outdated comment

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1044,8 +1044,6 @@ fn is_knowable<'o>(&mut self, stack: &TraitObligationStack<'o, 'tcx>) -> Option<
     }
 
     /// Returns `true` if the global caches can be used.
-    /// Do note that if the type itself is not in the
-    /// global tcx, the local caches will be used.
     fn can_use_global_caches(&self, param_env: ty::ParamEnv<'tcx>) -> bool {
         // If there are any inference variables in the `ParamEnv`, then we
         // always use a cache local to this particular scope. Otherwise, we