rollup merge of #22024: alexcrichton/ascii

* Move the type parameter on the `AsciiExt` trait to an associated type named
  `Owned`.
* Move `ascii::escape_default` to using an iterator.

This is a breaking change due to the removal of the type parameter on the
`AsciiExt` trait as well as the modifications to the `escape_default` function
to returning an iterator. Manual implementations of `AsciiExt` (or `AsciiExt`
bounds) should be adjusted to remove the type parameter and using the new
`escape_default` should be relatively straightforward.

[breaking-change]

1 files changed, 4 insertions, 6 deletions

diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 583095e1574..4b021f2434f 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -2761,15 +2761,13 @@ impl<'a> State<'a> {
             ast::LitStr(ref st, style) => self.print_string(&st, style),
             ast::LitByte(byte) => {
                 let mut res = String::from_str("b'");
-                ascii::escape_default(byte, |c| res.push(c as char));
+                res.extend(ascii::escape_default(byte).map(|c| c as char));
                 res.push('\'');
                 word(&mut self.s, &res[])
             }
             ast::LitChar(ch) => {
                 let mut res = String::from_str("'");
-                for c in ch.escape_default() {
-                    res.push(c);
-                }
+                res.extend(ch.escape_default());
                 res.push('\'');
                 word(&mut self.s, &res[])
             }
@@ -2809,8 +2807,8 @@ impl<'a> State<'a> {
             ast::LitBinary(ref v) => {
                 let mut escaped: String = String::new();
                 for &ch in &**v {
-                    ascii::escape_default(ch as u8,
-                                          |ch| escaped.push(ch as char));
+                    escaped.extend(ascii::escape_default(ch as u8)
+                                         .map(|c| c as char));
                 }
                 word(&mut self.s, &format!("b\"{}\"", escaped)[])
             }