From 0f0be5e498ac29e9011c7a29a7612871c0bc393f Mon Sep 17 00:00:00 2001
From: Guillaume Maudoux <layus.on@gmail.com>
Date: Wed, 3 Aug 2016 08:15:18 +0200
Subject: [PATCH] Warn for conflict between synaptics and libinput

---
 nixos/modules/services/x11/hardware/libinput.nix  | 8 ++++++++
 nixos/modules/services/x11/hardware/synaptics.nix | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/nixos/modules/services/x11/hardware/libinput.nix b/nixos/modules/services/x11/hardware/libinput.nix
index 14c7131e611c..47ce9e566045 100644
--- a/nixos/modules/services/x11/hardware/libinput.nix
+++ b/nixos/modules/services/x11/hardware/libinput.nix
@@ -227,6 +227,14 @@ in {
         EndSection
       '';
 
+    assertions = [
+      # already present in synaptics.nix
+      /* {
+        assertion = !config.services.xserver.synaptics.enable;
+        message = "Synaptics and libinput are incompatible, you cannot enable both (in services.xserver).";
+      } */
+    ];
+
   };
 
 }
diff --git a/nixos/modules/services/x11/hardware/synaptics.nix b/nixos/modules/services/x11/hardware/synaptics.nix
index e74b19c8e710..5c068e89dd71 100644
--- a/nixos/modules/services/x11/hardware/synaptics.nix
+++ b/nixos/modules/services/x11/hardware/synaptics.nix
@@ -205,6 +205,13 @@ in {
         EndSection
       '';
 
+    assertions = [
+      {
+        assertion = !config.services.xserver.libinput.enable;
+        message = "Synaptics and libinput are incompatible, you cannot enable both (in services.xserver).";
+      }
+    ];
+
   };
 
 }