From e0a068cb97225dcdc539c8989e96013399e1f9c9 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Thu, 21 May 2015 17:04:34 +0200
Subject: [PATCH] nix-shell: Barf if -p and -E are both used

Closes #454, #455.
---
 scripts/nix-build.in | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/nix-build.in b/scripts/nix-build.in
index 5745a1e06..5e988cc41 100755
--- a/scripts/nix-build.in
+++ b/scripts/nix-build.in
@@ -217,6 +217,8 @@ for (my $n = 0; $n < scalar @ARGV; $n++) {
     }
 }
 
+die "$0: ‘-p’ and ‘-E’ are mutually exclusive\n" if $packages && $fromArgs;
+
 if ($packages) {
     push @instArgs, "--expr";
     @exprs = (