Upgrade nixpkgs to current master and add an upgrade checklist (#1579)

* simplify haskell packages overrides based on new nixpkgs
* update Nix gitignore
* simplify Haskell packages overlay

Co-authored-by: monacoremo <monacoremo>

nix/patches/nixpkgs-revert-ghc-bootstrap.patch

@@ -1,31 +1,31 @@
-From ba48fc5bf1db795e31778fd67a9d72f28437d6c3 Mon Sep 17 00:00:00 2001
+From f9e4b7fd7a93ab643db0b1c84003987400bbe120 Mon Sep 17 00:00:00 2001
 From: Remo <remo>
-Date: Tue, 19 May 2020 13:07:54 +0200
+Date: Sun, 23 Aug 2020 12:01:48 +0200
 Subject: [PATCH] Revert "ghc: 8.6.3-binary -> 8.6.5-binary"
 
 This reverts commit 3c7ef6bcd85e3e133ac6f2ab5e238934d56d902e.
 ---
- .../ghc/{8.6.5-binary.nix => 8.6.3-binary.nix}   | 13 ++++++-------
- pkgs/top-level/haskell-packages.nix              | 16 ++++++++--------
- 2 files changed, 14 insertions(+), 15 deletions(-)
- rename pkgs/development/compilers/ghc/{8.6.5-binary.nix => 8.6.3-binary.nix} (95%)
+ .../{8.6.5-binary.nix => 8.6.3-binary.nix}    | 13 +++++-----
+ pkgs/top-level/haskell-packages.nix           | 25 ++++++++-----------
+ 2 files changed, 16 insertions(+), 22 deletions(-)
+ rename pkgs/development/compilers/ghc/{8.6.5-binary.nix => 8.6.3-binary.nix} (94%)
 
 diff --git a/pkgs/development/compilers/ghc/8.6.5-binary.nix b/pkgs/development/compilers/ghc/8.6.3-binary.nix
-similarity index 95%
+similarity index 94%
 rename from pkgs/development/compilers/ghc/8.6.5-binary.nix
 rename to pkgs/development/compilers/ghc/8.6.3-binary.nix
-index 97793d91289..9e0fd12b96c 100644
+index 41af279e83f..5853a470efc 100644
 --- a/pkgs/development/compilers/ghc/8.6.5-binary.nix
 +++ b/pkgs/development/compilers/ghc/8.6.3-binary.nix
 @@ -27,19 +27,18 @@ let
  in
- 
+
  stdenv.mkDerivation rec {
 -  version = "8.6.5";
 +  version = "8.6.3";
- 
+
    name = "ghc-${version}-binary";
- 
+
 -  # https://downloads.haskell.org/~ghc/8.6.5/
    src = fetchurl ({
      i686-linux = {
@@ -52,28 +52,29 @@ index 97793d91289..9e0fd12b96c 100644
    }.${stdenv.hostPlatform.system}
      or (throw "cannot bootstrap GHC on this platform"));
 diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
-index 13c5b721301..1bce80e5774 100644
+index 3e85109527e..388210b83fb 100644
 --- a/pkgs/top-level/haskell-packages.nix
 +++ b/pkgs/top-level/haskell-packages.nix
-@@ -4,7 +4,7 @@ let
+@@ -4,7 +4,8 @@ let
    # These are attributes in compiler and packages that don't support integer-simple.
    integerSimpleExcludes = [
      "ghc822Binary"
 -    "ghc865Binary"
 +    "ghc863Binary"
-     "ghc844"
++    "ghc844"
      "ghcjs"
      "ghcjs86"
-@@ -42,7 +42,7 @@ in {
- 
+     "integer-simple"
+@@ -47,7 +48,7 @@ in {
+
      ghc822Binary = callPackage ../development/compilers/ghc/8.2.2-binary.nix { };
- 
+
 -    ghc865Binary = callPackage ../development/compilers/ghc/8.6.5-binary.nix { };
 +    ghc863Binary = callPackage ../development/compilers/ghc/8.6.3-binary.nix { };
- 
-     ghc844 = callPackage ../development/compilers/ghc/8.4.4.nix {
+
+     ghc865 = callPackage ../development/compilers/ghc/8.6.5.nix {
        bootPkgs = packages.ghc822Binary;
-@@ -57,19 +57,19 @@ in {
+@@ -56,31 +57,25 @@ in {
        llvmPackages = pkgs.llvmPackages_6;
      };
      ghc882 = callPackage ../development/compilers/ghc/8.8.2.nix {
@@ -85,6 +86,13 @@ index 13c5b721301..1bce80e5774 100644
      };
      ghc883 = callPackage ../development/compilers/ghc/8.8.3.nix {
 -      bootPkgs = packages.ghc865Binary;
++      bootPkgs = packages.ghc863Binary;
+       inherit (buildPackages.python3Packages) sphinx;
+       buildLlvmPackages = buildPackages.llvmPackages_7;
+       llvmPackages = pkgs.llvmPackages_7;
+     };
+     ghc884 = callPackage ../development/compilers/ghc/8.8.4.nix {
+-      bootPkgs = packages.ghc865Binary;
 +      bootPkgs = packages.ghc863Binary;
        inherit (buildPackages.python3Packages) sphinx;
        buildLlvmPackages = buildPackages.llvmPackages_7;
@@ -92,11 +100,17 @@ index 13c5b721301..1bce80e5774 100644
      };
      ghc8101 = callPackage ../development/compilers/ghc/8.10.1.nix {
 -      bootPkgs = packages.ghc865Binary;
+-      inherit (buildPackages.python3Packages) sphinx;
+-      buildLlvmPackages = buildPackages.llvmPackages_9;
+-      llvmPackages = pkgs.llvmPackages_9;
+-    };
+-    ghc8102 = callPackage ../development/compilers/ghc/8.10.2.nix {
+-      bootPkgs = packages.ghc865Binary;
 +      bootPkgs = packages.ghc863Binary;
        inherit (buildPackages.python3Packages) sphinx;
        buildLlvmPackages = buildPackages.llvmPackages_9;
        llvmPackages = pkgs.llvmPackages_9;
-@@ -112,9 +112,9 @@ in {
+@@ -133,9 +128,9 @@ in {
        compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.2.x.nix { };
        packageSetConfig = bootstrapPackageSet;
      };
@@ -109,6 +123,6 @@ index 13c5b721301..1bce80e5774 100644
        compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-8.6.x.nix { };
        packageSetConfig = bootstrapPackageSet;
      };
--- 
-2.25.1
+--
+2.28.0