From f31adf28b7ac2cc31081ddbd566f94932740564e Mon Sep 17 00:00:00 2001
From: Vincent Laporte <Vincent.Laporte@gmail.com>
Date: Thu, 14 May 2020 16:39:04 +0200
Subject: [PATCH] ocamlPackages.dune_2: use pkgs.dune_2 for OCaml < 4.07

---
 pkgs/top-level/ocaml-packages.nix | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 26d2d9fed47..eafd4521707 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -217,7 +217,12 @@ let
 
     dune = callPackage ../development/tools/ocaml/dune { };
 
-    dune_2 = callPackage ../development/tools/ocaml/dune/2.nix { };
+    dune_2 =
+      if lib.versionAtLeast ocaml.version "4.07"
+      then callPackage ../development/tools/ocaml/dune/2.nix { }
+      else if lib.versionAtLeast ocaml.version "4.02"
+      then pkgs.dune_2
+      else throw "dune_2 is not available for OCaml ${ocaml.version}";
 
     dune-build-info = callPackage ../development/ocaml-modules/dune-build-info { };