elixir: default to 1.12; init 1.12

pkgs/development/beam-modules/default.nix

@@ -40,7 +40,12 @@ let
       erlang-ls = callPackage ./erlang-ls { };
 
       # BEAM-based languages.
-      elixir = elixir_1_11;
+      elixir = elixir_1_12;
+
+      elixir_1_12 = lib'.callElixir ../interpreters/elixir/1.12.nix {
+        inherit erlang;
+        debugInfo = true;
+      };
 
       elixir_1_11 = lib'.callElixir ../interpreters/elixir/1.11.nix {
         inherit erlang;
@@ -62,6 +67,8 @@ let
         debugInfo = true;
       };
 
+      # Remove old versions of elixir, when the supports fades out:
+      # https://hexdocs.pm/elixir/compatibility-and-deprecations.html
       elixir_1_7 = lib'.callElixir ../interpreters/elixir/1.7.nix {
         inherit erlang;
         debugInfo = true;
@@ -69,9 +76,6 @@ let
 
       elixir_ls = callPackage ./elixir_ls.nix { inherit elixir fetchMixDeps mixRelease; };
 
-      # Remove old versions of elixir, when the supports fades out:
-      # https://hexdocs.pm/elixir/compatibility-and-deprecations.html
-
       lfe = lfe_1_3;
       lfe_1_2 = lib'.callLFE ../interpreters/lfe/1.2.nix { inherit erlang buildRebar3 buildHex; };
       lfe_1_3 = lib'.callLFE ../interpreters/lfe/1.3.nix { inherit erlang buildRebar3 buildHex; };

pkgs/development/interpreters/elixir/1.12.nix

@@ -0,0 +1,9 @@
+{ mkDerivation }:
+
+# How to obtain `sha256`:
+# nix-prefetch-url --unpack https://github.com/elixir-lang/elixir/archive/v${version}.tar.gz
+mkDerivation {
+  version = "1.12.0";
+  sha256 = "sha256-Jnxi0vFYMnwEgTqkPncZbj+cR57hjvH77RCseJdUoFs=";
+  minimumOTPVersion = "22";
+}

pkgs/top-level/all-packages.nix

@@ -12040,7 +12040,7 @@ in
   inherit (beam.interpreters)
     erlang erlangR24 erlangR23 erlangR22 erlangR21 erlangR20 erlangR19 erlangR18
     erlang_odbc erlang_javac erlang_odbc_javac erlang_basho_R16B02
-    elixir elixir_1_11 elixir_1_10 elixir_1_9 elixir_1_8 elixir_1_7
+    elixir elixir_1_12 elixir_1_11 elixir_1_10 elixir_1_9 elixir_1_8 elixir_1_7
     elixir_ls;
 
   erlang_nox = beam_nox.interpreters.erlang;

pkgs/top-level/beam-packages.nix

@@ -126,7 +126,7 @@ rec {
     # access for example elixir built with different version of Erlang, use
     # `beam.packages.erlangR23.elixir`.
     inherit (packages.erlang)
-      elixir elixir_1_11 elixir_1_10 elixir_1_9 elixir_1_8 elixir_1_7 elixir_ls;
+      elixir elixir_1_12 elixir_1_11 elixir_1_10 elixir_1_9 elixir_1_8 elixir_1_7 elixir_ls;
 
     inherit (packages.erlang) lfe lfe_1_2 lfe_1_3;
   };