Auto merge of rust-lang#91064 - matthiaskrgr:rollup-2ijidpt, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#88361 (Makes docs for references a little less confusing)
 - rust-lang#90089 (Improve display of enum variants)
 - rust-lang#90956 (Add a regression test for rust-lang#87573)
 - rust-lang#90999 (fix CTFE/Miri simd_insert/extract on array-style repr(simd) types)
 - rust-lang#91026 (rustdoc doctest: detect `fn main` after an unexpected semicolon)
 - rust-lang#91035 (Put back removed empty line)
 - rust-lang#91044 (Turn all 0x1b_u8 into '\x1b' or b'\x1b')
 - rust-lang#91054 (rustdoc: Fix some unescaped HTML tags in docs)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -419,48 +419,33 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             sym::simd_insert => {
                 let index = u64::from(self.read_scalar(&args[1])?.to_u32()?);
                 let elem = &args[2];
-                let input = &args[0];
-                let (len, e_ty) = input.layout.ty.simd_size_and_type(*self.tcx);
+                let (input, input_len) = self.operand_to_simd(&args[0])?;
+                let (dest, dest_len) = self.place_to_simd(dest)?;
+                assert_eq!(input_len, dest_len, "Return vector length must match input length");
                 assert!(
-                    index < len,
-                    "Index `{}` must be in bounds of vector type `{}`: `[0, {})`",
+                    index < dest_len,
+                    "Index `{}` must be in bounds of vector with length {}`",
                     index,
-                    e_ty,
-                    len
-                );
-                assert_eq!(
-                    input.layout, dest.layout,
-                    "Return type `{}` must match vector type `{}`",
-                    dest.layout.ty, input.layout.ty
-                );
-                assert_eq!(
-                    elem.layout.ty, e_ty,
-                    "Scalar element type `{}` must match vector element type `{}`",
-                    elem.layout.ty, e_ty
+                    dest_len
                 );
 
-                for i in 0..len {
-                    let place = self.place_index(dest, i)?;
-                    let value = if i == index { *elem } else { self.operand_index(input, i)? };
-                    self.copy_op(&value, &place)?;
+                for i in 0..dest_len {
+                    let place = self.mplace_index(&dest, i)?;
+                    let value =
+                        if i == index { *elem } else { self.mplace_index(&input, i)?.into() };
+                    self.copy_op(&value, &place.into())?;
                 }
             }
             sym::simd_extract => {
                 let index = u64::from(self.read_scalar(&args[1])?.to_u32()?);
-                let (len, e_ty) = args[0].layout.ty.simd_size_and_type(*self.tcx);
+                let (input, input_len) = self.operand_to_simd(&args[0])?;
                 assert!(
-                    index < len,
-                    "index `{}` is out-of-bounds of vector type `{}` with length `{}`",
+                    index < input_len,
+                    "index `{}` must be in bounds of vector with length `{}`",
                     index,
-                    e_ty,
-                    len
-                );
-                assert_eq!(
-                    e_ty, dest.layout.ty,
-                    "Return type `{}` must match vector element type `{}`",
-                    dest.layout.ty, e_ty
+                    input_len
                 );
-                self.copy_op(&self.operand_index(&args[0], index)?, dest)?;
+                self.copy_op(&self.mplace_index(&input, index)?.into(), dest)?;
             }
             sym::likely | sym::unlikely | sym::black_box => {
                 // These just return their argument

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -437,6 +437,18 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         })
     }
 
+    /// Converts a repr(simd) operand into an operand where `place_index` accesses the SIMD elements.
+    /// Also returns the number of elements.
+    pub fn operand_to_simd(
+        &self,
+        base: &OpTy<'tcx, M::PointerTag>,
+    ) -> InterpResult<'tcx, (MPlaceTy<'tcx, M::PointerTag>, u64)> {
+        // Basically we just transmute this place into an array following simd_size_and_type.
+        // This only works in memory, but repr(simd) types should never be immediates anyway.
+        assert!(base.layout.ty.is_simd());
+        self.mplace_to_simd(&base.assert_mem_place())
+    }
+
     /// Read from a local. Will not actually access the local if reading from a ZST.
     /// Will not access memory, instead an indirect `Operand` is returned.
     ///

compiler/rustc_const_eval/src/interpret/place.rs

@@ -200,7 +200,7 @@ impl<'tcx, Tag: Provenance> MPlaceTy<'tcx, Tag> {
             }
         } else {
             // Go through the layout.  There are lots of types that support a length,
-            // e.g., SIMD types.
+            // e.g., SIMD types. (But not all repr(simd) types even have FieldsShape::Array!)
             match self.layout.fields {
                 FieldsShape::Array { count, .. } => Ok(count),
                 _ => bug!("len not supported on sized type {:?}", self.layout.ty),
@@ -533,6 +533,22 @@ where
         })
     }
 
