From 7068e2245213a481078d24135094c1f925cff8c9 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Sat, 28 Feb 2026 15:03:54 +0000
Subject: [PATCH 1/2] Fix conditional return type on $this not using subtracted
 type

- When a method has a conditional return type like `@return ($this is self::A ? int : null)`,
  and `$this` has a subtracted type (e.g. `$this(X~X::A)` from narrowing), the conditional
  was not properly resolved because the subtracted type was not propagated
- The root cause was in `StaticType::transformStaticType` which transforms `StaticType`
  instances in return types but did not propagate the calling type's subtracted type
- Added subtracted type propagation in `StaticType::transformStaticType` to match the
  behavior of `CalledOnTypeUnresolvedMethodPrototypeReflection::transformStaticType`
- New regression test in tests/PHPStan/Analyser/nsrt/bug-12244.php

Closes https://github.com/phpstan/phpstan/issues/12244
---
 src/Type/StaticType.php                   |  7 +++++
 tests/PHPStan/Analyser/nsrt/bug-12244.php | 32 +++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-12244.php

diff --git a/src/Type/StaticType.php b/src/Type/StaticType.php
index 0243c96256..a7bd9932f2 100644
--- a/src/Type/StaticType.php
+++ b/src/Type/StaticType.php
@@ -369,6 +369,13 @@ private function transformStaticType(Type $type, ClassMemberAccessAnswerer $scop
 					$type = new self($type->getClassReflection(), $type->getSubtractedType());
 				}
 
+				if ($this->getSubtractedType() !== null && $type->getSubtractedType() === null) {
+					$type = $type->changeSubtractedType($this->getSubtractedType());
+					if (!$type instanceof StaticType) {
+						return $traverse($type);
+					}
+				}
+
 				if (!$isFinal || $type instanceof ThisType) {
 					return $traverse($type);
 				}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-12244.php b/tests/PHPStan/Analyser/nsrt/bug-12244.php
new file mode 100644
index 0000000000..ba792e4625
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-12244.php
@@ -0,0 +1,32 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug12244;
+
+use function PHPStan\Testing\assertType;
+
+enum X: string {
+	case A = 'a';
+	case B = 'b';
+	case C = 'c';
+
+	/** @return ($this is self::A ? int : null) */
+	public function get(): ?int {
+		return ($this === self::A) ? 123 : null;
+	}
+
+	public function doSomething(): void {
+		if ($this !== self::A) {
+			assertType('$this(Bug12244\X~Bug12244\X::A)', $this);
+			assertType('null', $this->get());
+		}
+	}
+
+	public static function doSomethingFor(X $x): void {
+		if ($x !== self::A) {
+			assertType('Bug12244\X~Bug12244\X::A', $x);
+			assertType('null', $x->get());
+		}
+	}
+}

From f8715871b88c858d4c2e3ac61980536c57b3e4bf Mon Sep 17 00:00:00 2001
From: Vincent Langlet <vincentlanglet@hotmail.fr>
Date: Sat, 28 Feb 2026 16:57:27 +0100
Subject: [PATCH 2/2] Simplify

---
 src/Type/StaticType.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Type/StaticType.php b/src/Type/StaticType.php
index a7bd9932f2..2f1e27ee22 100644
--- a/src/Type/StaticType.php
+++ b/src/Type/StaticType.php
@@ -369,8 +369,8 @@ private function transformStaticType(Type $type, ClassMemberAccessAnswerer $scop
 					$type = new self($type->getClassReflection(), $type->getSubtractedType());
 				}
 
-				if ($this->getSubtractedType() !== null && $type->getSubtractedType() === null) {
-					$type = $type->changeSubtractedType($this->getSubtractedType());
+				if ($this->getSubtractedType() !== null) {
+					$type = $type->subtract($this->getSubtractedType());
 					if (!$type instanceof StaticType) {
 						return $traverse($type);
 					}