diff --git a/src/zaye.zig b/src/zaye.zig
index c3facb2..b9819e8 100644
--- a/src/zaye.zig
+++ b/src/zaye.zig
@@ -266,7 +266,7 @@ pub const Value = union(enum) {
         }
 
         fn endMap(self: *Builder, diag: *ParseDiagnostic) !void {
-            var top = self.container_stack.pop();
+            const top = self.container_stack.pop();
 
             if (top != .map) {
                 diag.setMessage("map ended when a map was not the top container");