auto merge of #19777 : nikomatsakis/rust/warn-on-shadowing, r=acrichto

per rfc 459
cc https://github.com/rust-lang/rust/issues/19390

One question is: should we start by warning, and only switch to hard error later? I think we discussed something like this in the meeting. 

r? @alexcrichton 

2 files changed, 4 insertions, 4 deletions

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 3c7a4a81d20..354b53bfc01 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -468,8 +468,8 @@ pub struct ExtCtxt<'a> {
 }
 
 impl<'a> ExtCtxt<'a> {
-    pub fn new<'a>(parse_sess: &'a parse::ParseSess, cfg: ast::CrateConfig,
-                   ecfg: expand::ExpansionConfig) -> ExtCtxt<'a> {
+    pub fn new(parse_sess: &'a parse::ParseSess, cfg: ast::CrateConfig,
+               ecfg: expand::ExpansionConfig) -> ExtCtxt<'a> {
         let env = initial_syntax_expander_table(&ecfg);
         ExtCtxt {
             parse_sess: parse_sess,
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 50c7258fe1c..da908f46ff6 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -275,8 +275,8 @@ impl<'a> StringReader<'a> {
     }
 
     /// Converts CRLF to LF in the given string, raising an error on bare CR.
-    fn translate_crlf<'a>(&self, start: BytePos,
-                          s: &'a str, errmsg: &'a str) -> str::CowString<'a> {
+    fn translate_crlf<'b>(&self, start: BytePos,
+                          s: &'b str, errmsg: &'b str) -> str::CowString<'b> {
         let mut i = 0u;
         while i < s.len() {
             let str::CharRange { ch, next } = s.char_range_at(i);