diff --git a/lib/PhpParser/Builder/Param.php b/lib/PhpParser/Builder/Param.php
index 0ea91683..90bbb603 100644
--- a/lib/PhpParser/Builder/Param.php
+++ b/lib/PhpParser/Builder/Param.php
@@ -47,7 +47,7 @@ class Param implements PhpParser\Builder
     /**
      * Sets type for the parameter.
      *
-     * @param string|Node\Name|Node\NullableType|Node\UnionType $type Parameter type
+     * @param string|Node\Name|Node\ComplexType $type Parameter type
      *
      * @return $this The builder instance (for fluid interface)
      */
@@ -63,7 +63,7 @@ class Param implements PhpParser\Builder
     /**
      * Sets type for the parameter.
      *
-     * @param string|Node\Name|Node\NullableType|Node\UnionType $type Parameter type
+     * @param string|Node\Name|Node\ComplexType $type Parameter type
      *
      * @return $this The builder instance (for fluid interface)
      *
diff --git a/lib/PhpParser/BuilderHelpers.php b/lib/PhpParser/BuilderHelpers.php
index 835e929f..2f0e9127 100644
--- a/lib/PhpParser/BuilderHelpers.php
+++ b/lib/PhpParser/BuilderHelpers.php
@@ -2,13 +2,13 @@
 
 namespace PhpParser;
 
+use PhpParser\Node\ComplexType;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Identifier;
 use PhpParser\Node\Name;
 use PhpParser\Node\NullableType;
 use PhpParser\Node\Scalar;
 use PhpParser\Node\Stmt;
-use PhpParser\Node\UnionType;
 
 /**
  * This class defines helpers used in the implementation of builders. Don't use it directly.
@@ -154,18 +154,18 @@ final class BuilderHelpers
      * In particular, builtin types become Identifiers, custom types become Names and nullables
      * are wrapped in NullableType nodes.
      *
-     * @param string|Name|Identifier|NullableType|UnionType $type The type to normalize
+     * @param string|Name|Identifier|ComplexType $type The type to normalize
      *
-     * @return Name|Identifier|NullableType|UnionType The normalized type
+     * @return Name|Identifier|ComplexType The normalized type
      */
     public static function normalizeType($type) {
         if (!is_string($type)) {
             if (
                 !$type instanceof Name && !$type instanceof Identifier &&
-                !$type instanceof NullableType && !$type instanceof UnionType
+                !$type instanceof ComplexType
             ) {
                 throw new \LogicException(
-                    'Type must be a string, or an instance of Name, Identifier, NullableType or UnionType'
+                    'Type must be a string, or an instance of Name, Identifier or ComplexType'
                 );
             }
             return $type;
diff --git a/lib/PhpParser/Node/ComplexType.php b/lib/PhpParser/Node/ComplexType.php
new file mode 100644
index 00000000..9505532a
--- /dev/null
+++ b/lib/PhpParser/Node/ComplexType.php
@@ -0,0 +1,14 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\Node;
+
+use PhpParser\NodeAbstract;
+
+/**
+ * This is a base class for complex types, including nullable types and union types.
+ *
+ * It does not provide any shared behavior and exists only for type-checking purposes.
+ */
+abstract class ComplexType extends NodeAbstract
+{
+}
diff --git a/lib/PhpParser/Node/Expr/ArrowFunction.php b/lib/PhpParser/Node/Expr/ArrowFunction.php
index d293f0ae..2eb8213a 100644
--- a/lib/PhpParser/Node/Expr/ArrowFunction.php
+++ b/lib/PhpParser/Node/Expr/ArrowFunction.php
@@ -17,7 +17,7 @@ class ArrowFunction extends Expr implements FunctionLike
     /** @var Node\Param[] */
     public $params = [];
 
-    /** @var null|Node\Identifier|Node\Name|Node\NullableType|Node\UnionType */
+    /** @var null|Node\Identifier|Node\Name|Node\ComplexType */
     public $returnType;
 
