From fda35f803baff711a60354bc89d775106c65cfa5 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <rvanvelzen1@gmail.com>
Date: Tue, 15 Apr 2025 21:23:27 +0200
Subject: [PATCH] Fix specifying types on nullsafe true/false comparison

---
 src/Analyser/TypeSpecifier.php            |  4 +-
 tests/PHPStan/Analyser/nsrt/bug-12866.php | 65 +++++++++++++++++++++++
 2 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-12866.php

diff --git a/src/Analyser/TypeSpecifier.php b/src/Analyser/TypeSpecifier.php
index f7d01f2da6..ff08ce4503 100644
--- a/src/Analyser/TypeSpecifier.php
+++ b/src/Analyser/TypeSpecifier.php
@@ -1134,7 +1134,7 @@ private function specifyTypesForConstantBinaryExpression(
 	{
 		if (!$context->null() && $constantType->isFalse()->yes()) {
 			$types = $this->create($exprNode, $constantType, $context, false, $scope, $rootExpr);
-			if ($exprNode instanceof Expr\NullsafeMethodCall || $exprNode instanceof Expr\NullsafePropertyFetch) {
+			if (!$context->true() && ($exprNode instanceof Expr\NullsafeMethodCall || $exprNode instanceof Expr\NullsafePropertyFetch)) {
 				return $types;
 			}
 
@@ -1148,7 +1148,7 @@ private function specifyTypesForConstantBinaryExpression(
 
 		if (!$context->null() && $constantType->isTrue()->yes()) {
 			$types = $this->create($exprNode, $constantType, $context, false, $scope, $rootExpr);
-			if ($exprNode instanceof Expr\NullsafeMethodCall || $exprNode instanceof Expr\NullsafePropertyFetch) {
+			if (!$context->true() && ($exprNode instanceof Expr\NullsafeMethodCall || $exprNode instanceof Expr\NullsafePropertyFetch)) {
 				return $types;
 			}
 
diff --git a/tests/PHPStan/Analyser/nsrt/bug-12866.php b/tests/PHPStan/Analyser/nsrt/bug-12866.php
new file mode 100644
index 0000000000..4360d8bdd1
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-12866.php
@@ -0,0 +1,65 @@
+<?php declare(strict_types = 1); // lint >= 8.0
+
+namespace Bug12866;
+
+use function PHPStan\Testing\assertType;
+
+interface I
+{
+	/**
+	 * @phpstan-assert-if-true A $this
+	 */
+	public function isA(): bool;
+}
+
+class A implements I
+{
+	public function isA(): bool
+	{
+		return true;
+	}
+}
+
+class B implements I
+{
+	public function isA(): bool
+	{
+		return false;
+	}
+}
+
+function takesI(I $i): void
+{
+	if (!$i->isA()) {
+		return;
+	}
+
+	assertType('Bug12866\\A', $i);
+}
+
+function takesIStrictComparison(I $i): void
+{
+	if ($i->isA() !== true) {
+		return;
+	}
+
+	assertType('Bug12866\\A', $i);
+}
+
+function takesNullableI(?I $i): void
+{
+	if (!$i?->isA()) {
+		return;
+	}
+
+	assertType('Bug12866\\A', $i);
+}
+
+function takesNullableIStrictComparison(?I $i): void
+{
+	if ($i?->isA() !== true) {
+		return;
+	}
+
+	assertType('Bug12866\\A', $i);
+}