diff --git a/cap-async-std/src/fs/mod.rs b/cap-async-std/src/fs/mod.rs
index 1b693128..b04c5bce 100644
--- a/cap-async-std/src/fs/mod.rs
+++ b/cap-async-std/src/fs/mod.rs
@@ -40,6 +40,9 @@ pub use cap_primitives::fs::{DirBuilder, FileType, Metadata, OpenOptions, Permis
 // Re-export conditional types from `cap_primitives`.
 #[cfg(any(unix, target_os = "vxworks", all(windows, windows_file_type_ext)))]
 pub use cap_primitives::fs::FileTypeExt;
+pub use cap_primitives::fs::MetadataExt;
+#[cfg(unix)]
+pub use cap_primitives::fs::PermissionsExt;
 
 // Re-export things from `async_std` that we can use as-is.
 #[cfg(target_os = "wasi")]
diff --git a/cap-async-std/src/fs_utf8/mod.rs b/cap-async-std/src/fs_utf8/mod.rs
index 7c3c4a6e..c656ee5e 100644
--- a/cap-async-std/src/fs_utf8/mod.rs
+++ b/cap-async-std/src/fs_utf8/mod.rs
@@ -25,6 +25,9 @@ pub use crate::fs::{DirBuilder, FileType, Metadata, OpenOptions, Permissions};
 // Re-export conditional types from `cap_primitives`.
 #[cfg(any(unix, target_os = "vxworks", all(windows, windows_file_type_ext)))]
 pub use cap_primitives::fs::FileTypeExt;
+pub use cap_primitives::fs::MetadataExt;
+#[cfg(unix)]
+pub use cap_primitives::fs::PermissionsExt;
 
 // Re-export `camino` to make it easy for users to depend on the same
 // version we do, because we use its types in our public API.
diff --git a/cap-fs-ext/build.rs b/cap-fs-ext/build.rs
index 6e8f4d3f..5ea6ad2d 100644
--- a/cap-fs-ext/build.rs
+++ b/cap-fs-ext/build.rs
@@ -21,20 +21,60 @@ fn use_feature(feature: &str) {
 
 /// Test whether the rustc at `var("RUSTC")` supports the given feature.
 fn has_feature(feature: &str) -> bool {
+    can_compile(&format!(
+        "#![allow(stable_features)]\n#![feature({})]",
+        feature
+    ))
+}
+
+/// Test whether the rustc at `var("RUSTC")` can compile the given code.
+fn can_compile<T: AsRef<str>>(test: T) -> bool {
+    use std::process::Stdio;
+
     let out_dir = var("OUT_DIR").unwrap();
     let rustc = var("RUSTC").unwrap();
+    let target = var("TARGET").unwrap();
+
+    // Use `RUSTC_WRAPPER` if it's set, unless it's set to an empty string,
+    // as documented [here].
+    // [here]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-reads
+    let wrapper = var("RUSTC_WRAPPER")
+        .ok()
+        .and_then(|w| if w.is_empty() { None } else { Some(w) });
 
-    let mut child = std::process::Command::new(rustc)
-        .arg("--crate-type=rlib") // Don't require `main`.
+    let mut cmd = if let Some(wrapper) = wrapper {
+        let mut cmd = std::process::Command::new(wrapper);
+        // The wrapper's first argument is supposed to be the path to rustc.
+        cmd.arg(rustc);
+        cmd
+    } else {
+        std::process::Command::new(rustc)
+    };
+
+    cmd.arg("--crate-type=rlib") // Don't require `main`.
         .arg("--emit=metadata") // Do as little as possible but still parse.
+        .arg("--target")
+        .arg(target)
         .arg("--out-dir")
-        .arg(out_dir) // Put the output somewhere inconsequential.
+        .arg(out_dir); // Put the output somewhere inconsequential.
+
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
+    }
+
+    let mut child = cmd
         .arg("-") // Read from stdin.
-        .stdin(std::process::Stdio::piped()) // Stdin is a pipe.
+        .stdin(Stdio::piped()) // Stdin is a pipe.
+        .stderr(Stdio::null()) // Errors from feature detection aren't interesting and can be confusing.
         .spawn()
         .unwrap();
 
-    writeln!(child.stdin.take().unwrap(), "#![feature({})]", feature).unwrap();
+    writeln!(child.stdin.take().unwrap(), "{}", test.as_ref()).unwrap();
 
     child.wait().unwrap().success()
 }
diff --git a/cap-fs-ext/src/metadata_ext.rs b/cap-fs-ext/src/metadata_ext.rs
index 44c74a1e..fbacfcf7 100644
--- a/cap-fs-ext/src/metadata_ext.rs
+++ b/cap-fs-ext/src/metadata_ext.rs
@@ -75,17 +75,17 @@ impl MetadataExt for std::fs::Metadata {
 impl MetadataExt for cap_primitives::fs::Metadata {
     #[inline]
     fn dev(&self) -> u64 {
-        std::os::unix::fs::MetadataExt::dev(self)
+        cap_primitives::fs::MetadataExt::dev(self)
     }
 
     #[inline]
     fn ino(&self) -> u64 {
-        std::os::unix::fs::MetadataExt::ino(self)
+        cap_primitives::fs::MetadataExt::ino(self)
     }
 
     #[inline]
     fn nlink(&self) -> u64 {
-        std::os::unix::fs::MetadataExt::nlink(self)
+        cap_primitives::fs::MetadataExt::nlink(self)
     }
 }
 
diff --git a/cap-primitives/build.rs b/cap-primitives/build.rs
index 966799b5..7fbba9a5 100644
--- a/cap-primitives/build.rs
+++ b/cap-primitives/build.rs
@@ -25,20 +25,60 @@ fn use_feature(feature: &str) {
 
 /// Test whether the rustc at `var("RUSTC")` supports the given feature.
 fn has_feature(feature: &str) -> bool {
+    can_compile(&format!(
+        "#![allow(stable_features)]\n#![feature({})]",
+        feature
+    ))
+}
+
+/// Test whether the rustc at `var("RUSTC")` can compile the given code.
+fn can_compile<T: AsRef<str>>(test: T) -> bool {
+    use std::process::Stdio;
+
     let out_dir = var("OUT_DIR").unwrap();
     let rustc = var("RUSTC").unwrap();
+    let target = var("TARGET").unwrap();
+
+    // Use `RUSTC_WRAPPER` if it's set, unless it's set to an empty string,
+    // as documented [here].
+    // [here]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-reads
+    let wrapper = var("RUSTC_WRAPPER")
+        .ok()
+        .and_then(|w| if w.is_empty() { None } else { Some(w) });
 
