From 74d1c9a1ca1cd6199a8771444e9bc4d6b7737f46 Mon Sep 17 00:00:00 2001
From: Ondrej Mirtes <ondrej@mirtes.cz>
Date: Tue, 9 May 2023 15:03:38 +0200
Subject: [PATCH] Report `?->` call on always-null

---
 src/Analyser/NodeScopeResolver.php                        | 4 ++++
 tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php       | 8 ++++++++
 tests/PHPStan/Rules/Methods/data/nullsafe-method-call.php | 7 +++++++
 .../PHPStan/Rules/Properties/AccessPropertiesRuleTest.php | 8 ++++++++
 tests/PHPStan/Rules/Properties/data/bug-4559.php          | 4 ++--
 .../Rules/Properties/data/nullsafe-property-fetch.php     | 7 +++++++
 6 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index c64670a657..1d577ead2e 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -1647,6 +1647,10 @@ private function lookForExpressionCallback(MutatingScope $scope, Expr $expr, Clo
 	private function ensureShallowNonNullability(MutatingScope $scope, Scope $originalScope, Expr $exprToSpecify): EnsuredNonNullabilityResult
 	{
 		$exprType = $scope->getType($exprToSpecify);
+		$isNull = $exprType->isNull();
+		if ($isNull->yes()) {
+			return new EnsuredNonNullabilityResult($scope, []);
+		}
 		$exprTypeWithoutNull = TypeCombinator::removeNull($exprType);
 		if ($exprType->equals($exprTypeWithoutNull)) {
 			$originalExprType = $originalScope->getType($exprToSpecify);
diff --git a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
index b81d2bd964..d90457661f 100644
--- a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
+++ b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
@@ -1742,6 +1742,14 @@ public function testNullSafe(): void
 				'Parameter #1 $passedByRef of method NullsafeMethodCall\Foo::doBaz() is passed by reference, so it expects variables only.',
 				27,
 			],
+			[
+				'Cannot call method foo() on null.',
+				33,
+			],
+			[
+				'Cannot call method foo() on null.',
+				34,
+			],
 		]);
 	}
 
diff --git a/tests/PHPStan/Rules/Methods/data/nullsafe-method-call.php b/tests/PHPStan/Rules/Methods/data/nullsafe-method-call.php
index dbe6ef395d..0eb89b8ae8 100644
--- a/tests/PHPStan/Rules/Methods/data/nullsafe-method-call.php
+++ b/tests/PHPStan/Rules/Methods/data/nullsafe-method-call.php
@@ -27,4 +27,11 @@ public function doLorem(?self $selfOrNull): void
 		$this->doBaz($selfOrNull?->test->test);
 	}
 
+	public function doNull(): void
+	{
+		$null = null;
+		$null->foo();
+		$null?->foo();
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php b/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php
index 28d38a1bcf..d2bfbbfbc2 100644
--- a/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php
+++ b/tests/PHPStan/Rules/Properties/AccessPropertiesRuleTest.php
@@ -487,6 +487,14 @@ public function testNullSafe(): void
 				'Cannot access property $bar on string.',
 				22,
 			],
+			[
+				'Cannot access property $foo on null.',
+				28,
+			],
+			[
+				'Cannot access property $foo on null.',
+				29,
+			],
 		]);
 	}
 
diff --git a/tests/PHPStan/Rules/Properties/data/bug-4559.php b/tests/PHPStan/Rules/Properties/data/bug-4559.php
index 30136d761b..e3c0b6952f 100644
--- a/tests/PHPStan/Rules/Properties/data/bug-4559.php
+++ b/tests/PHPStan/Rules/Properties/data/bug-4559.php
@@ -4,9 +4,9 @@
 
 class HelloWorld
 {
-	public function doBar()
+	public function doBar(string $s)
 	{
-		$response = json_decode('');
+		$response = json_decode($s);
 		if (isset($response->error->code)) {
 			echo $response->error->message ?? '';
 		}
diff --git a/tests/PHPStan/Rules/Properties/data/nullsafe-property-fetch.php b/tests/PHPStan/Rules/Properties/data/nullsafe-property-fetch.php
index 9c6bbb66c4..d2a693fe64 100644
--- a/tests/PHPStan/Rules/Properties/data/nullsafe-property-fetch.php
+++ b/tests/PHPStan/Rules/Properties/data/nullsafe-property-fetch.php
@@ -22,4 +22,11 @@ public function doBar(string $string, ?string $nullableString): void
 		echo $nullableString?->bar ?? 4;
 	}
 
+	public function doNull(): void
+	{
+		$null = null;
+		$null->foo;
+		$null?->foo;
+	}
+
 }