From e832df4e9912e2a0616922f508290dafefcf73a0 Mon Sep 17 00:00:00 2001
From: Ondrej Mirtes <ondrej@mirtes.cz>
Date: Sat, 23 Jan 2021 12:59:42 +0100
Subject: [PATCH] Inline `@var` above property should not pollute scope inside
 methods

---
 src/Analyser/MutatingScope.php                |  6 +++---
 src/Analyser/NodeScopeResolver.php            |  4 ++++
 .../Variables/DefinedVariableRuleTest.php     | 15 ++++++++++++++
 .../PHPStan/Rules/Variables/data/bug-4412.php | 20 +++++++++++++++++++
 4 files changed, 42 insertions(+), 3 deletions(-)
 create mode 100644 tests/PHPStan/Rules/Variables/data/bug-4412.php

diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
index 31b8af5e49..ea967494ba 100644
--- a/src/Analyser/MutatingScope.php
+++ b/src/Analyser/MutatingScope.php
@@ -2663,7 +2663,7 @@ private function enterFunctionLike(
 		bool $preserveThis
 	): self
 	{
-		$variableTypes = $this->getVariableTypes();
+		$variableTypes = [];
 		$nativeExpressionTypes = [];
 		foreach (ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getParameters() as $parameter) {
 			$parameterType = $parameter->getType();
@@ -2674,8 +2674,8 @@ private function enterFunctionLike(
 			$nativeExpressionTypes[sprintf('$%s', $parameter->getName())] = $parameter->getNativeType();
 		}
 
-		if (!$preserveThis && array_key_exists('this', $variableTypes)) {
-			unset($variableTypes['this']);
+		if ($preserveThis && array_key_exists('this', $this->variableTypes)) {
+			$variableTypes['this'] = $this->variableTypes['this'];
 		}
 
 		return $this->scopeFactory->create(
diff --git a/src/Analyser/NodeScopeResolver.php b/src/Analyser/NodeScopeResolver.php
index dc94fe0a97..70de374379 100644
--- a/src/Analyser/NodeScopeResolver.php
+++ b/src/Analyser/NodeScopeResolver.php
@@ -2777,6 +2777,10 @@ private function processStmtVarAnnotation(MutatingScope $scope, Node\Stmt $stmt,
 					continue;
 				}
 
+				if ($scope->isInClass() && $scope->getFunction() === null) {
+					continue;
+				}
+
 				if ($scope->canAnyVariableExist()) {
 					$certainty = TrinaryLogic::createYes();
 				}
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index 5fd71c1d07..41150a8c21 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -884,4 +884,19 @@ public function testBug3515(): void
 		]);
 	}
 
+	public function testBug4412(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->polluteCatchScopeWithTryAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-4412.php'], [
+			[
+				'Undefined variable: $a',
+				17,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Variables/data/bug-4412.php b/tests/PHPStan/Rules/Variables/data/bug-4412.php
new file mode 100644
index 0000000000..a8fd1970fe
--- /dev/null
+++ b/tests/PHPStan/Rules/Variables/data/bug-4412.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Bug4412;
+
+/**
+ * @phpstan-template T of \Exception
+ */
+class B
+{
+	/** @var self<\Exception> $a */
+	public $a;
+
+	/**
+	 * @phpstan-return T
+	 */
+	public function get() {
+		return $a->get();
+	}
+
+}