-    let mut child = std::process::Command::new(rustc)
-        .arg("--crate-type=rlib") // Don't require `main`.
+    let mut cmd = if let Some(wrapper) = wrapper {
+        let mut cmd = std::process::Command::new(wrapper);
+        // The wrapper's first argument is supposed to be the path to rustc.
+        cmd.arg(rustc);
+        cmd
+    } else {
+        std::process::Command::new(rustc)
+    };
+
+    cmd.arg("--crate-type=rlib") // Don't require `main`.
         .arg("--emit=metadata") // Do as little as possible but still parse.
+        .arg("--target")
+        .arg(target)
         .arg("--out-dir")
-        .arg(out_dir) // Put the output somewhere inconsequential.
+        .arg(out_dir); // Put the output somewhere inconsequential.
+
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
+    }
+
+    let mut child = cmd
         .arg("-") // Read from stdin.
-        .stdin(std::process::Stdio::piped()) // Stdin is a pipe.
+        .stdin(Stdio::piped()) // Stdin is a pipe.
+        .stderr(Stdio::null()) // Errors from feature detection aren't interesting and can be confusing.
         .spawn()
         .unwrap();
 
-    writeln!(child.stdin.take().unwrap(), "#![feature({})]", feature).unwrap();
+    writeln!(child.stdin.take().unwrap(), "{}", test.as_ref()).unwrap();
 
     child.wait().unwrap().success()
 }
diff --git a/cap-primitives/src/fs/metadata.rs b/cap-primitives/src/fs/metadata.rs
index afcda83d..ed214e2a 100644
--- a/cap-primitives/src/fs/metadata.rs
+++ b/cap-primitives/src/fs/metadata.rs
@@ -1,4 +1,4 @@
-use crate::fs::{FileType, ImplFileTypeExt, MetadataExt, Permissions};
+use crate::fs::{FileType, ImplFileTypeExt, ImplMetadataExt, Permissions};
 use crate::time::SystemTime;
 use std::{fs, io};
 
@@ -18,7 +18,7 @@ pub struct Metadata {
     pub(crate) modified: Option<SystemTime>,
     pub(crate) accessed: Option<SystemTime>,
     pub(crate) created: Option<SystemTime>,
-    pub(crate) ext: MetadataExt,
+    pub(crate) ext: ImplMetadataExt,
 }
 
 #[allow(clippy::len_without_is_empty)]
@@ -27,7 +27,7 @@ impl Metadata {
     #[inline]
     pub fn from_file(file: &fs::File) -> io::Result<Self> {
         let std = file.metadata()?;
-        let ext = MetadataExt::from(file, &std)?;
+        let ext = ImplMetadataExt::from(file, &std)?;
         let file_type = ImplFileTypeExt::from(file, &std)?;
         Ok(Self::from_parts(std, ext, file_type))
     }
@@ -41,13 +41,13 @@ impl Metadata {
     /// [`std::fs::Metadata::volume_serial_number`]: https://doc.rust-lang.org/std/os/windows/fs/trait.MetadataExt.html#tymethod.volume_serial_number
     #[inline]
     pub fn from_just_metadata(std: fs::Metadata) -> Self {
-        let ext = MetadataExt::from_just_metadata(&std);
+        let ext = ImplMetadataExt::from_just_metadata(&std);
         let file_type = ImplFileTypeExt::from_just_metadata(&std);
         Self::from_parts(std, ext, file_type)
     }
 
     #[inline]
-    fn from_parts(std: fs::Metadata, ext: MetadataExt, file_type: FileType) -> Self {
+    fn from_parts(std: fs::Metadata, ext: ImplMetadataExt, file_type: FileType) -> Self {
         Self {
             file_type,
             len: std.len(),
@@ -198,129 +198,215 @@ impl Metadata {
     }
 }
 
+/// Unix-specific extensions for [`MetadataExt`].
+///
+/// This corresponds to [`std::os::unix::fs::MetadataExt`].
+#[cfg(any(unix, target_os = "vxworks"))]
+pub trait MetadataExt {
+    /// Returns the ID of the device containing the file.
+    fn dev(&self) -> u64;
+    /// Returns the inode number.
+    fn ino(&self) -> u64;
+    /// Returns the rights applied to this file.
+    fn mode(&self) -> u32;
+    /// Returns the number of hard links pointing to this file.
+    fn nlink(&self) -> u64;
+    /// Returns the user ID of the owner of this file.
+    fn uid(&self) -> u32;
+    /// Returns the group ID of the owner of this file.
+    fn gid(&self) -> u32;
+    /// Returns the device ID of this file (if it is a special one).
+    fn rdev(&self) -> u64;
+    /// Returns the total size of this file in bytes.
+    fn size(&self) -> u64;
+    /// Returns the last access time of the file, in seconds since Unix Epoch.
+    fn atime(&self) -> i64;
+    /// Returns the last access time of the file, in nanoseconds since [`atime`].
+    fn atime_nsec(&self) -> i64;
+    /// Returns the last modification time of the file, in seconds since Unix Epoch.
+    fn mtime(&self) -> i64;
+    /// Returns the last modification time of the file, in nanoseconds since [`mtime`].
+    fn mtime_nsec(&self) -> i64;
+    /// Returns the last status change time of the file, in seconds since Unix Epoch.
+    fn ctime(&self) -> i64;
+    /// Returns the last status change time of the file, in nanoseconds since [`ctime`].
+    fn ctime_nsec(&self) -> i64;
+    /// Returns the block size for filesystem I/O.
+    fn blksize(&self) -> u64;
+    /// Returns the number of blocks allocated to the file, in 512-byte units.
+    fn blocks(&self) -> u64;
+    #[cfg(target_os = "vxworks")]
+    fn attrib(&self) -> u8;
+}
+
+/// WASI-specific extensions for [`MetadataExt`].
+///
+/// This corresponds to [`std::os::wasi::fs::MetadataExt`].
+#[cfg(target_os = "wasi")]
+pub trait MetadataExt {
+    /// Returns the ID of the device containing the file.
+    fn dev(&self) -> u64;
+    /// Returns the inode number.
+    fn ino(&self) -> u64;
+    /// Returns the number of hard links pointing to this file.
+    fn nlink(&self) -> u64;
+    /// Returns the total size of this file in bytes.
+    fn size(&self) -> u64;
+    /// Returns the last access time of the file, in seconds since Unix Epoch.
+    fn atim(&self) -> u64;
+    /// Returns the last modification time of the file, in seconds since Unix Epoch.
+    fn mtim(&self) -> u64;
+    /// Returns the last status change time of the file, in seconds since Unix Epoch.
+    fn ctim(&self) -> u64;
+}
+
+/// Windows-specific extensions to [`Metadata`].
+#[cfg(windows)]
+pub trait MetadataExt {
+    /// Returns the value of the `dwFileAttributes` field of this metadata.
+    fn file_attributes(&self) -> u32;
+    /// Returns the value of the `ftCreationTime` field of this metadata.
+    fn creation_time(&self) -> u64;
+    /// Returns the value of the `ftLastAccessTime` field of this metadata.
+    fn last_access_time(&self) -> u64;
+    /// Returns the value of the `ftLastWriteTime` field of this metadata.
+    fn last_write_time(&self) -> u64;
+    /// Returns the value of the `nFileSize{High,Low}` fields of this metadata.
+    fn file_size(&self) -> u64;
+    /// Returns the value of the `dwVolumeSerialNumber` field of this metadata.
+    #[cfg(windows_by_handle)]
+    fn volume_serial_number(&self) -> Option<u32>;
+    /// Returns the value of the `nNumberOfLinks` field of this metadata.
+    #[cfg(windows_by_handle)]
+    fn number_of_links(&self) -> Option<u32>;
+    /// Returns the value of the `nFileIndex{Low,High}` fields of this metadata.
+    #[cfg(windows_by_handle)]
+    fn file_index(&self) -> Option<u64>;
+}
+
 #[cfg(unix)]
-impl std::os::unix::fs::MetadataExt for Metadata {
+impl MetadataExt for Metadata {
     #[inline]
     fn dev(&self) -> u64 {
-        self.ext.dev()
+        crate::fs::MetadataExt::dev(&self.ext)
     }
 