+    /// Converts a repr(simd) place into a place where `place_index` accesses the SIMD elements.
+    /// Also returns the number of elements.
+    pub fn mplace_to_simd(
+        &self,
+        base: &MPlaceTy<'tcx, M::PointerTag>,
+    ) -> InterpResult<'tcx, (MPlaceTy<'tcx, M::PointerTag>, u64)> {
+        // Basically we just transmute this place into an array following simd_size_and_type.
+        // (Transmuting is okay since this is an in-memory place. We also double-check the size
+        // stays the same.)
+        let (len, e_ty) = base.layout.ty.simd_size_and_type(*self.tcx);
+        let array = self.tcx.mk_array(e_ty, len);
+        let layout = self.layout_of(array)?;
+        assert_eq!(layout.size, base.layout.size);
+        Ok((MPlaceTy { layout, ..*base }, len))
+    }
+
     /// Gets the place of a field inside the place, and also the field's type.
     /// Just a convenience function, but used quite a bit.
     /// This is the only projection that might have a side-effect: We cannot project
@@ -594,6 +610,16 @@ where
         })
     }
 
+    /// Converts a repr(simd) place into a place where `place_index` accesses the SIMD elements.
+    /// Also returns the number of elements.
+    pub fn place_to_simd(
+        &mut self,
+        base: &PlaceTy<'tcx, M::PointerTag>,
+    ) -> InterpResult<'tcx, (MPlaceTy<'tcx, M::PointerTag>, u64)> {
+        let mplace = self.force_allocation(base)?;
+        self.mplace_to_simd(&mplace)
+    }
+
     /// Computes a place. You should only use this if you intend to write into this
     /// place; for reading, a more efficient alternative is `eval_place_for_read`.
     pub fn eval_place(

compiler/rustc_middle/src/ty/sty.rs

@@ -1805,17 +1805,22 @@ impl<'tcx> TyS<'tcx> {
     pub fn simd_size_and_type(&self, tcx: TyCtxt<'tcx>) -> (u64, Ty<'tcx>) {
         match self.kind() {
             Adt(def, substs) => {
+                assert!(def.repr.simd(), "`simd_size_and_type` called on non-SIMD type");
                 let variant = def.non_enum_variant();
                 let f0_ty = variant.fields[0].ty(tcx, substs);
 
                 match f0_ty.kind() {
+                    // If the first field is an array, we assume it is the only field and its
+                    // elements are the SIMD components.
                     Array(f0_elem_ty, f0_len) => {
                         // FIXME(repr_simd): https://github.com/rust-lang/rust/pull/78863#discussion_r522784112
                         // The way we evaluate the `N` in `[T; N]` here only works since we use
                         // `simd_size_and_type` post-monomorphization. It will probably start to ICE
                         // if we use it in generic code. See the `simd-array-trait` ui test.
                         (f0_len.eval_usize(tcx, ParamEnv::empty()) as u64, f0_elem_ty)
                     }
+                    // Otherwise, the fields of this Adt are the SIMD components (and we assume they
+                    // all have the same type).
                     _ => (variant.fields.len() as u64, f0_ty),
                 }
             }

library/core/src/char/methods.rs

@@ -1250,7 +1250,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_alphabetic());
     /// assert!(uppercase_g.is_ascii_alphabetic());
@@ -1284,7 +1284,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_uppercase());
     /// assert!(uppercase_g.is_ascii_uppercase());
@@ -1318,7 +1318,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_lowercase());
     /// assert!(!uppercase_g.is_ascii_lowercase());
@@ -1355,7 +1355,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_alphanumeric());
     /// assert!(uppercase_g.is_ascii_alphanumeric());
@@ -1389,7 +1389,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_digit());
     /// assert!(!uppercase_g.is_ascii_digit());
@@ -1426,7 +1426,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_hexdigit());
     /// assert!(!uppercase_g.is_ascii_hexdigit());
@@ -1464,7 +1464,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_punctuation());
     /// assert!(!uppercase_g.is_ascii_punctuation());
@@ -1498,7 +1498,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_graphic());
     /// assert!(uppercase_g.is_ascii_graphic());
@@ -1549,7 +1549,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_whitespace());
     /// assert!(!uppercase_g.is_ascii_whitespace());
@@ -1585,7 +1585,7 @@ impl char {
     /// let percent = '%';
     /// let space = ' ';
     /// let lf = '\n';
-    /// let esc: char = 0x1b_u8.into();
+    /// let esc = '\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_control());
     /// assert!(!uppercase_g.is_ascii_control());

