First attempt

Author: andreabedini

builder/comp-builder.nix

@@ -82,7 +82,7 @@ let self =
 , enableTSanRTS ? false
 
 # LLVM
-, useLLVM ? ghc.useLLVM
+, useLLVM ? false
 , smallAddressSpace ? false
 
 }@drvArgs:

builder/hspkg-builder.nix

@@ -18,10 +18,6 @@ config:
 , ...
 }@pkg:
 
-assert (if ghc.isHaskellNixCompiler or false then true
-  else throw ("It is likely you used `haskell.compiler.X` instead of `haskell-nix.compiler.X`"
-    + pkgs.lib.optionalString (name != null) (" for " + name)));
-
 let
   # Some packages bundled with GHC are not the same as they are in hackage.
   bundledSrc = {

lib/call-cabal-project-to-nix.nix

@@ -107,9 +107,6 @@ let
               pkgs.haskell-nix.compiler."${compiler-nix-name}";
 
 in
-  assert (if ghc'.isHaskellNixCompiler or false then true
-    else throw ("It is likely you used `haskell.compiler.X` instead of `haskell-nix.compiler.X`"
-      + forName));
 
 let
   ghc = ghc';

overlays/ghc-packages.nix

@@ -163,7 +163,7 @@ in rec {
               inherit subDir;
               includeSiblings = true;
             }
-            else "${ghc.passthru.configured-src}/${subDir}";
+            else "${ghc.configured-src}/${subDir}";
         nix = callCabal2Nix ghcName "${ghcName}-${pkgName}" src;
       }) (ghc-extra-pkgs ghc.version))
     final.buildPackages.haskell-nix.compiler;

test/with-nixpkgs-ghc/default.nix

@@ -0,0 +1,38 @@
+let
+
+  haskell-nix = import ../../default.nix { };
+  nixpkgs = haskell-nix.inputs.nixpkgs.outPath;
+
+  o2 = (
+    final: prev: {
+      haskell-nix = prev.haskell-nix // {
+        compiler = prev.haskell-nix.compiler // {
+          ghc8107 = prev.haskell.compiler.ghc8107 // {
+            # Add stuff not in nixpkgs ghc
+            configured-src = prev.haskell-nix.compiler.ghc8107.configured-src; # Needed for reinstallableLibGhc to work
+          };
+        };
+      };
+    }
+  );
+
+  pkgs = import nixpkgs {
+    system = __currentSystem;
+    inherit (haskell-nix) config;
+    overlays = [
+      # haskell-nix.overlays.haskell
+      # haskell-nix.overlays.tools
+      haskell-nix.overlay
+      o2
+    ];
+  };
+
+  prj = pkgs.haskell-nix.cabalProject {
+    src = ./empty;
+    cabalProject = "extra-packages: lens";
+    compiler-nix-name = "ghc8107";
+  };
+in
+
+prj.plan-nix
+