Seal all extension traits

library/std/src/ffi/os_str.rs

@@ -76,6 +76,10 @@ pub struct OsString {
     inner: Buf,
 }
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for OsString {}
+
 /// Borrowed reference to an OS string (see [`OsString`]).
 ///
 /// This type represents a borrowed reference to a string in the operating system's preferred
@@ -100,6 +104,10 @@ pub struct OsStr {
     inner: Slice,
 }
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for OsStr {}
+
 impl OsString {
     /// Constructs a new empty `OsString`.
     ///

library/std/src/fs.rs

@@ -92,6 +92,10 @@ pub struct File {
     inner: fs_imp::File,
 }
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for File {}
+
 /// Metadata information about a file.
 ///
 /// This structure is returned from the [`metadata`] or
@@ -102,6 +106,10 @@ pub struct File {
 #[derive(Clone)]
 pub struct Metadata(fs_imp::FileAttr);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for Metadata {}
+
 /// Iterator over the entries in a directory.
 ///
 /// This iterator is returned from the [`read_dir`] function of this module and
@@ -128,6 +136,10 @@ pub struct ReadDir(fs_imp::ReadDir);
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct DirEntry(fs_imp::DirEntry);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for DirEntry {}
+
 /// Options and flags which can be used to configure how a file is opened.
 ///
 /// This builder exposes the ability to configure how a [`File`] is opened and
@@ -167,6 +179,10 @@ pub struct DirEntry(fs_imp::DirEntry);
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct OpenOptions(fs_imp::OpenOptions);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for OpenOptions {}
+
 /// Representation of the various permissions on a file.
 ///
 /// This module only currently provides one bit of information,
@@ -179,12 +195,20 @@ pub struct OpenOptions(fs_imp::OpenOptions);
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Permissions(fs_imp::FilePermissions);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for Permissions {}
+
 /// A structure representing a type of file with accessors for each file type.
 /// It is returned by [`Metadata::file_type`] method.
 #[stable(feature = "file_type", since = "1.1.0")]
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct FileType(fs_imp::FileType);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for FileType {}
+
 /// A builder used to create directories in various manners.
 ///
 /// This builder also supports platform-specific options.
@@ -195,6 +219,10 @@ pub struct DirBuilder {
     recursive: bool,
 }
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for DirBuilder {}
+
 /// Indicates how large a buffer to pre-allocate before reading the entire file.
 fn initial_buffer_size(file: &File) -> usize {
     // Allocate one extra byte so the buffer doesn't need to grow before the

library/std/src/lib.rs

@@ -579,3 +579,11 @@ include!("keyword_docs.rs");
 // is unconditional, so the unstable feature needs to be defined somewhere.
 #[unstable(feature = "restricted_std", issue = "none")]
 mod __restricted_std_workaround {}
+
+mod sealed {
+    /// This trait being unreachable from outside the crate
+    /// prevents outside implementations of our extension traits.
+    /// This allows adding more trait methods in the future.
+    #[unstable(feature = "sealed", issue = "none")]
+    pub trait Sealed {}
+}

library/std/src/os/android/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::android::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/dragonfly/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::dragonfly::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/emscripten/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::emscripten::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/freebsd/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::freebsd::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/fuchsia/fs.rs

@@ -1,13 +1,14 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 /// OS-specific extensions to [`fs::Metadata`].
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_dev(&self) -> u64;
     #[stable(feature = "metadata_ext2", since = "1.8.0")]

library/std/src/os/haiku/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::haiku::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/illumos/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::illumos::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/ios/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::ios::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/linux/fs.rs

@@ -3,6 +3,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -12,7 +13,7 @@ use crate::os::linux::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/macos/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::macos::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/netbsd/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::netbsd::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/openbsd/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::openbsd::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/redox/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::redox::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/solaris/fs.rs

@@ -1,6 +1,7 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 #[allow(deprecated)]
@@ -10,7 +11,7 @@ use crate::os::solaris::raw;
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     /// Gain a reference to the underlying `stat` structure which contains
     /// the raw information returned by the OS.
     ///

library/std/src/os/vxworks/fs.rs

@@ -1,12 +1,13 @@
 #![stable(feature = "metadata_ext", since = "1.1.0")]
 
 use crate::fs::Metadata;
+use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
 
 ///
 /// [`fs::Metadata`]: crate::fs::Metadata
 #[stable(feature = "metadata_ext", since = "1.1.0")]
-pub trait MetadataExt {
+pub trait MetadataExt: Sealed {
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_dev(&self) -> u64;
     #[stable(feature = "metadata_ext2", since = "1.8.0")]

library/std/src/process.rs

@@ -498,6 +498,10 @@ pub struct Command {
     inner: imp::Command,
 }
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for Command {}
+
 impl Command {
     /// Constructs a new `Command` for launching the program at
     /// path `program`, with the following default configuration:
@@ -1375,6 +1379,10 @@ impl From<fs::File> for Stdio {
 #[stable(feature = "process", since = "1.0.0")]
 pub struct ExitStatus(imp::ExitStatus);
 
+/// Allows extension traits within `std`.
+#[unstable(feature = "sealed", issue = "none")]
+impl crate::sealed::Sealed for ExitStatus {}
+
 impl ExitStatus {
     /// Was termination successful? Signal termination is not considered a
     /// success, and success is defined as a zero exit status.