diff --git a/src/validation/rules/VariablesAreInputTypesRule.js b/src/validation/rules/VariablesAreInputTypesRule.js
index f16cb7461d..0dc9daa250 100644
--- a/src/validation/rules/VariablesAreInputTypesRule.js
+++ b/src/validation/rules/VariablesAreInputTypesRule.js
@@ -20,7 +20,7 @@ export function VariablesAreInputTypesRule(
   context: ValidationContext,
 ): ASTVisitor {
   return {
-    VariableDefinition(node: VariableDefinitionNode): ?GraphQLError {
+    VariableDefinition(node: VariableDefinitionNode) {
       const type = typeFromAST(context.getSchema(), node.type);
 
       if (type && !isInputType(type)) {