rollup merge of #23601: nikomatsakis/by-value-index

This is a [breaking-change]. When indexing a generic map (hashmap, etc) using the `[]` operator, it is now necessary to borrow explicitly, so change `map[key]` to `map[&key]` (consistent with the `get` routine). However, indexing of string-valued maps with constant strings can now be written `map["abc"]`.

r? @japaric
cc @aturon @Gankro

2 files changed, 3 insertions, 3 deletions

diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 0eaca9af4f0..2fe77bf7a54 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -513,7 +513,7 @@ impl<'a, 'b> Context<'a, 'b> {
             let lname = self.ecx.ident_of(&format!("__arg{}",
                                                   *name));
             pats.push(self.ecx.pat_ident(e.span, lname));
-            names[self.name_positions[*name]] =
+            names[*self.name_positions.get(name).unwrap()] =
                 Some(Context::format_arg(self.ecx, e.span, arg_ty,
                                          self.ecx.expr_ident(e.span, lname)));
             heads.push(self.ecx.expr_addr_of(e.span, e));
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 7a2ae55e914..5940b791843 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -236,7 +236,7 @@ pub fn compile<'cx>(cx: &'cx mut ExtCtxt,
                                      argument_gram);
 
     // Extract the arguments:
-    let lhses = match *argument_map[lhs_nm] {
+    let lhses = match **argument_map.get(&lhs_nm).unwrap() {
         MatchedSeq(ref s, _) => /* FIXME (#2543) */ (*s).clone(),
         _ => cx.span_bug(def.span, "wrong-structured lhs")
     };
@@ -245,7 +245,7 @@ pub fn compile<'cx>(cx: &'cx mut ExtCtxt,
         check_lhs_nt_follows(cx, &**lhs, def.span);
     }
 
-    let rhses = match *argument_map[rhs_nm] {
+    let rhses = match **argument_map.get(&rhs_nm).unwrap() {
         MatchedSeq(ref s, _) => /* FIXME (#2543) */ (*s).clone(),
         _ => cx.span_bug(def.span, "wrong-structured rhs")
     };