From b51dff431c1e7d37cec97e0fe7c8945547dfd7f0 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 27 Apr 2020 18:55:20 +0200
Subject: [PATCH] Improve error message when an argument is not a flake

---
 src/nix/installables.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/nix/installables.cc b/src/nix/installables.cc
index 0c2c5fe63..3871536e1 100644
--- a/src/nix/installables.cc
+++ b/src/nix/installables.cc
@@ -468,7 +468,10 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
                     if (s.find('/') != std::string::npos && (storePath = follow(s)))
                         result.push_back(std::make_shared<InstallableStorePath>(store, store->printStorePath(*storePath)));
                     else
-                        throw Error("unrecognized argument '%s'", s);
+                        throw Error(
+                            pathExists(s)
+                            ? "path '%s' is not a flake or a store path"
+                            : "don't know how to handle argument '%s'", s);
                 }
             }
         }