     #[inline]
     fn ino(&self) -> u64 {
-        self.ext.ino()
+        crate::fs::MetadataExt::ino(&self.ext)
     }
 
     #[inline]
     fn mode(&self) -> u32 {
-        self.ext.mode()
+        crate::fs::MetadataExt::mode(&self.ext)
     }
 
     #[inline]
     fn nlink(&self) -> u64 {
-        self.ext.nlink()
+        crate::fs::MetadataExt::nlink(&self.ext)
     }
 
     #[inline]
     fn uid(&self) -> u32 {
-        self.ext.uid()
+        crate::fs::MetadataExt::uid(&self.ext)
     }
 
     #[inline]
     fn gid(&self) -> u32 {
-        self.ext.gid()
+        crate::fs::MetadataExt::gid(&self.ext)
     }
 
     #[inline]
     fn rdev(&self) -> u64 {
-        self.ext.rdev()
+        crate::fs::MetadataExt::rdev(&self.ext)
     }
 
     #[inline]
     fn size(&self) -> u64 {
-        self.ext.size()
+        crate::fs::MetadataExt::size(&self.ext)
     }
 
     #[inline]
     fn atime(&self) -> i64 {
-        self.ext.atime()
+        crate::fs::MetadataExt::atime(&self.ext)
     }
 
     #[inline]
     fn atime_nsec(&self) -> i64 {
-        self.ext.atime_nsec()
+        crate::fs::MetadataExt::atime_nsec(&self.ext)
     }
 
     #[inline]
     fn mtime(&self) -> i64 {
-        self.ext.mtime()
+        crate::fs::MetadataExt::mtime(&self.ext)
     }
 
     #[inline]
     fn mtime_nsec(&self) -> i64 {
-        self.ext.mtime_nsec()
+        crate::fs::MetadataExt::mtime_nsec(&self.ext)
     }
 
     #[inline]
     fn ctime(&self) -> i64 {
-        self.ext.ctime()
+        crate::fs::MetadataExt::ctime(&self.ext)
     }
 
     #[inline]
     fn ctime_nsec(&self) -> i64 {
-        self.ext.ctime_nsec()
+        crate::fs::MetadataExt::ctime_nsec(&self.ext)
     }
 
     #[inline]
     fn blksize(&self) -> u64 {
-        self.ext.blksize()
+        crate::fs::MetadataExt::blksize(&self.ext)
     }
 
     #[inline]
     fn blocks(&self) -> u64 {
-        self.ext.blocks()
+        crate::fs::MetadataExt::blocks(&self.ext)
     }
 }
 
 #[cfg(target_os = "wasi")]
-impl std::os::wasi::fs::MetadataExt for Metadata {
+impl MetadataExt for Metadata {
     #[inline]
     fn dev(&self) -> u64 {
-        self.ext.dev()
+        crate::fs::MetadataExt::dev(&self.ext)
     }
 
     #[inline]
     fn ino(&self) -> u64 {
-        self.ext.ino()
+        crate::fs::MetadataExt::ino(&self.ext)
     }
 
     #[inline]
     fn nlink(&self) -> u64 {
-        self.ext.nlink()
+        crate::fs::MetadataExt::nlink(&self.ext)
     }
 
     #[inline]
     fn size(&self) -> u64 {
-        self.ext.size()
+        crate::fs::MetadataExt::size(&self.ext)
     }
 
     #[inline]
     fn atim(&self) -> u64 {
-        self.ext.atim()
+        crate::fs::MetadataExt::atim(&self.ext)
     }
 
     #[inline]
     fn mtim(&self) -> u64 {
-        self.ext.mtim()
+        crate::fs::MetadataExt::mtim(&self.ext)
     }
 
     #[inline]
     fn ctim(&self) -> u64 {
-        self.ext.ctim()
+        crate::fs::MetadataExt::ctim(&self.ext)
     }
 }
 
 #[cfg(target_os = "vxworks")]
-impl std::os::vxworks::fs::MetadataExt for Metadata {
+impl MetadataExt for Metadata {
     #[inline]
     fn dev(&self) -> u64 {
         self.ext.dev()
@@ -402,8 +488,8 @@ impl std::os::vxworks::fs::MetadataExt for Metadata {
     }
 }
 
