Auto merge of #63214 - Centril:rollup-hdb7dnx, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #62663 (More questionmarks in doctests)
 - #62969 (Changing the structure of `mir::interpret::InterpError`)
 - #63153 (Remove redundant method with const variable resolution)
 - #63189 (Doc improvements)
 - #63198 (Allow trailing comma in macro 2.0 declarations.)
 - #63202 (Fix ICE in #63135)
 - #63203 (Make is_mutable use PlaceRef instead of it's fields)

Failed merges:

r? @ghost

Author: bors

Diff for: src/libcore/array.rs

@@ -24,9 +24,12 @@ use crate::slice::{Iter, IterMut};
 /// layout in memory of a fixed size array (for example, for unsafe
 /// initialization).
 ///
-/// Note that the traits AsRef and AsMut provide similar methods for types that
+/// Note that the traits [`AsRef`] and [`AsMut`] provide similar methods for types that
 /// may not be fixed-size arrays. Implementors should prefer those traits
 /// instead.
+///
+/// [`AsRef`]: ../convert/trait.AsRef.html
+/// [`AsMut`]: ../convert/trait.AsMut.html
 #[unstable(feature = "fixed_size_array", issue = "27778")]
 pub unsafe trait FixedSizeArray<T> {
     /// Converts the array to immutable slice

Diff for: src/libcore/convert.rs

@@ -427,7 +427,7 @@ pub trait TryInto<T>: Sized {
 /// - [`try_from`] is reflexive, which means that `TryFrom<T> for T`
 /// is implemented and cannot fail -- the associated `Error` type for
 /// calling `T::try_from()` on a value of type `T` is [`Infallible`].
-/// When the [`!`] type is stablized [`Infallible`] and [`!`] will be
+/// When the [`!`] type is stabilized [`Infallible`] and [`!`] will be
 /// equivalent.
 ///
 /// `TryFrom<T>` can be implemented as follows:

Diff for: src/libcore/future/future.rs

@@ -17,11 +17,13 @@ use crate::task::{Context, Poll};
 /// final value. This method does not block if the value is not ready. Instead,
 /// the current task is scheduled to be woken up when it's possible to make
 /// further progress by `poll`ing again. The `context` passed to the `poll`
-/// method can provide a `Waker`, which is a handle for waking up the current
+/// method can provide a [`Waker`], which is a handle for waking up the current
 /// task.
 ///
 /// When using a future, you generally won't call `poll` directly, but instead
 /// `.await` the value.
+///
+/// [`Waker`]: ../task/struct.Waker.html
 #[doc(spotlight)]
 #[must_use = "futures do nothing unless you `.await` or poll them"]
 #[stable(feature = "futures_api", since = "1.36.0")]

