std: Rename Show/String to Debug/Display

This commit is an implementation of [RFC 565][rfc] which is a stabilization of
the `std::fmt` module and the implementations of various formatting traits.
Specifically, the following changes were performed:

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0565-show-string-guidelines.md

* The `Show` trait is now deprecated, it was renamed to `Debug`
* The `String` trait is now deprecated, it was renamed to `Display`
* Many `Debug` and `Display` implementations were audited in accordance with the
  RFC and audited implementations now have the `#[stable]` attribute
  * Integers and floats no longer print a suffix
  * Smart pointers no longer print details that they are a smart pointer
  * Paths with `Debug` are now quoted and escape characters
* The `unwrap` methods on `Result` now require `Display` instead of `Debug`
* The `Error` trait no longer has a `detail` method and now requires that
  `Display` must be implemented. With the loss of `String`, this has moved into
  libcore.
* `impl<E: Error> FromError<E> for Box<Error>` now exists
* `derive(Show)` has been renamed to `derive(Debug)`. This is not currently
  warned about due to warnings being emitted on stage1+

While backwards compatibility is attempted to be maintained with a blanket
implementation of `Display` for the old `String` trait (and the same for
`Show`/`Debug`) this is still a breaking change due to primitives no longer
implementing `String` as well as modifications such as `unwrap` and the `Error`
trait. Most code is fairly straightforward to update with a rename or tweaks of
method calls.

[breaking-change]
Closes #21436

1 files changed, 9 insertions, 9 deletions

diff --git a/src/libcore/ops.rs b/src/libcore/ops.rs
index 7131253d5c4..853e4adb892 100644
--- a/src/libcore/ops.rs
+++ b/src/libcore/ops.rs
@@ -885,10 +885,10 @@ pub trait IndexMut<Index: ?Sized> {
 #[unstable = "API still in development"]
 pub struct FullRange;
 
-#[unstable = "API still in development"]
-impl fmt::Show for FullRange {
+#[stable]
+impl fmt::Debug for FullRange {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Show::fmt("..", fmt)
+        fmt::Debug::fmt("..", fmt)
     }
 }
 
@@ -944,8 +944,8 @@ impl<Idx: Clone + Step> DoubleEndedIterator for Range<Idx> {
 #[unstable = "API still in development"]
 impl<Idx: Clone + Step> ExactSizeIterator for Range<Idx> {}
 
-#[unstable = "API still in development"]
-impl<Idx: fmt::Show> fmt::Show for Range<Idx> {
+#[stable]
+impl<Idx: fmt::Debug> fmt::Debug for Range<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "{:?}..{:?}", self.start, self.end)
     }
@@ -973,8 +973,8 @@ impl<Idx: Clone + Step> Iterator for RangeFrom<Idx> {
     }
 }
 
-#[unstable = "API still in development"]
-impl<Idx: fmt::Show> fmt::Show for RangeFrom<Idx> {
+#[stable]
+impl<Idx: fmt::Debug> fmt::Debug for RangeFrom<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "{:?}..", self.start)
     }
@@ -989,8 +989,8 @@ pub struct RangeTo<Idx> {
     pub end: Idx,
 }
 
-#[unstable = "API still in development"]
-impl<Idx: fmt::Show> fmt::Show for RangeTo<Idx> {
+#[stable]
+impl<Idx: fmt::Debug> fmt::Debug for RangeTo<Idx> {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
         write!(fmt, "..{:?}", self.end)
     }