diff --git a/src/Type/Php/ArrayFirstLastDynamicReturnTypeExtension.php b/src/Type/Php/ArrayFirstLastDynamicReturnTypeExtension.php
index 18a7d547ec..859f36f1f0 100644
--- a/src/Type/Php/ArrayFirstLastDynamicReturnTypeExtension.php
+++ b/src/Type/Php/ArrayFirstLastDynamicReturnTypeExtension.php
@@ -6,6 +6,7 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\FunctionReflection;
+use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\NullType;
 use PHPStan\Type\Type;
@@ -19,7 +20,12 @@ final class ArrayFirstLastDynamicReturnTypeExtension implements DynamicFunctionR
 
 	public function isFunctionSupported(FunctionReflection $functionReflection): bool
 	{
-		return in_array($functionReflection->getName(), ['array_first', 'array_last'], true);
+		return in_array($functionReflection->getName(), [
+			'array_key_first',
+			'array_key_last',
+			'array_first',
+			'array_last',
+		], true);
 	}
 
 	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): ?Type
@@ -37,13 +43,24 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 			return new NullType();
 		}
 
-		$valueType = $argType->getIterableValueType();
+		switch ($functionReflection->getName()) {
+			case 'array_key_first':
+			case 'array_key_last':
+				$resultType = $argType->getIterableKeyType();
+				break;
+			case 'array_first':
+			case 'array_last':
+				$resultType = $argType->getIterableValueType();
+				break;
+			default:
+				throw new ShouldNotHappenException();
+		}
 
 		if ($iterableAtLeastOnce->yes()) {
-			return $valueType;
+			return $resultType;
 		}
 
-		return TypeCombinator::union($valueType, new NullType());
+		return TypeCombinator::union($resultType, new NullType());
 	}
 
 }
diff --git a/src/Type/Php/ArrayKeyFirstDynamicReturnTypeExtension.php b/src/Type/Php/ArrayKeyFirstDynamicReturnTypeExtension.php
deleted file mode 100644
index 2e926f7554..0000000000
--- a/src/Type/Php/ArrayKeyFirstDynamicReturnTypeExtension.php
+++ /dev/null
@@ -1,43 +0,0 @@
-<?php declare(strict_types = 1);
-
-namespace PHPStan\Type\Php;
-
-use PhpParser\Node\Expr\FuncCall;
-use PHPStan\Analyser\Scope;
-use PHPStan\DependencyInjection\AutowiredService;
-use PHPStan\Reflection\FunctionReflection;
-use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\NullType;
-use PHPStan\Type\Type;
-use PHPStan\Type\TypeCombinator;
-
-#[AutowiredService]
-final class ArrayKeyFirstDynamicReturnTypeExtension implements DynamicFunctionReturnTypeExtension
-{
-
-	public function isFunctionSupported(FunctionReflection $functionReflection): bool
-	{
-		return $functionReflection->getName() === 'array_key_first';
-	}
-
-	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): ?Type
-	{
-		if (!isset($functionCall->getArgs()[0])) {
-			return null;
-		}
-
-		$argType = $scope->getType($functionCall->getArgs()[0]->value);
-		$iterableAtLeastOnce = $argType->isIterableAtLeastOnce();
-		if ($iterableAtLeastOnce->no()) {
-			return new NullType();
-		}
-
-		$keyType = $argType->getIterableKeyType();
-		if ($iterableAtLeastOnce->yes()) {
-			return $keyType;
-		}
-
-		return TypeCombinator::union($keyType, new NullType());
-	}
-
-}
diff --git a/src/Type/Php/ArrayKeyLastDynamicReturnTypeExtension.php b/src/Type/Php/ArrayKeyLastDynamicReturnTypeExtension.php
deleted file mode 100644
index a750c9bea5..0000000000
--- a/src/Type/Php/ArrayKeyLastDynamicReturnTypeExtension.php
+++ /dev/null
@@ -1,43 +0,0 @@
-<?php declare(strict_types = 1);
-
-namespace PHPStan\Type\Php;
-
-use PhpParser\Node\Expr\FuncCall;
-use PHPStan\Analyser\Scope;
-use PHPStan\DependencyInjection\AutowiredService;
-use PHPStan\Reflection\FunctionReflection;
-use PHPStan\Type\DynamicFunctionReturnTypeExtension;
-use PHPStan\Type\NullType;
-use PHPStan\Type\Type;
-use PHPStan\Type\TypeCombinator;
-
-#[AutowiredService]
-final class ArrayKeyLastDynamicReturnTypeExtension implements DynamicFunctionReturnTypeExtension
-{
-
-	public function isFunctionSupported(FunctionReflection $functionReflection): bool
-	{
-		return $functionReflection->getName() === 'array_key_last';
-	}
-
-	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): ?Type
-	{
-		if (!isset($functionCall->getArgs()[0])) {
-			return null;
-		}
-
-		$argType = $scope->getType($functionCall->getArgs()[0]->value);
-		$iterableAtLeastOnce = $argType->isIterableAtLeastOnce();
-		if ($iterableAtLeastOnce->no()) {
-			return new NullType();
-		}
-
-		$keyType = $argType->getIterableKeyType();
-		if ($iterableAtLeastOnce->yes()) {
-			return $keyType;
-		}
-
-		return TypeCombinator::union($keyType, new NullType());
-	}
-
-}