-#[cfg(all(windows, windows_by_handle))]
-impl std::os::windows::fs::MetadataExt for Metadata {
+#[cfg(windows)]
+impl MetadataExt for Metadata {
     #[inline]
     fn file_attributes(&self) -> u32 {
         self.ext.file_attributes()
@@ -430,16 +516,19 @@ impl std::os::windows::fs::MetadataExt for Metadata {
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn volume_serial_number(&self) -> Option<u32> {
         self.ext.volume_serial_number()
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn number_of_links(&self) -> Option<u32> {
         self.ext.number_of_links()
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn file_index(&self) -> Option<u64> {
         self.ext.file_index()
     }
diff --git a/cap-primitives/src/fs/mod.rs b/cap-primitives/src/fs/mod.rs
index 09050d9b..63a6cf41 100644
--- a/cap-primitives/src/fs/mod.rs
+++ b/cap-primitives/src/fs/mod.rs
@@ -75,14 +75,16 @@ pub use file_type::_WindowsFileTypeExt;
 pub use follow_symlinks::FollowSymlinks;
 pub use hard_link::hard_link;
 pub use is_file_read_write::is_file_read_write;
-pub use metadata::Metadata;
 #[cfg(windows)]
 pub use metadata::_WindowsByHandle;
+pub use metadata::{Metadata, MetadataExt};
 pub use open::open;
 pub use open_ambient::open_ambient;
 pub use open_dir::*;
 pub use open_options::OpenOptions;
 pub use permissions::Permissions;
+#[cfg(unix)]
+pub use permissions::PermissionsExt;
 pub use read_dir::{read_base_dir, read_dir, ReadDir};
 pub use read_link::{read_link, read_link_contents};
 pub use remove_dir::remove_dir;
diff --git a/cap-primitives/src/fs/permissions.rs b/cap-primitives/src/fs/permissions.rs
index be356b68..eefaae66 100644
--- a/cap-primitives/src/fs/permissions.rs
+++ b/cap-primitives/src/fs/permissions.rs
@@ -1,5 +1,5 @@
 #[cfg(not(windows))]
-use crate::fs::PermissionsExt;
+use crate::fs::ImplPermissionsExt;
 #[cfg(unix)]
 use rustix::fs::RawMode;
 use std::{fs, io};
@@ -17,7 +17,7 @@ pub struct Permissions {
     pub(crate) readonly: bool,
 
     #[cfg(any(unix, target_os = "vxworks"))]
-    pub(crate) ext: PermissionsExt,
+    pub(crate) ext: ImplPermissionsExt,
 }
 
 impl Permissions {
@@ -29,7 +29,7 @@ impl Permissions {
             readonly: std.readonly(),
 
             #[cfg(any(unix, target_os = "vxworks"))]
-            ext: PermissionsExt::from_std(std),
+            ext: ImplPermissionsExt::from_std(std),
         }
     }
 
@@ -90,29 +90,44 @@ impl Permissions {
     }
 }
 
+/// Unix-specific extensions to [`Permissions`].
 #[cfg(unix)]
-impl std::os::unix::fs::PermissionsExt for Permissions {
+pub trait PermissionsExt {
+    /// Returns the underlying raw `st_mode` bits that contain the standard
+    /// Unix permissions for this file.
+    fn mode(&self) -> u32;
+
+    /// Sets the underlying raw bits for this set of permissions.
+    fn set_mode(&mut self, mode: u32);
+
+    /// Creates a new instance of `Permissions` from the given set of Unix
+    /// permission bits.
+    fn from_mode(mode: u32) -> Self;
+}
+
+#[cfg(unix)]
+impl PermissionsExt for Permissions {
     #[inline]
     fn mode(&self) -> u32 {
-        self.ext.mode()
+        std::os::unix::fs::PermissionsExt::mode(&self.ext)
     }
 
     #[inline]
     fn set_mode(&mut self, mode: u32) {
-        self.ext.set_mode(mode)
+        std::os::unix::fs::PermissionsExt::set_mode(&mut self.ext, mode)
     }
 
     #[inline]
     fn from_mode(mode: u32) -> Self {
         Self {
-            readonly: PermissionsExt::readonly(mode as RawMode),
-            ext: PermissionsExt::from_mode(mode),
+            readonly: ImplPermissionsExt::readonly(mode as RawMode),
+            ext: std::os::unix::fs::PermissionsExt::from_mode(mode),
         }
     }
 }
 
 #[cfg(target_os = "vxworks")]
-impl std::os::unix::fs::PermissionsExt for Permissions {
+impl PermissionsExt for Permissions {
     #[inline]
     fn mode(&self) -> u32 {
         self.ext.mode()
@@ -126,8 +141,8 @@ impl std::os::unix::fs::PermissionsExt for Permissions {
     #[inline]
     fn from_mode(mode: u32) -> Self {
         Self {
-            readonly: PermissionsExt::readonly(mode),
-            ext: PermissionsExt::from(mode),
+            readonly: ImplPermissionsExt::readonly(mode),
+            ext: ImplPermissionsExt::from(mode),
         }
     }
 }
diff --git a/cap-primitives/src/rustix/freebsd/fs/set_permissions_impl.rs b/cap-primitives/src/rustix/freebsd/fs/set_permissions_impl.rs
index 9df0a752..ab9bc311 100644
--- a/cap-primitives/src/rustix/freebsd/fs/set_permissions_impl.rs
+++ b/cap-primitives/src/rustix/freebsd/fs/set_permissions_impl.rs
@@ -1,6 +1,5 @@
-use crate::fs::Permissions;
+use crate::fs::{Permissions, PermissionsExt};
 use rustix::fs::{chmodat, AtFlags, Mode};
-use std::os::unix::fs::PermissionsExt;
 use std::path::Path;
 use std::{fs, io};
 
diff --git a/cap-primitives/src/rustix/freebsd/fs/stat_impl.rs b/cap-primitives/src/rustix/freebsd/fs/stat_impl.rs
index 3a7620cb..aa4bbe65 100644
--- a/cap-primitives/src/rustix/freebsd/fs/stat_impl.rs
+++ b/cap-primitives/src/rustix/freebsd/fs/stat_impl.rs
@@ -1,4 +1,4 @@
-use crate::fs::{manually, FollowSymlinks, Metadata, MetadataExt};
+use crate::fs::{manually, FollowSymlinks, ImplMetadataExt, Metadata};
 use rustix::fs::{statat, AtFlags};
 use std::path::Path;
 use std::{fs, io};
@@ -18,5 +18,5 @@ pub(crate) fn stat_impl(
         } else {
             AtFlags::SYMLINK_NOFOLLOW
         };
-    Ok(MetadataExt::from_rustix(statat(start, path, flags)?))
+    Ok(ImplMetadataExt::from_rustix(statat(start, path, flags)?))
 }
diff --git a/cap-primitives/src/rustix/fs/dir_entry_inner.rs b/cap-primitives/src/rustix/fs/dir_entry_inner.rs
index cba5238e..35923880 100644
--- a/cap-primitives/src/rustix/fs/dir_entry_inner.rs
+++ b/cap-primitives/src/rustix/fs/dir_entry_inner.rs
@@ -1,12 +1,13 @@
 use crate::fs::{
-    FileType, FollowSymlinks, ImplFileTypeExt, Metadata, OpenOptions, ReadDir, ReadDirInner,
+    FileType, FollowSymlinks, ImplFileTypeExt, Metadata, MetadataExt, OpenOptions, ReadDir,
+    ReadDirInner,
 };
 use rustix::fs::DirEntry;
 use std::ffi::{OsStr, OsString};
 #[cfg(unix)]
-use std::os::unix::{ffi::OsStrExt, fs::MetadataExt};
+use std::os::unix::ffi::OsStrExt;
 #[cfg(target_os = "wasi")]
-use std::os::wasi::{ffi::OsStrExt, fs::MetadataExt};
+use std::os::wasi::ffi::OsStrExt;
 use std::{fmt, fs, io};
 
