Move warning logic into cabal-project.nix (#2203)

* Move warning logic into cabal-project.nix

This also adds `old-compiler-warning` project argument we can use to switch off the warning when building hadrian.  We build hadrian with ghc 9.6.2 from nixpkgs because 9.6.5 may not be present in nixpkgs.

* Fix ci

* ifdLevel 2

* ifdLevel 3

* Better fix

* Update overlays/bootstrap.nix

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Keep nix 2.4 fix

* Fix warning for llvm compilers

* Fix warning for llvm compilers

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: hamishmack

compiler/ghc/default.nix

@@ -253,7 +253,7 @@ let
           then "ghc928"
           else "ghc962";
     in
-    buildPackages.pinned-haskell-nix.tool compiler-nix-name "hadrian" {
+    buildPackages.haskell-nix.tool compiler-nix-name "hadrian" {
       compilerSelection = p: p.haskell.compiler;
       index-state = buildPackages.haskell-nix.internalHackageIndexState;
       # Verions of hadrian that comes with 9.6 depends on `time`
@@ -268,6 +268,7 @@ let
           then ../../materialized/${compiler-nix-name}/hadrian-ghc98
         else ../../materialized/${compiler-nix-name}/hadrian-ghc99;
       modules = [{
+        reinstallableLibGhc = false;
         # Apply the patches in a way that does not require using something
         # like `srcOnly`. The problem with `pkgs.srcOnly` was that it had to run
         # on a platform at eval time.

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

@@ -99,7 +99,9 @@ let
               (compilerSelection pkgs)."${compiler-nix-name}";
 
 in let
-  ghc = ghc';
+  ghc = if ghc' ? latestVersion
+    then __trace "WARNING: ${ghc'.version} is out of date, consider using upgrading to ${ghc'.latestVersion}." ghc'
+    else ghc';
   subDir' = src.origSubDir or "";
   subDir = pkgs.lib.strings.removePrefix "/" subDir';
 

modules/cabal-project.nix

@@ -18,7 +18,6 @@ in {
       type = str;
       description = "The name of the ghc compiler to use eg. \"ghc884\"";
       # Map short version names to the latest GHC version.
-      # TODO: perhaps combine this with the `latestVer` mapping in `overlays/boostrap.nix`.
       apply = name: pkgs.haskell-nix.resolve-compiler-name name;
     };
     compilerSelection = mkOption {