Fix intersection of two identical ThisType

Author: ondrejmirtes

Diff for: src/Type/ThisType.php

@@ -5,6 +5,7 @@
 use PHPStan\Reflection\ClassReflection;
 use PHPStan\Reflection\ReflectionProviderStaticAccessor;
 use PHPStan\TrinaryLogic;
+use function get_class;
 use function sprintf;
 
 /** @api */
@@ -23,6 +24,33 @@ public function __construct(
 		parent::__construct($classReflection, $subtractedType);
 	}
 
+	public function equals(Type $type): bool
+	{
+		if (get_class($type) !== static::class) {
+			return false;
+		}
+
+		/** @var ThisType $type */
+		$type = $type;
+		$equals = $this->getStaticObjectType()->equals($type->getStaticObjectType());
+		if (!$equals) {
+			return false;
+		}
+
+		if ($this->getTraitReflection() === null) {
+			if ($type->getTraitReflection() === null) {
+				return true;
+			}
+
+			return false;
+		}
+		if ($type->getTraitReflection() === null) {
+			return false;
+		}
+
+		return $this->getTraitReflection()->getName() === $type->getTraitReflection()->getName();
+	}
+
 	public function changeBaseClass(ClassReflection $classReflection): StaticType
 	{
 		return new self($classReflection, $this->getSubtractedType(), $this->traitReflection);
@@ -50,6 +78,10 @@ function () use ($callback): string {
 	public function isSuperTypeOf(Type $type): TrinaryLogic
 	{
 		if ($type instanceof self) {
+			if ($this->equals($type)) {
+				return TrinaryLogic::createYes();
+			}
+
 			return $this->getStaticObjectType()->isSuperTypeOf($type);
 		}
 

Diff for: tests/PHPStan/Analyser/data/trait-instance-of.php

@@ -43,7 +43,7 @@ public function test(): string {
 		}
 
 		if ($this instanceof ATrait1Class) {
-			assertType('*NEVER*', $this);
+			assertType('$this(TraitInstanceOf\FinalTrait2Class~TraitInstanceOf\FinalTrait2Class)&TraitInstanceOf\ATrait1Class', $this);
 			return 'hello world';
 		}
 

Diff for: tests/PHPStan/Type/TypeCombinatorTest.php

@@ -47,6 +47,8 @@
 use Test\ClassWithToString;
 use Test\FirstInterface;
 use Throwable;
+use TraitInstanceOf\ATrait1Class;
+use TraitInstanceOf\Trait1;
 use Traversable;
 use function array_map;
 use function array_reverse;
@@ -3978,6 +3980,15 @@ public function dataIntersect(): iterable
 			IntersectionType::class,
 			'$this(TraitInstanceOf\FinalTrait2Class~TraitInstanceOf\FinalOther)&NonExistantClass',
 		];
+
+		yield [
+			[
+				new ThisType($reflectionProvider->getClass(ATrait1Class::class), null, $reflectionProvider->getClass(Trait1::class)),
+				new ThisType($reflectionProvider->getClass(ATrait1Class::class), null, $reflectionProvider->getClass(Trait1::class)),
+			],
+			ThisType::class,
+			'$this(TraitInstanceOf\ATrait1Class)',
+		];
 	}
 
 	/**