 pub(crate) struct DirEntryInner {
diff --git a/cap-primitives/src/rustix/fs/is_same_file.rs b/cap-primitives/src/rustix/fs/is_same_file.rs
index 382e436b..c6acf9ca 100644
--- a/cap-primitives/src/rustix/fs/is_same_file.rs
+++ b/cap-primitives/src/rustix/fs/is_same_file.rs
@@ -1,5 +1,4 @@
-use crate::fs::Metadata;
-use rustix::fs::MetadataExt;
+use crate::fs::{Metadata, MetadataExt};
 use std::{fs, io};
 
 /// Determine if `a` and `b` refer to the same inode on the same device.
diff --git a/cap-primitives/src/rustix/fs/metadata_ext.rs b/cap-primitives/src/rustix/fs/metadata_ext.rs
index 7091017e..0cd9de03 100644
--- a/cap-primitives/src/rustix/fs/metadata_ext.rs
+++ b/cap-primitives/src/rustix/fs/metadata_ext.rs
@@ -1,6 +1,6 @@
 #![allow(clippy::useless_conversion)]
 
-use crate::fs::{ImplFileTypeExt, Metadata, PermissionsExt};
+use crate::fs::{ImplFileTypeExt, ImplPermissionsExt, Metadata};
 use crate::time::{Duration, SystemClock, SystemTime};
 #[cfg(target_os = "linux")]
 use rustix::fs::{makedev, Statx, StatxFlags};
@@ -8,7 +8,7 @@ use rustix::fs::{RawMode, Stat};
 use std::{fs, io};
 
 #[derive(Debug, Clone)]
-pub(crate) struct MetadataExt {
+pub(crate) struct ImplMetadataExt {
     dev: u64,
     ino: u64,
     #[cfg(not(target_os = "wasi"))]
@@ -45,7 +45,7 @@ pub(crate) struct MetadataExt {
     ctim: u64,
 }
 
-impl MetadataExt {
+impl ImplMetadataExt {
     /// Constructs a new instance of `Self` from the given [`std::fs::File`]
     /// and [`std::fs::Metadata`].
     #[inline]
@@ -106,9 +106,9 @@ impl MetadataExt {
             file_type: ImplFileTypeExt::from_raw_mode(stat.st_mode as RawMode),
             len: u64::try_from(stat.st_size).unwrap(),
             #[cfg(not(target_os = "wasi"))]
-            permissions: PermissionsExt::from_raw_mode(stat.st_mode as RawMode),
+            permissions: ImplPermissionsExt::from_raw_mode(stat.st_mode as RawMode),
             #[cfg(target_os = "wasi")]
-            permissions: PermissionsExt::default(),
+            permissions: ImplPermissionsExt::default(),
 
             #[cfg(not(any(target_os = "netbsd", target_os = "wasi")))]
             modified: system_time_from_rustix(
@@ -238,7 +238,7 @@ impl MetadataExt {
         Metadata {
             file_type: ImplFileTypeExt::from_raw_mode(RawMode::from(statx.stx_mode)),
             len: u64::try_from(statx.stx_size).unwrap(),
-            permissions: PermissionsExt::from_raw_mode(RawMode::from(statx.stx_mode)),
+            permissions: ImplPermissionsExt::from_raw_mode(RawMode::from(statx.stx_mode)),
             modified: if statx.stx_mask & StatxFlags::MTIME.bits() != 0 {
                 system_time_from_rustix(statx.stx_mtime.tv_sec, statx.stx_mtime.tv_nsec as _)
             } else {
@@ -295,7 +295,7 @@ fn system_time_from_rustix(sec: i64, nsec: u64) -> Option<SystemTime> {
     }
 }
 
-impl rustix::fs::MetadataExt for MetadataExt {
+impl crate::fs::MetadataExt for ImplMetadataExt {
     #[inline]
     fn dev(&self) -> u64 {
         self.dev
diff --git a/cap-primitives/src/rustix/fs/mod.rs b/cap-primitives/src/rustix/fs/mod.rs
index ac45f84a..1ef574b9 100644
--- a/cap-primitives/src/rustix/fs/mod.rs
+++ b/cap-primitives/src/rustix/fs/mod.rs
@@ -113,10 +113,10 @@ pub(crate) use is_file_read_write_impl::is_file_read_write_impl;
 pub(crate) use is_root_dir::is_root_dir;
 #[allow(unused_imports)]
 pub(crate) use is_same_file::{is_different_file, is_different_file_metadata, is_same_file};
-pub(crate) use metadata_ext::MetadataExt;
+pub(crate) use metadata_ext::ImplMetadataExt;
 pub(crate) use open_options_ext::OpenOptionsExt;
 pub(crate) use open_unchecked::{open_ambient_impl, open_unchecked};
-pub(crate) use permissions_ext::PermissionsExt;
+pub(crate) use permissions_ext::ImplPermissionsExt;
 pub(crate) use read_dir_inner::ReadDirInner;
 pub(crate) use read_link_unchecked::read_link_unchecked;
 pub(crate) use remove_dir_all_impl::{remove_dir_all_impl, remove_open_dir_all_impl};
diff --git a/cap-primitives/src/rustix/fs/permissions_ext.rs b/cap-primitives/src/rustix/fs/permissions_ext.rs
index a84ed905..4b6e04b4 100644
--- a/cap-primitives/src/rustix/fs/permissions_ext.rs
+++ b/cap-primitives/src/rustix/fs/permissions_ext.rs
@@ -3,13 +3,13 @@ use rustix::fs::RawMode;
 use std::fs;
 
