Dynamic "assert" throw type extension

conf/config.neon

@@ -1319,6 +1319,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\AssertThrowTypeExtension
+		tags:
+			- phpstan.dynamicFunctionThrowTypeExtension
+
 	-
 		class: PHPStan\Type\Php\BackedEnumFromMethodDynamicReturnTypeExtension
 		tags:

src/Type/Php/AssertThrowTypeExtension.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\DynamicFunctionThrowTypeExtension;
+use PHPStan\Type\ObjectType;
+use PHPStan\Type\Type;
+use Throwable;
+use function count;
+
+class AssertThrowTypeExtension implements DynamicFunctionThrowTypeExtension
+{
+
+	public function isFunctionSupported(FunctionReflection $functionReflection): bool
+	{
+		return $functionReflection->getName() === 'assert';
+	}
+
+	public function getThrowTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $funcCall, Scope $scope): ?Type
+	{
+		if (count($funcCall->getArgs()) < 2) {
+			return $functionReflection->getThrowType();
+		}
+
+		$customThrow = $scope->getType($funcCall->getArgs()[1]->value);
+		if ((new ObjectType(Throwable::class))->isSuperTypeOf($customThrow)->yes()) {
+			return $customThrow;
+		}
+
+		return $functionReflection->getThrowType();
+	}
+
+}

tests/PHPStan/Rules/Exceptions/CatchWithUnthrownExceptionRuleTest.php

@@ -475,4 +475,18 @@ public function testMagicMethods(): void
 		]);
 	}
 
+	public function testBug5650(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5650.php'], [
+			[
+				'Dead catch - RuntimeException is never thrown in the try block.',
+				24,
+			],
+			[
+				'Dead catch - RuntimeException is never thrown in the try block.',
+				32,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Exceptions/data/bug-5650.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Bug5650;
+
+function (): void {
+	try {
+		assert(false, new RuntimeException("I am being thrown"));
+	} catch (\RuntimeException $e) {
+
+	}
+};
+
+function (): void {
+	try {
+		assert(true, new RuntimeException("I could be but this time am not being thrown"));
+	} catch (\RuntimeException $e) {
+
+	}
+};
+
+function (): void {
+	try {
+		assert(false);
+	} catch (\RuntimeException $e) {
+
+	}
+};
+
+function (): void {
+	try {
+		assert(true);
+	} catch (\RuntimeException $e) {
+
+	}
+};