Auto merge of #55114 - oli-obk:fx#map, r=nikomatsakis

Deprecate the `FxHashMap()` and `FxHashSet()` constructor function hack

Author: bors

src/bootstrap/cache.rs

@@ -169,19 +169,21 @@ impl Ord for Interned<String> {
     }
 }
 
-struct TyIntern<T> {
+struct TyIntern<T: Hash + Clone + Eq> {
     items: Vec<T>,
     set: HashMap<T, Interned<T>>,
 }
 
-impl<T: Hash + Clone + Eq> TyIntern<T> {
-    fn new() -> TyIntern<T> {
+impl<T: Hash + Clone + Eq> Default for TyIntern<T> {
+    fn default() -> Self {
         TyIntern {
             items: Vec::new(),
-            set: HashMap::new(),
+            set: Default::default(),
         }
     }
+}
 
+impl<T: Hash + Clone + Eq> TyIntern<T> {
     fn intern_borrow<B>(&mut self, item: &B) -> Interned<T>
     where
         B: Eq + Hash + ToOwned<Owned=T> + ?Sized,
@@ -212,19 +214,13 @@ impl<T: Hash + Clone + Eq> TyIntern<T> {
     }
 }
 
+#[derive(Default)]
 pub struct Interner {
     strs: Mutex<TyIntern<String>>,
     paths: Mutex<TyIntern<PathBuf>>,
 }
 
 impl Interner {
-    fn new() -> Interner {
-        Interner {
-            strs: Mutex::new(TyIntern::new()),
-            paths: Mutex::new(TyIntern::new()),
-        }
-    }
-
     pub fn intern_str(&self, s: &str) -> Interned<String> {
         self.strs.lock().unwrap().intern_borrow(s)
     }
@@ -238,7 +234,7 @@ impl Interner {
 }
 
 lazy_static! {
-    pub static ref INTERNER: Interner = Interner::new();
+    pub static ref INTERNER: Interner = Interner::default();
 }
 
 /// This is essentially a HashMap which allows storing any type in its input and

src/libarena/lib.rs

@@ -114,10 +114,9 @@ impl<T> TypedArenaChunk<T> {
 
 const PAGE: usize = 4096;
 
-impl<T> TypedArena<T> {
+impl<T> Default for TypedArena<T> {
     /// Creates a new `TypedArena`.
-    #[inline]
-    pub fn new() -> TypedArena<T> {
+    fn default() -> TypedArena<T> {
         TypedArena {
             // We set both `ptr` and `end` to 0 so that the first call to
             // alloc() will trigger a grow().
@@ -127,7 +126,9 @@ impl<T> TypedArena<T> {
             _own: PhantomData,
         }
     }
+}
 
+impl<T> TypedArena<T> {
     /// Allocates an object in the `TypedArena`, returning a reference to it.
     #[inline]
     pub fn alloc(&self, object: T) -> &mut T {
@@ -296,15 +297,17 @@ pub struct DroplessArena {
 
 unsafe impl Send for DroplessArena {}
 
-impl DroplessArena {
-    pub fn new() -> DroplessArena {
+impl Default for DroplessArena {
+    fn default() -> DroplessArena {
         DroplessArena {
             ptr: Cell::new(0 as *mut u8),
             end: Cell::new(0 as *mut u8),
-            chunks: RefCell::new(vec![]),
+            chunks: Default::default(),
         }
     }
+}
 
+impl DroplessArena {
     pub fn in_arena<T: ?Sized>(&self, ptr: *const T) -> bool {
         let ptr = ptr as *const u8 as *mut u8;
         for chunk in &*self.chunks.borrow() {
@@ -419,18 +422,13 @@ impl DroplessArena {
     }
 }
 
+#[derive(Default)]
+// FIXME(@Zoxc): this type is entirely unused in rustc
 pub struct SyncTypedArena<T> {
     lock: MTLock<TypedArena<T>>,
 }
 
 impl<T> SyncTypedArena<T> {
-    #[inline(always)]
-    pub fn new() -> SyncTypedArena<T> {
-        SyncTypedArena {
-            lock: MTLock::new(TypedArena::new())
-        }
-    }
-
     #[inline(always)]
     pub fn alloc(&self, object: T) -> &mut T {
         // Extend the lifetime of the result since it's limited to the lock guard
@@ -452,18 +450,12 @@ impl<T> SyncTypedArena<T> {
     }
 }
 
