Update ghc 8.4.4 based tools to ghc 8.6.5

.gitattributes

@@ -4,3 +4,4 @@
 nix-tools/.plan.nix/*.nix linguist-generated=true
 nix-tools/pkgs.nix linguist-generated=true
 .stack-to-nix.cache linguist-generated=true
+materialized/**/* linguist-generated=true

builder/make-config-files.nix

@@ -33,28 +33,6 @@ let
        dep.components.library # Regular package dependency
     or dep;                   # or a sublib
 
-  catPkgExactDep = p: ''
-    cat ${p}/exactDep/configure-flags >> $out/configure-flags
-    cat ${p}/exactDep/cabal.config >> $out/cabal.config
-  '';
-
-  catGhcPkgExactDep = p: ''
-    if [ -e ${ghc}/exactDeps/${p} ]; then
-      cat ${ghc}/exactDeps/${p}/configure-flags >> $out/configure-flags
-      cat ${ghc}/exactDeps/${p}/cabal.config >> $out/cabal.config
-    fi
-  '';
-
-  catPkgEnvDep = p: ''
-    cat ${p}/envDep >> $out/ghc-environment
-  '';
-
-  catGhcPkgEnvDep = p: ''
-    if [ -e ${ghc}/envDeps/${p} ]; then
-      cat ${ghc}/envDeps/${p} >> $out/ghc-environment
-    fi
-  '';
-
   # Work our suitable packageCfgDir subdirectory
   isGhcjs        = ghc.isGhcjs or false;
   ghcCommand'    = if isGhcjs then "ghcjs" else "ghc";
@@ -94,10 +72,13 @@ in { identifier, component, fullName, flags ? {}, needsProfiling ? false }:
       "extra-framework-dirs" = map (p: "${p}/Library/Frameworks") component.frameworks;
     })}
 
-    # Copy over the nonReinstallablePkgs from the global package db.
-    ${lib.concatMapStringsSep "\n" (p: ''
-      find ${ghc}/lib/${ghc.name}/package.conf.d -name '${p}*.conf' -exec cp -f {} $out/${packageCfgDir} \;
-    '') nonReinstallablePkgs}
+    ghc=${ghc}
+    ${ # Copy over the nonReinstallablePkgs from the global package db.
+    ''
+      for p in ${lib.concatStringsSep " " nonReinstallablePkgs}; do
+        find $ghc/lib/${ghc.name}/package.conf.d -name $p'*.conf' -exec cp -f {} $out/${packageCfgDir} \;
+      done
+    ''}
 
     for l in "${cfgFiles}"; do
       if [ -n "$l" ]; then
@@ -110,29 +91,49 @@ in { identifier, component, fullName, flags ? {}, needsProfiling ? false }:
       fi
     done
 
-    # Note: we pass `clear` first to ensure that we never consult the implicit global package db.
-    ${flagsAndConfig "package-db" ["clear" "$out/${packageCfgDir}"]}
+    ${ # Note: we pass `clear` first to ensure that we never consult the implicit global package db.
+      flagsAndConfig "package-db" ["clear" "$out/${packageCfgDir}"]
+    }
 
     echo ${lib.concatStringsSep " " (lib.mapAttrsToList (fname: val: "--flags=${lib.optionalString (!val) "-" + fname}") flags)} >> $out/configure-flags
 
