Use $crate and macro reexport to reduce duplicated code

Many of libstd's macros are now re-exported from libcore and libcollections.
Their libstd definitions have moved to a macros_stage0 module and can disappear
after the next snapshot.

Where the two crates had already diverged, I took the libstd versions as
they're generally newer and better-tested. See e.g. d3c831b, which was a fix to
libstd's assert_eq!() that didn't make it into libcore's.

Fixes #16806.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/libstd/time/duration.rs b/src/libstd/time/duration.rs
index d48b0342b3b..ac1f0c5d803 100644
--- a/src/libstd/time/duration.rs
+++ b/src/libstd/time/duration.rs
@@ -17,8 +17,10 @@ use ops::{Add, Sub, Mul, Div, Neg, FnOnce};
 use option::Option;
 use option::Option::{Some, None};
 use num::Int;
-use result::Result;
-use result::Result::{Ok, Err};
+use result::Result::Ok;
+
+// NOTE: for old macros; remove after the next snapshot
+#[cfg(stage0)] use result::Result::Err;
 
 /// The number of nanoseconds in a microsecond.
 const NANOS_PER_MICRO: i32 = 1000;