Introduce Scope::getMaybeDefinedVariables()

src/Analyser/MutatingScope.php

@@ -574,6 +574,27 @@ public function getDefinedVariables(): array
 		return $variables;
 	}
 
+	/**
+	 * @api
+	 * @return array<int, string>
+	 */
+	public function getMaybeDefinedVariables(): array
+	{
+		$variables = [];
+		foreach ($this->expressionTypes as $exprString => $holder) {
+			if (!$holder->getExpr() instanceof Variable) {
+				continue;
+			}
+			if (!$holder->getCertainty()->maybe()) {
+				continue;
+			}
+
+			$variables[] = substr($exprString, 1);
+		}
+
+		return $variables;
+	}
+
 	private function isGlobalVariable(string $variableName): bool
 	{
 		return in_array($variableName, self::SUPERGLOBAL_VARIABLES, true);

src/Analyser/Scope.php

@@ -67,6 +67,11 @@ public function canAnyVariableExist(): bool;
 	 */
 	public function getDefinedVariables(): array;
 
+	/**
+	 * @return array<int, string>
+	 */
+	public function getMaybeDefinedVariables(): array;
+
 	public function hasConstant(Name $name): bool;
 
 	public function getPropertyReflection(Type $typeWithProperty, string $propertyName): ?ExtendedPropertyReflection;

tests/PHPStan/Analyser/ScopeTest.php

@@ -5,16 +5,21 @@
 use PhpParser\Node\Expr\ConstFetch;
 use PhpParser\Node\Name\FullyQualified;
 use PHPStan\Testing\PHPStanTestCase;
+use PHPStan\TrinaryLogic;
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\IntegerRangeType;
 use PHPStan\Type\ObjectType;
+use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VerbosityLevel;
 
+/**
+ * @covers \PHPStan\Analyser\MutatingScope
+ */
 class ScopeTest extends PHPStanTestCase
 {
 
@@ -248,4 +253,26 @@ public function testGetConstantType(): void
 		$this->assertSame('int<1, max>', $type->describe(VerbosityLevel::precise()));
 	}
 
+	public function testDefinedVariables(): void
+	{
+		/** @var ScopeFactory $scopeFactory */
+		$scopeFactory = self::getContainer()->getByType(ScopeFactory::class);
+		$scope = $scopeFactory->create(ScopeContext::create('file.php'))
+			->assignVariable('a', new ConstantStringType('a'), new StringType(), TrinaryLogic::createYes())
+			->assignVariable('b', new ConstantStringType('b'), new StringType(), TrinaryLogic::createMaybe());
+
+		$this->assertSame(['a'], $scope->getDefinedVariables());
+	}
+
+	public function testMaybeDefinedVariables(): void
+	{
+		/** @var ScopeFactory $scopeFactory */
+		$scopeFactory = self::getContainer()->getByType(ScopeFactory::class);
+		$scope = $scopeFactory->create(ScopeContext::create('file.php'))
+			->assignVariable('a', new ConstantStringType('a'), new StringType(), TrinaryLogic::createYes())
+			->assignVariable('b', new ConstantStringType('b'), new StringType(), TrinaryLogic::createMaybe());
+
+		$this->assertSame(['b'], $scope->getMaybeDefinedVariables());
+	}
+
 }