diff --git a/json.zig b/json.zig
index 0990c57c5476e475d66a0dcc4f314ae92f37041c..2de2397190f969a3f4115eaceffebe1a1749febc 100644
--- a/json.zig
+++ b/json.zig
@@ -454,8 +454,8 @@ pub const Document = struct {
     extras: []const u8,
     root: ValueIndex,
 
-    pub fn deinit(doc: *const Document, alloc: std.mem.Allocator) void {
-        alloc.free(doc.extras);
+    pub fn deinit(this: *const Document, alloc: std.mem.Allocator) void {
+        alloc.free(this.extras);
     }
 };