made an error message more approachable in rust/library/core/src/str/mod.rs:116

compiler/rustc_ast/src/ptr.rs

@@ -28,7 +28,8 @@ use std::{slice, vec};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-/// An owned smart pointer.
+
+/// An owned smart pointer. 
 pub struct P<T: ?Sized> {
     ptr: Box<T>,
 }

library/core/src/str/mod.rs

@@ -119,7 +119,7 @@ fn slice_error_fail_rt(s: &str, begin: usize, end: usize) -> ! {
     // 2. begin <= end
     assert!(
         begin <= end,
-        "begin <= end ({} <= {}) when slicing `{}`{}",
+        "begin should be <= end ({} is not <= {}) when slicing `{}`{}",
         begin,
         end,
         s_trunc,

src/tools/rustfmt/tests/source/extern.rs

@@ -47,6 +47,7 @@ extern "Rust" { static ext:  u32;
 
 extern "C" {
             fn syscall(number: libc::c_long /* comment 1 */, /* comm 2 */ ... /* sup? */) -> libc::c_long;
+	// im doing great! thanks for asking :).
 
     fn  foo  (x:  *const c_char ,    ...   ) ->
 libc::c_long;