Damian's magic hack

Author: dkegel-fastly

compiler/interface.go

@@ -591,23 +591,31 @@ func signature(sig *types.Signature) string {
 			if i > 0 {
 				s += ", "
 			}
-			s += sig.Params().At(i).Type().String()
+			s += emptyInterfaceToAny(sig.Params().At(i).Type().String())
 		}
 		s += ")"
 	}
 	if sig.Results().Len() == 0 {
 		// keep as-is
 	} else if sig.Results().Len() == 1 {
-		s += " " + sig.Results().At(0).Type().String()
+		s += " " + emptyInterfaceToAny(sig.Results().At(0).Type().String())
 	} else {
 		s += " ("
 		for i := 0; i < sig.Results().Len(); i++ {
 			if i > 0 {
 				s += ", "
 			}
-			s += sig.Results().At(i).Type().String()
+			s += emptyInterfaceToAny(sig.Results().At(i).Type().String())
 		}
 		s += ")"
 	}
 	return s
 }
+
+func emptyInterfaceToAny(typ string) string {
+	if typ == "interface{}" {
+		return "any"
+	}
+
+	return typ
+}