Fix missing detection of dead code in expressions

src/Analyser/ExpressionResult.php

@@ -28,6 +28,7 @@ public function __construct(
 		private array $impurePoints,
 		?callable $truthyScopeCallback = null,
 		?callable $falseyScopeCallback = null,
+		private bool $isAlwaysTerminating = false,
 	)
 	{
 		$this->truthyScopeCallback = $truthyScopeCallback;
@@ -90,4 +91,9 @@ public function getFalseyScope(): MutatingScope
 		return $this->falseyScope;
 	}
 
+	public function isAlwaysTerminating(): bool
+	{
+		return $this->isAlwaysTerminating;
+	}
+
 }

tests/PHPStan/Rules/DeadCode/UnreachableStatementRuleTest.php

@@ -5,6 +5,7 @@
 use PHPStan\Rules\Rule;
 use PHPStan\Testing\RuleTestCase;
 use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\RequiresPhp;
 
 /**
  * @extends RuleTestCase<UnreachableStatementRule>
@@ -240,4 +241,100 @@ public function testMultipleUnreachable(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.1')]
+	public function testBug11909(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/bug-11909.php'], [
+			[
+				'Unreachable statement - code above always terminates.',
+				10,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.1')]
+	public function testBug13232a(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/bug-13232a.php'], [
+			[
+				'Unreachable statement - code above always terminates.',
+				10,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				17,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				23,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				32,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				38,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				44,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				52,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				61,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				70,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.1')]
+	public function testBug13232b(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/bug-13232b.php'], [
+			[
+				'Unreachable statement - code above always terminates.',
+				19,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.1')]
+	public function testBug13232c(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/bug-13232c.php'], [
+			[
+				'Unreachable statement - code above always terminates.',
+				12,
+			],
+			[
+				'Unreachable statement - code above always terminates.',
+				20,
+			],
+		]);
+	}
+
+	#[RequiresPhp('>= 8.1')]
+	public function testBug13232d(): void
+	{
+		$this->treatPhpDocTypesAsCertain = false;
+		$this->analyse([__DIR__ . '/data/bug-13232d.php'], [
+			[
+				'Unreachable statement - code above always terminates.',
+				11,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/DeadCode/data/bug-11909.php

@@ -0,0 +1,10 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11909;
+
+function doFoo(): never {
+	throw new LogicException("throws");
+}
+
+echo doFoo();
+echo "hello";

tests/PHPStan/Rules/DeadCode/data/bug-13232a.php

@@ -0,0 +1,84 @@
+<?php
+
+namespace Bug13232a;
+
+final class HelloWorld
+{
+	public function sayHa(): void
+	{
+		echo sprintf("Hello, %s no way", $this->neverReturnsMethod());
+		echo 'this will never happen';
+	}
+
+	public function sayHi(): void
+	{
+		echo 'Hello, ' . neverReturns()
+			. ' no way';
+		echo 'this will never happen';
+	}
+
+	public function sayHo(): void
+	{
+		echo "Hello, {$this->neverReturnsMethod()} no way";
+		echo 'this will never happen';
+	}
+
+	public function sayHe(): void
+	{
+		$callable = function (): never {
+			exit();
+		};
+		echo sprintf("Hello, %s no way", $callable());
+		echo 'this will never happen';
+	}
+
+	public function sayHe2(): void
+	{
+		$this->doFoo($this->neverReturnsMethod());
+		echo 'this will never happen';
+	}
+
+	public function sayHe3(): void
+	{
+		self::doStaticFoo($this->neverReturnsMethod());
+		echo 'this will never happen';
+	}
+
+	public function sayHuu(): void
+	{
+		$x = [
+			$this->neverReturnsMethod()
+		];
+		echo 'this will never happen';
+	}
+
+	public function sayClosure(): void
+	{
+		$callable = function (): never {
+			exit();
+		};
+		$callable();
+		echo 'this will never happen';
+	}
+
+	public function sayIIFE(): void
+	{
+		(function (): never {
+			exit();
+		})();
+
+		echo 'this will never happen';
+	}
+
+	function neverReturnsMethod(): never {
+		exit();
+	}
+
+	public function doFoo() {}
+
+	static public function doStaticFoo() {}
+}
+function neverReturns(): never {
+	exit();
+}
+

tests/PHPStan/Rules/DeadCode/data/bug-13232b.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Bug13232b;
+
+final class HelloWorld
+{
+	public function sayHello(): void
+	{
+		if (rand(0, 1)) {
+			$x = new Foo();
+		} else {
+			$x = '1';
+		}
+		echo 'Hello, ' . mightReturnNever($x)
+			. ' no way';
+
+		echo 'Hello, ' . mightReturnNever(new Foo())
+			. ' no way';
+		echo 'this will never happen';
+	}
+}
+
+/** @phpstan-return ($x is Foo ? never : string) */
+function mightReturnNever(mixed $x)
+{
+	if ($x instanceof Foo) {
+		throw new LogicException();
+	}
+	return "hello";
+}
+
+class Foo
+{
+}

tests/PHPStan/Rules/DeadCode/data/bug-13232c.php

@@ -0,0 +1,52 @@
+<?php // lint >= 8.0
+
+namespace Bug13232c;
+
+final class HelloWorld
+{
+	public function sayHello(): void
+	{
+		echo 'Hello, ' . $this->returnNever()
+			. ' no way';
+
+		echo 'this will never happen';
+	}
+
+	static public function sayStaticHello(): void
+	{
+		echo 'Hello, ' . self::staticReturnNever()
+			. ' no way';
+
+		echo 'this will never happen';
+	}
+
+	public function sayNullsafeHello(?self $x): void
+	{
+		echo 'Hello, ' . $x?->returnNever()
+			. ' no way';
+
+		echo 'this might happen, in case $x is null';
+	}
+
+	public function sayMaybeHello(): void
+	{
+		if (rand(0, 1)) {
+			echo 'Hello, ' . $this->returnNever()
+				. ' no way';
+		}
+
+		echo 'this might happen';
+	}
+
+	function returnNever(): never
+
+	{
+		exit();
+	}
+
+	static function staticReturnNever(): never
+	{
+		exit();
+	}
+
+}

tests/PHPStan/Rules/DeadCode/data/bug-13232d.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Bug13232d;
+
+final class HelloWorld
+{
+	public function sayHi(): void
+	{
+		$x = 'Hello, ' . neverReturns()
+			. ' no way';
+		$x .= 'this will never happen';
+	}
+}
+function neverReturns(): never {}
+