Add `: Box<_>` or `::Box<_>` type annotations to various places.

This is the kind of change that one is expected to need to make to
accommodate overloaded-`box`.

----

Note that this is not *all* of the changes necessary to accommodate
Issue 22181.  It is merely the subset of those cases where there was
already a let-binding in place that made it easy to add the necesasry
type ascription.

(For unnamed intermediate `Box` values, one must go down a different
route; `Box::new` is the option that maximizes portability, but has
potential inefficiency depending on whether the call is inlined.)

----

There is one place worth note, `run-pass/coerce-match.rs`, where I
used an ugly form of `Box<_>` type ascription where I would have
preferred to use `Box::new` to accommodate overloaded-`box`.  I
deliberately did not use `Box::new` here, because that is already done
in coerce-match-calls.rs.

----

Precursor for overloaded-`box` and placement-`in`; see Issue 22181.

1 files changed, 6 insertions, 6 deletions

diff --git a/src/libstd/old_io/net/ip.rs b/src/libstd/old_io/net/ip.rs
index 9c89c943994..f1634cd4229 100644
--- a/src/libstd/old_io/net/ip.rs
+++ b/src/libstd/old_io/net/ip.rs
@@ -323,22 +323,22 @@ impl<'a> Parser<'a> {
     }
 
     fn read_ip_addr(&mut self) -> Option<IpAddr> {
-        let ipv4_addr = |p: &mut Parser| p.read_ipv4_addr();
-        let ipv6_addr = |p: &mut Parser| p.read_ipv6_addr();
-        self.read_or(&mut [box ipv4_addr, box ipv6_addr])
+        let ipv4_addr: Box<_> = box |p: &mut Parser| p.read_ipv4_addr();
+        let ipv6_addr: Box<_> = box |p: &mut Parser| p.read_ipv6_addr();
+        self.read_or(&mut [ipv4_addr, ipv6_addr])
     }
 
     fn read_socket_addr(&mut self) -> Option<SocketAddr> {
         let ip_addr = |p: &mut Parser| {
-            let ipv4_p = |p: &mut Parser| p.read_ip_addr();
-            let ipv6_p = |p: &mut Parser| {
+            let ipv4_p: Box<_> = box |p: &mut Parser| p.read_ip_addr();
+            let ipv6_p: Box<_> = box |p: &mut Parser| {
                 let open_br = |p: &mut Parser| p.read_given_char('[');
                 let ip_addr = |p: &mut Parser| p.read_ipv6_addr();
                 let clos_br = |p: &mut Parser| p.read_given_char(']');
                 p.read_seq_3::<char, IpAddr, char, _, _, _>(open_br, ip_addr, clos_br)
                         .map(|t| match t { (_, ip, _) => ip })
             };
-            p.read_or(&mut [box ipv4_p, box ipv6_p])
+            p.read_or(&mut [ipv4_p, ipv6_p])
         };
         let colon = |p: &mut Parser| p.read_given_char(':');
         let port  = |p: &mut Parser| p.read_number(10, 5, 0x10000).map(|n| n as u16);