haskell.compiler.ghc912: 9.12.1 -> 9.12.2

Keeping ghc9121 in release-haskell.nix is pointless since it has a
miscompilation bug that affects central packages.

Co-authored-by: sternenseemann <sternenseemann@systemli.org>

pkgs/top-level/haskell-packages.nix

@@ -393,7 +393,7 @@ in
         buildTargetLlvmPackages = pkgsBuildTarget.llvmPackages_19;
         llvmPackages = pkgs.llvmPackages_19;
       };
-      ghc912 = compiler.ghc9121;
+      ghc912 = compiler.ghc9122;
       ghcHEAD = callPackage ../development/compilers/ghc/head.nix {
         bootPkgs =
           # No suitable bindist packaged yet
@@ -565,7 +565,7 @@ in
         ghc = bh.compiler.ghc9122;
         compilerConfig = callPackage ../development/haskell-modules/configuration-ghc-9.12.x.nix { };
       };
-      ghc912 = packages.ghc9121;
+      ghc912 = packages.ghc9122;
       ghcHEAD = callPackage ../development/haskell-modules {
         buildHaskellPackages = bh.packages.ghcHEAD;
         ghc = bh.compiler.ghcHEAD;

pkgs/top-level/release-haskell.nix

@@ -77,7 +77,8 @@ let
     ghc983
     ghc984
     ghc9101
-    ghc9121
+    # exclude ghc9121 due to severe miscompilation bug
+    ghc9122
   ];
 
   # packagePlatforms applied to `haskell.packages.*`
@@ -582,7 +583,7 @@ let
       hlint = lib.subtractLists [
         compilerNames.ghc902
         compilerNames.ghc9101
-        compilerNames.ghc9121
+        compilerNames.ghc9122
       ] released;
       hpack = released;
       hsdns = released;
@@ -601,10 +602,10 @@ let
       ghc-lib-parser = released;
       ghc-lib-parser-ex = released;
       ghc-source-gen = lib.subtractLists [
-        compilerNames.ghc9121
+        compilerNames.ghc9122
       ] released;
       ghc-tags = lib.subtractLists [
-        compilerNames.ghc9121
+        compilerNames.ghc9122
       ] released;
       hashable = released;
       primitive = released;
@@ -615,7 +616,7 @@ let
       ];
       weeder = lib.subtractLists [
         compilerNames.ghc9101
-        compilerNames.ghc9121
+        compilerNames.ghc9122
       ] released;
     })
     {