diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index dc0774c8..2cb10054 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -1079,6 +1079,15 @@ class CompilerBase extends \PhpAot\Core\Translator
             }
         } elseif ($this->isPropertyFetch($left)) {
             $var = $this->parsePropertyFetch($left, true);
+        } elseif ($this->isArrayDimFetch($left)) {
+            $tmp = $this->parseIdentifier($left->var);
+            var_dump($tmp);
+            if ($this->isVarExpr($left->var) and $this->getVarType($tmp) === self::TYPE_STR) {
+                if ($left->dim === null) {
+                    $this->fatalError($left, 'Cannot use [] for strings');
+                }
+                return $tmp . '.offsetSet(' . $this->parseExpr($left->dim) . ', ' . $this->convertExprType($expr, $this->detectExprType($left), $this->detectExprType($right)) . ')';
+            }
         }
 
         return $var . ' = ' . $this->convertExprType($expr, $this->detectExprType($left), $this->detectExprType($right));
@@ -1689,6 +1698,11 @@ class CompilerBase extends \PhpAot\Core\Translator
                     $this->fatalError($node->var, "The variable `{$node->var->name}` is undefined");
                 }
             }
+            if ($this->getVarType($var) === self::TYPE_STR) {
+                if ($node->dim === null) {
+                    $this->fatalError($node, 'Cannot use [] for strings');
+                }
+            }
         }
 
         if ($node->dim === null) {
diff --git a/tests/aot/str-offset-set.phpt b/tests/aot/str-offset-set.phpt
new file mode 100644
index 00000000..6954557c
--- /dev/null
+++ b/tests/aot/str-offset-set.phpt
@@ -0,0 +1,12 @@
+--TEST--
+strlen
+--FILE--
+<?php
+$s1 = "hello world";
+$s2 = "php";
+$s1[1] = $s2[1] = '_';
+var_dump($s1, $s2);
+?>
+--EXPECT--
+string(11) "h_llo world"
+string(3) "p_p"