auto merge of #15585 : bgamari/rust/subst-bug, r=pnkfelix

This branch has a fix for #15557 (a2bcef9) as well as a variety of patches I found useful while debugging this issue. These include adding `Show` impls to a variety of types, including the majority of `syntax::ast` and some of `middle::ty`.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/libsyntax/owned_slice.rs b/src/libsyntax/owned_slice.rs
index 530ea013112..7eb6709919a 100644
--- a/src/libsyntax/owned_slice.rs
+++ b/src/libsyntax/owned_slice.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::fmt;
 use std::default::Default;
 use std::hash;
 use std::{mem, raw, ptr, slice};
@@ -22,6 +23,17 @@ pub struct OwnedSlice<T> {
     len: uint,
 }
 
+impl<T:fmt::Show> fmt::Show for OwnedSlice<T> {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        try!("OwnedSlice {{".fmt(fmt));
+        for i in self.iter() {
+            try!(i.fmt(fmt));
+        }
+        try!("}}".fmt(fmt));
+        Ok(())
+    }
+}
+
 #[unsafe_destructor]
 impl<T> Drop for OwnedSlice<T> {
     fn drop(&mut self) {