diff --git a/src/Psalm/Internal/Clause.php b/src/Psalm/Internal/Clause.php
index 38c1b06ab06..b9a7a7a69b3 100644
--- a/src/Psalm/Internal/Clause.php
+++ b/src/Psalm/Internal/Clause.php
@@ -159,11 +159,11 @@ function ($value) use ($var_id): string {
 
                         if ($value[0] === '!') {
                             $negate = true;
-                            $value = substr($value, 1);
+                            $value = \substr($value, 1);
                         }
 
                         if ($value[0] === '=') {
-                            $value = substr($value, 1);
+                            $value = \substr($value, 1);
                         }
 
                         if ($negate) {
@@ -189,7 +189,7 @@ function ($value) use ($var_id): string {
             return '(' . implode(') || (', $clause_strings) . ')';
         }
 
-        return reset($clause_strings);
+        return \reset($clause_strings);
     }
 
     public function makeUnique() : self