Diff for: src/libcore/macros.rs

@@ -353,11 +353,15 @@ macro_rules! r#try {
 /// use std::fmt::Write as FmtWrite;
 /// use std::io::Write as IoWrite;
 ///
-/// let mut s = String::new();
-/// let mut v = Vec::new();
-/// write!(&mut s, "{} {}", "abc", 123).unwrap(); // uses fmt::Write::write_fmt
-/// write!(&mut v, "s = {:?}", s).unwrap(); // uses io::Write::write_fmt
-/// assert_eq!(v, b"s = \"abc 123\"");
+/// fn main() -> Result<(), Box<dyn std::error::Error>> {
+///     let mut s = String::new();
+///     let mut v = Vec::new();
+///
+///     write!(&mut s, "{} {}", "abc", 123)?; // uses fmt::Write::write_fmt
+///     write!(&mut v, "s = {:?}", s)?; // uses io::Write::write_fmt
+///     assert_eq!(v, b"s = \"abc 123\"");
+///     Ok(())
+/// }
 /// ```
 ///
 /// Note: This macro can be used in `no_std` setups as well.
@@ -399,14 +403,17 @@ macro_rules! write {
 /// # Examples
 ///
 /// ```
-/// use std::io::Write;
+/// use std::io::{Write, Result};
 ///
-/// let mut w = Vec::new();
-/// writeln!(&mut w).unwrap();
-/// writeln!(&mut w, "test").unwrap();
-/// writeln!(&mut w, "formatted {}", "arguments").unwrap();
+/// fn main() -> Result<()> {
+///     let mut w = Vec::new();
+///     writeln!(&mut w)?;
+///     writeln!(&mut w, "test")?;
+///     writeln!(&mut w, "formatted {}", "arguments")?;
 ///
-/// assert_eq!(&w[..], "\ntest\nformatted arguments\n".as_bytes());
+///     assert_eq!(&w[..], "\ntest\nformatted arguments\n".as_bytes());
+///     Ok(())
+/// }
 /// ```
 ///
 /// A module can import both `std::fmt::Write` and `std::io::Write` and call `write!` on objects
@@ -417,11 +424,15 @@ macro_rules! write {
 /// use std::fmt::Write as FmtWrite;
 /// use std::io::Write as IoWrite;
 ///
-/// let mut s = String::new();
-/// let mut v = Vec::new();
-/// writeln!(&mut s, "{} {}", "abc", 123).unwrap(); // uses fmt::Write::write_fmt
-/// writeln!(&mut v, "s = {:?}", s).unwrap(); // uses io::Write::write_fmt
-/// assert_eq!(v, b"s = \"abc 123\\n\"\n");
+/// fn main() -> Result<(), Box<dyn std::error::Error>> {
+///     let mut s = String::new();
+///     let mut v = Vec::new();
+///
+///     writeln!(&mut s, "{} {}", "abc", 123)?; // uses fmt::Write::write_fmt
+///     writeln!(&mut v, "s = {:?}", s)?; // uses io::Write::write_fmt
+///     assert_eq!(v, b"s = \"abc 123\\n\"\n");
+///     Ok(())
+/// }
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]

Diff for: src/libcore/mem/maybe_uninit.rs

@@ -434,7 +434,7 @@ impl<T> MaybeUninit<T> {
     /// Reads the value from the `MaybeUninit<T>` container. The resulting `T` is subject
     /// to the usual drop handling.
     ///
-    /// Whenever possible, it is preferrable to use [`assume_init`] instead, which
+    /// Whenever possible, it is preferable to use [`assume_init`] instead, which
     /// prevents duplicating the content of the `MaybeUninit<T>`.
     ///
     /// # Safety

Diff for: src/libcore/ptr/mod.rs

@@ -1611,7 +1611,7 @@ impl<T: ?Sized> *const T {
     /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be
     /// used with the `add` method.
     ///
-    /// There are no guarantees whatsover that offsetting the pointer will not overflow or go
+    /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go
     /// beyond the allocation that the pointer points into. It is up to the caller to ensure that
     /// the returned offset is correct in all terms other than alignment.
     ///
@@ -2412,7 +2412,7 @@ impl<T: ?Sized> *mut T {
     /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be
     /// used with the `add` method.
     ///
-    /// There are no guarantees whatsover that offsetting the pointer will not overflow or go
+    /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go
     /// beyond the allocation that the pointer points into. It is up to the caller to ensure that
     /// the returned offset is correct in all terms other than alignment.
     ///

Diff for: src/librustc/infer/canonical/canonicalizer.rs

@@ -693,7 +693,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
         const_var: &'tcx ty::Const<'tcx>
     ) -> &'tcx ty::Const<'tcx> {
         let infcx = self.infcx.expect("encountered const-var without infcx");
-        let bound_to = infcx.resolve_const_var(const_var);
+        let bound_to = infcx.shallow_resolve(const_var);
         if bound_to != const_var {
             self.fold_const(bound_to)
         } else {

Diff for: src/librustc/infer/mod.rs

@@ -1351,23 +1351,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         }
     }
 
