diff --git a/src/Psalm/Checker/Statements/Block/SwitchChecker.php b/src/Psalm/Checker/Statements/Block/SwitchChecker.php
index 84cf2c60d..718a7b62a 100644
--- a/src/Psalm/Checker/Statements/Block/SwitchChecker.php
+++ b/src/Psalm/Checker/Statements/Block/SwitchChecker.php
@@ -180,8 +180,6 @@ class SwitchChecker
                     if ($possibly_redefined_vars === null) {
                         $possibly_redefined_vars = $case_redefined_vars;
                     } else {
-                        $possibly_redefined_vars = [];
-
                         foreach ($case_redefined_vars as $var_id => $type) {
                             if (!isset($possibly_redefined_vars[$var_id])) {
                                 $possibly_redefined_vars[$var_id] = $type;
diff --git a/tests/SwitchTypeTest.php b/tests/SwitchTypeTest.php
index 23c0ff3a2..91c63d26a 100644
--- a/tests/SwitchTypeTest.php
+++ b/tests/SwitchTypeTest.php
@@ -201,6 +201,28 @@ class SwitchTypeTest extends TestCase
                             throw new RuntimeException("none found");
                     }',
             ],
+            'switchBools' => [
+                '<?php
+                    $x = false;
+                    $y = false;
+
+                    foreach ([1, 2, 3] as $v)  {
+                        switch($v) {
+                            case 3:
+                                $y = true;
+                                break;
+                            case 2:
+                                $x = true;
+                                break;
+                            default:
+                                break;
+                        }
+                    }',
+                'assertions' => [
+                    '$x' => 'bool',
+                    '$y' => 'bool',
+                ],
+            ],
         ];
     }