diff --git a/src/Psalm/Checker/StatementsChecker.php b/src/Psalm/Checker/StatementsChecker.php
index f75680601..71b63aa24 100644
--- a/src/Psalm/Checker/StatementsChecker.php
+++ b/src/Psalm/Checker/StatementsChecker.php
@@ -2211,6 +2211,16 @@ class StatementsChecker
         return null;
     }
 
+    public static function getArrayVarId(PhpParser\Node\Expr $stmt)
+    {
+        if ($stmt instanceof PhpParser\Node\Expr\ArrayDimFetch && $stmt->dim instanceof PhpParser\Node\Scalar\String_) {
+            $root_var_id = self::getArrayVarId($stmt->var);
+            return $root_var_id ? $root_var_id . '[\'' . $stmt->dim->value . '\']' : null;
+        }
+
+        return self::getVarId($stmt);
+    }
+
     protected function checkArrayAssignment(PhpParser\Node\Expr\ArrayDimFetch $stmt, Context $context, Type\Union $assignment_value_type)
     {
         if ($stmt->dim && $this->checkExpression($stmt->dim, $context, false) === false) {
diff --git a/src/Psalm/Checker/TypeChecker.php b/src/Psalm/Checker/TypeChecker.php
index ea1d34dae..6b7e57903 100644
--- a/src/Psalm/Checker/TypeChecker.php
+++ b/src/Psalm/Checker/TypeChecker.php
@@ -256,7 +256,7 @@ class TypeChecker
             }
             else if ($conditional->expr instanceof PhpParser\Node\Expr\Isset_) {
                 foreach ($conditional->expr->vars as $isset_var) {
-                    $var_name = StatementsChecker::getVarId($isset_var);
+                    $var_name = StatementsChecker::getVarId($isset_var) ?: StatementsChecker::getArrayVarId($isset_var);
                     if ($var_name) {
                         $if_types[$var_name] = 'null';
                     }
@@ -409,7 +409,7 @@ class TypeChecker
         }
         else if ($conditional instanceof PhpParser\Node\Expr\Isset_) {
             foreach ($conditional->vars as $isset_var) {
-                $var_name = StatementsChecker::getVarId($isset_var);
+                $var_name = StatementsChecker::getVarId($isset_var) ?: StatementsChecker::getArrayVarId($isset_var);
                 if ($var_name) {
                     $if_types[$var_name] = '!null';
                 }