-    pub fn resolve_const_var(
-        &self,
-        ct: &'tcx ty::Const<'tcx>
-    ) -> &'tcx ty::Const<'tcx> {
-        if let ty::Const { val: ConstValue::Infer(InferConst::Var(v)), .. } = ct {
-            self.const_unification_table
-                .borrow_mut()
-                .probe_value(*v)
-                .val
-                .known()
-                .map(|c| self.resolve_const_var(c))
-                .unwrap_or(ct)
-        } else {
-            ct
-        }
-    }
-
     pub fn fully_resolve<T: TypeFoldable<'tcx>>(&self, value: &T) -> FixupResult<'tcx, T> {
         /*!
          * Attempts to resolve all type/region/const variables in
@@ -1586,7 +1569,7 @@ impl<'a, 'tcx> ShallowResolver<'a, 'tcx> {
                 // it can be resolved to an int/float variable, which
                 // can then be recursively resolved, hence the
                 // recursion. Note though that we prevent type
-                // variables from unifyxing to other type variables
+                // variables from unifying to other type variables
                 // directly (though they may be embedded
                 // structurally), and we prevent cycles in any case,
                 // so this recursion should always be of very limited
@@ -1626,17 +1609,15 @@ impl<'a, 'tcx> TypeFolder<'tcx> for ShallowResolver<'a, 'tcx> {
     }
 
     fn fold_const(&mut self, ct: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
-        match ct {
-            ty::Const { val: ConstValue::Infer(InferConst::Var(vid)), .. } => {
+        if let ty::Const { val: ConstValue::Infer(InferConst::Var(vid)), .. } = ct {
                 self.infcx.const_unification_table
                     .borrow_mut()
                     .probe_value(*vid)
                     .val
                     .known()
-                    .map(|c| self.fold_const(c))
                     .unwrap_or(ct)
-            }
-            _ => ct,
+        } else {
+            ct
         }
     }
 }

Diff for: src/librustc/mir/interpret/allocation.rs

@@ -235,17 +235,17 @@ impl<'tcx, Tag: Copy, Extra: AllocationExtra<Tag>> Allocation<Tag, Extra> {
     {
         assert_eq!(ptr.offset.bytes() as usize as u64, ptr.offset.bytes());
         let offset = ptr.offset.bytes() as usize;
-        match self.bytes[offset..].iter().position(|&c| c == 0) {
+        Ok(match self.bytes[offset..].iter().position(|&c| c == 0) {
             Some(size) => {
                 let size_with_null = Size::from_bytes((size + 1) as u64);
                 // Go through `get_bytes` for checks and AllocationExtra hooks.
                 // We read the null, so we include it in the request, but we want it removed
                 // from the result, so we do subslicing.
-                Ok(&self.get_bytes(cx, ptr, size_with_null)?[..size])
+                &self.get_bytes(cx, ptr, size_with_null)?[..size]
             }
             // This includes the case where `offset` is out-of-bounds to begin with.
-            None => err!(UnterminatedCString(ptr.erase_tag())),
-        }
+            None => throw_unsup!(UnterminatedCString(ptr.erase_tag())),
+        })
     }
 
     /// Validates that `ptr.offset` and `ptr.offset + size` do not point to the middle of a
@@ -446,7 +446,7 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
         if self.relocations(cx, ptr, size).is_empty() {
             Ok(())
         } else {
-            err!(ReadPointerAsBytes)
+            throw_unsup!(ReadPointerAsBytes)
         }
     }
 
@@ -516,7 +516,7 @@ impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
         self.undef_mask.is_range_defined(
             ptr.offset,
             ptr.offset + size,
-        ).or_else(|idx| err!(ReadUndefBytes(idx)))
+        ).or_else(|idx| throw_unsup!(ReadUndefBytes(idx)))
     }
 
     pub fn mark_definedness(