no EPR on leaf value as errors throw

Author: mohawk2

src/execution/execute.js

@@ -1016,7 +1016,7 @@ function completeValue(
   // If field type is a leaf type, Scalar or Enum, serialize to a valid value,
   // returning null if serialization is not possible.
   if (isLeafType(returnType)) {
-    return completeLeafValue(returnType, result);
+    return { data: completeLeafValue(returnType, result) };
   }
 
   // If field type is an abstract type, Interface or Union, determine the
@@ -1119,10 +1119,7 @@ function flattenEPRs(
  * Complete a Scalar or Enum by serializing to a valid value, returning
  * null if serialization is not possible.
  */
-function completeLeafValue(
-  returnType: GraphQLLeafType,
-  result: mixed,
-): ExecutionPartialResult<mixed> {
+function completeLeafValue(returnType: GraphQLLeafType, result: mixed): mixed {
   invariant(returnType.serialize, 'Missing serialize method on type');
   const serializedResult = returnType.serialize(result);
   if (isInvalid(serializedResult)) {
@@ -1131,7 +1128,7 @@ function completeLeafValue(
         `received: ${String(result)}`,
     );
   }
-  return { data: serializedResult };
+  return serializedResult;
 }
 
 /**