diff --git a/CHANGES.current b/CHANGES.current
index e0b7f0897..23c800f94 100644
--- a/CHANGES.current
+++ b/CHANGES.current
@@ -7,6 +7,10 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.0.1 (in progress)
 ===========================
 
+2019-06-28: wsfulton
+            [MzScheme, OCaml] #1559 $arg and $input were incorrectly substituted in the
+            argout typemap when two or more arguments were present.
+
 2019-06-24: wsfulton
             [Python, Ruby] #1538 Remove the UnknownExceptionHandler class in order to be
             C++17 compliant as it uses std::unexpected_handler which was removed in C++17.
diff --git a/Source/Modules/mzscheme.cxx b/Source/Modules/mzscheme.cxx
index 543874172..788681330 100644
--- a/Source/Modules/mzscheme.cxx
+++ b/Source/Modules/mzscheme.cxx
@@ -221,7 +221,6 @@ public:
 
     Wrapper *f = NewWrapper();
     String *proc_name = NewString("");
-    String *source = NewString("");
     String *target = NewString("");
     String *arg = NewString("");
     String *cleanup = NewString("");
@@ -312,10 +311,9 @@ public:
       String *ln = Getattr(p, "lname");
 
       // Produce names of source and target
-      Clear(source);
       Clear(target);
       Clear(arg);
-      Printf(source, "argv[%d]", i);
+      String *source = NewStringf("argv[%d]", i);
       Printf(target, "%s", ln);
       Printv(arg, Getattr(p, "name"), NIL);
 
@@ -339,6 +337,7 @@ public:
       if (i >= numreq) {
 	Printf(f->code, "}\n");
       }
+      Delete(source);
     }
 
     /* Insert constraint checking code */
@@ -465,7 +464,6 @@ public:
     }
 
     Delete(proc_name);
-    Delete(source);
     Delete(target);
     Delete(arg);
     Delete(outarg);
diff --git a/Source/Modules/ocaml.cxx b/Source/Modules/ocaml.cxx
index ad9c94800..6f2a34962 100644
--- a/Source/Modules/ocaml.cxx
+++ b/Source/Modules/ocaml.cxx
@@ -473,7 +473,6 @@ public:
 
     Wrapper *f = NewWrapper();
     String *proc_name = NewString("");
-    String *source = NewString("");
     String *target = NewString("");
     String *arg = NewString("");
     String *cleanup = NewString("");
@@ -580,10 +579,9 @@ public:
       pt = SwigType_typedef_qualified(pt);
 
       // Produce names of source and target
-      Clear(source);
       Clear(target);
       Clear(arg);
-      Printf(source, "caml_list_nth(args,%d)", i);
+      String *source = NewStringf("caml_list_nth(args,%d)", i);
       Printf(target, "%s", ln);
       Printv(arg, Getattr(p, "name"), NIL);
 
@@ -607,6 +605,7 @@ public:
       if (i >= numreq) {
 	Printf(f->code, "}\n");
       }
+      Delete(source);
     }
 
     /* Insert constraint checking code */
@@ -787,7 +786,6 @@ public:
       Printf(f_mlibody, "val %s : c_obj -> c_obj\n", mangled_name);
 
     Delete(proc_name);
-    Delete(source);
     Delete(target);
     Delete(arg);
     Delete(outarg);