 #[derive(Debug, Clone, Eq, PartialEq)]
-pub(crate) struct PermissionsExt {
+pub(crate) struct ImplPermissionsExt {
     #[cfg(not(target_os = "wasi"))]
     mode: RawMode,
 }
 
 #[cfg(not(target_os = "wasi"))]
-impl PermissionsExt {
+impl ImplPermissionsExt {
     /// Constructs a new instance of `Self` from the given
     /// [`std::fs::Permissions`].
     #[inline]
@@ -50,7 +50,7 @@ impl PermissionsExt {
 }
 
 #[cfg(not(target_os = "wasi"))]
-impl std::os::unix::fs::PermissionsExt for PermissionsExt {
+impl std::os::unix::fs::PermissionsExt for ImplPermissionsExt {
     fn mode(&self) -> u32 {
         self.mode as u32
     }
@@ -67,7 +67,7 @@ impl std::os::unix::fs::PermissionsExt for PermissionsExt {
 }
 
 #[cfg(target_os = "wasi")]
-impl PermissionsExt {
+impl ImplPermissionsExt {
     pub(crate) fn default() -> Permissions {
         Permissions { readonly: false }
     }
diff --git a/cap-primitives/src/rustix/fs/set_symlink_permissions_unchecked.rs b/cap-primitives/src/rustix/fs/set_symlink_permissions_unchecked.rs
index 4c5ff30a..fb3a8f02 100644
--- a/cap-primitives/src/rustix/fs/set_symlink_permissions_unchecked.rs
+++ b/cap-primitives/src/rustix/fs/set_symlink_permissions_unchecked.rs
@@ -1,7 +1,7 @@
 use crate::fs::Permissions;
-use rustix::fs::{chmodat, AtFlags, Mode};
 #[cfg(unix)]
-use std::os::unix::fs::PermissionsExt;
+use crate::fs::PermissionsExt;
+use rustix::fs::{chmodat, AtFlags, Mode};
 use std::path::Path;
 use std::{fs, io};
 
diff --git a/cap-primitives/src/rustix/fs/stat_unchecked.rs b/cap-primitives/src/rustix/fs/stat_unchecked.rs
index 6c35bd3f..f10b926b 100644
--- a/cap-primitives/src/rustix/fs/stat_unchecked.rs
+++ b/cap-primitives/src/rustix/fs/stat_unchecked.rs
@@ -1,4 +1,4 @@
-use crate::fs::{FollowSymlinks, Metadata, MetadataExt};
+use crate::fs::{FollowSymlinks, ImplMetadataExt, Metadata};
 use rustix::fs::{statat, AtFlags};
 use std::path::Path;
 use std::{fs, io};
@@ -50,7 +50,7 @@ pub(crate) fn stat_unchecked(
                     if state == 0 {
                         STATX_STATE.store(2, Ordering::Relaxed);
                     }
-                    return Ok(MetadataExt::from_rustix_statx(statx));
+                    return Ok(ImplMetadataExt::from_rustix_statx(statx));
                 }
                 Err(rustix::io::Errno::NOSYS) => STATX_STATE.store(1, Ordering::Relaxed),
                 Err(rustix::io::Errno::PERM) if state == 0 => {
@@ -75,5 +75,5 @@ pub(crate) fn stat_unchecked(
         }
     }
 
-    Ok(statat(start, path, atflags).map(MetadataExt::from_rustix)?)
+    Ok(statat(start, path, atflags).map(ImplMetadataExt::from_rustix)?)
 }
diff --git a/cap-primitives/src/rustix/linux/fs/file_metadata.rs b/cap-primitives/src/rustix/linux/fs/file_metadata.rs
index 3ad72a69..4f24a5dc 100644
--- a/cap-primitives/src/rustix/linux/fs/file_metadata.rs
+++ b/cap-primitives/src/rustix/linux/fs/file_metadata.rs
@@ -1,4 +1,4 @@
-use crate::fs::{Metadata, MetadataExt};
+use crate::fs::{ImplMetadataExt, Metadata};
 use rustix::fs::{statat, AtFlags};
 use std::sync::atomic::AtomicBool;
 use std::sync::atomic::Ordering::Relaxed;
@@ -23,5 +23,5 @@ pub(super) fn file_metadata(file: &fs::File) -> io::Result<Metadata> {
     }
 
     // If `fstat` with `O_PATH` isn't supported, use `statat` with `AT_EMPTY_PATH`.
-    Ok(statat(file, "", AtFlags::EMPTY_PATH).map(MetadataExt::from_rustix)?)
+    Ok(statat(file, "", AtFlags::EMPTY_PATH).map(ImplMetadataExt::from_rustix)?)
 }
diff --git a/cap-primitives/src/windows/fs/is_same_file.rs b/cap-primitives/src/windows/fs/is_same_file.rs
index 86a6d9eb..9bf7aba4 100644
--- a/cap-primitives/src/windows/fs/is_same_file.rs
+++ b/cap-primitives/src/windows/fs/is_same_file.rs
@@ -1,12 +1,12 @@
+use crate::fs::ImplMetadataExt;
 #[cfg(windows_by_handle)]
 use crate::fs::Metadata;
-use crate::fs::MetadataExt;
 use std::{fs, io};
 
 /// Determine if `a` and `b` refer to the same inode on the same device.
 pub(crate) fn is_same_file(a: &fs::File, b: &fs::File) -> io::Result<bool> {
-    let a_metadata = MetadataExt::from(a, &a.metadata()?)?;
-    let b_metadata = MetadataExt::from(b, &b.metadata()?)?;
+    let a_metadata = ImplMetadataExt::from(a, &a.metadata()?)?;
+    let b_metadata = ImplMetadataExt::from(b, &b.metadata()?)?;
     Ok(a_metadata.is_same_file(&b_metadata))
 }
 
@@ -15,7 +15,7 @@ pub(crate) fn is_same_file(a: &fs::File, b: &fs::File) -> io::Result<bool> {
 #[cfg(windows_by_handle)]
 #[allow(dead_code)]
 pub(crate) fn is_same_file_metadata(a: &Metadata, b: &Metadata) -> io::Result<bool> {
-    use std::os::windows::fs::MetadataExt;
+    use crate::fs::MetadataExt;
     Ok(a.volume_serial_number() == b.volume_serial_number() && a.file_index() == b.file_index())
 }
 
diff --git a/cap-primitives/src/windows/fs/metadata_ext.rs b/cap-primitives/src/windows/fs/metadata_ext.rs
index 64797c77..ed692855 100644
--- a/cap-primitives/src/windows/fs/metadata_ext.rs
+++ b/cap-primitives/src/windows/fs/metadata_ext.rs
@@ -1,24 +1,21 @@
 #![allow(clippy::useless_conversion)]
 
