diff --git a/src/compilerlib/pb_codegen_encode_yojson.ml b/src/compilerlib/pb_codegen_encode_yojson.ml
index 2badc3b..3471050 100644
--- a/src/compilerlib/pb_codegen_encode_yojson.ml
+++ b/src/compilerlib/pb_codegen_encode_yojson.ml
@@ -136,13 +136,17 @@ let gen_rft_variant sc rf_label { Ot.v_constructors; _ } =
           F.sub_scope sc (fun sc ->
               match vc_field_type with
               | Ot.Vct_nullary ->
-                F.linep sc "| %s -> (\"%s\", `Null) :: assoc" vc_constructor json_label
+                F.linep sc "| %s -> (\"%s\", `Null) :: assoc" vc_constructor
+                  json_label
               | Ot.Vct_non_nullary_constructor field_type ->
                 (match
                    gen_field var_name json_label field_type vc_payload_kind
                  with
-                | None -> F.linep sc "| %s -> (\"%s\", `Null) :: assoc" vc_constructor json_label
-                | Some exp -> F.linep sc "| %s v -> %s :: assoc" vc_constructor exp)))
+                | None ->
+                  F.linep sc "| %s -> (\"%s\", `Null) :: assoc" vc_constructor
+                    json_label
+                | Some exp ->
+                  F.linep sc "| %s v -> %s :: assoc" vc_constructor exp)))
         v_constructors);
 
   F.linep sc "in (* match v.%s *)" rf_label