Rollup merge of #59818 - crlf0710:eliminate_libstd_fnbox, r=cramertj

Eliminate `FnBox` usages from libstd.

7 files changed, 9 insertions, 17 deletions

diff --git a/src/libstd/sys/cloudabi/thread.rs b/src/libstd/sys/cloudabi/thread.rs
index f853346e0e6..7da16c4d247 100644
--- a/src/libstd/sys/cloudabi/thread.rs
+++ b/src/libstd/sys/cloudabi/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::cmp;
 use crate::ffi::CStr;
 use crate::io;
@@ -22,7 +21,7 @@ unsafe impl Sync for Thread {}
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(stack: usize, p: Box<dyn FnBox()>) -> io::Result<Thread> {
+    pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
         let p = box p;
         let mut native: libc::pthread_t = mem::zeroed();
         let mut attr: libc::pthread_attr_t = mem::zeroed();
diff --git a/src/libstd/sys/redox/thread.rs b/src/libstd/sys/redox/thread.rs
index ae0b91b4d6c..9d40a7e8bb8 100644
--- a/src/libstd/sys/redox/thread.rs
+++ b/src/libstd/sys/redox/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::ffi::CStr;
 use crate::io;
 use crate::mem;
@@ -19,7 +18,7 @@ unsafe impl Sync for Thread {}
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(_stack: usize, p: Box<dyn FnBox()>) -> io::Result<Thread> {
+    pub unsafe fn new(_stack: usize, p: Box<dyn FnOnce()>) -> io::Result<Thread> {
         let p = box p;
 
         let id = cvt(syscall::clone(syscall::CLONE_VM | syscall::CLONE_FS | syscall::CLONE_FILES))?;
diff --git a/src/libstd/sys/sgx/thread.rs b/src/libstd/sys/sgx/thread.rs
index 565a523ebe0..b9f42d4ad1c 100644
--- a/src/libstd/sys/sgx/thread.rs
+++ b/src/libstd/sys/sgx/thread.rs
@@ -1,5 +1,4 @@
 #![cfg_attr(test, allow(dead_code))] // why is this necessary?
-use crate::boxed::FnBox;
 use crate::ffi::CStr;
 use crate::io;
 use crate::time::Duration;
@@ -13,17 +12,16 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
 mod task_queue {
     use crate::sync::{Mutex, MutexGuard, Once};
     use crate::sync::mpsc;
-    use crate::boxed::FnBox;
 
     pub type JoinHandle = mpsc::Receiver<()>;
 
     pub(super) struct Task {
-        p: Box<dyn FnBox()>,
+        p: Box<dyn FnOnce()>,
         done: mpsc::Sender<()>,
     }
 
     impl Task {
-        pub(super) fn new(p: Box<dyn FnBox()>) -> (Task, JoinHandle) {
+        pub(super) fn new(p: Box<dyn FnOnce()>) -> (Task, JoinHandle) {
             let (done, recv) = mpsc::channel();
             (Task { p, done }, recv)
         }
@@ -51,7 +49,7 @@ mod task_queue {
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(_stack: usize, p: Box<dyn FnBox()>)
+    pub unsafe fn new(_stack: usize, p: Box<dyn FnOnce()>)
         -> io::Result<Thread>
     {
         let mut queue_lock = task_queue::lock();
diff --git a/src/libstd/sys/unix/thread.rs b/src/libstd/sys/unix/thread.rs
index feb15e8f585..f7d604ac4c8 100644
--- a/src/libstd/sys/unix/thread.rs
+++ b/src/libstd/sys/unix/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::cmp;
 use crate::ffi::CStr;
 use crate::io;
@@ -39,7 +38,7 @@ unsafe fn pthread_attr_setstacksize(_attr: *mut libc::pthread_attr_t,
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(stack: usize, p: Box<dyn FnBox()>)
+    pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>)
                           -> io::Result<Thread> {
         let p = box p;
         let mut native: libc::pthread_t = mem::zeroed();
diff --git a/src/libstd/sys/wasi/thread.rs b/src/libstd/sys/wasi/thread.rs
index 9d3c6ac59d1..5e69e4d948f 100644
--- a/src/libstd/sys/wasi/thread.rs
+++ b/src/libstd/sys/wasi/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::cmp;
 use crate::ffi::CStr;
 use crate::io;
@@ -13,7 +12,7 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(_stack: usize, _p: Box<dyn FnBox()>)
+    pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>)
         -> io::Result<Thread>
     {
         unsupported()
diff --git a/src/libstd/sys/wasm/thread.rs b/src/libstd/sys/wasm/thread.rs
index a65c413119f..1dc786cd5d7 100644
--- a/src/libstd/sys/wasm/thread.rs
+++ b/src/libstd/sys/wasm/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::ffi::CStr;
 use crate::io;
 use crate::sys::{unsupported, Void};
@@ -10,7 +9,7 @@ pub const DEFAULT_MIN_STACK_SIZE: usize = 4096;
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(_stack: usize, _p: Box<dyn FnBox()>)
+    pub unsafe fn new(_stack: usize, _p: Box<dyn FnOnce()>)
         -> io::Result<Thread>
     {
         unsupported()
diff --git a/src/libstd/sys/windows/thread.rs b/src/libstd/sys/windows/thread.rs
index 1b0a811f13b..ebdf3612e06 100644
--- a/src/libstd/sys/windows/thread.rs
+++ b/src/libstd/sys/windows/thread.rs
@@ -1,4 +1,3 @@
-use crate::boxed::FnBox;
 use crate::io;
 use crate::ffi::CStr;
 use crate::mem;
@@ -20,7 +19,7 @@ pub struct Thread {
 
 impl Thread {
     // unsafe: see thread::Builder::spawn_unchecked for safety requirements
-    pub unsafe fn new(stack: usize, p: Box<dyn FnBox()>)
+    pub unsafe fn new(stack: usize, p: Box<dyn FnOnce()>)
                           -> io::Result<Thread> {
         let p = box p;