Auto merge of #32909 - sanxiyn:unused-trait-import-2, r=alexcrichton

Remove unused trait imports

src/libsyntax/errors/mod.rs

@@ -19,7 +19,6 @@ use errors::emitter::{Emitter, EmitterWriter};
 
 use std::cell::{RefCell, Cell};
 use std::{error, fmt};
-use std::io::prelude::*;
 use std::rc::Rc;
 use term;
 
@@ -653,8 +652,6 @@ pub enum Level {
 
 impl fmt::Display for Level {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use std::fmt::Display;
-
         self.to_str().fmt(f)
     }
 }

src/libsyntax/parse/mod.rs

@@ -19,7 +19,6 @@ use ptr::P;
 use str::char_at;
 
 use std::cell::RefCell;
-use std::io::Read;
 use std::iter;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;

src/libsyntax/parse/parser.rs

@@ -59,7 +59,6 @@ use ptr::P;
 use parse::PResult;
 
 use std::collections::HashSet;
-use std::io::prelude::*;
 use std::mem;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;

src/libsyntax/util/interner.rs

@@ -115,14 +115,12 @@ impl Ord for RcStr {
 
 impl fmt::Debug for RcStr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use std::fmt::Debug;
         self[..].fmt(f)
     }
 }
 
 impl fmt::Display for RcStr {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use std::fmt::Display;
         self[..].fmt(f)
     }
 }