diff --git a/resources/buildConfigDefinitions.js b/resources/buildConfigDefinitions.js
index 1a3cbb4b55..0581a290b5 100644
--- a/resources/buildConfigDefinitions.js
+++ b/resources/buildConfigDefinitions.js
@@ -9,7 +9,6 @@
  * To rebuild the definitions file, run
  * `$ node resources/buildConfigDefinitions.js`
  */
-const parsers = require('../src/Options/parsers');
 
 /** The types of nested options. */
 const nestedOptionTypes = [
@@ -190,6 +189,8 @@ function mapperFor(elt, t) {
 }
 
 function parseDefaultValue(elt, value, t) {
+  /* istanbul ignore next: lazy require (not module scope) so specs don't double-instrument parsers.js; only reached by `npm run definitions` */
+  const parsers = require('../src/Options/parsers');
   let literalValue;
   if (t.isStringTypeAnnotation(elt)) {
     if (value == '""' || value == "''") {