Register snapshots and switch logging over to use of log_full or #error / #debug.

src/test/compile-fail/while-loop-constraints.rs

@@ -3,5 +3,12 @@ fn main() {
 
     let y: int = 42;
     let x: int;
-    while true { log y; while true { while true { while true { x <- y; } } } }
+    while true {
+        log_full(core::debug, y);
+        while true {
+            while true {
+                while true { x <- y; }
+            }
+        }
+    }
 }