rollup merge of #20481: seanmonstar/fmt-show-string

Conflicts:
	src/compiletest/runtest.rs
	src/libcore/fmt/mod.rs
	src/libfmt_macros/lib.rs
	src/libregex/parse.rs
	src/librustc/middle/cfg/construct.rs
	src/librustc/middle/dataflow.rs
	src/librustc/middle/infer/higher_ranked/mod.rs
	src/librustc/middle/ty.rs
	src/librustc_back/archive.rs
	src/librustc_borrowck/borrowck/fragments.rs
	src/librustc_borrowck/borrowck/gather_loans/mod.rs
	src/librustc_resolve/lib.rs
	src/librustc_trans/back/link.rs
	src/librustc_trans/save/mod.rs
	src/librustc_trans/trans/base.rs
	src/librustc_trans/trans/callee.rs
	src/librustc_trans/trans/common.rs
	src/librustc_trans/trans/consts.rs
	src/librustc_trans/trans/controlflow.rs
	src/librustc_trans/trans/debuginfo.rs
	src/librustc_trans/trans/expr.rs
	src/librustc_trans/trans/monomorphize.rs
	src/librustc_typeck/astconv.rs
	src/librustc_typeck/check/method/mod.rs
	src/librustc_typeck/check/mod.rs
	src/librustc_typeck/check/regionck.rs
	src/librustc_typeck/collect.rs
	src/libsyntax/ext/format.rs
	src/libsyntax/ext/source_util.rs
	src/libsyntax/ext/tt/transcribe.rs
	src/libsyntax/parse/mod.rs
	src/libsyntax/parse/token.rs
	src/test/run-pass/issue-8898.rs

src/libstd/os.rs

@@ -93,7 +93,7 @@ pub const TMPBUF_SZ : uint = 1000u;
 ///
 /// // We assume that we are in a valid directory.
 /// let current_working_directory = os::getcwd().unwrap();
-/// println!("The current directory is {}", current_working_directory.display());
+/// println!("The current directory is {:?}", current_working_directory.display());
 /// ```
 pub fn getcwd() -> IoResult<Path> {
     sys::os::getcwd()
@@ -934,7 +934,7 @@ impl fmt::Show for MapError {
 
 impl Error for MapError {
     fn description(&self) -> &str { "memory map error" }
-    fn detail(&self) -> Option<String> { Some(self.to_string()) }
+    fn detail(&self) -> Option<String> { Some(format!("{:?}", self)) }
 }
 
 impl FromError<MapError> for Box<Error> {