Fix wrong inference on preg_match != false

src/Analyser/TypeSpecifier.php

@@ -339,13 +339,15 @@ public function specifyTypesInCondition(
 				&& count($expr->right->getArgs()) >= 3
 				&& $expr->right->name instanceof Name
 				&& in_array(strtolower((string) $expr->right->name), ['preg_match'], true)
-				&& IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($leftType)->yes()
+				&& (
+					IntegerRangeType::fromInterval(1, null)->isSuperTypeOf($leftType)->yes()
+					|| ($expr instanceof Expr\BinaryOp\Smaller && IntegerRangeType::fromInterval(0, null)->isSuperTypeOf($leftType)->yes())
+				)
 			) {
-				return $this->specifyTypesInCondition(
-					$scope,
-					new Expr\BinaryOp\NotIdentical($expr->right, new ConstFetch(new Name('false'))),
-					$context,
-				)->setRootExpr($expr);
+				// 0 < preg_match or 1 <= preg_match becomes 1 === preg_match
+				$newExpr = new Expr\BinaryOp\Identical($expr->right, new Node\Scalar\Int_(1));
+
+				return $this->specifyTypesInCondition($scope, $newExpr, $context)->setRootExpr($expr);
 			}
 
 			if (

src/Type/Php/PregMatchTypeSpecifyingExtension.php

@@ -55,10 +55,18 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			$flagsType = $scope->getType($flagsArg->value);
 		}
 
+		if ($context->true() && $context->falsey()) {
+			$wasMatched = TrinaryLogic::createMaybe();
+		} elseif ($context->true()) {
+			$wasMatched = TrinaryLogic::createYes();
+		} else {
+			$wasMatched = TrinaryLogic::createNo();
+		}
+
 		if ($functionReflection->getName() === 'preg_match') {
-			$matchedType = $this->regexShapeMatcher->matchExpr($patternArg->value, $flagsType, TrinaryLogic::createFromBoolean($context->true()), $scope);
+			$matchedType = $this->regexShapeMatcher->matchExpr($patternArg->value, $flagsType, $wasMatched, $scope);
 		} else {
-			$matchedType = $this->regexShapeMatcher->matchAllExpr($patternArg->value, $flagsType, TrinaryLogic::createFromBoolean($context->true()), $scope);
+			$matchedType = $this->regexShapeMatcher->matchAllExpr($patternArg->value, $flagsType, $wasMatched, $scope);
 		}
 		if ($matchedType === null) {
 			return new SpecifiedTypes();

tests/PHPStan/Analyser/nsrt/bug-11293.php

@@ -30,7 +30,7 @@ public function sayHello3(string $s): void
 	public function sayHello4(string $s): void
 	{
 		if (preg_match('/data-(\d{6})\.json$/', $s, $matches) <= 0) {
-			assertType('array{}', $matches);
+			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}
@@ -41,7 +41,7 @@ public function sayHello4(string $s): void
 	public function sayHello5(string $s): void
 	{
 		if (preg_match('/data-(\d{6})\.json$/', $s, $matches) < 1) {
-			assertType('array{}', $matches);
+			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}
@@ -52,7 +52,7 @@ public function sayHello5(string $s): void
 	public function sayHello6(string $s): void
 	{
 		if (1 > preg_match('/data-(\d{6})\.json$/', $s, $matches)) {
-			assertType('array{}', $matches);
+			assertType('list{0?: string, 1?: non-falsy-string&numeric-string}', $matches);
 
 			return;
 		}

tests/PHPStan/Rules/Comparison/BooleanAndConstantConditionRuleTest.php

@@ -432,6 +432,13 @@ public function testBug5365(): void
 		$this->analyse([__DIR__ . '/data/bug-5365.php'], []);
 	}
 
+	public function testBug11908(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->reportAlwaysTrueInLastCondition = true;
+		$this->analyse([__DIR__ . '/data/bug-11908.php'], []);
+	}
+
 	public function testBug8555(): void
 	{
 		$this->treatPhpDocTypesAsCertain = true;

tests/PHPStan/Rules/Comparison/data/bug-11908.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11908;
+
+$matches = false;
+if (preg_match('/a/', '', $matches) !== false && $matches) {
+	var_export($matches);
+}

tests/PHPStan/Rules/Variables/IssetRuleTest.php

@@ -473,6 +473,13 @@ public function testBug12771(): void
 		$this->analyse([__DIR__ . '/data/bug-12771.php'], []);
 	}
 
+	public function testBug11708(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+
+		$this->analyse([__DIR__ . '/data/bug-11708.php'], []);
+	}
+
 	public function testIssetAfterRememberedConstructor(): void
 	{
 		$this->treatPhpDocTypesAsCertain = true;

tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php

@@ -342,6 +342,13 @@ public function testBug10577(): void
 		$this->analyse([__DIR__ . '/data/bug-10577.php'], []);
 	}
 
+	public function testBug11708(): void
+	{
+		$this->treatPhpDocTypesAsCertain = true;
+
+		$this->analyse([__DIR__ . '/data/bug-11708.php'], []);
+	}
+
 	public function testBug10610(): void
 	{
 		$this->treatPhpDocTypesAsCertain = true;

tests/PHPStan/Rules/Variables/data/bug-11708.php

@@ -0,0 +1,19 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11708;
+
+class HelloWorld
+{
+	public function sayHello(): void
+	{
+		$xRequestStart = sprintf('t=%s', uniqid('fake_timestamp_'));
+
+		$matches = [];
+		if (false === preg_match('/^t=(\d+)$/', (string) $xRequestStart, $matches)) {
+			return;
+		}
+
+		$requestStart = $matches[1] ?? null;
+		$requestStart2 = isset($matches[1]);
+	}
+}