diff --git a/include/thirdparty/ScssPhp/ScssPhp/Compiler.php b/include/thirdparty/ScssPhp/ScssPhp/Compiler.php
index c7c449a..7335bcb 100644
--- a/include/thirdparty/ScssPhp/ScssPhp/Compiler.php
+++ b/include/thirdparty/ScssPhp/ScssPhp/Compiler.php
@@ -3177,14 +3177,14 @@ class Compiler
                 // 1. op[op name][left type][right type]
                 // 2. op[left type][right type] (passing the op as first arg
                 // 3. op[op name]
-                $fn = "op${ucOpName}${ucLType}${ucRType}";
+                $fn = "op{$ucOpName}{$ucLType}{$ucRType}";
 
                 if (
                     \is_callable([$this, $fn]) ||
-                    (($fn = "op${ucLType}${ucRType}") &&
+                    (($fn = "op{$ucLType}{$ucRType}") &&
                         \is_callable([$this, $fn]) &&
                         $passOp = true) ||
-                    (($fn = "op${ucOpName}") &&
+                    (($fn = "op{$ucOpName}") &&
                         \is_callable([$this, $fn]) &&
                         $genOp = true)
                 ) {