Resolve isset/empty/?? chains from handler-built descriptors

src/Analyser/ExprHandler/ArrayDimFetchHandler.php

@@ -15,6 +15,7 @@
 use PHPStan\Analyser\ExpressionResultStorage;
 use PHPStan\Analyser\ExprHandler;
 use PHPStan\Analyser\ExprHandler\Helper\NullsafeShortCircuitingHelper;
+use PHPStan\Analyser\IssetabilityDescriptor;
 use PHPStan\Analyser\MutatingScope;
 use PHPStan\Analyser\NodeScopeResolver;
 use PHPStan\Analyser\NoopNodeCallback;
@@ -125,6 +126,7 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			throwPoints: $throwPoints,
 			impurePoints: $impurePoints,
 			containsNullsafe: $varResult->containsNullsafe(),
+			issetabilityDescriptor: IssetabilityDescriptor::offset($varResult, $dimResult),
 		);
 	}
 

src/Analyser/ExprHandler/AssignOpHandler.php

@@ -15,14 +15,17 @@
 use PHPStan\Analyser\ExpressionResultStorage;
 use PHPStan\Analyser\ExprHandler;
 use PHPStan\Analyser\ExprHandler\Helper\ImplicitToStringCallHelper;
+use PHPStan\Analyser\ExprHandler\Helper\NonNullabilityHelper;
 use PHPStan\Analyser\InternalThrowPoint;
 use PHPStan\Analyser\MutatingScope;
 use PHPStan\Analyser\NodeScopeResolver;
+use PHPStan\Analyser\NoopNodeCallback;
 use PHPStan\Analyser\Scope;
 use PHPStan\Analyser\SpecifiedTypes;
 use PHPStan\Analyser\TypeSpecifier;
 use PHPStan\Analyser\TypeSpecifierContext;
 use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Node\CoalesceExpressionNode;
 use PHPStan\Reflection\InitializerExprTypeResolver;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Constant\ConstantIntegerType;
@@ -45,6 +48,7 @@ public function __construct(
 		private InitializerExprTypeResolver $initializerExprTypeResolver,
 		private ImplicitToStringCallHelper $implicitToStringCallHelper,
 		private ExpressionResultFactory $expressionResultFactory,
+		private NonNullabilityHelper $nonNullabilityHelper,
 	)
 	{
 	}
@@ -57,6 +61,17 @@ public function supports(Expr $expr): bool
 	public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Expr $expr, MutatingScope $scope, ExpressionResultStorage $storage, callable $nodeCallback, ExpressionContext $context): ExpressionResult
 	{
 		$beforeScope = $scope;
+		$condResult = null;
+		if ($expr instanceof Expr\AssignOp\Coalesce) {
+			// `$lvalue ??= ...` is `$lvalue = $lvalue ?? ...`: price the left side
+			// once as a read (mirroring CoalesceHandler's left-side processing) so
+			// its result carries the isset descriptor for NullCoalesceRule. The
+			// NoopNodeCallback avoids duplicate reports and the read's scope is
+			// discarded: processAssignVar() walks the target itself.
+			$nonNullabilityResult = $this->nonNullabilityHelper->ensureNonNullability($scope, $expr->var);
+			$condScope = $nodeScopeResolver->lookForSetAllowedUndefinedExpressions($nonNullabilityResult->getScope(), $expr->var);
+			$condResult = $nodeScopeResolver->processExprNode($stmt, $expr->var, $condScope, $storage, new NoopNodeCallback(), $context->enterDeep());
+		}
 		$assignResult = $this->assignHandler->processAssignVar(
 			$nodeScopeResolver,
 			$scope,
@@ -114,6 +129,10 @@ function (MutatingScope $scope) use ($stmt, $expr, $nodeCallback, $context, $sto
 			$impurePoints = array_merge($impurePoints, $toStringResult->getImpurePoints());
 		}
 
+		if ($expr instanceof Expr\AssignOp\Coalesce) {
+			$nodeScopeResolver->callNodeCallbackWithExpression($nodeCallback, new CoalesceExpressionNode($expr, $condResult, 'on left side of ??='), $beforeScope, $storage, $context);
+		}
+
 		return $this->expressionResultFactory->create(
 			$scope,
 			beforeScope: $beforeScope,

src/Analyser/ExprHandler/CoalesceHandler.php

@@ -18,6 +18,7 @@
 use PHPStan\Analyser\TypeSpecifier;
 use PHPStan\Analyser\TypeSpecifierContext;
 use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Node\CoalesceExpressionNode;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\NeverType;
@@ -135,6 +136,8 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			$scope = $scope->filterByTruthyValue(new Expr\Isset_([$expr->left]))->mergeWith($rightResult->getScope());
 		}
 
