Update some comments

compiler/rustc_middle/src/ty/sty.rs

@@ -152,6 +152,7 @@ pub enum TyKind<'tcx> {
 
     /// The anonymous type of a closure. Used to represent the type of
     /// `|a| a`.
+    /// For the order of the substs see the `ClosureSubsts` type's documentation.
     Closure(DefId, SubstsRef<'tcx>),
 
     /// The anonymous type of a generator. Used to represent the type of

compiler/rustc_typeck/src/check/upvar.rs

@@ -335,11 +335,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     // Returns a list of `Ty`s for each upvar.
     fn final_upvar_tys(&self, closure_id: DefId) -> Vec<Ty<'tcx>> {
-        // Presently an unboxed closure type cannot "escape" out of a
-        // function, so we will only encounter ones that originated in the
-        // local crate or were inlined into it along with some function.
-        // This may change if abstract return types of some sort are
-        // implemented.
         self.typeck_results
             .borrow()
             .closure_min_captures_flattened(closure_id)