Fix variable scope

Author: zonuexe

src/Rules/Variables/DefinedVariableRule.php

@@ -3,13 +3,13 @@
 namespace PHPStan\Rules\Variables;
 
 use PhpParser\Node;
+use PhpParser\Node\Expr\BinaryOp\Identical;
 use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Scalar\String_;
 use PHPStan\Analyser\Scope;
 use PHPStan\Rules\IdentifierRuleError;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
-use PHPStan\Type\Constant\ConstantStringType;
-use function array_map;
 use function array_merge;
 use function in_array;
 use function is_string;
@@ -37,14 +37,18 @@ public function processNode(Node $node, Scope $scope): array
 	{
 		$errors = [];
 		if (is_string($node->name)) {
-			$variableNames = [$node->name];
+			$variableNameScopes = [$node->name => $scope];
 		} else {
-			$fetchType = $scope->getType($node->name);
-			$variableNames = array_map(static fn (ConstantStringType $type): string => $type->getValue(), $fetchType->getConstantStrings());
+			$nameType = $scope->getType($node->name);
+			$variableNameScopes = [];
+			foreach ($nameType->getConstantStrings() as $constantString) {
+				$name = $constantString->getValue();
+				$variableNameScopes[$name] = $scope->filterByTruthyValue(new Identical($node->name, new String_($name)));
+			}
 		}
 
-		foreach ($variableNames as $name) {
-			$errors = array_merge($errors, $this->processSingleVariable($scope, $node, $name));
+		foreach ($variableNameScopes as $name => $variableScope) {
+			$errors = array_merge($errors, $this->processSingleVariable($variableScope, $node, $name));
 		}
 
 		return $errors;

tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php

@@ -1117,6 +1117,62 @@ public function testDynamicAccess(): void
 				'Undefined variable: $buz',
 				18,
 			],
+			[
+				'Variable $foo might not be defined.',
+				36,
+			],
+			[
+				'Variable $foo might not be defined.',
+				37,
+			],
+			[
+				'Variable $bar might not be defined.',
+				38,
+			],
+			[
+				'Variable $bar might not be defined.',
+				40,
+			],
+			[
+				'Variable $foo might not be defined.',
+				41,
+			],
+			[
+				'Variable $bar might not be defined.',
+				42,
+			],
+			[
+				'Undefined variable: $buz',
+				44,
+			],
+			[
+				'Undefined variable: $foo',
+				45,
+			],
+			[
+				'Undefined variable: $bar',
+				46,
+			],
+			[
+				'Undefined variable: $buz',
+				49,
+			],
+			[
+				'Variable $bar might not be defined.',
+				49,
+			],
+			[
+				'Variable $foo might not be defined.',
+				49,
+			],
+			[
+				'Variable $foo might not be defined.',
+				50,
+			],
+			[
+				'Variable $bar might not be defined.',
+				51,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Variables/data/dynamic-access.php

@@ -18,4 +18,37 @@ public function test(string $string, object $obj): void
 		echo ${$this->name};
 	}
 
+	public function testScope(): void
+	{
+		$name1 = 'foo';
+		$rand = rand();
+		if ($rand === 1) {
+			$foo = 1;
+			$name = $name1;
+		} elseif ($rand === 2) {
+			$name = 'bar';
+			$bar = 'str';
+		} else {
+			$name = 'buz';
+		}
+
+		if ($name === 'foo') {
+			echo $$name; // ok
+			echo $foo; // ok
+			echo $bar;
+		} elseif ($name === 'bar') {
+			echo $$name; // ok
+			echo $foo;
+			echo $bar; // ok
+		} else {
+			echo $$name; // ok
+			echo $foo;
+			echo $bar;
+		}
+
+		echo $$name; // ok
+		echo $foo;
+		echo $bar;
+	}
+
 }