library/core/src/num/mod.rs

@@ -428,7 +428,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_alphabetic());
     /// assert!(uppercase_g.is_ascii_alphabetic());
@@ -462,7 +462,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_uppercase());
     /// assert!(uppercase_g.is_ascii_uppercase());
@@ -496,7 +496,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_lowercase());
     /// assert!(!uppercase_g.is_ascii_lowercase());
@@ -533,7 +533,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_alphanumeric());
     /// assert!(uppercase_g.is_ascii_alphanumeric());
@@ -567,7 +567,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_digit());
     /// assert!(!uppercase_g.is_ascii_digit());
@@ -604,7 +604,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_hexdigit());
     /// assert!(!uppercase_g.is_ascii_hexdigit());
@@ -642,7 +642,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_punctuation());
     /// assert!(!uppercase_g.is_ascii_punctuation());
@@ -676,7 +676,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(uppercase_a.is_ascii_graphic());
     /// assert!(uppercase_g.is_ascii_graphic());
@@ -727,7 +727,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_whitespace());
     /// assert!(!uppercase_g.is_ascii_whitespace());
@@ -763,7 +763,7 @@ impl u8 {
     /// let percent = b'%';
     /// let space = b' ';
     /// let lf = b'\n';
-    /// let esc = 0x1b_u8;
+    /// let esc = b'\x1b';
     ///
     /// assert!(!uppercase_a.is_ascii_control());
     /// assert!(!uppercase_g.is_ascii_control());

library/core/src/primitive_docs.rs

@@ -1104,11 +1104,10 @@ mod prim_usize {}
 /// * [`Clone`] \(Note that this will not defer to `T`'s `Clone` implementation if it exists!)
 /// * [`Deref`]
 /// * [`Borrow`]
-/// * [`Pointer`]
+/// * [`fmt::Pointer`]
 ///
 /// [`Deref`]: ops::Deref
 /// [`Borrow`]: borrow::Borrow
-/// [`Pointer`]: fmt::Pointer
 ///
 /// `&mut T` references get all of the above except `Copy` and `Clone` (to prevent creating
 /// multiple simultaneous mutable borrows), plus the following, regardless of the type of its
@@ -1124,7 +1123,7 @@ mod prim_usize {}
 /// The following traits are implemented on `&T` references if the underlying `T` also implements
 /// that trait:
 ///
-/// * All the traits in [`std::fmt`] except [`Pointer`] and [`fmt::Write`]
+/// * All the traits in [`std::fmt`] except [`fmt::Pointer`] (which is implemented regardless of the type of its referent) and [`fmt::Write`]
 /// * [`PartialOrd`]
 /// * [`Ord`]
 /// * [`PartialEq`]
@@ -1133,9 +1132,9 @@ mod prim_usize {}
 /// * [`Fn`] \(in addition, `&T` references get [`FnMut`] and [`FnOnce`] if `T: Fn`)
 /// * [`Hash`]
 /// * [`ToSocketAddrs`]
+/// * [`Send`] \(`&T` references also require <code>T: [Sync]</code>)
 ///
 /// [`std::fmt`]: fmt
-/// ['Pointer`]: fmt::Pointer
 /// [`Hash`]: hash::Hash
 #[doc = concat!("[`ToSocketAddrs`]: ", include_str!("../primitive_docs/net_tosocketaddrs.md"))]
 ///
@@ -1150,7 +1149,6 @@ mod prim_usize {}
 /// * [`ExactSizeIterator`]
 /// * [`FusedIterator`]
 /// * [`TrustedLen`]
-/// * [`Send`] \(note that `&T` references only get `Send` if <code>T: [Sync]</code>)
 /// * [`io::Write`]
 /// * [`Read`]
 /// * [`Seek`]