diff --git a/src/libstd/sys/windows/ext/fs.rs b/src/libstd/sys/windows/ext/fs.rs
index aaffe8dadf872..28d9b3e047633 100644
--- a/src/libstd/sys/windows/ext/fs.rs
+++ b/src/libstd/sys/windows/ext/fs.rs
@@ -25,41 +25,41 @@ use sys_common::{AsInnerMut, AsInner};
 pub trait OpenOptionsExt {
     /// Overrides the `dwDesiredAccess` argument to the call to `CreateFile`
     /// with the specified value.
-    fn desired_access(&mut self, access: i32) -> &mut Self;
+    fn desired_access(&mut self, access: u32) -> &mut Self;
 
     /// Overrides the `dwCreationDisposition` argument to the call to
     /// `CreateFile` with the specified value.
     ///
     /// This will override any values of the standard `create` flags, for
     /// example.
-    fn creation_disposition(&mut self, val: i32) -> &mut Self;
+    fn creation_disposition(&mut self, val: u32) -> &mut Self;
 
     /// Overrides the `dwFlagsAndAttributes` argument to the call to
     /// `CreateFile` with the specified value.
     ///
     /// This will override any values of the standard flags on the
     /// `OpenOptions` structure.
-    fn flags_and_attributes(&mut self, val: i32) -> &mut Self;
+    fn flags_and_attributes(&mut self, val: u32) -> &mut Self;
 
     /// Overrides the `dwShareMode` argument to the call to `CreateFile` with
     /// the specified value.
     ///
     /// This will override any values of the standard flags on the
     /// `OpenOptions` structure.
-    fn share_mode(&mut self, val: i32) -> &mut Self;
+    fn share_mode(&mut self, val: u32) -> &mut Self;
 }
 
 impl OpenOptionsExt for OpenOptions {
-    fn desired_access(&mut self, access: i32) -> &mut OpenOptions {
+    fn desired_access(&mut self, access: u32) -> &mut OpenOptions {
         self.as_inner_mut().desired_access(access); self
     }
-    fn creation_disposition(&mut self, access: i32) -> &mut OpenOptions {
+    fn creation_disposition(&mut self, access: u32) -> &mut OpenOptions {
         self.as_inner_mut().creation_disposition(access); self
     }
-    fn flags_and_attributes(&mut self, access: i32) -> &mut OpenOptions {
+    fn flags_and_attributes(&mut self, access: u32) -> &mut OpenOptions {
         self.as_inner_mut().flags_and_attributes(access); self
     }
-    fn share_mode(&mut self, access: i32) -> &mut OpenOptions {
+    fn share_mode(&mut self, access: u32) -> &mut OpenOptions {
         self.as_inner_mut().share_mode(access); self
     }
 }
diff --git a/src/libstd/sys/windows/fs.rs b/src/libstd/sys/windows/fs.rs
index 03a56e2958a6e..4401a52d71fff 100644
--- a/src/libstd/sys/windows/fs.rs
+++ b/src/libstd/sys/windows/fs.rs
@@ -158,17 +158,17 @@ impl OpenOptions {
     pub fn append(&mut self, append: bool) { self.append = append; }
     pub fn create(&mut self, create: bool) { self.create = create; }
     pub fn truncate(&mut self, truncate: bool) { self.truncate = truncate; }
-    pub fn creation_disposition(&mut self, val: i32) {
-        self.creation_disposition = Some(val as libc::DWORD);
+    pub fn creation_disposition(&mut self, val: u32) {
+        self.creation_disposition = Some(val);
     }
-    pub fn flags_and_attributes(&mut self, val: i32) {
-        self.flags_and_attributes = Some(val as libc::DWORD);
+    pub fn flags_and_attributes(&mut self, val: u32) {
+        self.flags_and_attributes = Some(val);
     }
-    pub fn desired_access(&mut self, val: i32) {
-        self.desired_access = Some(val as libc::DWORD);
+    pub fn desired_access(&mut self, val: u32) {
+        self.desired_access = Some(val);
     }
-    pub fn share_mode(&mut self, val: i32) {
-        self.share_mode = Some(val as libc::DWORD);
+    pub fn share_mode(&mut self, val: u32) {
+        self.share_mode = Some(val);
     }
     pub fn security_attributes(&mut self, attrs: libc::LPSECURITY_ATTRIBUTES) {
         self.security_attributes = attrs as usize;
@@ -221,7 +221,7 @@ impl File {
     fn open_reparse_point(path: &Path) -> io::Result<File> {
         let mut opts = OpenOptions::new();
         opts.read(true);
-        opts.flags_and_attributes(c::FILE_FLAG_OPEN_REPARSE_POINT as i32);
+        opts.flags_and_attributes(c::FILE_FLAG_OPEN_REPARSE_POINT);
         File::open(path, &opts)
     }