diff --git a/src/scalars/GeoJSON/codegenScalarType.ts b/src/scalars/GeoJSON/codegenScalarType.ts
index d46221c40..63c40a96c 100644
--- a/src/scalars/GeoJSON/codegenScalarType.ts
+++ b/src/scalars/GeoJSON/codegenScalarType.ts
@@ -1,5 +1,7 @@
-// Helper function to generate Position type
-const generatePositionType = () => `[number, number] | [number, number, number]`;
+// Helper function to generate Position type.
+// Parenthesized so that array usages (`${generatePositionType()}[]`) apply `[]`
+// to the whole union rather than only the second member.
+const generatePositionType = () => `([number, number] | [number, number, number])`;
 
 // Helper function to generate BBox type
 const generateBBoxType = () =>