[DeadCode] Clean casted CallLike in Assign Expr on RemoveUnusedVariableAssignRector (#1889)

Co-authored-by: Jack Leigh <leighman@users.noreply.github.com>

rules-tests/DeadCode/Rector/Assign/RemoveUnusedVariableAssignRector/Fixture/clean_cast_assign_expr_call_like.php.inc

@@ -0,0 +1,31 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Assign\RemoveUnusedVariableAssignRector\Fixture;
+
+final class CleanCastAssignExprCallLike
+{
+    public function run()
+    {
+        $response = (object) $this->api_post("whatever", []);
+
+        return 5;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Assign\RemoveUnusedVariableAssignRector\Fixture;
+
+final class CleanCastAssignExprCallLike
+{
+    public function run()
+    {
+        $this->api_post("whatever", []);
+
+        return 5;
+    }
+}
+
+?>

rules/DeadCode/Rector/Assign/RemoveUnusedVariableAssignRector.php

@@ -8,6 +8,7 @@ use PhpParser\Node;
 use PhpParser\Node\Arg;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\Cast;
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\MethodCall;
 use PhpParser\Node\Expr\New_;
@@ -109,13 +110,23 @@ CODE_SAMPLE
 
         if ($this->hasCallLikeInAssignExpr($node->expr)) {
             // keep the expr, can have side effect
-            return $node->expr;
+            return $this->cleanCastedExpr($node->expr);
         }
 
         $this->removeNode($node);
         return $node;
     }
 
+    private function cleanCastedExpr(Expr $expr): Expr
+    {
+        if (! $expr instanceof Cast) {
+            return $expr;
+        }
+
+        $castedExpr = $expr->expr;
+        return $this->cleanCastedExpr($castedExpr);
+    }
+
     private function hasCallLikeInAssignExpr(Expr $expr): bool
     {
         return (bool) $this->betterNodeFinder->findFirst(