     /** @var Expr */
diff --git a/lib/PhpParser/Node/Expr/Closure.php b/lib/PhpParser/Node/Expr/Closure.php
index 56e621f2..56ddea6a 100644
--- a/lib/PhpParser/Node/Expr/Closure.php
+++ b/lib/PhpParser/Node/Expr/Closure.php
@@ -16,7 +16,7 @@ class Closure extends Expr implements FunctionLike
     public $params;
     /** @var ClosureUse[] use()s */
     public $uses;
-    /** @var null|Node\Identifier|Node\Name|Node\NullableType|Node\UnionType Return type */
+    /** @var null|Node\Identifier|Node\Name|Node\ComplexType Return type */
     public $returnType;
     /** @var Node\Stmt[] Statements */
     public $stmts;
diff --git a/lib/PhpParser/Node/FunctionLike.php b/lib/PhpParser/Node/FunctionLike.php
index bbcf53e5..5a825e73 100644
--- a/lib/PhpParser/Node/FunctionLike.php
+++ b/lib/PhpParser/Node/FunctionLike.php
@@ -23,7 +23,7 @@ interface FunctionLike extends Node
     /**
      * Get the declared return type or null
      *
-     * @return null|Identifier|Name|NullableType|UnionType
+     * @return null|Identifier|Name|ComplexType
      */
     public function getReturnType();
 
diff --git a/lib/PhpParser/Node/NullableType.php b/lib/PhpParser/Node/NullableType.php
index 36463657..d68e26a3 100644
--- a/lib/PhpParser/Node/NullableType.php
+++ b/lib/PhpParser/Node/NullableType.php
@@ -2,9 +2,7 @@
 
 namespace PhpParser\Node;
 
-use PhpParser\NodeAbstract;
-
-class NullableType extends NodeAbstract
+class NullableType extends ComplexType
 {
     /** @var Identifier|Name Type */
     public $type;
diff --git a/lib/PhpParser/Node/Param.php b/lib/PhpParser/Node/Param.php
index 315b5f24..1e90b794 100644
--- a/lib/PhpParser/Node/Param.php
+++ b/lib/PhpParser/Node/Param.php
@@ -6,7 +6,7 @@ use PhpParser\NodeAbstract;
 
 class Param extends NodeAbstract
 {
-    /** @var null|Identifier|Name|NullableType|UnionType Type declaration */
+    /** @var null|Identifier|Name|ComplexType Type declaration */
     public $type;
     /** @var bool Whether parameter is passed by reference */
     public $byRef;
@@ -24,14 +24,14 @@ class Param extends NodeAbstract
     /**
      * Constructs a parameter node.
      *
-     * @param Expr\Variable|Expr\Error                           $var        Parameter variable
-     * @param null|Expr                                          $default    Default value
-     * @param null|string|Identifier|Name|NullableType|UnionType $type       Type declaration
-     * @param bool                                               $byRef      Whether is passed by reference
-     * @param bool                                               $variadic   Whether this is a variadic argument
-     * @param array                                              $attributes Additional attributes
-     * @param int                                                $flags      Optional visibility flags
-     * @param AttributeGroup[]                                   $attrGroups PHP attribute groups
+     * @param Expr\Variable|Expr\Error                $var        Parameter variable
+     * @param null|Expr                               $default    Default value
+     * @param null|string|Identifier|Name|ComplexType $type       Type declaration
+     * @param bool                                    $byRef      Whether is passed by reference
+     * @param bool                                    $variadic   Whether this is a variadic argument
+     * @param array                                   $attributes Additional attributes
+     * @param int                                     $flags      Optional visibility flags
+     * @param AttributeGroup[]                        $attrGroups PHP attribute groups
      */
     public function __construct(
         $var, Expr $default = null, $type = null,
diff --git a/lib/PhpParser/Node/Stmt/ClassMethod.php b/lib/PhpParser/Node/Stmt/ClassMethod.php
index 92157fab..09b877a9 100644
--- a/lib/PhpParser/Node/Stmt/ClassMethod.php
+++ b/lib/PhpParser/Node/Stmt/ClassMethod.php
@@ -15,7 +15,7 @@ class ClassMethod extends Node\Stmt implements FunctionLike
     public $name;
     /** @var Node\Param[] Parameters */
     public $params;
-    /** @var null|Node\Identifier|Node\Name|Node\NullableType|Node\UnionType Return type */
+    /** @var null|Node\Identifier|Node\Name|Node\ComplexType Return type */
     public $returnType;
     /** @var Node\Stmt[]|null Statements */
     public $stmts;
diff --git a/lib/PhpParser/Node/Stmt/Function_.php b/lib/PhpParser/Node/Stmt/Function_.php
index f08481fa..3fa24f49 100644
--- a/lib/PhpParser/Node/Stmt/Function_.php
+++ b/lib/PhpParser/Node/Stmt/Function_.php
@@ -16,7 +16,7 @@ class Function_ extends Node\Stmt implements FunctionLike
     public $name;
     /** @var Node\Param[] Parameters */
     public $params;
-    /** @var null|Node\Identifier|Node\Name|Node\NullableType|Node\UnionType Return type */
+    /** @var null|Node\Identifier|Node\Name|Node\ComplexType Return type */
     public $returnType;
     /** @var Node\Stmt[] Statements */
     public $stmts;
diff --git a/lib/PhpParser/Node/Stmt/Property.php b/lib/PhpParser/Node/Stmt/Property.php
index 4f04805d..bc781bbf 100644
--- a/lib/PhpParser/Node/Stmt/Property.php
+++ b/lib/PhpParser/Node/Stmt/Property.php
@@ -3,10 +3,9 @@
 namespace PhpParser\Node\Stmt;
 
