fix(fragmentArguments): arguments on directives for nested fields (graphql#4180)

fixes up just merged graphql#4015

this was actually intended to be in graphql#4015, but due to branch confusion
not originally included

now we also have a test!

Author: yaacovCR

src/execution/__tests__/variables-test.ts

@@ -1515,6 +1515,20 @@ describe('Execute: Handles inputs', () => {
       });
     });
 
+    it('when argument passed to a directive on a nested field', () => {
+      const result = executeQueryWithFragmentArguments(`
+        query {
+          ...a(value: true)
+        }
+        fragment a($value: Boolean!) on TestType {
+          nested { echo(input: "echo") @skip(if: $value) }
+        }
+      `);
+      expect(result).to.deep.equal({
+        data: { nested: {} },
+      });
+    });
+
     /* TODO: add back when @defer and @stream are supported
     it('when a nullable argument to a directive with a field default is not provided and shadowed by an operation variable', () => {
       // this test uses the @defer directive and incremental delivery because the `if` argument for skip/include have no field defaults

src/execution/collectFields.ts

@@ -46,7 +46,6 @@ interface CollectFieldsContext {
   schema: GraphQLSchema;
   fragments: ObjMap<FragmentDetails>;
   variableValues: { [variable: string]: unknown };
-  fragmentVariableValues?: FragmentVariables;
   runtimeType: GraphQLObjectType;
   visitedFragmentNames: Set<string>;
 }
@@ -107,9 +106,15 @@ export function collectSubfields(
   const subGroupedFieldSet = new AccumulatorMap<string, FieldDetails>();
 
   for (const fieldDetail of fieldGroup) {
-    const node = fieldDetail.node;
-    if (node.selectionSet) {
-      collectFieldsImpl(context, node.selectionSet, subGroupedFieldSet);
+    const selectionSet = fieldDetail.node.selectionSet;
+    if (selectionSet) {
+      const { fragmentVariables } = fieldDetail;
+      collectFieldsImpl(
+        context,
+        selectionSet,
+        subGroupedFieldSet,
+        fragmentVariables,
+      );
     }
   }