diff --git a/src/execution/values.js b/src/execution/values.js
index b941374fbf..0c9610dba9 100644
--- a/src/execution/values.js
+++ b/src/execution/values.js
@@ -124,11 +124,11 @@ export function getArgumentValues(
   variableValues?: ?ObjMap<mixed>,
 ): { [argument: string]: mixed, ... } {
   const coercedValues = {};
-  const argDefs = def.args;
   const argNodes = node.arguments;
-  if (!argDefs || !argNodes) {
+  if (!argNodes) {
     return coercedValues;
   }
+  const argDefs = def.args;
   const argNodeMap = keyMap(argNodes, arg => arg.name.value);
   for (let i = 0; i < argDefs.length; i++) {
     const argDef = argDefs[i];
diff --git a/src/type/schema.js b/src/type/schema.js
index 95071d39bd..7214b343ad 100644
--- a/src/type/schema.js
+++ b/src/type/schema.js
@@ -352,10 +352,8 @@ function typeMapReducer(map: TypeMap, type: ?GraphQLType): TypeMap {
 
   if (isObjectType(type) || isInterfaceType(type)) {
     for (const field of objectValues(type.getFields())) {
-      if (field.args) {
-        const fieldArgTypes = field.args.map(arg => arg.type);
-        reducedMap = fieldArgTypes.reduce(typeMapReducer, reducedMap);
-      }
+      const fieldArgTypes = field.args.map(arg => arg.type);
+      reducedMap = fieldArgTypes.reduce(typeMapReducer, reducedMap);
       reducedMap = typeMapReducer(reducedMap, field.type);
     }
   }