diff --git a/.circleci/config.yml b/.circleci/config.yml
index afab01398c..37ff79d4b5 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -156,6 +156,32 @@ jobs:
           key: cabal-{{ .Environment.HIE_CACHE }}-{{ arch }}-{{ .Environment.CIRCLE_JOB }}
           paths:
             - ~/.cabal
+  nix:
+    working_directory: ~/build
+    environment:
+        - NIXPKGS_ALLOW_BROKEN: 1
+    docker:
+        - image: nixorg/nix:circleci
+    steps:
+      - checkout
+      - run:
+          name: Sync submodules
+          command: git submodule sync --recursive
+      - run:
+          name: Update submodules
+          command: git submodule update --recursive --init
+      - restore-cache:
+          keys:
+            - cabal-{{ .Environment.HIE_CACHE }}-{{ arch }}-{{ .Environment.CIRCLE_JOB }}
+      - run:
+          name: Build
+          command: nix-shell -j4 --run "cabal new-update && cabal new-build -j1 --enable-tests"
+          no_output_timeout: 30m
+      - save_cache:
+          key: cabal-{{ .Environment.HIE_CACHE }}-{{ arch }}-{{ .Environment.CIRCLE_JOB }}
+          paths:
+            - ~/.cabal
+
 
 
 workflows:
@@ -170,3 +196,4 @@ workflows:
       - ghc-8.10.1
       # - ghc-nightly
       - cabal
+      - nix
diff --git a/nix/sources.json b/nix/sources.json
index dc54fcea3e..a9d23e339a 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -17,10 +17,10 @@
         "homepage": "https://github.com/NixOS/nixpkgs",
         "owner": "NixOS",
         "repo": "nixpkgs-channels",
-        "rev": "b8c367a7bd05e3a514c2b057c09223c74804a21b",
-        "sha256": "0y17zxhwdw0afml2bwkmhvkymd9fv242hksl3l3xz82gmlg1zks4",
+        "rev": "2c4e0f37a6d5d33666b550a1b85daf46b37f1b25",
+        "sha256": "0hqr6ci0rgg1fyfg7w2182vgbi0cq472p2j8r7mcmkbpdwwi6i69",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs-channels/archive/b8c367a7bd05e3a514c2b057c09223c74804a21b.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/2c4e0f37a6d5d33666b550a1b85daf46b37f1b25.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }
diff --git a/shell.nix b/shell.nix
index 076161c96f..4e30fab9ac 100644
--- a/shell.nix
+++ b/shell.nix
@@ -3,19 +3,35 @@
 # while reducing Nix maintenance costs.
 # It does **not** aim to replace Cabal/Stack with Nix
 
+# Maintaining this file:
+#
+# - Dealing with broken nix-shell
+#
+#     1. Bump the nixpkgs version using `niv update nixpkgs`
+#     2. Comment out any remaining failing packages
+#
+# - Dealing with broken cabal build inside nix-shell:
+#
+#    If my understanding of cabal new-build is correct this should never happen,
+#    assuming that cabal new-build does succeed outside nix-shell
 
 { sources ? import nix/sources.nix,
   nixpkgs ? import sources.nixpkgs {},
-  compiler ? "default"
+  compiler ? "default",
+  hoogle ? false
  }:
 with nixpkgs;
 
 let defaultCompiler = "ghc" + lib.replaceStrings ["."] [""] haskellPackages.ghc.version;
     haskellPackagesForProject = p:
         if compiler == "default" || compiler == defaultCompiler
-            then haskellPackages.ghcWithPackages p
-            # for all other compilers there is no Nix cache so dont bother building deps with NIx
-            else haskell.packages.${compiler}.ghcWithPackages (_: []);
+            then if hoogle
+                then haskellPackages.ghcWithHoogle p
+                else haskellPackages.ghcWithPackages p
+            # for all other compilers there is no Nix cache so dont bother building deps
+            else if hoogle
+                then  haskell.packages.${compiler}.ghcWithHoogle (_: [])
+                else haskell.packages.${compiler}.ghcWithPackages (_: []);
 
     retrie = with haskell.lib; dontCheck(disableLibraryProfiling(haskellPackages.retrie));
     compilerWithPackages = haskellPackagesForProject(p:
@@ -42,7 +58,7 @@ let defaultCompiler = "ghc" + lib.replaceStrings ["."] [""] haskellPackages.ghc.
           data-default-instances-old-locale
           extra
           floskell
-          fourmolu
+        #   fourmolu
           fuzzy
           generic-deriving
           ghc-check
@@ -94,9 +110,10 @@ in
 stdenv.mkDerivation {
   name = "haskell-language-server";
   buildInputs = [
+    git
     gmp
-    zlib
     ncurses
+    zlib
 
     haskellPackages.cabal-install
     haskellPackages.hlint
diff --git a/src/Ide/Plugin/Example.hs b/src/Ide/Plugin/Example.hs
index 63f7083b37..1e77471f46 100644
--- a/src/Ide/Plugin/Example.hs
+++ b/src/Ide/Plugin/Example.hs
@@ -37,6 +37,7 @@ import Ide.Plugin
 import Ide.Types
 import Language.Haskell.LSP.Types
 import Text.Regex.TDFA.Text()
+import Development.IDE.GHC.Compat (ParsedModule(ParsedModule))
 
 -- ---------------------------------------------------------------------
 
@@ -106,7 +107,9 @@ mkDiag file diagSource sev loc msg = (file, D.ShowDiag,)
 
 -- | Generate code actions.
 codeAction :: CodeActionProvider
-codeAction _lf _state _pid (TextDocumentIdentifier uri) _range CodeActionContext{_diagnostics=List _xs} = do
+codeAction _lf state _pid (TextDocumentIdentifier uri) _range CodeActionContext{_diagnostics=List _xs} = do
+    let Just nfp = uriToNormalizedFilePath $ toNormalizedUri uri
+    Just (ParsedModule{},_) <- runIdeAction "example" (shakeExtras state) $ useWithStaleFast GetParsedModule nfp
     let
       title = "Add TODO Item 1"
       tedit = [TextEdit (Range (Position 2 0) (Position 2 0))