Fix phpstan/phpstan#14351: Missing errors arround use of $this (#5278)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

Makefile

@@ -135,6 +135,7 @@ lint:
 		--exclude tests/PHPStan/Rules/Functions/data/bug-14241.php \
 		--exclude tests/PHPStan/Rules/Variables/data/bug-14349.php \
 		--exclude tests/PHPStan/Rules/Variables/data/bug-14352.php \
+		--exclude tests/PHPStan/Rules/Variables/data/bug-14351.php \
 		src tests
 
 install-paratest:

src/Analyser/NodeScopeResolver.php

@@ -1974,6 +1974,7 @@ public function processStmtNode(
 					}
 
 					$variableName = $catchNode->var->name;
+					$this->callNodeCallback($nodeCallback, new VariableAssignNode($catchNode->var, new TypeExpr($catchType)), $scope, $storage);
 				}
 
 				$catchScopeResult = $this->processStmtNodesInternal($catchNode, $catchNode->stmts, $catchScope->enterCatchType($catchType, $variableName), $storage, $nodeCallback, $context);

src/Rules/Variables/ThisInGlobalStatementRule.php

@@ -0,0 +1,48 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Variables;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\Variable;
+use PHPStan\Analyser\Scope;
+use PHPStan\DependencyInjection\RegisteredRule;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use function is_string;
+
+/**
+ * @implements Rule<Node\Stmt\Global_>
+ */
+#[RegisteredRule(level: 0)]
+final class ThisInGlobalStatementRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Stmt\Global_::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$errors = [];
+		foreach ($node->vars as $var) {
+			if (!$var instanceof Variable) {
+				continue;
+			}
+			if (!is_string($var->name)) {
+				continue;
+			}
+			if ($var->name !== 'this') {
+				continue;
+			}
+
+			$errors[] = RuleErrorBuilder::message('Cannot use $this as global variable.')
+				->identifier('global.this')
+				->nonIgnorable()
+				->build();
+		}
+
+		return $errors;
+	}
+
+}

src/Rules/Variables/ThisInStaticStatementRule.php

@@ -0,0 +1,44 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Variables;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\DependencyInjection\RegisteredRule;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use function is_string;
+
+/**
+ * @implements Rule<Node\Stmt\Static_>
+ */
+#[RegisteredRule(level: 0)]
+final class ThisInStaticStatementRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Stmt\Static_::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		$errors = [];
+		foreach ($node->vars as $var) {
+			if (!is_string($var->var->name)) {
+				continue;
+			}
+			if ($var->var->name !== 'this') {
+				continue;
+			}
+
+			$errors[] = RuleErrorBuilder::message('Cannot use $this as static variable.')
+				->identifier('static.this')
+				->nonIgnorable()
+				->build();
+		}
+
+		return $errors;
+	}
+
+}

tests/PHPStan/Rules/Variables/InvalidVariableAssignRuleTest.php

@@ -88,6 +88,16 @@ public function testBug14352(): void
 		]);
 	}
 
+	public function testBug14351(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14351.php'], [
+			[
+				'Cannot re-assign $this.',
+				9,
+			],
+		]);
+	}
+
 	public function testBug14349(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-14349.php'], [

tests/PHPStan/Rules/Variables/ParameterOutAssignedTypeRuleTest.php

@@ -91,4 +91,19 @@ public function testBug14124b(): void
 		$this->analyse([__DIR__ . '/data/bug-14124b.php'], []);
 	}
 
+	public function testCatchVariable(): void
+	{
+		$this->analyse([__DIR__ . '/data/parameter-out-catch-variable.php'], [
+			[
+				'Parameter &$p @param-out type of function ParameterOutCatchVariable\foo() expects int, Exception given.',
+				11,
+			],
+			[
+				'Parameter &$p by-ref type of function ParameterOutCatchVariable\bar() expects int, Exception given.',
+				19,
+				'You can change the parameter out type with @param-out PHPDoc tag.',
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Variables/ThisInGlobalStatementRuleTest.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Variables;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<ThisInGlobalStatementRule>
+ */
+class ThisInGlobalStatementRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new ThisInGlobalStatementRule();
+	}
+
+	public function testBug14351(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14351.php'], [
+			[
+				'Cannot use $this as global variable.',
+				15,
+			],
+		]);
+	}
+
+}

tests/PHPStan/Rules/Variables/ThisInStaticStatementRuleTest.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules\Variables;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<ThisInStaticStatementRule>
+ */
+class ThisInStaticStatementRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new ThisInStaticStatementRule();
+	}
+
+	public function testBug14351(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14351.php'], [
+			[
+				'Cannot use $this as static variable.',
+				19,
+			],
+		]);
+	}
+
+}

tests/PHPStan/Rules/Variables/data/bug-14351.php

@@ -0,0 +1,20 @@
+<?php declare(strict_types = 1);
+
+namespace Bug14351;
+
+class C {
+	function foo(): void {
+		try {
+			throw new \Exception();
+		} catch (\Exception $this) { // should report: Cannot re-assign $this
+		}
+	}
+}
+
+function foo(): void {
+	global $this; // should report: Cannot use $this as global variable
+}
+
+function bar(): void {
+	static $this; // should report: Cannot use $this as static variable
+}

tests/PHPStan/Rules/Variables/data/parameter-out-catch-variable.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace ParameterOutCatchVariable;
+
+/**
+ * @param-out int $p
+ */
+function foo(&$p): void {
+	try {
+		throw new \Exception();
+	} catch (\Exception $p) {
+
+	}
+}
+
+function bar(int &$p): void {
+	try {
+		throw new \Exception();
+	} catch (\Exception $p) {
+
+	}
+}