+		$nodeScopeResolver->callNodeCallbackWithExpression($nodeCallback, new CoalesceExpressionNode($expr, $condResult, 'on left side of ??'), $beforeScope, $storage, $context);
+
 		return $this->expressionResultFactory->create(
 			$scope,
 			beforeScope: $beforeScope,

src/Analyser/ExprHandler/EmptyHandler.php

@@ -19,6 +19,7 @@
 use PHPStan\Analyser\TypeSpecifier;
 use PHPStan\Analyser\TypeSpecifierContext;
 use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Node\EmptyExpressionNode;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\Constant\ConstantBooleanType;
@@ -95,6 +96,8 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 		$scope = $this->nonNullabilityHelper->revertNonNullability($scope, $nonNullabilityResult->getSpecifiedExpressions());
 		$scope = $nodeScopeResolver->lookForUnsetAllowedUndefinedExpressions($scope, $expr->expr);
 
+		$nodeScopeResolver->callNodeCallbackWithExpression($nodeCallback, new EmptyExpressionNode($expr, $exprResult), $beforeScope, $storage, $context);
+
 		return $this->expressionResultFactory->create(
 			$scope,
 			beforeScope: $beforeScope,

src/Analyser/ExprHandler/IssetHandler.php

@@ -29,6 +29,7 @@
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Node\Expr\TypeExpr;
 use PHPStan\Node\IssetExpr;
+use PHPStan\Node\IssetExpressionNode;
 use PHPStan\Rules\Arrays\AllowedArrayKeysTypes;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Accessory\HasOffsetType;
@@ -352,10 +353,12 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 		$impurePoints = [];
 		$nonNullabilityResults = [];
 		$isAlwaysTerminating = false;
+		$varResults = [];
 		foreach ($expr->vars as $var) {
 			$nonNullabilityResult = $this->nonNullabilityHelper->ensureNonNullability($scope, $var);
 			$scope = $nodeScopeResolver->lookForSetAllowedUndefinedExpressions($nonNullabilityResult->getScope(), $var);
 			$varResult = $nodeScopeResolver->processExprNode($stmt, $var, $scope, $storage, $nodeCallback, $context->enterDeep());
+			$varResults[] = $varResult;
 			$scope = $varResult->getScope();
 			$hasYield = $hasYield || $varResult->hasYield();
 			$throwPoints = array_merge($throwPoints, $varResult->getThrowPoints());
@@ -388,6 +391,8 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			$scope = $this->nonNullabilityHelper->revertNonNullability($scope, $nonNullabilityResult->getSpecifiedExpressions());
 		}
 
+		$nodeScopeResolver->callNodeCallbackWithExpression($nodeCallback, new IssetExpressionNode($expr, $varResults), $beforeScope, $storage, $context);
+
 		return $this->expressionResultFactory->create(
 			$scope,
 			beforeScope: $beforeScope,

src/Analyser/ExprHandler/PropertyFetchHandler.php

@@ -14,6 +14,7 @@
 use PHPStan\Analyser\ExprHandler;
 use PHPStan\Analyser\ExprHandler\Helper\NullsafeShortCircuitingHelper;
 use PHPStan\Analyser\InternalThrowPoint;
+use PHPStan\Analyser\IssetabilityDescriptor;
 use PHPStan\Analyser\MutatingScope;
 use PHPStan\Analyser\NodeScopeResolver;
 use PHPStan\Analyser\Scope;
@@ -22,6 +23,7 @@
 use PHPStan\Analyser\TypeSpecifierContext;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Php\PhpVersion;
+use PHPStan\Rules\Properties\FoundPropertyReflection;
 use PHPStan\Rules\Properties\PropertyReflectionFinder;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
@@ -95,6 +97,7 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			throwPoints: $throwPoints,
 			impurePoints: $impurePoints,
 			containsNullsafe: $varResult->containsNullsafe(),
+			issetabilityDescriptor: IssetabilityDescriptor::property($varResult, fn (MutatingScope $s): ?FoundPropertyReflection => $this->propertyReflectionFinder->findPropertyReflectionFromNode($expr, $s), $expr),
 		);
 	}
 

