lint: Resolve the easier clippy lints

Hopefully the changes are self-explanatory and uncontroversial. This
eliminates much of the noise from `cargo clippy` and, for my purposes,
gives me a reasonable way to use it as a tool when writing and reviewing
code.

Here is the Clippy invocation I was using:

    cargo +nightly clippy -- -W clippy::correctness -A renamed_and_removed_lints -Aclippy::{blacklisted_name,borrowed_box,cast_lossless,cast_ptr_alignment,enum_variant_names,identity_op,if_same_then_else,mut_from_ref,needless_pass_by_value,new_without_default,new_without_default_derive,or_fun_call,ptr_arg,should_implement_trait,single_match,too_many_arguments,trivially_copy_pass_by_ref,unreadable_literal,unsafe_vector_initialization,useless_transmute}

TEST=cargo check --features wl-dmabuf,gpu,usb-emulation
TEST=boot linux

Change-Id: I55eb1b4a72beb2f762480e3333a921909314a0a2
Reviewed-on: https://chromium-review.googlesource.com/1356911
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>

3 files changed, 18 insertions, 17 deletions

diff --git a/usb_util/src/error.rs b/usb_util/src/error.rs
index 6ba5421..e819a52 100644
--- a/usb_util/src/error.rs
+++ b/usb_util/src/error.rs
@@ -27,24 +27,24 @@ pub enum Error {
 
 impl fmt::Debug for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            &Error::Success(_v) => write!(f, "Success (no error)"),
-            &Error::IO => write!(f, "Input/output error"),
-            &Error::InvalidParam => write!(f, "Invalid parameter"),
-            &Error::Access => write!(f, "Access denied (insufficient permissions)"),
-            &Error::NoDevice => write!(f, "No such device (it may have been disconnected)"),
-            &Error::NotFound => write!(f, "Entity not found"),
-            &Error::Busy => write!(f, "Resource busy"),
-            &Error::Timeout => write!(f, "Operation timed out"),
-            &Error::Overflow => write!(f, "Overflow"),
-            &Error::Pipe => write!(f, "Pipe error"),
-            &Error::Interrupted => write!(f, "System call interrupted (perhaps due to signal)"),
-            &Error::NoMem => write!(f, "Insufficient memory"),
-            &Error::NotSupported => write!(
+        match *self {
+            Error::Success(_v) => write!(f, "Success (no error)"),
+            Error::IO => write!(f, "Input/output error"),
+            Error::InvalidParam => write!(f, "Invalid parameter"),
+            Error::Access => write!(f, "Access denied (insufficient permissions)"),
+            Error::NoDevice => write!(f, "No such device (it may have been disconnected)"),
+            Error::NotFound => write!(f, "Entity not found"),
+            Error::Busy => write!(f, "Resource busy"),
+            Error::Timeout => write!(f, "Operation timed out"),
+            Error::Overflow => write!(f, "Overflow"),
+            Error::Pipe => write!(f, "Pipe error"),
+            Error::Interrupted => write!(f, "System call interrupted (perhaps due to signal)"),
+            Error::NoMem => write!(f, "Insufficient memory"),
+            Error::NotSupported => write!(
                 f,
                 "Operation not supported or unimplemented on this platform"
             ),
-            &Error::Other => write!(f, "Other error"),
+            Error::Other => write!(f, "Other error"),
         }
     }
 }
diff --git a/usb_util/src/lib.rs b/usb_util/src/lib.rs
index a0170f3..82d35b5 100644
--- a/usb_util/src/lib.rs
+++ b/usb_util/src/lib.rs
@@ -7,6 +7,7 @@
 #![allow(non_camel_case_types)]
 #![allow(non_snake_case)]
 #![allow(non_upper_case_globals)]
+#[cfg_attr(feature = "cargo-clippy", allow(clippy))]
 mod bindings;
 
 extern crate data_model;
diff --git a/usb_util/src/libusb_context.rs b/usb_util/src/libusb_context.rs
index 016ea22..65cd2cc 100644
--- a/usb_util/src/libusb_context.rs
+++ b/usb_util/src/libusb_context.rs
@@ -191,8 +191,8 @@ impl Iterator for PollFdIter {
             }
 
             self.index += 1;
-            // Safe because 'current_ptr' is not null.
-            Some((**current_ptr).clone())
+            // Safe because '*current_ptr' is not null.
+            Some(**current_ptr)
         }
     }
 }