-    # Provide a cabal config without remote package repositories
-    echo "write-ghc-environment-files: never" >> $out/cabal.config
-
-    # Provide a GHC environment file
-    cat > $out/ghc-environment <<EOF
-    package-db $out/${packageCfgDir}
-    EOF
-
-    ${lib.concatMapStringsSep "\n" catPkgEnvDep libDeps}
-    ${lib.concatMapStringsSep "\n" catGhcPkgEnvDep (lib.remove "ghc" nonReinstallablePkgs)}
+    ${ # Provide a cabal config without remote package repositories
+    ''
+      echo "write-ghc-environment-files: never" >> $out/cabal.config
+    ''}
+
+    ${ # Provide a GHC environment file
+    ''
+      cat > $out/ghc-environment <<EOF
+      package-db $out/${packageCfgDir}
+      EOF
+    ''}
+
+    ${ lib.optionalString component.doExactConfig ''
+      echo "--exact-configuration" >> $out/configure-flags
+      echo "allow-newer: ${identifier.name}:*" >> $out/cabal.config
+      echo "allow-older: ${identifier.name}:*" >> $out/cabal.config
+    ''}
+
+    for p in ${lib.concatStringsSep " " libDeps}; do
+      cat $p/envDep >> $out/ghc-environment
+      ${ lib.optionalString component.doExactConfig ''
+        cat $p/exactDep/configure-flags >> $out/configure-flags
+        cat $p/exactDep/cabal.config >> $out/cabal.config
+      ''}
+    done
+    for p in ${lib.concatStringsSep " " (lib.remove "ghc" nonReinstallablePkgs)}; do
+      if [ -e $ghc/envDeps/$p ]; then
+        cat $ghc/envDeps/$p >> $out/ghc-environment
+      fi
+    done
   '' + lib.optionalString component.doExactConfig ''
-    echo "--exact-configuration" >> $out/configure-flags
-    echo "allow-newer: ${identifier.name}:*" >> $out/cabal.config
-    echo "allow-older: ${identifier.name}:*" >> $out/cabal.config
-
-    ${lib.concatMapStringsSep "\n" catPkgExactDep libDeps}
-    ${lib.concatMapStringsSep "\n" catGhcPkgExactDep nonReinstallablePkgs}
-
+    for p in ${lib.concatStringsSep " " nonReinstallablePkgs}; do
+      if [ -e $ghc/exactDeps/$p ]; then
+        cat $ghc/exactDeps/$p/configure-flags >> $out/configure-flags
+        cat $ghc/exactDeps/$p/cabal.config >> $out/cabal.config
+      fi
+    done 
   ''
   # This code originates in the `generic-builder.nix` from nixpkgs.  However GHC has been fixed
   # to drop unused libraries referneced from libraries; and this patch is usually included in the
@@ -156,12 +157,13 @@ in { identifier, component, fullName, flags ? {}, needsProfiling ? false }:
   #   's/ /\n/g ; s/\n\n*/\n/g; s/^\n//;'      Puts each field on its own line.
   #   's|/nix/store/|''${pkgroot}/../../../|'  Convert store path to pkgroot relative path
   #   's|''${pkgroot}/../../../|/nix/store/|'  Convert pkgroot relative path to store path
-  + lib.optionalString stdenv.isDarwin ''
+
     # Work around a limit in the macOS Sierra linker on the number of paths
     # referenced by any one dynamic library:
     #
     # Create a local directory with symlinks of the *.dylib (macOS shared
     # libraries) from all the dependencies.
+  + lib.optionalString stdenv.isDarwin ''
     local dynamicLinksDir="$out/lib/links"
     mkdir -p $dynamicLinksDir
     # Enumerate dynamic-library-dirs with ''${pkgroot} expanded.

ci.nix

@@ -6,7 +6,7 @@
 , restrictEval ? false }:
 let
   inherit (import ./ci-lib.nix) dimension platformFilterGeneric filterAttrsOnlyRecursive;
-  inherit (import ./default.nix {}) sources nixpkgsArgs;
+  inherit (import ./default.nix { checkMaterialization = false; }) sources nixpkgsArgs;
   nixpkgsVersions = {
     "R1909" = "nixpkgs-1909";
     "R2003" = "nixpkgs-2003";

default.nix

@@ -1,26 +1,50 @@
-let haskellNix = rec {
+let haskellNix = {
+      checkMaterialization ? false,  # Allows us to easily switch on materialization checking
+      defaultCompilerNixName ? null, # Quick way to override the default compiler e.g. "ghc883"
+      system ? builtins.currentSystem,
+      ... }: rec {
     sources = {
       inherit (import ./nixpkgs/default.nix) nixpkgs-1909 nixpkgs-2003 nixpkgs-default;
     };
 
     config   = import ./config.nix;
-    overlays = [ allOverlays.combined ];
+    overlays = [ allOverlays.combined ] ++ (
+      if checkMaterialization == true
+        then [(
+          final: prev: {
+            haskell-nix = prev.haskell-nix // {
+              checkMaterialization = true;
+            };
+          }
+        )]
+        else []
+    ) ++ (
+      if defaultCompilerNixName != null
+        then [(
+          final: prev: {
+            haskell-nix = prev.haskell-nix // {
+              inherit defaultCompilerNixName;
+            };
+          }
+        )]
+        else []
+    );
     allOverlays = import ./overlays;
-    nixpkgsArgs = { inherit config overlays; };
+    nixpkgsArgs = { inherit config overlays system; };
     pkgs = import sources.nixpkgs-default nixpkgsArgs;
   };
 
-  haskellNixV1 = haskellNix.nixpkgsArgs;
+  haskellNixV1 = (haskellNix {}).nixpkgsArgs;
   haskellNixV2 = haskellNix;
 
   v1DeprecationMessage = "Version 1 is deprecated: use version 2 (nixpkgs arguments are available as the `nixpkgsArgs` attribute of version 2)";
 # If no arguments, then you get V1
 # I'd like to make importing directly issue a warning, but I couldn't figure out a way to make it happen
 in haskellNixV1 // {
-  __functor = _: { version ? 2 }:
+  __functor = _: { version ? 2, ... }@args:
     if version == 1
     then builtins.trace v1DeprecationMessage haskellNixV1
     else if version == 2
-    then haskellNixV2
+    then haskellNixV2 args
     else builtins.throw ("haskell.nix: unknown version: " + (builtins.toString version));
 }

flake.nix

@@ -4,7 +4,10 @@
   edition = 201909;
 
   outputs = { self }: {
-    overlay = self.overlays.combined;
+    # Using the eval-on-build version here as the plan is that
+    # `builtins.currentSystem` will not be supported in flakes.
+    # https://github.com/NixOS/rfcs/pull/49/files#diff-a5a138ca225433534de8d260f225fe31R429
+    overlay = self.overlays.combined-eval-on-build;
     overlays = import ./overlays;
     config = import ./config.nix;
     sources = import ./nixpkgs;

