diff --git a/src/Type/Parser/Lexer/AliasLexer.php b/src/Type/Parser/Lexer/AliasLexer.php
index 4957d16..685cf0f 100644
--- a/src/Type/Parser/Lexer/AliasLexer.php
+++ b/src/Type/Parser/Lexer/AliasLexer.php
@@ -6,14 +6,12 @@ namespace CuyZ\Valinor\Type\Parser\Lexer;
 
 use CuyZ\Valinor\Type\Parser\Lexer\Token\Token;
 use CuyZ\Valinor\Utility\Reflection\ClassAliasParser;
+use CuyZ\Valinor\Utility\Reflection\Reflection;
 use ReflectionClass;
-
 use ReflectionFunction;
-
 use Reflector;
 
-use function class_exists;
-use function interface_exists;
+use function strtolower;
 
 /** @internal */
 final class AliasLexer implements TypeLexer
@@ -43,7 +41,7 @@ final class AliasLexer implements TypeLexer
     {
         $alias = ClassAliasParser::get()->resolveAlias($symbol, $this->reflection);
 
-        if ($alias !== $symbol) {
+        if (strtolower($alias) !== strtolower($symbol)) {
             return $alias;
         }
 
@@ -77,7 +75,7 @@ final class AliasLexer implements TypeLexer
 
         $full = $namespace . '\\' . $symbol;
 
-        if (class_exists($full) || interface_exists($full)) {
+        if (Reflection::classOrInterfaceExists($full)) {
             return $full;
         }
 
diff --git a/src/Type/Parser/Lexer/NativeLexer.php b/src/Type/Parser/Lexer/NativeLexer.php
index f7baaec..ad5d2c1 100644
--- a/src/Type/Parser/Lexer/NativeLexer.php
+++ b/src/Type/Parser/Lexer/NativeLexer.php
@@ -29,11 +29,10 @@ use CuyZ\Valinor\Type\Parser\Lexer\Token\Token;
 use CuyZ\Valinor\Type\Parser\Lexer\Token\UnionToken;
 use CuyZ\Valinor\Type\Parser\Lexer\Token\UnknownSymbolToken;
 use CuyZ\Valinor\Utility\Polyfill;
+use CuyZ\Valinor\Utility\Reflection\Reflection;
 use UnitEnum;
 
-use function class_exists;
 use function filter_var;
-use function interface_exists;
 use function is_numeric;
 use function strtolower;
 use function substr;
@@ -109,7 +108,8 @@ final class NativeLexer implements TypeLexer
             return new EnumNameToken($symbol);
         }
 
-        if (class_exists($symbol) || interface_exists($symbol)) {
+        if (Reflection::classOrInterfaceExists($symbol)) {
+            /** @var class-string $symbol */
             return new ClassNameToken($symbol);
         }
 
diff --git a/src/Type/Types/ClassStringType.php b/src/Type/Types/ClassStringType.php
index 9923671..9b4db37 100644
--- a/src/Type/Types/ClassStringType.php
+++ b/src/Type/Types/ClassStringType.php
@@ -11,9 +11,8 @@ use CuyZ\Valinor\Type\Type;
 use CuyZ\Valinor\Type\Types\Exception\CannotCastValue;
 use CuyZ\Valinor\Type\Types\Exception\InvalidClassString;
 use CuyZ\Valinor\Type\Types\Exception\InvalidUnionOfClassString;
+use CuyZ\Valinor\Utility\Reflection\Reflection;
 
-use function class_exists;
-use function interface_exists;
 use function is_object;
 use function is_string;
 use function method_exists;
@@ -51,7 +50,7 @@ final class ClassStringType implements StringType, CompositeType
             return false;
         }
 
-        if (! class_exists($value) && ! interface_exists($value)) {
+        if (! Reflection::classOrInterfaceExists($value)) {
             return false;
         }
 
diff --git a/src/Utility/Reflection/Reflection.php b/src/Utility/Reflection/Reflection.php
index 0819eaf..102838c 100644
--- a/src/Utility/Reflection/Reflection.php
+++ b/src/Utility/Reflection/Reflection.php
@@ -18,8 +18,10 @@ use ReflectionUnionType;
 use Reflector;
 use RuntimeException;
 
+use function class_exists;
 use function get_class;
 use function implode;
+use function interface_exists;
 use function preg_match_all;
 use function preg_replace;
 use function spl_object_hash;
@@ -39,6 +41,18 @@ final class Reflection
     /** @var array<string, ReflectionFunction> */
     private static array $functionReflection = [];
 
