From fabecca4fd530b6357b6422a6444d0aa3e935a33 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Sat, 29 Aug 2026 09:26:28 +0200
Subject: [PATCH] Fix double backslash in FunctionFirstClassCallableRector

Strip leading backslash before building the callable name so a fully
qualified string callable like '\trim' produces \trim(...) instead of
invalid \\trim(...).

Claude-Session: https://claude.ai/code/session_01NAL2P8PQ3MY37Faby2r8st
---
 .../Fixture/leading_backslash.php.inc         | 27 +++++++++++++++++++
 .../FunctionFirstClassCallableRector.php      |  9 ++++---
 2 files changed, 33 insertions(+), 3 deletions(-)
 create mode 100644 rules-tests/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector/Fixture/leading_backslash.php.inc

diff --git a/rules-tests/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector/Fixture/leading_backslash.php.inc b/rules-tests/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector/Fixture/leading_backslash.php.inc
new file mode 100644
index 00000000000..14a46694060
--- /dev/null
+++ b/rules-tests/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector/Fixture/leading_backslash.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\Tests\CodingStyle\Rector\FuncCall\FunctionFirstClassCallableRector\Fixture;
+
+final class LeadingBackslash
+{
+    public function run(array $input)
+    {
+        return \array_map('\trim', $input);
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\CodingStyle\Rector\FuncCall\FunctionFirstClassCallableRector\Fixture;
+
+final class LeadingBackslash
+{
+    public function run(array $input)
+    {
+        return \array_map(\trim(...), $input);
+    }
+}
+
+?>
diff --git a/rules/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector.php b/rules/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector.php
index 8b98d55fcf0..b94041c893c 100644
--- a/rules/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector.php
+++ b/rules/CodingStyle/Rector/FuncCall/FunctionFirstClassCallableRector.php
@@ -101,11 +101,14 @@ public function refactor(Node $node): ?FuncCall
                 continue;
             }
 
+            $isFullyQualified = str_starts_with($arg->value->value, '\\');
+            $callableName = ltrim($arg->value->value, '\\');
+
             $node->args[$key] = new Arg(
                 new FuncCall(
-                    str_contains($arg->value->value, '\\')
-                        ? new FullyQualified($arg->value->value)
-                        : new Name($arg->value->value),
+                    $isFullyQualified || str_contains($callableName, '\\')
+                        ? new FullyQualified($callableName)
+                        : new Name($callableName),
                     [new VariadicPlaceholder()]
                 ),
                 name: $arg->name