+#[derive(Default)]
 pub struct SyncDroplessArena {
     lock: MTLock<DroplessArena>,
 }
 
 impl SyncDroplessArena {
-    #[inline(always)]
-    pub fn new() -> SyncDroplessArena {
-        SyncDroplessArena {
-            lock: MTLock::new(DroplessArena::new())
-        }
-    }
-
     #[inline(always)]
     pub fn in_arena<T: ?Sized>(&self, ptr: *const T) -> bool {
         self.lock.lock().in_arena(ptr)
@@ -508,7 +500,7 @@ mod tests {
 
     #[test]
     pub fn test_unused() {
-        let arena: TypedArena<Point> = TypedArena::new();
+        let arena: TypedArena<Point> = TypedArena::default();
         assert!(arena.chunks.borrow().is_empty());
     }
 
@@ -546,7 +538,7 @@ mod tests {
             }
         }
 
-        let arena = Wrap(TypedArena::new());
+        let arena = Wrap(TypedArena::default());
 
         let result = arena.alloc_outer(|| Outer {
             inner: arena.alloc_inner(|| Inner { value: 10 }),
@@ -557,15 +549,15 @@ mod tests {
 
     #[test]
     pub fn test_copy() {
-        let arena = TypedArena::new();
+        let arena = TypedArena::default();
         for _ in 0..100000 {
             arena.alloc(Point { x: 1, y: 2, z: 3 });
         }
     }
 
     #[bench]
     pub fn bench_copy(b: &mut Bencher) {
-        let arena = TypedArena::new();
+        let arena = TypedArena::default();
         b.iter(|| arena.alloc(Point { x: 1, y: 2, z: 3 }))
     }
 
@@ -584,7 +576,7 @@ mod tests {
 
     #[test]
     pub fn test_noncopy() {
-        let arena = TypedArena::new();
+        let arena = TypedArena::default();
         for _ in 0..100000 {
             arena.alloc(Noncopy {
                 string: "hello world".to_string(),
@@ -595,15 +587,15 @@ mod tests {
 
     #[test]
     pub fn test_typed_arena_zero_sized() {
-        let arena = TypedArena::new();
+        let arena = TypedArena::default();
         for _ in 0..100000 {
             arena.alloc(());
         }
     }
 
     #[test]
     pub fn test_typed_arena_clear() {
-        let mut arena = TypedArena::new();
+        let mut arena = TypedArena::default();
         for _ in 0..10 {
             arena.clear();
             for _ in 0..10000 {
@@ -628,7 +620,7 @@ mod tests {
     fn test_typed_arena_drop_count() {
         let counter = Cell::new(0);
         {
-            let arena: TypedArena<DropCounter> = TypedArena::new();
+            let arena: TypedArena<DropCounter> = TypedArena::default();
             for _ in 0..100 {
                 // Allocate something with drop glue to make sure it doesn't leak.
                 arena.alloc(DropCounter { count: &counter });
@@ -640,7 +632,7 @@ mod tests {
     #[test]
     fn test_typed_arena_drop_on_clear() {
         let counter = Cell::new(0);
-        let mut arena: TypedArena<DropCounter> = TypedArena::new();
+        let mut arena: TypedArena<DropCounter> = TypedArena::default();
         for i in 0..10 {
             for _ in 0..100 {
                 // Allocate something with drop glue to make sure it doesn't leak.
@@ -667,7 +659,7 @@ mod tests {
     fn test_typed_arena_drop_small_count() {
         DROP_COUNTER.with(|c| c.set(0));
         {
-            let arena: TypedArena<SmallDroppable> = TypedArena::new();
+            let arena: TypedArena<SmallDroppable> = TypedArena::default();
             for _ in 0..100 {
                 // Allocate something with drop glue to make sure it doesn't leak.
                 arena.alloc(SmallDroppable);
@@ -679,7 +671,7 @@ mod tests {
 
     #[bench]
     pub fn bench_noncopy(b: &mut Bencher) {
-        let arena = TypedArena::new();
+        let arena = TypedArena::default();
         b.iter(|| {
             arena.alloc(Noncopy {
                 string: "hello world".to_string(),