fix miri backtrace panic

src/interpreter/mod.rs

@@ -1188,13 +1188,7 @@ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 ppaux::parameterized(f, self.1, self.0, ppaux::Ns::Value, &[])
             }
         }
-        let inst = Instance(def_id, substs);
-        match ::std::panic::catch_unwind(|| {
-            format!("inside call to {}", inst)
-        }) {
-            Ok(msg) => err.span_note(span, &msg),
-            Err(_) => err.span_note(span, &format!("ppaux::parameterized failed: {:?}, {:?}", def_id, substs)),
-        };
+        err.span_note(span, &format!("inside call to {}", Instance(def_id, substs)));
     }
     err.emit();
 }

src/interpreter/terminator.rs

@@ -218,7 +218,7 @@ fn eval_fn_call(
                     Some((ptr, block)) => (Some(ptr), StackPopCleanup::Goto(block)),
                     None => (None, StackPopCleanup::None),
                 };
-                self.push_stack_frame(def_id, span, mir, resolved_substs, return_ptr, return_to_block)?;
+                self.push_stack_frame(resolved_def_id, span, mir, resolved_substs, return_ptr, return_to_block)?;
 
                 for (i, (src, src_ty)) in arg_srcs.into_iter().enumerate() {
                     let dest = self.frame().locals[i];

tests/run-pass/try-operator-custom.rs

@@ -0,0 +1,13 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    assert!(Ok::<i32, String>(42) == Ok(42));
+}