From 3ff6186af1786bd08217bd0b29afb95eacec0f47 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 24 Jan 2022 14:32:25 +0100
Subject: [PATCH 1/3] Add a test for nix-assertion failures in nix-env

---
 tests/user-envs.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/user-envs.nix b/tests/user-envs.nix
index 43eff1a686b..6ac896ed831 100644
--- a/tests/user-envs.nix
+++ b/tests/user-envs.nix
@@ -9,7 +9,8 @@ assert foo == "foo";
 let
 
   makeDrv = name: progName: (mkDerivation {
-    inherit name progName system;
+    name = assert progName != "fail"; name;
+    inherit progName system;
     builder = ./user-envs.builder.sh;
   } // {
     meta = {
@@ -26,4 +27,5 @@ in
     (makeDrv "foo-2.0" "foo")
     (makeDrv "bar-0.1.1" "bar")
     (makeDrv "foo-0.1" "foo" // { meta.priority = 10; })
+    (makeDrv "fail-0.1" "fail")
   ]

From c4fc9b6a8d4fa279206814295729985dac7bc509 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 24 Jan 2022 15:08:16 +0100
Subject: [PATCH 2/3] ExprConcatStrings::show(): Print values instead of
 pointers

---
 src/libexpr/nixexpr.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 640c44c0166..2d2cd96cda6 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -191,7 +191,7 @@ void ExprConcatStrings::show(std::ostream & str) const
     str << "(";
     for (auto & i : *es) {
         if (first) first = false; else str << " + ";
-        str << i.second;
+        str << *i.second;
     }
     str << ")";
 }

From bed8270c0cbaa3007621ad2f0e722abcefe79702 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Mon, 24 Jan 2022 15:18:18 +0100
Subject: [PATCH 3/3] Fix parsing of variable names that are a prefix of
 '__curPos'

Fixes

  $ nix-instantiate --parse -E 'x: with x; _'
  (x: (with x; __curPos))
---
 src/libexpr/parser.y                         | 3 ++-
 tests/lang/eval-okay-regression-20220122.exp | 1 +
 tests/lang/eval-okay-regression-20220122.nix | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)
 create mode 100644 tests/lang/eval-okay-regression-20220122.exp
 create mode 100644 tests/lang/eval-okay-regression-20220122.nix

diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index a3e71393759..55f8abcb741 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -404,7 +404,8 @@ expr_select
 
 expr_simple
   : ID {
-      if (strncmp($1.p, "__curPos", $1.l) == 0)
+      std::string_view s = "__curPos";
+      if (strncmp($1.p, s.data(), s.size()) == 0)
           $$ = new ExprPos(CUR_POS);
       else
           $$ = new ExprVar(CUR_POS, data->symbols.create($1));
diff --git a/tests/lang/eval-okay-regression-20220122.exp b/tests/lang/eval-okay-regression-20220122.exp
new file mode 100644
index 00000000000..00750edc07d
--- /dev/null
+++ b/tests/lang/eval-okay-regression-20220122.exp
@@ -0,0 +1 @@
+3
diff --git a/tests/lang/eval-okay-regression-20220122.nix b/tests/lang/eval-okay-regression-20220122.nix
new file mode 100644
index 00000000000..694e9a13b7c
--- /dev/null
+++ b/tests/lang/eval-okay-regression-20220122.nix
@@ -0,0 +1 @@
+((_: _) 1) + ((__: __) 2)