Rollup merge of #48143 - nikomatsakis:termination_trait_in_tests, r=eddyb

Termination trait in tests

Support the `Termination` trait in unit tests (cc https://github.com/rust-lang/rust/issues/43301)

Also, a drive-by fix for #47075.

This is joint work with @bkchr.

4 files changed, 68 insertions, 83 deletions

diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 854cefcb597..d7d856fe3ad 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -500,11 +500,6 @@ mod memchr;
 // The runtime entry point and a few unstable public functions used by the
 // compiler
 pub mod rt;
-// The trait to support returning arbitrary types in the main function
-mod termination;
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-pub use self::termination::Termination;
 
 // Include a number of private modules that exist solely to provide
 // the rustdoc documentation for primitive types. Using `include!`
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 9b2f815b713..e25599b8bd8 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -1392,6 +1392,73 @@ pub fn id() -> u32 {
     ::sys::os::getpid()
 }
 
+#[cfg(target_arch = "wasm32")]
+mod exit {
+    pub const SUCCESS: i32 = 0;
+    pub const FAILURE: i32 = 1;
+}
+#[cfg(not(target_arch = "wasm32"))]
+mod exit {
+    use libc;
+    pub const SUCCESS: i32 = libc::EXIT_SUCCESS;
+    pub const FAILURE: i32 = libc::EXIT_FAILURE;
+}
+
+/// A trait for implementing arbitrary return types in the `main` function.
+///
+/// The c-main function only supports to return integers as return type.
+/// So, every type implementing the `Termination` trait has to be converted
+/// to an integer.
+///
+/// The default implementations are returning `libc::EXIT_SUCCESS` to indicate
+/// a successful execution. In case of a failure, `libc::EXIT_FAILURE` is returned.
+#[cfg_attr(not(test), lang = "termination")]
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+#[rustc_on_unimplemented =
+  "`main` can only return types that implement {Termination}, not `{Self}`"]
+pub trait Termination {
+    /// Is called to get the representation of the value as status code.
+    /// This status code is returned to the operating system.
+    fn report(self) -> i32;
+}
+
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+impl Termination for () {
+    fn report(self) -> i32 { exit::SUCCESS }
+}
+
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+impl<T: Termination, E: fmt::Debug> Termination for Result<T, E> {
+    fn report(self) -> i32 {
+        match self {
+            Ok(val) => val.report(),
+            Err(err) => {
+                eprintln!("Error: {:?}", err);
+                exit::FAILURE
+            }
+        }
+    }
+}
+
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+impl Termination for ! {
+    fn report(self) -> i32 { unreachable!(); }
+}
+
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+impl Termination for bool {
+    fn report(self) -> i32 {
+        if self { exit::SUCCESS } else { exit::FAILURE }
+    }
+}
+
+#[unstable(feature = "termination_trait_lib", issue = "43301")]
+impl Termination for i32 {
+    fn report(self) -> i32 {
+        self
+    }
+}
+
 #[cfg(all(test, not(any(target_os = "cloudabi", target_os = "emscripten"))))]
 mod tests {
     use io::prelude::*;
diff --git a/src/libstd/rt.rs b/src/libstd/rt.rs
index 9dbaf784f89..e1392762a59 100644
--- a/src/libstd/rt.rs
+++ b/src/libstd/rt.rs
@@ -68,7 +68,7 @@ fn lang_start_internal(main: &(Fn() -> i32 + Sync + ::panic::RefUnwindSafe),
 
 #[cfg(not(test))]
 #[lang = "start"]
-fn lang_start<T: ::termination::Termination + 'static>
+fn lang_start<T: ::process::Termination + 'static>
     (main: fn() -> T, argc: isize, argv: *const *const u8) -> isize
 {
     lang_start_internal(&move || main().report(), argc, argv)
diff --git a/src/libstd/termination.rs b/src/libstd/termination.rs
deleted file mode 100644
index dc7fa53aab6..00000000000
--- a/src/libstd/termination.rs
+++ /dev/null
@@ -1,77 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use fmt::Debug;
-#[cfg(target_arch = "wasm32")]
-mod exit {
-    pub const SUCCESS: i32 = 0;
-    pub const FAILURE: i32 = 1;
-}
-#[cfg(not(target_arch = "wasm32"))]
-mod exit {
-    use libc;
-    pub const SUCCESS: i32 = libc::EXIT_SUCCESS;
-    pub const FAILURE: i32 = libc::EXIT_FAILURE;
-}
-
-/// A trait for implementing arbitrary return types in the `main` function.
-///
-/// The c-main function only supports to return integers as return type.
-/// So, every type implementing the `Termination` trait has to be converted
-/// to an integer.
-///
-/// The default implementations are returning `libc::EXIT_SUCCESS` to indicate
-/// a successful execution. In case of a failure, `libc::EXIT_FAILURE` is returned.
-#[cfg_attr(not(test), lang = "termination")]
-#[unstable(feature = "termination_trait", issue = "43301")]
-#[rustc_on_unimplemented =
-  "`main` can only return types that implement {Termination}, not `{Self}`"]
-pub trait Termination {
-    /// Is called to get the representation of the value as status code.
-    /// This status code is returned to the operating system.
-    fn report(self) -> i32;
-}
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-impl Termination for () {
-    fn report(self) -> i32 { exit::SUCCESS }
-}
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-impl<T: Termination, E: Debug> Termination for Result<T, E> {
-    fn report(self) -> i32 {
-        match self {
-            Ok(val) => val.report(),
-            Err(err) => {
-                eprintln!("Error: {:?}", err);
-                exit::FAILURE
-            }
-        }
-    }
-}
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-impl Termination for ! {
-    fn report(self) -> i32 { unreachable!(); }
-}
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-impl Termination for bool {
-    fn report(self) -> i32 {
-        if self { exit::SUCCESS } else { exit::FAILURE }
-    }
-}
-
-#[unstable(feature = "termination_trait", issue = "43301")]
-impl Termination for i32 {
-    fn report(self) -> i32 {
-        self
-    }
-}