src/Analyser/ExprHandler/StaticPropertyFetchHandler.php

@@ -16,13 +16,15 @@
 use PHPStan\Analyser\ExprHandler;
 use PHPStan\Analyser\ExprHandler\Helper\NullsafeShortCircuitingHelper;
 use PHPStan\Analyser\ImpurePoint;
+use PHPStan\Analyser\IssetabilityDescriptor;
 use PHPStan\Analyser\MutatingScope;
 use PHPStan\Analyser\NodeScopeResolver;
 use PHPStan\Analyser\Scope;
 use PHPStan\Analyser\SpecifiedTypes;
 use PHPStan\Analyser\TypeSpecifier;
 use PHPStan\Analyser\TypeSpecifierContext;
 use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Rules\Properties\FoundPropertyReflection;
 use PHPStan\Rules\Properties\PropertyReflectionFinder;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\MixedType;
@@ -67,6 +69,7 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 		];
 		$isAlwaysTerminating = false;
 		$containsNullsafe = false;
+		$classResult = null;
 		if ($expr->class instanceof Expr) {
 			$classResult = $nodeScopeResolver->processExprNode($stmt, $expr->class, $scope, $storage, $nodeCallback, $context->enterDeep());
 			$hasYield = $classResult->hasYield();
@@ -94,6 +97,7 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			throwPoints: $throwPoints,
 			impurePoints: $impurePoints,
 			containsNullsafe: $containsNullsafe,
+			issetabilityDescriptor: IssetabilityDescriptor::property($classResult, fn (MutatingScope $s): ?FoundPropertyReflection => $this->propertyReflectionFinder->findPropertyReflectionFromNode($expr, $s), $expr),
 		);
 	}
 

src/Analyser/ExprHandler/VariableHandler.php

@@ -13,6 +13,7 @@
 use PHPStan\Analyser\ExpressionResultStorage;
 use PHPStan\Analyser\ExprHandler;
 use PHPStan\Analyser\ImpurePoint;
+use PHPStan\Analyser\IssetabilityDescriptor;
 use PHPStan\Analyser\MutatingScope;
 use PHPStan\Analyser\NodeScopeResolver;
 use PHPStan\Analyser\Scope;
@@ -103,6 +104,7 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 			$isAlwaysTerminating,
 			$throwPoints,
 			$impurePoints,
+			issetabilityDescriptor: is_string($expr->name) ? IssetabilityDescriptor::variable($expr->name) : null,
 			truthyScopeCallback: static fn (): MutatingScope => $scope->filterByTruthyValue($expr),
 			falseyScopeCallback: static fn (): MutatingScope => $scope->filterByFalseyValue($expr),
 		);

src/Analyser/ExpressionResult.php

@@ -35,6 +35,7 @@ public function __construct(
 		private array $throwPoints,
 		private array $impurePoints,
 		private bool $containsNullsafe = false,
+		private ?IssetabilityDescriptor $issetabilityDescriptor = null,
 		?callable $truthyScopeCallback = null,
 		?callable $falseyScopeCallback = null,
 	)
@@ -69,6 +70,32 @@ public function containsNullsafe(): bool
 		return $this->containsNullsafe;
 	}
 
+	/**
+	 * The isset/empty/?? view of this expression evaluated at the given
+	 * scope: folds the chain descriptor, or builds a leaf resolution from the
+	 * expression's own type when it is not a chain link (e.g. a method-call-rooted
+	 * base like $this->getFoo()['x']). $useNativeTypes selects native vs phpdoc.
+	 */
+	public function getIssetabilityResolution(MutatingScope $scope, bool $useNativeTypes): IssetabilityResolution
+	{
+		if ($this->issetabilityDescriptor !== null) {
+			return $this->issetabilityDescriptor->resolve($scope, $useNativeTypes, $this->expr);
+		}
+
+		$type = $this->getTypeOnScope($scope, $useNativeTypes);
+
+		return new IssetabilityResolution(
+			IssetabilityLinkInfo::leaf($type, $this->expr, $this->expr instanceof Expr\NullsafePropertyFetch),
+			null,
+		);
+	}
+
+	/** Prices this result's expression on the given scope in the requested flavour. */
+	public function getTypeOnScope(MutatingScope $scope, bool $useNativeTypes): Type
+	{
+		return $useNativeTypes ? $scope->getNativeType($this->expr) : $scope->getType($this->expr);
+	}
+
 	/**
 	 * @return InternalThrowPoint[]
 	 */

src/Analyser/ExpressionResultFactory.php

@@ -22,6 +22,7 @@ public function create(
 		array $throwPoints,
 		array $impurePoints,
 		bool $containsNullsafe = false,
+		?IssetabilityDescriptor $issetabilityDescriptor = null,
 		?callable $truthyScopeCallback = null,
 		?callable $falseyScopeCallback = null,
 	): ExpressionResult;