+use crate::fs::MetadataExt;
 use std::{fs, io};
 
 #[derive(Debug, Clone)]
-pub(crate) struct MetadataExt {
+pub(crate) struct ImplMetadataExt {
     file_attributes: u32,
-    #[cfg(windows_by_handle)]
     creation_time: u64,
-    #[cfg(windows_by_handle)]
     last_access_time: u64,
-    #[cfg(windows_by_handle)]
     last_write_time: u64,
-    #[cfg(windows_by_handle)]
     file_size: u64,
     volume_serial_number: Option<u32>,
     number_of_links: Option<u32>,
     file_index: Option<u64>,
 }
 
-impl MetadataExt {
+impl ImplMetadataExt {
     /// Constructs a new instance of `Self` from the given [`std::fs::File`]
     /// and [`std::fs::Metadata`].
     #[inline]
@@ -105,13 +102,9 @@ impl MetadataExt {
         use std::os::windows::fs::MetadataExt;
         Self {
             file_attributes: std.file_attributes(),
-            #[cfg(windows_by_handle)]
             creation_time: std.creation_time(),
-            #[cfg(windows_by_handle)]
             last_access_time: std.last_access_time(),
-            #[cfg(windows_by_handle)]
             last_write_time: std.last_write_time(),
-            #[cfg(windows_by_handle)]
             file_size: std.file_size(),
             volume_serial_number,
             number_of_links,
@@ -147,9 +140,7 @@ impl MetadataExt {
     }
 }
 
-#[cfg(windows_by_handle)]
-impl std::os::windows::fs::MetadataExt for MetadataExt {
-    #[inline]
+impl MetadataExt for ImplMetadataExt {
     fn file_attributes(&self) -> u32 {
         self.file_attributes
     }
@@ -175,16 +166,19 @@ impl std::os::windows::fs::MetadataExt for MetadataExt {
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn volume_serial_number(&self) -> Option<u32> {
         self.volume_serial_number
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn number_of_links(&self) -> Option<u32> {
         self.number_of_links
     }
 
     #[inline]
+    #[cfg(windows_by_handle)]
     fn file_index(&self) -> Option<u64> {
         self.file_index
     }
diff --git a/cap-std/build.rs b/cap-std/build.rs
index a11d1016..92d4b576 100644
--- a/cap-std/build.rs
+++ b/cap-std/build.rs
@@ -22,20 +22,60 @@ fn use_feature(feature: &str) {
 
 /// Test whether the rustc at `var("RUSTC")` supports the given feature.
 fn has_feature(feature: &str) -> bool {
+    can_compile(&format!(
+        "#![allow(stable_features)]\n#![feature({})]",
+        feature
+    ))
+}
+
+/// Test whether the rustc at `var("RUSTC")` can compile the given code.
+fn can_compile<T: AsRef<str>>(test: T) -> bool {
+    use std::process::Stdio;
+
     let out_dir = var("OUT_DIR").unwrap();
     let rustc = var("RUSTC").unwrap();
+    let target = var("TARGET").unwrap();
+
+    // Use `RUSTC_WRAPPER` if it's set, unless it's set to an empty string,
+    // as documented [here].
+    // [here]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-reads
+    let wrapper = var("RUSTC_WRAPPER")
+        .ok()
+        .and_then(|w| if w.is_empty() { None } else { Some(w) });
 
-    let mut child = std::process::Command::new(rustc)
-        .arg("--crate-type=rlib") // Don't require `main`.
+    let mut cmd = if let Some(wrapper) = wrapper {
+        let mut cmd = std::process::Command::new(wrapper);
+        // The wrapper's first argument is supposed to be the path to rustc.
+        cmd.arg(rustc);
+        cmd
+    } else {
+        std::process::Command::new(rustc)
+    };
+
+    cmd.arg("--crate-type=rlib") // Don't require `main`.
         .arg("--emit=metadata") // Do as little as possible but still parse.
+        .arg("--target")
+        .arg(target)
         .arg("--out-dir")
-        .arg(out_dir) // Put the output somewhere inconsequential.
+        .arg(out_dir); // Put the output somewhere inconsequential.
+
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
+    }
+
+    let mut child = cmd
         .arg("-") // Read from stdin.
-        .stdin(std::process::Stdio::piped()) // Stdin is a pipe.
+        .stdin(Stdio::piped()) // Stdin is a pipe.
+        .stderr(Stdio::null()) // Errors from feature detection aren't interesting and can be confusing.
         .spawn()
         .unwrap();
 
-    writeln!(child.stdin.take().unwrap(), "#![feature({})]", feature).unwrap();
+    writeln!(child.stdin.take().unwrap(), "{}", test.as_ref()).unwrap();
 
     child.wait().unwrap().success()
 }
diff --git a/cap-std/src/fs/mod.rs b/cap-std/src/fs/mod.rs
index 94883112..33c45682 100644
--- a/cap-std/src/fs/mod.rs
+++ b/cap-std/src/fs/mod.rs
@@ -38,3 +38,6 @@ pub use cap_primitives::fs::{DirBuilder, FileType, Metadata, OpenOptions, Permis
 // Re-export conditional types from `cap_primitives`.
 #[cfg(any(unix, target_os = "vxworks", all(windows, windows_file_type_ext)))]
 pub use cap_primitives::fs::FileTypeExt;
+pub use cap_primitives::fs::MetadataExt;
+#[cfg(unix)]
+pub use cap_primitives::fs::PermissionsExt;
diff --git a/cap-std/src/fs_utf8/mod.rs b/cap-std/src/fs_utf8/mod.rs
index c64220a6..996a7415 100644
--- a/cap-std/src/fs_utf8/mod.rs
+++ b/cap-std/src/fs_utf8/mod.rs
@@ -27,6 +27,9 @@ pub use crate::fs::{DirBuilder, FileType, Metadata, OpenOptions, Permissions};
 // Re-export conditional types from `cap_primitives`.
 #[cfg(any(unix, target_os = "vxworks", all(windows, windows_file_type_ext)))]
 pub use cap_primitives::fs::FileTypeExt;
+pub use cap_primitives::fs::MetadataExt;
+#[cfg(unix)]
+pub use cap_primitives::fs::PermissionsExt;
 
