std: Standardize (input, output) param orderings

This functions swaps the order of arguments to a few functions that previously
took (output, input) parameters, but now take (input, output) parameters (in
that order).

The affected functions are:

* ptr::copy
* ptr::copy_nonoverlapping
* slice::bytes::copy_memory
* intrinsics::copy
* intrinsics::copy_nonoverlapping

Closes #22890
[breaking-change]

1 files changed, 5 insertions, 5 deletions

diff --git a/src/libstd/old_io/mem.rs b/src/libstd/old_io/mem.rs
index 5f20c383bb7..64803191d4f 100644
--- a/src/libstd/old_io/mem.rs
+++ b/src/libstd/old_io/mem.rs
@@ -168,7 +168,7 @@ impl Reader for MemReader {
             let input = &self.buf[self.pos.. self.pos + write_len];
             let output = &mut buf[..write_len];
             assert_eq!(input.len(), output.len());
-            slice::bytes::copy_memory(output, input);
+            slice::bytes::copy_memory(input, output);
         }
         self.pos += write_len;
         assert!(self.pos <= self.buf.len());
@@ -212,7 +212,7 @@ impl<'a> Reader for &'a [u8] {
         {
             let input = &self[..write_len];
             let output = &mut buf[.. write_len];
-            slice::bytes::copy_memory(output, input);
+            slice::bytes::copy_memory(input, output);
         }
 
         *self = &self[write_len..];
@@ -287,13 +287,13 @@ impl<'a> Writer for BufWriter<'a> {
         let src_len = src.len();
 
         if dst_len >= src_len {
-            slice::bytes::copy_memory(dst, src);
+            slice::bytes::copy_memory(src, dst);
 
             self.pos += src_len;
 
             Ok(())
         } else {
-            slice::bytes::copy_memory(dst, &src[..dst_len]);
+            slice::bytes::copy_memory(&src[..dst_len], dst);
 
             self.pos += dst_len;
 
@@ -360,7 +360,7 @@ impl<'a> Reader for BufReader<'a> {
             let input = &self.buf[self.pos.. self.pos + write_len];
             let output = &mut buf[..write_len];
             assert_eq!(input.len(), output.len());
-            slice::bytes::copy_memory(output, input);
+            slice::bytes::copy_memory(input, output);
         }
         self.pos += write_len;
         assert!(self.pos <= self.buf.len());