Auto merge of #61203 - memoryruins:bare_trait_objects, r=Centril

Warn on bare_trait_objects by default

The `bare_trait_objects` lint is set to `warn` by default.
Most ui tests have been updated to use `dyn` to avoid creating noise in stderr files.

r? @Centril

cc #54910

Author: bors

src/librustc/lint/builtin.rs

@@ -255,7 +255,7 @@ declare_lint! {
 
 declare_lint! {
     pub BARE_TRAIT_OBJECTS,
-    Allow,
+    Warn,
     "suggest using `dyn Trait` for trait objects"
 }
 

src/libstd/error.rs

@@ -94,7 +94,7 @@ pub trait Error: Debug + Display {
     ///         "I'm the superhero of errors"
     ///     }
     ///
-    ///     fn cause(&self) -> Option<&Error> {
+    ///     fn cause(&self) -> Option<&dyn Error> {
     ///         Some(&self.side)
     ///     }
     /// }
@@ -244,7 +244,7 @@ impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> {
     ///
     /// let an_error = AnError;
     /// assert!(0 == mem::size_of_val(&an_error));
-    /// let a_boxed_error = Box::<Error>::from(an_error);
+    /// let a_boxed_error = Box::<dyn Error>::from(an_error);
     /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
     /// ```
     fn from(err: E) -> Box<dyn Error + 'a> {
@@ -287,7 +287,7 @@ impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync +
     ///
     /// let an_error = AnError;
     /// assert!(0 == mem::size_of_val(&an_error));
-    /// let a_boxed_error = Box::<Error + Send + Sync>::from(an_error);
+    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
     /// assert!(
     ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
     /// ```
@@ -309,7 +309,7 @@ impl From<String> for Box<dyn Error + Send + Sync> {
     /// use std::mem;
     ///
     /// let a_string_error = "a string error".to_string();
-    /// let a_boxed_error = Box::<Error + Send + Sync>::from(a_string_error);
+    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
     /// assert!(
     ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
     /// ```
@@ -344,7 +344,7 @@ impl From<String> for Box<dyn Error> {
     /// use std::mem;
     ///
     /// let a_string_error = "a string error".to_string();
-    /// let a_boxed_error = Box::<Error>::from(a_string_error);
+    /// let a_boxed_error = Box::<dyn Error>::from(a_string_error);
     /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
     /// ```
     fn from(str_err: String) -> Box<dyn Error> {
@@ -367,7 +367,7 @@ impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> {
     /// use std::mem;
     ///
     /// let a_str_error = "a str error";
-    /// let a_boxed_error = Box::<Error + Send + Sync>::from(a_str_error);
+    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error);
     /// assert!(
     ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
     /// ```
@@ -389,7 +389,7 @@ impl From<&str> for Box<dyn Error> {
     /// use std::mem;
     ///
     /// let a_str_error = "a str error";
-    /// let a_boxed_error = Box::<Error>::from(a_str_error);
+    /// let a_boxed_error = Box::<dyn Error>::from(a_str_error);
     /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
     /// ```
     fn from(err: &str) -> Box<dyn Error> {
@@ -412,7 +412,7 @@ impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> {
     /// use std::borrow::Cow;
     ///
     /// let a_cow_str_error = Cow::from("a str error");
-    /// let a_boxed_error = Box::<Error + Send + Sync>::from(a_cow_str_error);
+    /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
     /// assert!(
     ///     mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
     /// ```
@@ -436,7 +436,7 @@ impl<'a> From<Cow<'a, str>> for Box<dyn Error> {
     /// use std::borrow::Cow;
     ///
     /// let a_cow_str_error = Cow::from("a str error");
-    /// let a_boxed_error = Box::<Error>::from(a_cow_str_error);
+    /// let a_boxed_error = Box::<dyn Error>::from(a_cow_str_error);
     /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
     /// ```
     fn from(err: Cow<'a, str>) -> Box<dyn Error> {

src/libstd/fs.rs

@@ -1976,7 +1976,7 @@ pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
 /// use std::path::Path;
 ///
 /// // one possible implementation of walking a directory only visiting files
-/// fn visit_dirs(dir: &Path, cb: &Fn(&DirEntry)) -> io::Result<()> {
+/// fn visit_dirs(dir: &Path, cb: &dyn Fn(&DirEntry)) -> io::Result<()> {
 ///     if dir.is_dir() {
 ///         for entry in fs::read_dir(dir)? {
 ///             let entry = entry?;

