build: remove checkMaterialization flag

ci.nix

@@ -63,19 +63,16 @@ let
 in localLib.dimension "system" systems (systemName:
   { system, crossSystem }:
   let
-    # Check the pinned haskell.nix hashes for correctness.
-    checkMaterialization = true;
-
     # Shared libraries/executables for the build (current) system.
     localPackages = import ./default.nix {
-      inherit system checkMaterialization;
+      inherit system;
 
       enableStatic = false;
     };
 
     # Static libraries/executables for the host (cross) system.
     staticPackages = import ./default.nix {
-      inherit system crossSystem checkMaterialization;
+      inherit system crossSystem;
 
       enableStatic = true;
     };

default.nix

@@ -43,10 +43,7 @@
 , crossOverlays ? [ ]
   # Whether to use pkgs.pkgsStatic.* to obtain statically linked package
   # dependencies - ie. when building fully-static libraries or executables. 
-, enableStatic ? crossSystem != null
-  # Whether to check that the pinned hashes for haskell.nix are correct.
-  # Set to false by default since it's a lot slower, but true for ci.
-, checkMaterialization ? false }:
+, enableStatic ? crossSystem != null }:
 
 let
 
@@ -100,7 +97,7 @@ let
 
     hs = callPackage ./nix/pkgs/hs {
       inherit (pkgs) haskell-nix;
-      inherit checkMaterialization enableStatic;
+      inherit enableStatic;
     };
   };
 

nix/pkgs/hs/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, darwin, haskell-nix, gmp, zlib, libffi, checkMaterialization
+{ lib, stdenv, darwin, haskell-nix, gmp, zlib, libffi
 , enableStatic ? stdenv.hostPlatform.isStatic }:
 
 let
@@ -7,7 +7,7 @@ let
   index-state = "2020-09-24T00:00:00Z";
 
   project = haskell-nix.stackProject {
-    inherit compiler-nix-name index-state checkMaterialization;
+    inherit compiler-nix-name index-state;
 
     # This is incredibly difficult to get right, almost everything goes wrong.
     # See: https://github.com/input-output-hk/haskell.nix/issues/496