4 files changed, 11 insertions, 13 deletions
diff --git a/lib/std/io/buffered_reader.zig b/lib/std/io/buffered_reader.zig
index 2f6677c6a5..efc1d78cc4 100644
--- a/lib/std/io/buffered_reader.zig
+++ b/lib/std/io/buffered_reader.zig
@@ -20,8 +20,8 @@ pub fn BufferedReader(comptime buffer_size: usize, comptime ReaderType: type) ty
             var dest_index: usize = 0;
 
             while (dest_index < dest.len) {
-                const written = std.math.min(dest.len - dest_index, self.end - self.start);
-                std.mem.copy(u8, dest[dest_index..], self.buf[self.start .. self.start + written]);
+                const written = @min(dest.len - dest_index, self.end - self.start);
+                @memcpy(dest[dest_index..][0..written], self.buf[self.start..][0..written]);
                 if (written == 0) {
                     // buf empty, fill it
                     const n = try self.unbuffered_reader.read(self.buf[0..]);
@@ -115,11 +115,8 @@ test "io.BufferedReader Block" {
         }
 
         fn read(self: *Self, dest: []u8) Error!usize {
-            if (self.curr_read >= self.reads_allowed) {
-                return 0;
-            }
-            std.debug.assert(dest.len >= self.block.len);
-            std.mem.copy(u8, dest, self.block);
+            if (self.curr_read >= self.reads_allowed) return 0;
+            @memcpy(dest[0..self.block.len], self.block);
 
             self.curr_read += 1;
             return self.block.len;
diff --git a/lib/std/io/buffered_writer.zig b/lib/std/io/buffered_writer.zig
index 497a1810a7..906d6cce49 100644
--- a/lib/std/io/buffered_writer.zig
+++ b/lib/std/io/buffered_writer.zig
@@ -30,8 +30,9 @@ pub fn BufferedWriter(comptime buffer_size: usize, comptime WriterType: type) ty
                     return self.unbuffered_writer.write(bytes);
             }
 
-            mem.copy(u8, self.buf[self.end..], bytes);
-            self.end += bytes.len;
+            const new_end = self.end + bytes.len;
+            @memcpy(self.buf[self.end..new_end], bytes);
+            self.end = new_end;
             return bytes.len;
         }
     };
diff --git a/lib/std/io/fixed_buffer_stream.zig b/lib/std/io/fixed_buffer_stream.zig
index 2fcb260c72..c170dd1f74 100644
--- a/lib/std/io/fixed_buffer_stream.zig
+++ b/lib/std/io/fixed_buffer_stream.zig
@@ -45,10 +45,10 @@ pub fn FixedBufferStream(comptime Buffer: type) type {
         }
 
         pub fn read(self: *Self, dest: []u8) ReadError!usize {
-            const size = std.math.min(dest.len, self.buffer.len - self.pos);
+            const size = @min(dest.len, self.buffer.len - self.pos);
             const end = self.pos + size;
 
-            mem.copy(u8, dest[0..size], self.buffer[self.pos..end]);
+            @memcpy(dest[0..size], self.buffer[self.pos..end]);
             self.pos = end;
 
             return size;
@@ -67,7 +67,7 @@ pub fn FixedBufferStream(comptime Buffer: type) type {
             else
                 self.buffer.len - self.pos;
 
-            mem.copy(u8, self.buffer[self.pos .. self.pos + n], bytes[0..n]);
+            @memcpy(self.buffer[self.pos..][0..n], bytes[0..n]);
             self.pos += n;
 
             if (n == 0) return error.NoSpaceLeft;
diff --git a/lib/std/io/writer.zig b/lib/std/io/writer.zig
index 3160c37ff2..f4b2643e77 100644
--- a/lib/std/io/writer.zig
+++ b/lib/std/io/writer.zig
@@ -35,7 +35,7 @@ pub fn Writer(
 
         pub fn writeByteNTimes(self: Self, byte: u8, n: usize) Error!void {
             var bytes: [256]u8 = undefined;
-            mem.set(u8, bytes[0..], byte);
+            @memset(bytes[0..], byte);
 
             var remaining: usize = n;
             while (remaining > 0) {