diff --git a/src/Analyser/ExprHandler/ArrayHandler.php b/src/Analyser/ExprHandler/ArrayHandler.php
index e5fae7851b..6facf4fbec 100644
--- a/src/Analyser/ExprHandler/ArrayHandler.php
+++ b/src/Analyser/ExprHandler/ArrayHandler.php
@@ -15,6 +15,7 @@
 use PHPStan\Node\LiteralArrayItem;
 use PHPStan\Node\LiteralArrayNode;
 use PHPStan\Reflection\InitializerExprTypeResolver;
+use PHPStan\Type\MixedType;
 use PHPStan\Type\Type;
 use function array_merge;
 
@@ -60,12 +61,22 @@ public function processExpr(NodeScopeResolver $nodeScopeResolver, Stmt $stmt, Ex
 				$scope = $keyResult->getScope();
 			}
 
+			if ($arrayItem->byRef) {
+				$scope = $nodeScopeResolver->lookForSetAllowedUndefinedExpressions($scope, $arrayItem->value);
+			}
+
 			$valueResult = $nodeScopeResolver->processExprNode($stmt, $arrayItem->value, $scope, $storage, $nodeCallback, $context->enterDeep());
 			$hasYield = $hasYield || $valueResult->hasYield();
 			$throwPoints = array_merge($throwPoints, $valueResult->getThrowPoints());
 			$impurePoints = array_merge($impurePoints, $valueResult->getImpurePoints());
 			$isAlwaysTerminating = $isAlwaysTerminating || $valueResult->isAlwaysTerminating();
 			$scope = $valueResult->getScope();
+			if (!$arrayItem->byRef) {
+				continue;
+			}
+
+			$scope = $nodeScopeResolver->lookForUnsetAllowedUndefinedExpressions($scope, $arrayItem->value);
+			$scope = $scope->assignExpression($arrayItem->value, new MixedType(), new MixedType());
 		}
 		$nodeScopeResolver->callNodeCallback($nodeCallback, new LiteralArrayNode($expr, $itemNodes), $scope, $storage);
 
