Fix monomorphization of unboxed closures

This adds a `Substs` field to `ty_unboxed_closure` and plumbs basic
handling of it throughout the compiler. trans now correctly
monomorphizes captured free variables and llvm function defs.  This
fixes uses of unboxed closures which reference a free type or region
parameter from their environment in either their signature or free
variables.  Closes #16791

1 files changed, 6 insertions, 1 deletions

diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index 81deae86faa..943570743e8 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -425,7 +425,12 @@ pub fn ty_to_string(cx: &ctxt, typ: t) -> String {
                   bound_str)
       }
       ty_str => "str".to_string(),
-      ty_unboxed_closure(..) => "closure".to_string(),
+      ty_unboxed_closure(ref did, _, ref substs) => {
+          let unboxed_closures = cx.unboxed_closures.borrow();
+          unboxed_closures.find(did).map(|cl| {
+              closure_to_string(cx, &cl.closure_type.subst(cx, substs))
+          }).unwrap_or_else(|| "closure".to_string())
+      }
       ty_vec(t, sz) => {
           match sz {
               Some(n) => {