diff --git a/src/client/types/typing.js b/src/client/types/typing.js
index 0c386be..30eec3c 100644
--- a/src/client/types/typing.js
+++ b/src/client/types/typing.js
@@ -75,12 +75,18 @@ const defaultInvocation = (context, ops) => {
     type: 'invoke',
     args: args.map(([, {type}]) => {
       const {defaultLiteral} = typeDescription(type, undefined);
-      if ('undefined' !== defaultLiteral) {
+      if ('undefined' !== typeof defaultLiteral) {
         return ({
           type: 'literal',
           value: defaultLiteral,
         });
       }
+      if ('expressions' === type) {
+        return {
+          type: 'expressions',
+          expressions: [],
+        };
+      }
       return ({
         type: 'expression',
         // eslint-disable-next-line no-use-before-define
@@ -93,7 +99,8 @@ const defaultInvocation = (context, ops) => {
 export const defaultOps = (context, type, originalOps = []) => {
   const ops = [...originalOps];
   let evaluated;
-  let {type: opsType} = descriptionFromOps(context, originalOps);
+  debugger;
+  let {type: opsType} = descriptionFromOps(context, ops);
   const typesVisited = {[opsType]: true};
   while (!fitsInto(opsType, type) || 0 === ops.length) {
     evaluated = compile({type: 'expression', ops})(context);
@@ -133,5 +140,6 @@ export const defaultOps = (context, type, originalOps = []) => {
   if ('function' === typeof evaluated) {
     ops.push(defaultInvocation(context, ops));
   }
+  console.log({dops: ops})
   return ops;
 };