diff --git a/lib/default.nix b/lib/default.nix
index 2d7a0aebb0..e3e3de576f 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -160,15 +160,24 @@ in {
     let packageToComponents = _name: package:
           # look for the components with this group if there are any
           let components = package.components.${group} or {};
-          # set recurseForDerivations unless it's a derivation itself (e.g. the "library" component) or an empty set
-          in if lib.isDerivation components || components == {}
-             then components
-             else recurseIntoAttrs components;
+          in {
+            inherit (package.identifier) name;
+            # set recurseForDerivations unless it's a derivation itself (e.g. the "library" component) or an empty set
+            components =
+              if lib.isDerivation components || components == {}
+                then components
+                else recurseIntoAttrs components;
+          };
         packageFilter = _name: package: (package.isHaskell or false) && packageSel package;
         filteredPkgs = lib.filterAttrs packageFilter haskellPackages;
         # at this point we can filter out packages that don't have any of the given kind of component
-        packagesByComponent = lib.filterAttrs (_: components: components != {}) (lib.mapAttrs packageToComponents filteredPkgs);
-    in recurseIntoAttrs packagesByComponent;
+        packagesByComponent = lib.mapAttrsToList packageToComponents filteredPkgs;
+        packagesGroupedByName = builtins.groupBy (x: x.name) packagesByComponent;
+        combined =
+          lib.filterAttrs (_: components: components != {}) (
+            builtins.mapAttrs (_name: packages:
+              builtins.foldl' (a: b: a // b) {} (map (x: x.components) packages)) packagesGroupedByName);
+    in recurseIntoAttrs combined;
 
   # Equivalent to collectComponents with (_: true) as selection function.
   # Useful for pre-filtered package-set.
@@ -184,7 +193,7 @@ in {
   # This can be used to collect all the test runs in your project, so that can be run in CI.
   collectChecks = packageSel: haskellPackages:
     let packageFilter = _name: package: (package.isHaskell or false) && packageSel package;
-    in recurseIntoAttrs (lib.mapAttrs (_: p: p.checks) (lib.filterAttrs packageFilter haskellPackages));
+    in recurseIntoAttrs (lib.filterAttrs (_: x: x != {} && x != recurseIntoAttrs {}) (lib.mapAttrs (_: p: p.checks) (lib.filterAttrs packageFilter haskellPackages)));
 
   # Equivalent to collectChecks with (_: true) as selection function.
   # Useful for pre-filtered package-set.
diff --git a/modules/install-plan/redirect.nix b/modules/install-plan/redirect.nix
index b634904239..d2c7328b4f 100644
--- a/modules/install-plan/redirect.nix
+++ b/modules/install-plan/redirect.nix
@@ -1,7 +1,7 @@
 # Add `hsPkgs.${pkg-name}` based on the available targets in the plan.
 {pkgs, lib, config, ...}:
 let
-  redirect = redirectName: packageTargets:
+  redirect = existing: redirectName: packageTargets:
     let
       componentsByName = builtins.listToAttrs (map (x: { name = x.component-name; value = x.available; }) packageTargets);
       lookupComponent = collectionName: name: available:
@@ -14,8 +14,8 @@ let
         else if builtins.isString (builtins.head available)
           then throw "${builtins.head available} looking for ${attrPath}"
         else if collectionName == ""
-          then config.hsPkgs.${(builtins.head available).id}.components.library
-        else config.hsPkgs.${(builtins.head available).id}.components.${collectionName}.${name};
+          then existing.${(builtins.head available).id}.components.library
+        else existing.${(builtins.head available).id}.components.${collectionName}.${name};
       componentsWithPrefix = collectionName: prefix:
         lib.listToAttrs (lib.concatLists (lib.mapAttrsToList (n: available:
           lib.optional (lib.hasPrefix "${prefix}:" n && (builtins.length available != 1 || !builtins.elem (builtins.head available) ["TargetNotBuildable" "TargetNotLocal"])) (
@@ -24,44 +24,49 @@ let
               value = lookupComponent collectionName name available;
             in { inherit name value; }
           )) componentsByName));
-      defaultTargetPackage = config.hsPkgs.${(builtins.head (
+      defaultTargetId = (builtins.head (
           # Use the package identified by the library component
           componentsByName.lib or
           # Or by the first component
           componentsByName.${builtins.head (builtins.attrNames componentsByName)}
-        )).id};
-    in rec {
-      isRedirect = true;
+        )).id;
+      defaultTargetPackage = existing.${defaultTargetId};
+    in defaultTargetPackage // rec {
+      isRedirect = redirectName != defaultTargetId;
       identifier = rec { name = (builtins.head packageTargets).pkg-name; version = (builtins.head packageTargets).pkg-version; id = "${name}-${version}"; };
       components =
         lib.mapAttrs componentsWithPrefix pkgs.haskell-nix.haskellLib.componentPrefix
         // lib.optionalAttrs (componentsByName ? lib) {
           library = lookupComponent "" "" componentsByName.lib;
         };
-      checks = pkgs.recurseIntoAttrs (builtins.mapAttrs
-        (_: d: pkgs.haskell-nix.haskellLib.check d)
-          (lib.filterAttrs (_: d: d.config.doCheck) components.tests));
-      inherit (defaultTargetPackage) buildType setup;
+      checks = pkgs.recurseIntoAttrs (
+        lib.filterAttrs (_: x: x != {}) (
+          builtins.mapAttrs
+            (_: d: pkgs.haskell-nix.haskellLib.check d)
+              (lib.filterAttrs (_: d: d.config.doCheck) components.tests)));
     };
 in {
-  hsPkgs =
-    # Redirects with just the package name
-    builtins.removeAttrs (builtins.mapAttrs (packageName: packageTargets:
-      let
-        byVersion = builtins.groupBy (x: x.pkg-version) packageTargets;
-        versions = builtins.attrNames byVersion;
-      in if builtins.length versions != 1
-        then let
-            err = throw "Multiple versions for ${packageName} ${builtins.toJSON versions}";
-          in {
-            isRedirect = true;
-            identifier = { name = packageName; version = err; };
-            components = err;
-            checks = err;
-          }
-        else redirect packageName packageTargets) (builtins.groupBy (x: x.pkg-name) config.plan-json.targets)) config.preExistingPkgs
+  options.hsPkgs = lib.mkOption {
+    type = lib.types.unspecified;
+    apply = existing: existing //
+      # Redirects with just the package name
+      builtins.removeAttrs (builtins.mapAttrs (packageName: packageTargets:
+        let
+          byVersion = builtins.groupBy (x: x.pkg-version) packageTargets;
+          versions = builtins.attrNames byVersion;
+        in if builtins.length versions != 1
+          then let
+              err = throw "Multiple versions for ${packageName} ${builtins.toJSON versions}";
+            in {
+              isRedirect = true;
+              identifier = { name = packageName; version = err; };
+              components = err;
+              checks = err;
+            }
+          else redirect existing packageName packageTargets) (builtins.groupBy (x: x.pkg-name) config.plan-json.targets)) config.preExistingPkgs
 
-    # Redirect for `${name}-${version}`
-    // builtins.mapAttrs (packageNameAndVersion: packageTargets: redirect packageNameAndVersion packageTargets)
-          (builtins.groupBy (x: "${x.pkg-name}-${x.pkg-version}") config.plan-json.targets);
+      # Redirect for `${name}-${version}`
+      // builtins.mapAttrs (packageNameAndVersion: packageTargets: redirect existing packageNameAndVersion packageTargets)
+            (builtins.groupBy (x: "${x.pkg-name}-${x.pkg-version}") config.plan-json.targets);
+  };
 }