From 09d34887f805437a216a388aadce4bd83aaaab51 Mon Sep 17 00:00:00 2001
From: Ondrej Mirtes <ondrej@mirtes.cz>
Date: Fri, 23 Apr 2021 16:15:09 +0200
Subject: [PATCH] Built-in PHP functions without required parameters and no
 arguments passed do not have implicit throw point

---
 src/Analyser/NodeScopeResolver.php            | 24 ++++++++++++++++---
 .../Analyser/NodeScopeResolverTest.php        |  1 +
 tests/PHPStan/Analyser/data/bug-4838.php      | 24 +++++++++++++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 tests/PHPStan/Analyser/data/bug-4838.php

diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index 4a12206fab..423641eca1 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -1786,9 +1786,27 @@ function (MutatingScope $scope) use ($expr, $nodeCallback, $context): Expression
 						$throwPoints[] = ThrowPoint::createExplicit($scope, $throwType, true);
 					}
 				} elseif ($this->implicitThrows) {
-					$functionReturnedType = $scope->getType($expr);
-					if (!(new ObjectType(\Throwable::class))->isSuperTypeOf($functionReturnedType)->yes()) {
-						$throwPoints[] = ThrowPoint::createImplicit($scope);
+					$requiredParameters = null;
+					if ($parametersAcceptor !== null) {
+						$requiredParameters = 0;
+						foreach ($parametersAcceptor->getParameters() as $parameter) {
+							if ($parameter->isOptional()) {
+								continue;
+							}
+
+							$requiredParameters++;
+						}
+					}
+					if (
+						!$functionReflection->isBuiltin()
+						|| $requiredParameters === null
+						|| $requiredParameters > 0
+						|| count($expr->args) > 0
+					) {
+						$functionReturnedType = $scope->getType($expr);
+						if (!(new ObjectType(\Throwable::class))->isSuperTypeOf($functionReturnedType)->yes()) {
+							$throwPoints[] = ThrowPoint::createImplicit($scope);
+						}
 					}
 				}
 			} else {
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 4f857b815c..10512cbf3b 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -384,6 +384,7 @@ public function dataFileAsserts(): iterable
 
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/DateTimeDynamicReturnTypes.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4821.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4838.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/bug-4838.php b/tests/PHPStan/Analyser/data/bug-4838.php
new file mode 100644
index 0000000000..19f8022517
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/bug-4838.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Bug4838;
+
+use PHPStan\TrinaryLogic;
+use function PHPStan\Testing\assertVariableCertainty;
+
+class Foo
+{
+
+	public function doIt(): void
+	{
+		try {
+			$handle = tmpfile();
+
+			if (rand(1,10) > 5) {
+				throw new \LogicException();
+			}
+		} finally {
+			assertVariableCertainty(TrinaryLogic::createYes(), $handle);
+		}
+	}
+
+}