+    /**
+     * Case-sensitive implementation of `class_exists` and `interface_exists`.
+     */
+    public static function classOrInterfaceExists(string $name): bool
+    {
+        if (! class_exists($name) && ! interface_exists($name)) {
+            return false;
+        }
+
+        return self::class($name)->name === ltrim($name, '\\');
+    }
+
     /**
      * @param class-string $className
      * @return ReflectionClass<object>
@@ -132,7 +146,7 @@ final class Reflection
 
         if (PHP_VERSION_ID >= 8_00_00 && $reflection->isPromoted()) {
             $type = self::parseDocBlock(
-                // @phpstan-ignore-next-line / parameter is promoted so class exists for sure
+            // @phpstan-ignore-next-line / parameter is promoted so class exists for sure
                 self::sanitizeDocComment($reflection->getDeclaringClass()->getProperty($reflection->name)),
                 sprintf('@%s?var\s+%s', self::TOOL_EXPRESSION, self::TYPE_EXPRESSION)
             );
diff --git a/tests/Functional/Type/Parser/Lexer/NativeLexerTest.php b/tests/Functional/Type/Parser/Lexer/NativeLexerTest.php
index 8262dc5..f99f5b6 100644
--- a/tests/Functional/Type/Parser/Lexer/NativeLexerTest.php
+++ b/tests/Functional/Type/Parser/Lexer/NativeLexerTest.php
@@ -563,6 +563,11 @@ final class NativeLexerTest extends TestCase
                 'transformed' => 'array{foo: string}',
                 'type' => ShapedArrayType::class,
             ],
+            'Shaped array with key equal to class name' => [
+                'raw' => 'array{stdclass: string}',
+                'transformed' => 'array{stdclass: string}',
+                'type' => ShapedArrayType::class,
+            ],
             'Iterable type' => [
                 'raw' => 'iterable',
                 'transformed' => 'iterable',
diff --git a/tests/Integration/Mapping/Object/ShapedArrayValuesMappingTest.php b/tests/Integration/Mapping/Object/ShapedArrayValuesMappingTest.php
index b269902..3438f6b 100644
--- a/tests/Integration/Mapping/Object/ShapedArrayValuesMappingTest.php
+++ b/tests/Integration/Mapping/Object/ShapedArrayValuesMappingTest.php
@@ -38,6 +38,9 @@ final class ShapedArrayValuesMappingTest extends IntegrationTest
                 1337,
                 42.404,
             ],
+            'shapedArrayWithClassNameAsKey' => [
+                'stdclass' => 'foo',
+            ],
         ];
 
         foreach ([ShapedArrayValues::class, ShapedArrayValuesWithConstructor::class] as $class) {
@@ -55,6 +58,7 @@ final class ShapedArrayValuesMappingTest extends IntegrationTest
             self::assertSame('bar', $result->advancedShapedArray['mandatoryString']);
             self::assertSame(1337, $result->advancedShapedArray[0]);
             self::assertSame(42.404, $result->advancedShapedArray[1]);
+            self::assertSame('foo', $result->shapedArrayWithClassNameAsKey['stdclass']);
         }
     }
 
@@ -100,6 +104,9 @@ class ShapedArrayValues
 
     /** @var array{0: int, float, optionalString?: string, mandatoryString: string} */
     public array $advancedShapedArray;
+
+    /** @var array{stdclass: string} */
+    public array $shapedArrayWithClassNameAsKey;
 }
 
 class ShapedArrayValuesWithConstructor extends ShapedArrayValues
@@ -114,6 +121,7 @@ class ShapedArrayValuesWithConstructor extends ShapedArrayValues
      *     bar: int
      * } $shapedArrayOnSeveralLines
      * @param array{0: int, float, optionalString?: string, mandatoryString: string} $advancedShapedArray
+     * @param array{stdclass: string} $shapedArrayWithClassNameAsKey
      */
     public function __construct(
         array $basicShapedArrayWithStringKeys,
@@ -121,7 +129,8 @@ class ShapedArrayValuesWithConstructor extends ShapedArrayValues
         array $shapedArrayWithObject,
         array $shapedArrayWithOptionalValue,
         array $shapedArrayOnSeveralLines,
-        array $advancedShapedArray
+        array $advancedShapedArray,
+        array $shapedArrayWithClassNameAsKey
     ) {
         $this->basicShapedArrayWithStringKeys = $basicShapedArrayWithStringKeys;
         $this->basicShapedArrayWithIntegerKeys = $basicShapedArrayWithIntegerKeys;
@@ -129,5 +138,6 @@ class ShapedArrayValuesWithConstructor extends ShapedArrayValues
         $this->shapedArrayWithOptionalValue = $shapedArrayWithOptionalValue;
         $this->shapedArrayOnSeveralLines = $shapedArrayOnSeveralLines;
         $this->advancedShapedArray = $advancedShapedArray;
+        $this->shapedArrayWithClassNameAsKey = $shapedArrayWithClassNameAsKey;
     }
 }