Fix false positive with nullsafe operator

src/Rules/RuleLevelHelper.php

@@ -126,6 +126,11 @@ public function findTypeToCheck(
 		if (!$this->checkNullables && !$type instanceof NullType) {
 			$type = \PHPStan\Type\TypeCombinator::removeNull($type);
 		}
+
+		if (TypeCombinator::containsNull($type)) {
+			$type = $scope->getType($this->getNullsafeShortcircuitedExpr($var));
+		}
+
 		if (
 			$this->checkExplicitMixed
 			&& $type instanceof MixedType
@@ -188,4 +193,50 @@ public function findTypeToCheck(
 		return new FoundTypeResult($type, $directClassNames, []);
 	}
 
+	private function getNullsafeShortcircuitedExpr(Expr $expr): Expr
+	{
+		if ($expr instanceof Expr\NullsafeMethodCall) {
+			return new Expr\MethodCall($this->getNullsafeShortcircuitedExpr($expr->var), $expr->name, $expr->args);
+		}
+
+		if ($expr instanceof Expr\MethodCall) {
+			return new Expr\MethodCall($this->getNullsafeShortcircuitedExpr($expr->var), $expr->name, $expr->args);
+		}
+
+		if ($expr instanceof Expr\StaticCall && $expr->class instanceof Expr) {
+			return new Expr\StaticCall(
+				$this->getNullsafeShortcircuitedExpr($expr->class),
+				$expr->name,
+				$expr->args
+			);
+		}
+
+		if ($expr instanceof Expr\ArrayDimFetch) {
+			return new Expr\ArrayDimFetch($this->getNullsafeShortcircuitedExpr($expr->var), $expr->dim);
+		}
+
+		if ($expr instanceof Expr\NullsafePropertyFetch) {
+			return new Expr\PropertyFetch(
+				$this->getNullsafeShortcircuitedExpr($expr->var),
+				$expr->name
+			);
+		}
+
+		if ($expr instanceof Expr\PropertyFetch) {
+			return new Expr\PropertyFetch(
+				$this->getNullsafeShortcircuitedExpr($expr->var),
+				$expr->name
+			);
+		}
+
+		if ($expr instanceof Expr\StaticPropertyFetch && $expr->class instanceof Expr) {
+			return new Expr\StaticPropertyFetch(
+				$this->getNullsafeShortcircuitedExpr($expr->class),
+				$expr->name
+			);
+		}
+
+		return $expr;
+	}
+
 }

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -1719,4 +1719,22 @@ public function testNamedArguments(): void
 		]);
 	}
 
+	public function testBug4199(): void
+	{
+		if (!self::$useStaticReflectionProvider && PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('Test requires PHP 8.0.');
+		}
+
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+
+		$this->analyse([__DIR__ . '/data/bug-4199.php'], [
+			[
+				'Cannot call method answer() on Bug4199\Baz|null.',
+				37,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-4199.php

@@ -0,0 +1,38 @@
+<?php // lint >= 8.0
+
+namespace Bug4199;
+
+class Foo
+{
+	public function getBar(): ?Bar
+	{
+		return null;
+	}
+}
+
+class Bar
+{
+	public function getBaz(): Baz
+	{
+		return new Baz();
+	}
+	public function getBazOrNull(): ?Baz
+	{
+		return null;
+	}
+}
+
+class Baz
+{
+	public function answer(): int
+	{
+		return 42;
+	}
+}
+
+function (): void {
+	$foo = new Foo;
+	$answer = $foo->getBar()?->getBaz()->answer();
+
+	$answer2 = $foo->getBar()?->getBazOrNull()->answer();
+};