add test to ensure T_FN backfill is applied correctly

Author: alekitto

tests/Core/Tokenizer/AttributesTest.inc

@@ -22,6 +22,10 @@ function attribute_on_function_test() {}
 #[AttributeWithParams('foo', bar: ['bar' => 'foobar'])]
 function attribute_with_params_on_function_test() {}
 
+/* testAttributeWithShortClosureParameter */
+#[AttributeWithParams(static fn ($value) => ! $value)]
+function attribute_with_short_closure_param_test() {}
+
 /* testTwoAttributeOnTheSameLine */
 #[CustomAttribute] #[AttributeWithParams('foo')]
 function two_attribute_on_same_line_test() {}

tests/Core/Tokenizer/AttributesTest.php

@@ -128,6 +128,28 @@ public function dataAttribute()
                     T_CLOSE_PARENTHESIS,
                 ],
             ],
+            [
+                '/* testAttributeWithShortClosureParameter */',
+                17,
+                [
+                    T_STRING,
+                    T_OPEN_PARENTHESIS,
+                    T_STATIC,
+                    T_WHITESPACE,
+                    T_FN,
+                    T_WHITESPACE,
+                    T_OPEN_PARENTHESIS,
+                    T_VARIABLE,
+                    T_CLOSE_PARENTHESIS,
+                    T_WHITESPACE,
+                    T_FN_ARROW,
+                    T_WHITESPACE,
+                    T_BOOLEAN_NOT,
+                    T_WHITESPACE,
+                    T_VARIABLE,
+                    T_CLOSE_PARENTHESIS,
+                ],
+            ],
             [
                 '/* testAttributeGrouping */',
                 26,