 // Re-export `camino` to make it easy for users to depend on the same
 // version we do, because we use its types in our public API.
diff --git a/cap-tempfile/src/tempfile.rs b/cap-tempfile/src/tempfile.rs
index 88da2247..6dbd2a2c 100644
--- a/cap-tempfile/src/tempfile.rs
+++ b/cap-tempfile/src/tempfile.rs
@@ -265,7 +265,8 @@ mod test {
         // Test that we created with the right permissions
         #[cfg(any(target_os = "android", target_os = "linux"))]
         {
-            use rustix::fs::{MetadataExt, Mode};
+            use cap_std::fs_utf8::MetadataExt;
+            use rustix::fs::Mode;
             let umask = get_process_umask()?;
             let metadata = tf.as_file().metadata().unwrap();
             let mode = metadata.mode();
diff --git a/tests/dir-entry-ext.rs b/tests/dir-entry-ext.rs
index 32a326d1..5b36b6a4 100644
--- a/tests/dir-entry-ext.rs
+++ b/tests/dir-entry-ext.rs
@@ -15,7 +15,7 @@ fn test_dir_entry_ext() {
     // First try with the regular `metadata()`. All nones.
     #[cfg(all(windows, windows_by_handle))]
     for entry in check!(tmpdir.entries()) {
-        use std::os::windows::fs::MetadataExt;
+        use cap_std::fs::MetadataExt;
         let entry = check!(entry);
         assert!(check!(entry.metadata()).volume_serial_number().is_none());
         assert!(check!(entry.metadata()).number_of_links().is_none());
diff --git a/tests/fs.rs b/tests/fs.rs
index 483ef0c9..e14b4f41 100644
--- a/tests/fs.rs
+++ b/tests/fs.rs
@@ -334,7 +334,7 @@ fn file_test_io_read_write_at() {
 #[cfg(unix)]
 #[cfg_attr(any(target_os = "macos", target_os = "ios"), ignore)]
 fn set_get_unix_permissions() {
-    use std::os::unix::fs::PermissionsExt;
+    use cap_std::fs::PermissionsExt;
 
     let tmpdir = tmpdir();
     let filename = "set_get_unix_permissions";
diff --git a/tests/fs_additional.rs b/tests/fs_additional.rs
index 06cefa80..65dd0b6d 100644
--- a/tests/fs_additional.rs
+++ b/tests/fs_additional.rs
@@ -967,7 +967,10 @@ fn check_metadata(std: &std::fs::Metadata, cap: &cap_std::fs::Metadata) {
     #[cfg(unix)]
     {
         use std::os::unix::fs::PermissionsExt;
-        assert_eq!(std.permissions().mode(), cap.permissions().mode());
+        assert_eq!(
+            std.permissions().mode(),
+            cap_std::fs::PermissionsExt::mode(&cap.permissions())
+        );
     }
 
     // If the standard library supports file modified/accessed/created times,
@@ -1022,28 +1025,28 @@ fn check_metadata(std: &std::fs::Metadata, cap: &cap_std::fs::Metadata) {
     #[cfg(unix)]
     {
         use std::os::unix::fs::MetadataExt;
-        assert_eq!(std.dev(), cap.dev());
-        assert_eq!(std.ino(), cap.ino());
-        assert_eq!(std.mode(), cap.mode());
-        assert_eq!(std.nlink(), cap.nlink());
-        assert_eq!(std.uid(), cap.uid());
-        assert_eq!(std.gid(), cap.gid());
-        assert_eq!(std.rdev(), cap.rdev());
-        assert_eq!(std.size(), cap.size());
+        assert_eq!(std.dev(), cap_std::fs::MetadataExt::dev(cap));
+        assert_eq!(std.ino(), cap_std::fs::MetadataExt::ino(cap));
+        assert_eq!(std.mode(), cap_std::fs::MetadataExt::mode(cap));
+        assert_eq!(std.nlink(), cap_std::fs::MetadataExt::nlink(cap));
+        assert_eq!(std.uid(), cap_std::fs::MetadataExt::uid(cap));
+        assert_eq!(std.gid(), cap_std::fs::MetadataExt::gid(cap));
+        assert_eq!(std.rdev(), cap_std::fs::MetadataExt::rdev(cap));
+        assert_eq!(std.size(), cap_std::fs::MetadataExt::size(cap));
         assert!(
             ((std.atime() - i64::from(ACCESS_TOLERANCE_SEC))
                 ..(std.atime() + i64::from(ACCESS_TOLERANCE_SEC)))
-                .contains(&cap.atime()),
+                .contains(&cap_std::fs::MetadataExt::atime(cap)),
             "std atime {}, cap atime {}",
             std.atime(),
-            cap.atime()
+            cap_std::fs::MetadataExt::atime(cap)
         );
-        assert!((0..1_000_000_000).contains(&cap.atime_nsec()));
-        assert_eq!(std.mtime(), cap.mtime());
-        assert_eq!(std.mtime_nsec(), cap.mtime_nsec());
-        assert_eq!(std.ctime(), cap.ctime());
-        assert_eq!(std.ctime_nsec(), cap.ctime_nsec());
-        assert_eq!(std.blksize(), cap.blksize());
-        assert_eq!(std.blocks(), cap.blocks());
+        assert!((0..1_000_000_000).contains(&cap_std::fs::MetadataExt::atime_nsec(cap)));
+        assert_eq!(std.mtime(), cap_std::fs::MetadataExt::mtime(cap));
+        assert_eq!(std.mtime_nsec(), cap_std::fs::MetadataExt::mtime_nsec(cap));
+        assert_eq!(std.ctime(), cap_std::fs::MetadataExt::ctime(cap));
+        assert_eq!(std.ctime_nsec(), cap_std::fs::MetadataExt::ctime_nsec(cap));
+        assert_eq!(std.blksize(), cap_std::fs::MetadataExt::blksize(cap));
+        assert_eq!(std.blocks(), cap_std::fs::MetadataExt::blocks(cap));
     }
 }
diff --git a/tests/fs_utf8.rs b/tests/fs_utf8.rs
index 8d88e7c0..3af9eb4f 100644
--- a/tests/fs_utf8.rs
+++ b/tests/fs_utf8.rs
@@ -335,7 +335,7 @@ fn file_test_io_read_write_at() {
 #[cfg(unix)]
 #[cfg_attr(any(target_os = "macos", target_os = "ios"), ignore)]
 fn set_get_unix_permissions() {
-    use std::os::unix::fs::PermissionsExt;
+    use cap_std::fs::PermissionsExt;
 
     let tmpdir = tmpdir();
     let filename = "set_get_unix_permissions";