo returns] ""
+    # 3: Check, if "info method parameter" still works
+    ? [:info method parameter foo] ""
+    ? [list ::nsf::methodproperty [::nx::current] foo returns] ""
+    # 4: Set methodproperty to some value and check again
+    ::nsf::methodproperty [::nx::current] foo returns int
+    ? [list ::nsf::methodproperty [::nx::current] foo returns] "int"
+    ? [:info method parameter foo] ""
+    # 5: Reset methodproperty and query again
+    ::nsf::methodproperty [::nx::current] foo returns ""
+    ? [list ::nsf::methodproperty [::nx::current] foo returns] ""
+    ? [:info method parameter foo] ""
   }
 }
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