diff --git a/tests/PHPStan/Analyser/nsrt/bug-6799.php b/tests/PHPStan/Analyser/nsrt/bug-6799.php
new file mode 100644
index 0000000000..99938ec9ac
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-6799.php
@@ -0,0 +1,87 @@
+<?php declare(strict_types = 1);
+
+namespace Bug6799;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	/**
+	 * @param string[] $where
+	 * @param string $sqlTableName
+	 * @param mixed[] $filter
+	 * @param string $value
+	 */
+	protected function listingAddWhereFilterAtableDefault(array &$where, string $sqlTableName, array $filter, string $value): void
+	{
+		if ($value != "" && !empty($filter) && !empty($filter['sql']) && is_string($filter['sql'])) {
+			$where[] = "`" . $sqlTableName . "`.`" . (string)$filter['sql'] . "` = '" . $value . "'";
+		}
+	}
+
+	/**
+	 * @param string[] $filterValues
+	 * @param string[] $where
+	 * @param string[] $tables
+	 * @param mixed[] $filters
+	 */
+	protected function listingAddWhereFilterAtable(array $filterValues, array &$where, array &$tables, array $filters): void
+	{
+		if (!empty($filterValues) && !empty($filters)) {
+			$whereFilter = array();
+			foreach ($filterValues as $type => $value) {
+				call_user_func_array(array($this, 'listingAddWhereFilterAtableDefault'), array(&$whereFilter, 'xxxx', $filters[$type], $value));
+			}
+			assertType('mixed', $whereFilter);
+			if (count($whereFilter) > 0) {
+				$where[] = "(" . implode(" AND ", $whereFilter) . ")";
+			}
+		}
+	}
+}
+
+/**
+ * @param mixed $foo
+ */
+function foo($foo): void {}
+
+function testByRefInArray(): void
+{
+	$a = [];
+	assertType('array{}', $a);
+
+	$b = [&$a];
+	assertType('mixed', $a); // Could stay array{}
+
+	foo($b);
+	assertType('mixed', $a);
+}
+
+function testByRefInArrayWithKey(): void
+{
+	$a = 'hello';
+	assertType("'hello'", $a);
+
+	$b = ['key' => &$a];
+	assertType('mixed', $a); // Could stay 'hello'
+
+	$b['key'] = 42;
+	assertType('mixed', $a); // Could be 42
+}
+
+function testMultipleByRefInArray(): void
+{
+	$a = 1;
+	$c = 'test';
+
+	$b = [&$a, 'normal', &$c];
+	assertType('mixed', $a); // Could stay 1
+	assertType('mixed', $c); // Could stay 'test'
+
+	$b[0] = 2;
+	$b[1] = 'foo';
+	$b[2] = 'bar';
+
+	assertType('mixed', $a); // Could be 2
+	assertType('mixed', $c); // Could be 'bar'
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-6799b.php b/tests/PHPStan/Analyser/nsrt/bug-6799b.php
new file mode 100644
index 0000000000..f0af35d829
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-6799b.php
@@ -0,0 +1,47 @@
+<?php declare(strict_types = 1);
+
+namespace Bug6799b;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+
+
+	/**
+	 * listingAddWhereFilterAtableRoleCategory
+	 *
+	 * @param string[] $where
+	 * @param string $sqlTableName
+	 * @param mixed[] $filter
+	 * @param string $value
+	 *
+	 * @return void
+	 */
+	protected function listingAddWhereFilterAtableDefault(array &$where, string $sqlTableName, array $filter, string $value): void
+	{
+		if ($value != "" && !empty($filter) && !empty($filter['sql']) && is_string($filter['sql'])) {
+			$where[] = "`" . $sqlTableName . "`.`" . (string)$filter['sql'] . "` = '" . $value . "'";
+		}
+	}
+
+	/**
+	 * listingAddWhereFilterAtableFilter
+	 *
+	 * @param string[] $filterValues
+	 * @param string[] $where
+	 * @param string[] $tables
+	 * @param mixed[] $filters
+	 * @return void
+	 */
+	protected function listingAddWhereFilterAtable(array $filterValues, array &$where, array &$tables, array $filters): void
+	{
+		if (!empty($filterValues) && !empty($filters)) {
+			$whereFilter = array();
+			foreach ($filterValues as $type => $value) {
+				$this->listingAddWhereFilterAtableDefault($whereFilter, 'xxxxx', $filters[$type], $value);
+			}
+			assertType('array<string>', $whereFilter);
+		}
+	}
+}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-6799c.php b/tests/PHPStan/Analyser/nsrt/bug-6799c.php
new file mode 100644
index 0000000000..43e34ecb25
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-6799c.php
@@ -0,0 +1,17 @@
+<?php declare(strict_types = 1);
+
+namespace Bug6799C;
+
+use function PHPStan\Testing\assertType;
+
+// https://3v4l.org/g5UjS
+
+$a = [&$x];
+assertType('mixed', $x);
+
+function doFoo(array &$arr) {
+	$arr[0] = 'string';
+}
+
+doFoo($a);
+assertType('mixed', $x);
diff --git a/tests/PHPStan/Rules/Comparison/NumberComparisonOperatorsConstantConditionRuleTest.php b/tests/PHPStan/Rules/Comparison/NumberComparisonOperatorsConstantConditionRuleTest.php
index 5400e3edee..cb4e7ffe58 100644
--- a/tests/PHPStan/Rules/Comparison/NumberComparisonOperatorsConstantConditionRuleTest.php
+++ b/tests/PHPStan/Rules/Comparison/NumberComparisonOperatorsConstantConditionRuleTest.php
@@ -298,4 +298,9 @@ public function testBug12163(): void
 		]);
 	}
 
+	public function testBug6799(): void
+	{
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-6799.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
index 2dde59f142..4dd5b0bced 100644
--- a/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
+++ b/tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php
@@ -1430,4 +1430,14 @@ public function testBug14117(): void
 		]);
 	}
 
+	public function testBug6799c(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-6799c.php'], []);
+	}
+
 }