edition: Eliminate ref keyword

As described in:
https://doc.rust-lang.org/edition-guide/rust-2018/ownership-and-lifetimes/default-match-bindings.html
which also covers the new mental model that the Rust Book will use for
teaching binding modes and has been found to be more friendly for both
beginners and experienced users.

Before:

    match *opt {
        Some(ref v) => ...,
        None => ...,
    }

After:

    match opt {
        Some(v) => ...,
        None => ...,
    }

TEST=cargo check --all-features
TEST=local kokoro

Change-Id: I3c5800a9be36aaf5d3290ae3bd3116f699cb00b7
Reviewed-on: https://chromium-review.googlesource.com/1566669
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/msg_socket/msg_on_socket_derive/msg_on_socket_derive.rs b/msg_socket/msg_on_socket_derive/msg_on_socket_derive.rs
index 5116d7e..3779357 100644
--- a/msg_socket/msg_on_socket_derive/msg_on_socket_derive.rs
+++ b/msg_socket/msg_on_socket_derive/msg_on_socket_derive.rs
@@ -42,7 +42,7 @@ fn socket_msg_impl(input: DeriveInput) -> TokenStream {
 
 fn is_named_struct(ds: &DataStruct) -> bool {
     match &ds.fields {
-        &Fields::Named(ref _f) => true,
+        Fields::Named(_f) => true,
         _ => false,
     }
 }