diff --git a/composer.lock b/composer.lock
index 0ccf7d9..8b48f2c 100644
--- a/composer.lock
+++ b/composer.lock
@@ -1280,16 +1280,16 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "1.10.58",
+            "version": "1.10.59",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "a23518379ec4defd9e47cbf81019526861623ec2"
+                "reference": "e607609388d3a6d418a50a49f7940e8086798281"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/a23518379ec4defd9e47cbf81019526861623ec2",
-                "reference": "a23518379ec4defd9e47cbf81019526861623ec2",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/e607609388d3a6d418a50a49f7940e8086798281",
+                "reference": "e607609388d3a6d418a50a49f7940e8086798281",
                 "shasum": ""
             },
             "require": {
@@ -1338,7 +1338,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2024-02-12T20:02:57+00:00"
+            "time": "2024-02-20T13:59:13+00:00"
         },
         {
             "name": "phpunit/php-code-coverage",
diff --git a/rector.php b/rector.php
index 00c5a54..350fa51 100644
--- a/rector.php
+++ b/rector.php
@@ -14,6 +14,4 @@ return RectorConfig::configure()
     ])
     // uncomment to reach your current PHP version
     ->withPhpSets()
-    ->withRules([
-        AddVoidReturnTypeWhereNoReturnRector::class,
-    ]);
+    ->withPreparedSets(typeDeclarations : true);
diff --git a/src/FactorGraphs/Factor.php b/src/FactorGraphs/Factor.php
index a17dca4..841b584 100644
--- a/src/FactorGraphs/Factor.php
+++ b/src/FactorGraphs/Factor.php
@@ -31,9 +31,9 @@ abstract class Factor implements \Stringable
     }
 
     /**
-     * @return mixed The log-normalization constant of that factor
+     * @return float The log-normalization constant of that factor
      */
-    public function getLogNormalization()
+    public function getLogNormalization(): float
     {
         return 0;
     }
diff --git a/src/FactorGraphs/FactorGraphLayer.php b/src/FactorGraphs/FactorGraphLayer.php
index 4e39789..5601ede 100644
--- a/src/FactorGraphs/FactorGraphLayer.php
+++ b/src/FactorGraphs/FactorGraphLayer.php
@@ -21,7 +21,7 @@ abstract class FactorGraphLayer
     /**
      * @var array<int,array<int,object>>
      */
-    private $inputVariablesGroups = [];
+    private array $inputVariablesGroups = [];
 
     protected function __construct(private readonly TrueSkillFactorGraph $parentFactorGraph)
     {
diff --git a/src/TrueSkill/Factors/GaussianWeightedSumFactor.php b/src/TrueSkill/Factors/GaussianWeightedSumFactor.php
index 51c64c5..6575eeb 100644
--- a/src/TrueSkill/Factors/GaussianWeightedSumFactor.php
+++ b/src/TrueSkill/Factors/GaussianWeightedSumFactor.php
@@ -125,7 +125,7 @@ class GaussianWeightedSumFactor extends GaussianFactor
         }
     }
 
-    public function getLogNormalization()
+    public function getLogNormalization(): float
     {
         $vars = $this->getVariables();
         $messages = $this->getMessages();
diff --git a/src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php b/src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
index 5b08146..25887a2 100644
--- a/src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
+++ b/src/TrueSkill/Layers/PlayerPerformancesToTeamPerformancesLayer.php
@@ -37,7 +37,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
 
         return $this->scheduleSequence(
             array_map(
-                fn ($weightedSumFactor) => new ScheduleStep('Perf to Team Perf Step', $weightedSumFactor, 0),
+                fn ($weightedSumFactor): ScheduleStep => new ScheduleStep('Perf to Team Perf Step', $weightedSumFactor, 0),
                 $localFactors
             ),
             'all player perf to team perf schedule'
@@ -50,7 +50,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
     protected function createPlayerToTeamSumFactor(array $teamMembers, Variable $sumVariable): GaussianWeightedSumFactor
     {
         $weights = array_map(
-            function ($v) {
+            function ($v): float {
                 $player = $v->getKey();
 
                 return PartialPlay::getPartialPlayPercentage($player);
@@ -89,7 +89,7 @@ class PlayerPerformancesToTeamPerformancesLayer extends TrueSkillFactorGraphLaye
      */
     private function createOutputVariable(array $team): Variable
     {
-        $memberNames = array_map(fn ($currentPlayer) => (string)($currentPlayer->getKey()), $team);
+        $memberNames = array_map(fn ($currentPlayer): string => (string)($currentPlayer->getKey()), $team);
 
         $teamMemberNames = \implode(', ', $memberNames);
 
diff --git a/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php b/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
index e359164..db72d43 100644
--- a/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
+++ b/src/TrueSkill/Layers/PlayerPriorValuesToSkillsLayer.php
@@ -55,7 +55,7 @@ class PlayerPriorValuesToSkillsLayer extends TrueSkillFactorGraphLayer
 
         return $this->scheduleSequence(
             array_map(
-                fn ($prior) => new ScheduleStep('Prior to Skill Step', $prior, 0),
+                fn ($prior): ScheduleStep => new ScheduleStep('Prior to Skill Step', $prior, 0),
                 $localFactors
             ),
             'All priors'
diff --git a/src/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php b/src/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
index 525acde..80d66a9 100644
--- a/src/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
+++ b/src/TrueSkill/Layers/PlayerSkillsToPerformancesLayer.php
@@ -53,7 +53,7 @@ class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
 
         return $this->scheduleSequence(
             array_map(
-                fn ($likelihood) => new ScheduleStep('Skill to Perf step', $likelihood, 0),
+                fn ($likelihood): ScheduleStep => new ScheduleStep('Skill to Perf step', $likelihood, 0),
                 $localFactors
             ),
             'All skill to performance sending'
@@ -66,7 +66,7 @@ class PlayerSkillsToPerformancesLayer extends TrueSkillFactorGraphLayer
 
         return $this->scheduleSequence(
             array_map(
-                fn ($likelihood) => new ScheduleStep('name', $likelihood, 1),
+                fn ($likelihood): ScheduleStep => new ScheduleStep('name', $likelihood, 1),
                 $localFactors
             ),
             'All skill to performance sending'
diff --git a/src/TrueSkill/TrueSkillFactorGraph.php b/src/TrueSkill/TrueSkillFactorGraph.php
index 2ddd63f..064303b 100644
--- a/src/TrueSkill/TrueSkillFactorGraph.php
+++ b/src/TrueSkill/TrueSkillFactorGraph.php
@@ -39,7 +39,7 @@ class TrueSkillFactorGraph extends FactorGraph
     {
         $this->priorLayer = new PlayerPriorValuesToSkillsLayer($this, $teams);
         $newFactory = new VariableFactory(
-            fn () => GaussianDistribution::fromPrecisionMean(0, 0)
+            fn (): GaussianDistribution => GaussianDistribution::fromPrecisionMean(0, 0)
         );
 
         $this->setVariableFactory($newFactory);