diff --git a/lib/dependencies/ContextDependencyHelpers.js b/lib/dependencies/ContextDependencyHelpers.js
index 7ec4dac12d7..8b793b4f898 100644
--- a/lib/dependencies/ContextDependencyHelpers.js
+++ b/lib/dependencies/ContextDependencyHelpers.js
@@ -49,8 +49,7 @@ ContextDependencyHelpers.create = (
 	expr,
 	options,
 	contextOptions,
-	// when parser is not passed in, expressions won't be walked
-	parser = null
+	parser
 ) => {
 	if (param.isTemplateString()) {
 		let prefixRaw = param.quasis[0].string;
@@ -134,9 +133,7 @@ ContextDependencyHelpers.create = (
 				});
 			} else {
 				// Expression
-				if (parser) {
-					parser.walkExpression(part.expression);
-				}
+				parser.walkExpression(part.expression);
 			}
 		});
 
@@ -217,9 +214,7 @@ ContextDependencyHelpers.create = (
 			options.exprContextCritical &&
 			"the request of a dependency is an expression";
 
-		if (parser) {
-			parser.walkExpression(param.expression);
-		}
+		parser.walkExpression(param.expression);
 
 		return dep;
 	}