RegexArrayShapeMatcher - Fix PREG_UNMATCHED_AS_NULL with top level alternation

Author: staabm

src/Type/Php/RegexArrayShapeMatcher.php

@@ -170,7 +170,7 @@ private function matchRegex(string $regex, ?int $flags, TrinaryLogic $wasMatched
 $beforeCurrentCombo = false;
 } elseif ($beforeCurrentCombo && !$group->resetsGroupCounter()) {
 $group->forceNonOptional();
-} elseif ($group->getAlternationId() === $onlyTopLevelAlternationId) {
+} elseif ($group->getAlternationId() === $onlyTopLevelAlternationId && !$this->containsUnmatchedAsNull($flags ?? 0)) {
 unset($comboList[$groupId]);
 }
 }
@@ -191,7 +191,7 @@ private function matchRegex(string $regex, ?int $flags, TrinaryLogic $wasMatched
 }
 }
 
-if ($isOptionalAlternation) {
+if ($isOptionalAlternation && !$this->containsUnmatchedAsNull($flags ?? 0)) {
 $combiTypes[] = new ConstantArrayType([new ConstantIntegerType(0)], [new StringType()], [0], [], true);
 }
 

tests/PHPStan/Analyser/nsrt/bug-11311.php

@@ -65,3 +65,17 @@ function bug11331c(string $url):void {
 assertType('array{string, string|null, string|null, string, string}', $matches);
 }
 }
+
+class UnmatchedAsNullWithTopLevelAlternation {
+function doFoo(string $s): void {
+if (preg_match('/Price: (?:(£)|(€))\d+/', $s, $matches, PREG_UNMATCHED_AS_NULL)) {
+assertType('array{string, string|null, string|null}', $matches); // could be array{0: string, 1: null, 2: string}|array{0: string, 1: string, 2: null}
+}
+}
+
+function doBar(string $s): void {
+if (preg_match('/Price: (?:(£)|(€))?\d+/', $s, $matches, PREG_UNMATCHED_AS_NULL)) {
+assertType('array{string, string|null, string|null}', $matches);
+}
+}
+}