4 files changed, 22 insertions, 14 deletions
diff --git a/src/libstd/sys_common/backtrace.rs b/src/libstd/sys_common/backtrace.rs
index 1955f3ec9a2..20109d2d0d5 100644
--- a/src/libstd/sys_common/backtrace.rs
+++ b/src/libstd/sys_common/backtrace.rs
@@ -139,10 +139,10 @@ pub fn __rust_begin_short_backtrace<F, T>(f: F) -> T
 /// Controls how the backtrace should be formatted.
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum PrintFormat {
-    /// Show all the frames with absolute path for files.
-    Full = 2,
     /// Show only relevant data from the backtrace.
-    Short = 3,
+    Short = 2,
+    /// Show all the frames with absolute path for files.
+    Full = 3,
 }
 
 // For now logging is turned off by default, and this function checks to see
@@ -150,11 +150,10 @@ pub enum PrintFormat {
 pub fn log_enabled() -> Option<PrintFormat> {
     static ENABLED: atomic::AtomicIsize = atomic::AtomicIsize::new(0);
     match ENABLED.load(Ordering::SeqCst) {
-        0 => {},
+        0 => {}
         1 => return None,
-        2 => return Some(PrintFormat::Full),
-        3 => return Some(PrintFormat::Short),
-        _ => unreachable!(),
+        2 => return Some(PrintFormat::Short),
+        _ => return Some(PrintFormat::Full),
     }
 
     let val = match env::var_os("RUST_BACKTRACE") {
diff --git a/src/libstd/sys_common/mod.rs b/src/libstd/sys_common/mod.rs
index 27504d374dd..d0c4d6a7737 100644
--- a/src/libstd/sys_common/mod.rs
+++ b/src/libstd/sys_common/mod.rs
@@ -28,6 +28,16 @@
 use sync::Once;
 use sys;
 
+macro_rules! rtabort {
+    ($($t:tt)*) => (::sys_common::util::abort(format_args!($($t)*)))
+}
+
+macro_rules! rtassert {
+    ($e:expr) => (if !$e {
+        rtabort!(concat!("assertion failed: ", stringify!($e)));
+    })
+}
+
 pub mod at_exit_imp;
 #[cfg(feature = "backtrace")]
 pub mod backtrace;
@@ -101,10 +111,6 @@ pub fn at_exit<F: FnOnce() + Send + 'static>(f: F) -> Result<(), ()> {
     if at_exit_imp::push(Box::new(f)) {Ok(())} else {Err(())}
 }
 
-macro_rules! rtabort {
-    ($($t:tt)*) => (::sys_common::util::abort(format_args!($($t)*)))
-}
-
 /// One-time runtime cleanup.
 pub fn cleanup() {
     static CLEANUP: Once = Once::new();
diff --git a/src/libstd/sys_common/thread_local.rs b/src/libstd/sys_common/thread_local.rs
index a4aa3d96d25..d0d6224de0a 100644
--- a/src/libstd/sys_common/thread_local.rs
+++ b/src/libstd/sys_common/thread_local.rs
@@ -169,7 +169,7 @@ impl StaticKey {
                 self.key.store(key, Ordering::SeqCst);
             }
             INIT_LOCK.unlock();
-            assert!(key != 0);
+            rtassert!(key != 0);
             return key
         }
 
@@ -190,7 +190,7 @@ impl StaticKey {
             imp::destroy(key1);
             key2
         };
-        assert!(key != 0);
+        rtassert!(key != 0);
         match self.key.compare_and_swap(0, key as usize, Ordering::SeqCst) {
             // The CAS succeeded, so we've created the actual key
             0 => key as usize,
diff --git a/src/libstd/sys_common/util.rs b/src/libstd/sys_common/util.rs
index a391c7cc6ef..a373e980b97 100644
--- a/src/libstd/sys_common/util.rs
+++ b/src/libstd/sys_common/util.rs
@@ -10,10 +10,13 @@
 
 use fmt;
 use io::prelude::*;
-use sys::stdio::Stderr;
+use sys::stdio::{Stderr, stderr_prints_nothing};
 use thread;
 
 pub fn dumb_print(args: fmt::Arguments) {
+    if stderr_prints_nothing() {
+        return
+    }
     let _ = Stderr::new().map(|mut stderr| stderr.write_fmt(args));
 }