src/test/compile-fail/issue-23595-1.rs

@@ -5,7 +5,7 @@ use std::ops::{Index};
 trait Hierarchy {
     type Value;
     type ChildKey;
-    type Children = Index<Self::ChildKey, Output=Hierarchy>;
+    type Children = dyn Index<Self::ChildKey, Output=dyn Hierarchy>;
     //~^ ERROR: the value of the associated types `Value` (from the trait `Hierarchy`), `ChildKey`
 
     fn data(&self) -> Option<(Self::Value, Self::Children)>;

src/test/run-pass-fulldeps/pprust-expr-roundtrip.rs

@@ -62,7 +62,7 @@ fn make_x() -> P<Expr> {
 /// Iterate over exprs of depth up to `depth`. The goal is to explore all "interesting"
 /// combinations of expression nesting. For example, we explore combinations using `if`, but not
 /// `while` or `match`, since those should print and parse in much the same way as `if`.
-fn iter_exprs(depth: usize, f: &mut FnMut(P<Expr>)) {
+fn iter_exprs(depth: usize, f: &mut dyn FnMut(P<Expr>)) {
     if depth == 0 {
         f(make_x());
         return;

src/test/run-pass/alignment-gep-tup-like-1.rs

@@ -22,11 +22,11 @@ impl<A:Clone> Invokable<A> for Invoker<A> {
     }
 }
 
-fn f<A:Clone + 'static>(a: A, b: u16) -> Box<Invokable<A>+'static> {
+fn f<A:Clone + 'static>(a: A, b: u16) -> Box<dyn Invokable<A>+'static> {
     box Invoker {
         a: a,
         b: b,
-    } as (Box<Invokable<A>+'static>)
+    } as (Box<dyn Invokable<A>+'static>)
 }
 
 pub fn main() {

src/test/run-pass/associated-types/associated-types-doubleendediterator-object.rs

@@ -1,7 +1,7 @@
 // run-pass
 #![feature(box_syntax)]
 
-fn pairwise_sub(mut t: Box<DoubleEndedIterator<Item=isize>>) -> isize {
+fn pairwise_sub(mut t: Box<dyn DoubleEndedIterator<Item=isize>>) -> isize {
     let mut result = 0;
     loop {
         let front = t.next();

src/test/run-pass/associated-types/associated-types-eq-obj.rs

@@ -15,7 +15,7 @@ impl Foo for char {
     fn boo(&self) -> Bar { Bar }
 }
 
-fn baz(x: &Foo<A=Bar>) -> Bar {
+fn baz(x: &dyn Foo<A=Bar>) -> Bar {
     x.boo()
 }
 

src/test/run-pass/associated-types/associated-types-projection-in-object-type.rs

@@ -19,20 +19,20 @@ pub trait Subscriber {
 
 pub trait Publisher<'a> {
     type Output;
-    fn subscribe(&mut self, _: Box<Subscriber<Input=Self::Output> + 'a>);
+    fn subscribe(&mut self, _: Box<dyn Subscriber<Input=Self::Output> + 'a>);
 }
 
 pub trait Processor<'a> : Subscriber + Publisher<'a> { }
 
 impl<'a, P> Processor<'a> for P where P : Subscriber + Publisher<'a> { }
 
 struct MyStruct<'a> {
-    sub: Box<Subscriber<Input=u64> + 'a>
+    sub: Box<dyn Subscriber<Input=u64> + 'a>
 }
 
 impl<'a> Publisher<'a> for MyStruct<'a> {
     type Output = u64;
-    fn subscribe(&mut self, t : Box<Subscriber<Input=u64> + 'a>) {
+    fn subscribe(&mut self, t : Box<dyn Subscriber<Input=u64> + 'a>) {
         self.sub = t;
     }
 }

src/test/run-pass/autoref-autoderef/autoderef-method-on-trait.rs

@@ -11,6 +11,6 @@ impl double for usize {
 }
 
 pub fn main() {
-    let x: Box<_> = box (box 3usize as Box<double>);
+    let x: Box<_> = box (box 3usize as Box<dyn double>);
     assert_eq!(x.double(), 6);
 }