Make newtype_index macro use full path to resolve constants

src/librustc_data_structures/indexed_vec.rs

@@ -47,7 +47,7 @@ fn index(self) -> usize { self as usize }
 
         impl Idx for $name {
             fn new(value: usize) -> Self {
-                assert!(value < (u32::MAX) as usize);
+                assert!(value < (::std::u32::MAX) as usize);
                 $name(value as u32)
             }
             fn index(self) -> usize {
@@ -55,8 +55,8 @@ fn index(self) -> usize {
             }
         }
 
-        impl Debug for $name {
-            fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
+        impl ::std::fmt::Debug for $name {
+            fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
                 write!(fmt, "{}{}", $debug_name, self.0)
             }
         }

src/librustc_mir/transform/nll/mod.rs

@@ -19,8 +19,6 @@
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 use syntax_pos::DUMMY_SP;
 use std::collections::HashMap;
-use std::fmt::{self, Debug, Formatter};
-use std::u32;
 
 #[allow(dead_code)]
 struct NLLVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {