diff --git a/HtmlExtension.php b/HtmlExtension.php
index 4231c6a..d8a6c00 100644
--- a/HtmlExtension.php
+++ b/HtmlExtension.php
@@ -97,7 +97,7 @@ public static function htmlClasses(...$args): string
             } elseif (\is_array($arg)) {
                 foreach ($arg as $class => $condition) {
                     if (!\is_string($class)) {
-                        throw new RuntimeError(\sprintf('The html_classes function argument %d (key %d) should be a string, got "%s".', $i, $class, get_debug_type($class)));
+                        throw new RuntimeError(\sprintf('The "html_classes" function argument %d (key %d) should be a string, got "%s".', $i, $class, get_debug_type($class)));
                     }
                     if (!$condition) {
                         continue;
@@ -105,7 +105,7 @@ public static function htmlClasses(...$args): string
                     $classes[] = $class;
                 }
             } else {
-                throw new RuntimeError(\sprintf('The html_classes function argument %d should be either a string or an array, got "%s".', $i, get_debug_type($arg)));
+                throw new RuntimeError(\sprintf('The "html_classes" function argument %d should be either a string or an array, got "%s".', $i, get_debug_type($arg)));
             }
         }
 
diff --git a/Tests/Fixtures/html_classes_with_unsupported_arg.test b/Tests/Fixtures/html_classes_with_unsupported_arg.test
index 85faed6..21ca373 100644
--- a/Tests/Fixtures/html_classes_with_unsupported_arg.test
+++ b/Tests/Fixtures/html_classes_with_unsupported_arg.test
@@ -5,4 +5,4 @@
 --DATA--
 return []
 --EXCEPTION--
-Twig\Error\RuntimeError: The html_classes function argument 0 should be either a string or an array, got "boolean" in "index.twig" at line 2.
+Twig\Error\RuntimeError: The "html_classes" function argument 0 should be either a string or an array, got "bool" in "index.twig" at line 2.
diff --git a/Tests/Fixtures/html_classes_with_unsupported_key.test b/Tests/Fixtures/html_classes_with_unsupported_key.test
index b74748c..708cb25 100644
--- a/Tests/Fixtures/html_classes_with_unsupported_key.test
+++ b/Tests/Fixtures/html_classes_with_unsupported_key.test
@@ -5,4 +5,4 @@
 --DATA--
 return []
 --EXCEPTION--
-Twig\Error\RuntimeError: The html_classes function argument 0 (key 0) should be a string, got "integer" in "index.twig" at line 2.
+Twig\Error\RuntimeError: The "html_classes" function argument 0 (key 0) should be a string, got "int" in "index.twig" at line 2.