Seal process::Command extension traits.

Author: m-ou-se

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:

library/std/src/sys/unix/ext/process.rs

@@ -12,7 +12,7 @@ use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
 
 /// Unix-specific extensions to the [`process::Command`] builder.
 #[stable(feature = "rust1", since = "1.0.0")]
-pub trait CommandExt {
+pub trait CommandExt: Sealed {
     /// Sets the child process's user ID. This translates to a
     /// `setuid` call in the child process. Failure in the `setuid`
     /// call will cause the spawn to fail.

library/std/src/sys/windows/ext/process.rs

@@ -94,7 +94,7 @@ impl ExitStatusExt for process::ExitStatus {
 
 /// Windows-specific extensions to the [`process::Command`] builder.
 #[stable(feature = "windows_process_extensions", since = "1.16.0")]
-pub trait CommandExt {
+pub trait CommandExt: Sealed {
     /// Sets the [process creation flags][1] to be passed to `CreateProcess`.
     ///
     /// These will always be ORed with `CREATE_UNICODE_ENVIRONMENT`.