Bleeding edge - teach CatchWithUnthrownExceptionRule everything what DeadCatchRule does

Author: ondrejmirtes

conf/config.level4.neon

@@ -6,7 +6,6 @@ rules:
 	- PHPStan\Rules\Comparison\NumberComparisonOperatorsConstantConditionRule
 	- PHPStan\Rules\DeadCode\NoopRule
 	- PHPStan\Rules\DeadCode\UnreachableStatementRule
-	- PHPStan\Rules\Exceptions\DeadCatchRule
 	- PHPStan\Rules\Functions\CallToFunctionStamentWithoutSideEffectsRule
 	- PHPStan\Rules\Methods\CallToConstructorStatementWithoutSideEffectsRule
 	- PHPStan\Rules\Methods\CallToMethodStamentWithoutSideEffectsRule
@@ -153,6 +152,13 @@ services:
 	-
 		class: PHPStan\Rules\Exceptions\CatchWithUnthrownExceptionRule
 
+	-
+		class: PHPStan\Rules\Exceptions\DeadCatchRule
+		arguments:
+			bleedingEdge: %featureToggles.bleedingEdge%
+		tags:
+			- phpstan.rules.rule
+
 	-
 		class: PHPStan\Rules\Exceptions\OverwrittenExitPointByFinallyRule
 

src/Analyser/NodeScopeResolver.php

@@ -1233,7 +1233,7 @@ private function processStmtNode(
 						}
 
 						if (count($throwableThrowPoints) === 0) {
-							$nodeCallback(new CatchWithUnthrownExceptionNode($catchNode, $catchType), $scope);
+							$nodeCallback(new CatchWithUnthrownExceptionNode($catchNode, $catchType, $originalCatchType), $scope);
 							continue;
 						}
 

src/Node/CatchWithUnthrownExceptionNode.php

@@ -14,11 +14,14 @@ class CatchWithUnthrownExceptionNode extends NodeAbstract implements VirtualNode
 
 	private Type $caughtType;
 
-	public function __construct(Catch_ $originalNode, Type $caughtType)
+	private Type $originalCaughtType;
+
+	public function __construct(Catch_ $originalNode, Type $caughtType, Type $originalCaughtType)
 	{
 		parent::__construct($originalNode->getAttributes());
 		$this->originalNode = $originalNode;
 		$this->caughtType = $caughtType;
+		$this->originalCaughtType = $originalCaughtType;
 	}
 
 	public function getOriginalNode(): Catch_
@@ -31,6 +34,11 @@ public function getCaughtType(): Type
 		return $this->caughtType;
 	}
 
+	public function getOriginalCaughtType(): Type
+	{
+		return $this->originalCaughtType;
+	}
+
 	public function getType(): string
 	{
 		return 'PHPStan_Node_CatchWithUnthrownExceptionNode';

src/Rules/Exceptions/CatchWithUnthrownExceptionRule.php

@@ -7,6 +7,7 @@
 use PHPStan\Node\CatchWithUnthrownExceptionNode;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\NeverType;
 use PHPStan\Type\VerbosityLevel;
 
 /**
@@ -22,6 +23,14 @@ public function getNodeType(): string
 
 	public function processNode(Node $node, Scope $scope): array
 	{
+		if ($node->getCaughtType() instanceof NeverType) {
+			return [
+				RuleErrorBuilder::message(
+					sprintf('Dead catch - %s is already caught above.', $node->getOriginalCaughtType()->describe(VerbosityLevel::typeOnly()))
+				)->line($node->getLine())->build(),
+			];
+		}
+
 		return [
 			RuleErrorBuilder::message(
 				sprintf('Dead catch - %s is never thrown in the try block.', $node->getCaughtType()->describe(VerbosityLevel::typeOnly()))

src/Rules/Exceptions/DeadCatchRule.php

@@ -17,13 +17,24 @@
 class DeadCatchRule implements Rule
 {
 
+	private bool $bleedingEdge;
+
+	public function __construct(bool $bleedingEdge = false)
+	{
+		$this->bleedingEdge = $bleedingEdge;
+	}
+
 	public function getNodeType(): string
 	{
 		return Node\Stmt\TryCatch::class;
 	}
 
 	public function processNode(Node $node, Scope $scope): array
 	{
+		if ($this->bleedingEdge) {
+			return [];
+		}
+
 		$catchTypes = array_map(static function (Node\Stmt\Catch_ $catch): Type {
 			return TypeCombinator::union(...array_map(static function (Node\Name $className): ObjectType {
 				return new ObjectType($className->toString());

tests/PHPStan/Rules/Exceptions/CatchWithUnthrownExceptionRuleTest.php

@@ -171,4 +171,14 @@ public function testThrowExpression(): void
 		]);
 	}
 
+	public function testDeadCatch(): void
+	{
+		$this->analyse([__DIR__ . '/data/dead-catch.php'], [
+			[
+				'Dead catch - TypeError is already caught above.',
+				27,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Exceptions/data/dead-catch.php

@@ -8,7 +8,7 @@ class Foo
 	public function doFoo()
 	{
 		try {
-
+			doFoo();
 		} catch (\Exception $e) {
 
 		} catch (\TypeError $e) {
@@ -21,7 +21,7 @@ public function doFoo()
 	public function doBar()
 	{
 		try {
-
+			doFoo();
 		} catch (\Throwable $e) {
 
 		} catch (\TypeError $e) {