final polishes?

Author: yaacovCR

src/execution/values.ts

@@ -245,7 +245,8 @@ export function experimentalGetArgumentValues(
         ? fragmentVariableValues
         : variableValues;
       if (
-        scopedVariableValues?.coerced[variableName] === undefined &&
+        (scopedVariableValues == null ||
+          !Object.hasOwn(scopedVariableValues.coerced, variableName)) &&
         !isRequiredArgument(argDef)
       ) {
         if (argDef.defaultValue) {

src/utilities/coerceInputValue.ts

@@ -272,7 +272,7 @@ export function coerceInputLiteral(
 
   const leafType = assertLeafType(type);
   try {
-    return leafType.coerceInputLiteral !== undefined
+    return leafType.coerceInputLiteral
       ? leafType.coerceInputLiteral(
           replaceVariables(valueNode, variableValues, fragmentVariableValues),
         )

src/utilities/validateInputValue.ts

@@ -455,13 +455,9 @@ function validateInputLiteralImpl(
     let result;
     let caughtError;
     try {
-      result =
-        type.coerceInputLiteral !== undefined
-          ? type.coerceInputLiteral(
-              replaceVariables(valueNode),
-              hideSuggestions,
-            )
-          : type.parseLiteral(valueNode, undefined, hideSuggestions);
+      result = type.coerceInputLiteral
+        ? type.coerceInputLiteral(replaceVariables(valueNode), hideSuggestions)
+        : type.parseLiteral(valueNode, undefined, hideSuggestions);
     } catch (error) {
       if (error instanceof GraphQLError) {
         context.onError(error, pathToArray(path));