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

@@ -28,10 +28,6 @@
 , extra-hackage-tarballs ? []
 , ...
 }@args:
-# cabal-install versions before 2.4 will generate insufficient plan information.
-assert (if (builtins.compareVersions cabal-install.version "2.4.0.0") < 0
-         then throw "cabal-install (current version: ${cabal-install.version}) needs to be at least 2.4 for plan-to-nix to work without cabal-to-nix"
-         else true);
 
 let
   forName = pkgs.lib.optionalString (name != null) (" for " + name);
@@ -265,7 +261,7 @@ let
   '');
 
   # Dummy `ghc` that uses the captured output 
-  dummy-ghc = pkgs.writeTextFile {
+  dummy-ghc = pkgs.evalPackages.writeTextFile {
     name = "dummy-" + ghc.name;
     executable = true;
     destination = "/bin/${ghc.targetPrefix}ghc";
@@ -282,7 +278,7 @@ let
   };
 
   # Dummy `ghc-pkg` that uses the captured output 
-  dummy-ghc-pkg = pkgs.writeTextFile {
+  dummy-ghc-pkg = pkgs.evalPackages.writeTextFile {
     name = "dummy-pkg-" + ghc.name;
     executable = true;
     destination = "/bin/${ghc.targetPrefix}ghc-pkg";
@@ -306,8 +302,8 @@ let
         else null;
   } // pkgs.lib.optionalAttrs (checkMaterialization != null) {
     inherit checkMaterialization;
-  }) (runCommand (if name == null then "plan-to-nix-pkgs" else name + "-plan-to-nix-pkgs") {
-    nativeBuildInputs = [ nix-tools dummy-ghc dummy-ghc-pkg hpack cabal-install pkgs.rsync ];
+  }) (pkgs.evalPackages.runCommand (if name == null then "plan-to-nix-pkgs" else name + "-plan-to-nix-pkgs") {
+    nativeBuildInputs = [ nix-tools dummy-ghc dummy-ghc-pkg hpack cabal-install pkgs.evalPackages.rsync ];
     # Needed or stack-to-nix will die on unicode inputs
     LOCALE_ARCHIVE = pkgs.lib.optionalString (pkgs.stdenv.hostPlatform.libc == "glibc") "${pkgs.glibcLocales}/lib/locale/locale-archive";
     LANG = "en_US.UTF-8";

lib/default.nix

@@ -1,8 +1,32 @@
-{ stdenv, lib, haskellLib, runCommand, git, recurseIntoAttrs, srcOnly }:
+{ pkgs, stdenv, lib, haskellLib, recurseIntoAttrs, srcOnly }:
+
 
 with haskellLib;
 
-{
+let
+  # Why `final.evalPackages.buildPackages.git`?
+  # Why not just final.evalPackages.git?
+  #
+  # A problem arises when `evalPackages` is `buildPackages`.i
+  # As may be the case in a flake.
+  #
+  # It turns out `git` depends on `gdb` in a round about way:
+  #  git -> openssh -> libfido2 -> systemd -> python libxml -> Cython -> gdb
+  # Somewhere in that chain there should perhaps be a `buildPackages` so
+  # that the `gdb` that is used is not the one for debugging code in
+  # the `final` (but instead the one for debugging code in
+  # `final.buildPackages`).
+  #
+  # Using `final.buildPackages.git` causes two problems:
+  #
+  #   * Multiple versions of `git` (and that dependency chain
+  #     to `gdb` are needed when cross compiling).
+  #   * When `gdb` does not exist for `js`, so when cross
+  #     compiling with ghcjs `final.buildPackages.git` fails
+  #     to build at all.
+  inherit (pkgs.evalPackages.buildPackages) git;
+
+in {
   # Within the package components, these are the attribute names of
   # nested attrsets.
   subComponentTypes = [
@@ -181,7 +205,8 @@ with haskellLib;
 
   # Clean git directory based on `git ls-files --recurse-submodules`
   cleanGit = import ./clean-git.nix {
-    inherit lib runCommand git cleanSourceWith;
+    inherit lib git cleanSourceWith;
+    inherit (pkgs.evalPackages) runCommand;
   };
 
   # Check a test component