From cdf730ca3cdc5ce7dfb284986d39398ac23187b2 Mon Sep 17 00:00:00 2001
From: Alan Somers <asomers@gmail.com>
Date: Wed, 28 Nov 2018 10:47:12 -0700
Subject: Prefer `map(drop)` to `map(|_| ())`

I previously advocated for the latter syntax on stylistic grounds.  But
it generates less efficient code, because it creates a new lambda
function for each usage.  The optimizer does not combine them.  This
change saves about 6KB of code.
---
 src/sys/stat.rs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

(limited to 'src/sys/stat.rs')

diff --git a/src/sys/stat.rs b/src/sys/stat.rs
index 925c0ede..f3a2e7e3 100644
--- a/src/sys/stat.rs
+++ b/src/sys/stat.rs
@@ -131,7 +131,7 @@ pub fn fstatat<P: ?Sized + NixPath>(dirfd: RawFd, pathname: &P, f: AtFlags) -> R
 pub fn fchmod(fd: RawFd, mode: Mode) -> Result<()> {
     let res = unsafe { libc::fchmod(fd, mode.bits() as mode_t) };
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
 
 /// Flags for `fchmodat` function.
@@ -177,7 +177,7 @@ pub fn fchmodat<P: ?Sized + NixPath>(
         )
     })?;
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
 
 /// Change the access and modification times of a file.
@@ -196,7 +196,7 @@ pub fn utimes<P: ?Sized + NixPath>(path: &P, atime: &TimeVal, mtime: &TimeVal) -
         libc::utimes(cstr.as_ptr(), &times[0])
     })?;
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
 
 /// Change the access and modification times of a file without following symlinks.
@@ -216,7 +216,7 @@ pub fn lutimes<P: ?Sized + NixPath>(path: &P, atime: &TimeVal, mtime: &TimeVal)
         libc::lutimes(cstr.as_ptr(), &times[0])
     })?;
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
 
 /// Change the access and modification times of the file specified by a file descriptor.
@@ -229,7 +229,7 @@ pub fn futimens(fd: RawFd, atime: &TimeSpec, mtime: &TimeSpec) -> Result<()> {
     let times: [libc::timespec; 2] = [*atime.as_ref(), *mtime.as_ref()];
     let res = unsafe { libc::futimens(fd, &times[0]) };
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
 
 /// Flags for `utimensat` function.
@@ -277,5 +277,5 @@ pub fn utimensat<P: ?Sized + NixPath>(
         )
     })?;
 
-    Errno::result(res).map(|_| ())
+    Errno::result(res).map(drop)
 }
-- 
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