@@ -53,25 +53,25 @@ use crate::fmt;
5353/// # Examples
5454///
5555/// ```
56- /// use std::cell::RefCell ;
56+ /// use std::cell::Cell ;
5757/// use std::thread;
5858///
59- /// thread_local!(static FOO: RefCell <u32> = RefCell ::new(1));
59+ /// thread_local!(static FOO: Cell <u32> = Cell ::new(1));
6060///
61- /// FOO.with_borrow(|v| assert_eq!(*v , 1) );
62- /// FOO.with_borrow_mut(|v| *v = 2);
61+ /// assert_eq!(FOO.get() , 1);
62+ /// FOO.set( 2);
6363///
6464/// // each thread starts out with the initial value of 1
6565/// let t = thread::spawn(move|| {
66- /// FOO.with_borrow(|v| assert_eq!(*v , 1) );
67- /// FOO.with_borrow_mut(|v| *v = 3);
66+ /// assert_eq!(FOO.get() , 1);
67+ /// FOO.set( 3);
6868/// });
6969///
7070/// // wait for the thread to complete and bail out on panic
7171/// t.join().unwrap();
7272///
7373/// // we retain our original value of 2 despite the child thread
74- /// FOO.with_borrow(|v| assert_eq!(*v , 2) );
74+ /// assert_eq!(FOO.get() , 2);
7575/// ```
7676///
7777/// # Platform-specific behavior
@@ -141,15 +141,16 @@ impl<T: 'static> fmt::Debug for LocalKey<T> {
141141/// Publicity and attributes for each static are allowed. Example:
142142///
143143/// ```
144- /// use std::cell::RefCell;
144+ /// use std::cell::{Cell, RefCell};
145+ ///
145146/// thread_local! {
146- /// pub static FOO: RefCell <u32> = RefCell ::new(1);
147+ /// pub static FOO: Cell <u32> = Cell ::new(1);
147148///
148- /// static BAR: RefCell<f32> = RefCell::new(1.0);
149+ /// static BAR: RefCell<Vec< f32>> = RefCell::new(vec![ 1.0, 2.0] );
149150/// }
150151///
151- /// FOO.with_borrow(|v| assert_eq!(*v , 1) );
152- /// BAR.with_borrow(|v| assert_eq!(*v, 1 .0));
152+ /// assert_eq!(FOO.get() , 1);
153+ /// BAR.with_borrow(|v| assert_eq!(v[1], 2 .0));
153154/// ```
154155///
155156/// Note that only shared references (`&T`) to the inner data may be obtained, so a
@@ -164,12 +165,13 @@ impl<T: 'static> fmt::Debug for LocalKey<T> {
164165/// track any additional state.
165166///
166167/// ```
167- /// use std::cell::Cell;
168+ /// use std::cell::RefCell;
169+ ///
168170/// thread_local! {
169- /// pub static FOO: Cell< u32> = const { Cell ::new(1 ) };
171+ /// pub static FOO: RefCell<Vec< u32>> = const { RefCell ::new(Vec::new() ) };
170172/// }
171173///
172- /// assert_eq!(FOO.get (), 1 );
174+ /// FOO.with_borrow(|v| assert_eq!(v.len (), 0) );
173175/// ```
174176///
175177/// See [`LocalKey` documentation][`std::thread::LocalKey`] for more
@@ -279,10 +281,9 @@ impl<T: 'static> LocalKey<T> {
279281 where
280282 F : FnOnce ( & T ) -> R ,
281283 {
282- unsafe {
283- let thread_local = ( self . inner ) ( None ) . ok_or ( AccessError ) ?;
284- Ok ( f ( thread_local) )
285- }
284+ // SAFETY: `inner` is safe to call within the lifetime of the thread
285+ let thread_local = unsafe { ( self . inner ) ( None ) . ok_or ( AccessError ) ? } ;
286+ Ok ( f ( thread_local) )
286287 }
287288
288289 /// Acquires a reference to the value in this TLS key, initializing it with
@@ -301,14 +302,17 @@ impl<T: 'static> LocalKey<T> {
301302 where
302303 F : FnOnce ( Option < T > , & T ) -> R ,
303304 {
304- unsafe {
305- let mut init = Some ( init) ;
306- let reference = ( self . inner ) ( Some ( & mut init) ) . expect (
305+ let mut init = Some ( init) ;
306+
307+ // SAFETY: `inner` is safe to call within the lifetime of the thread
308+ let reference = unsafe {
309+ ( self . inner ) ( Some ( & mut init) ) . expect (
307310 "cannot access a Thread Local Storage value \
308311,
309- ) ;
310- f ( init, reference)
311- }
312+ )
313+ } ;
314+
315+ f ( init, reference)
312316 }
313317}
314318
@@ -377,7 +381,7 @@ impl<T: 'static> LocalKey<Cell<T>> {
377381 where
378382 T : Copy ,
379383 {
380- self . with ( |cell| cell . get ( ) )
384+ self . with ( Cell :: get)
381385 }
382386
383387 /// Takes the contained value, leaving `Default::default()` in its place.
@@ -407,7 +411,7 @@ impl<T: 'static> LocalKey<Cell<T>> {
407411 where
408412 T : Default ,
409413 {
410- self . with ( |cell| cell . take ( ) )
414+ self . with ( Cell :: take)
411415 }
412416
413417 /// Replaces the contained value, returning the old value.
@@ -578,7 +582,7 @@ impl<T: 'static> LocalKey<RefCell<T>> {
578582 where
579583 T : Default ,
580584 {
581- self . with ( |cell| cell . take ( ) )
585+ self . with ( RefCell :: take)
582586 }
583587
584588 /// Replaces the contained value, returning the old value.
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