update comment again as requested

Author: IntegralPilot

compiler/rustc_builtin_macros/src/test.rs

@@ -207,7 +207,7 @@ pub(crate) fn expand_test_or_bench(
     };
 
     let test_fn = if is_bench {
-        // A collision-resistant ident for a lambda, using the user's function name within it to avoid collisions.
+        // avoid name collisions by using the function name within the identifier, see bug #148275
         let bencher_param =
             Ident::from_str_and_span(&format!("__bench_{}", fn_.ident.name), attr_sp);
         cx.expr_call(