 use PhpParser\Node;
+use PhpParser\Node\ComplexType;
 use PhpParser\Node\Identifier;
 use PhpParser\Node\Name;
-use PhpParser\Node\NullableType;
-use PhpParser\Node\UnionType;
 
 class Property extends Node\Stmt
 {
@@ -14,7 +13,7 @@ class Property extends Node\Stmt
     public $flags;
     /** @var PropertyProperty[] Properties */
     public $props;
-    /** @var null|Identifier|Name|NullableType|UnionType Type declaration */
+    /** @var null|Identifier|Name|ComplexType Type declaration */
     public $type;
     /** @var Node\AttributeGroup[] PHP attribute groups */
     public $attrGroups;
@@ -22,11 +21,11 @@ class Property extends Node\Stmt
     /**
      * Constructs a class property list node.
      *
-     * @param int                                                $flags      Modifiers
-     * @param PropertyProperty[]                                 $props      Properties
-     * @param array                                              $attributes Additional attributes
-     * @param null|string|Identifier|Name|NullableType|UnionType $type       Type declaration
-     * @param Node\AttributeGroup[]                              $attrGroups PHP attribute groups
+     * @param int                                     $flags      Modifiers
+     * @param PropertyProperty[]                      $props      Properties
+     * @param array                                   $attributes Additional attributes
+     * @param null|string|Identifier|Name|ComplexType $type       Type declaration
+     * @param Node\AttributeGroup[]                   $attrGroups PHP attribute groups
      */
     public function __construct(int $flags, array $props, array $attributes = [], $type = null, array $attrGroups = []) {
         $this->attributes = $attributes;
diff --git a/lib/PhpParser/Node/UnionType.php b/lib/PhpParser/Node/UnionType.php
index c8f45235..61c2d810 100644
--- a/lib/PhpParser/Node/UnionType.php
+++ b/lib/PhpParser/Node/UnionType.php
@@ -2,9 +2,7 @@
 
 namespace PhpParser\Node;
 
-use PhpParser\NodeAbstract;
-
-class UnionType extends NodeAbstract
+class UnionType extends ComplexType
 {
     /** @var (Identifier|Name)[] Types */
     public $types;
diff --git a/test/PhpParser/Builder/ParamTest.php b/test/PhpParser/Builder/ParamTest.php
index 05b3c912..9fe81607 100644
--- a/test/PhpParser/Builder/ParamTest.php
+++ b/test/PhpParser/Builder/ParamTest.php
@@ -177,7 +177,7 @@ class ParamTest extends \PHPUnit\Framework\TestCase
 
     public function testInvalidTypeError() {
         $this->expectException(\LogicException::class);
-        $this->expectExceptionMessage('Type must be a string, or an instance of Name, Identifier, NullableType or UnionType');
+        $this->expectExceptionMessage('Type must be a string, or an instance of Name, Identifier or ComplexType');
         $this->createParamBuilder('test')->setType(new \stdClass);
     }
 
diff --git a/test/PhpParser/BuilderHelpersTest.php b/test/PhpParser/BuilderHelpersTest.php
index da6348f6..c848dbb6 100644
--- a/test/PhpParser/BuilderHelpersTest.php
+++ b/test/PhpParser/BuilderHelpersTest.php
@@ -146,7 +146,7 @@ class BuilderHelpersTest extends \PHPUnit\Framework\TestCase
         $this->assertEquals($intIdentifier, $nullable->type);
 
         $this->expectException(\LogicException::class);
-        $this->expectExceptionMessage('Type must be a string, or an instance of Name, Identifier, NullableType or UnionType');
+        $this->expectExceptionMessage('Type must be a string, or an instance of Name, Identifier or ComplexType');
         BuilderHelpers::normalizeType(1);
     }