Auto merge of rust-lang#94314 - matthiaskrgr:rollup-hmed8n7, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#89887 (Change `char` type in debuginfo to DW_ATE_UTF)
 - rust-lang#94267 (Remove unused ordering derivations and bounds for `SimplifiedTypeGen`)
 - rust-lang#94270 (Miri: relax fn ptr check)
 - rust-lang#94273 (add matching doc to errorkind)
 - rust-lang#94283 (remove feature gate in control_flow examples)
 - rust-lang#94288 (Cleanup a few Decoder methods)
 - rust-lang#94292 (riscv32imc_esp_espidf: set max_atomic_width to 64)
 - rust-lang#94296 (:arrow_up: rust-analyzer)
 - rust-lang#94300 (Fix a typo in documentation of `array::IntoIter::new_unchecked`)

Failed merges:

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

Author: bors

Diff for: compiler/rustc_ast/src/ast.rs

@@ -2418,8 +2418,7 @@ impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
 }
 
 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
-    fn decode(d: &mut D) -> AttrId {
-        d.read_unit();
+    fn decode(_: &mut D) -> AttrId {
         crate::attr::mk_attr_id()
     }
 }

Diff for: compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -87,7 +87,7 @@ const DW_ATE_signed: c_uint = 0x05;
 #[allow(non_upper_case_globals)]
 const DW_ATE_unsigned: c_uint = 0x07;
 #[allow(non_upper_case_globals)]
-const DW_ATE_unsigned_char: c_uint = 0x08;
+const DW_ATE_UTF: c_uint = 0x10;
 
 pub const UNKNOWN_LINE_NUMBER: c_uint = 0;
 pub const UNKNOWN_COLUMN_NUMBER: c_uint = 0;
@@ -933,7 +933,7 @@ fn basic_type_metadata<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'l
         ty::Never => ("!", DW_ATE_unsigned),
         ty::Tuple(elements) if elements.is_empty() => ("()", DW_ATE_unsigned),
         ty::Bool => ("bool", DW_ATE_boolean),
-        ty::Char => ("char", DW_ATE_unsigned_char),
+        ty::Char => ("char", DW_ATE_UTF),
         ty::Int(int_ty) if cpp_like_debuginfo => (int_ty.msvc_basic_name(), DW_ATE_signed),
         ty::Uint(uint_ty) if cpp_like_debuginfo => (uint_ty.msvc_basic_name(), DW_ATE_unsigned),
         ty::Float(float_ty) if cpp_like_debuginfo => (float_ty.msvc_basic_name(), DW_ATE_float),

Diff for: compiler/rustc_const_eval/src/interpret/validity.rs

@@ -567,22 +567,27 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
             }
             ty::FnPtr(_sig) => {
                 let value = try_validation!(
-                    self.ecx.read_immediate(value),
+                    self.ecx.read_scalar(value).and_then(|v| v.check_init()),
                     self.path,
                     err_unsup!(ReadPointerAsBytes) => { "part of a pointer" } expected { "a proper pointer or integer value" },
+                    err_ub!(InvalidUninitBytes(None)) => { "uninitialized bytes" } expected { "a proper pointer or integer value" },
                 );
-                // Make sure we print a `ScalarMaybeUninit` (and not an `ImmTy`) in the error
-                // message below.
-                let value = value.to_scalar_or_uninit();
-                let _fn = try_validation!(
-                    value.check_init().and_then(|ptr| self.ecx.memory.get_fn(self.ecx.scalar_to_ptr(ptr))),
-                    self.path,
-                    err_ub!(DanglingIntPointer(..)) |
-                    err_ub!(InvalidFunctionPointer(..)) |
-                    err_ub!(InvalidUninitBytes(None)) =>
-                        { "{:x}", value } expected { "a function pointer" },
-                );
-                // FIXME: Check if the signature matches
+                let ptr = self.ecx.scalar_to_ptr(value);
+                // Ensure the pointer is non-null.
+                if self.ecx.memory.ptr_may_be_null(ptr) {
+                    throw_validation_failure!(self.path, { "a potentially null function pointer" });
+                }
+                // If we check references recursively, also check that this points to a function.
+                if let Some(_) = self.ref_tracking {
+                    let _fn = try_validation!(
+                        self.ecx.memory.get_fn(ptr),
+                        self.path,
+                        err_ub!(DanglingIntPointer(..)) |
+                        err_ub!(InvalidFunctionPointer(..)) =>
+                            { "{:x}", value } expected { "a function pointer" },
+                    );
+                    // FIXME: Check if the signature matches
+                }
                 Ok(true)
             }
             ty::Never => throw_validation_failure!(self.path, { "a value of the never type `!`" }),

Diff for: compiler/rustc_data_structures/src/fingerprint.rs

@@ -153,9 +153,7 @@ impl<E: rustc_serialize::Encoder> Encodable<E> for Fingerprint {
 impl<D: rustc_serialize::Decoder> Decodable<D> for Fingerprint {
     #[inline]
     fn decode(d: &mut D) -> Self {
-        let mut bytes = [0u8; 16];
-        d.read_raw_bytes_into(&mut bytes);
-        Fingerprint::from_le_bytes(bytes)
+        Fingerprint::from_le_bytes(d.read_raw_bytes(16).try_into().unwrap())
     }
 }
 

Diff for: compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -316,7 +316,7 @@ impl<'a, 'tcx> DecodeContext<'a, 'tcx> {
     }
 
     #[inline]
-    pub fn read_raw_bytes(&mut self, len: usize) -> &'a [u8] {
+    pub fn read_raw_bytes(&mut self, len: usize) -> &[u8] {
         self.opaque.read_raw_bytes(len)
     }
 }

Diff for: compiler/rustc_middle/src/mir/predecessors.rs

@@ -63,8 +63,7 @@ impl<S: serialize::Encoder> serialize::Encodable<S> for PredecessorCache {
 
 impl<D: serialize::Decoder> serialize::Decodable<D> for PredecessorCache {
     #[inline]
-    fn decode(d: &mut D) -> Self {
-        let () = d.read_unit();
+    fn decode(_: &mut D) -> Self {
         Self::new()
     }
 }

Diff for: compiler/rustc_middle/src/ty/codec.rs

@@ -465,8 +465,6 @@ macro_rules! implement_ty_decoder {
 
             impl<$($typaram ),*> Decoder for $DecoderName<$($typaram),*> {
                 $crate::__impl_decoder_methods! {
-                    read_unit -> ();
-
                     read_u128 -> u128;
                     read_u64 -> u64;
                     read_u32 -> u32;
@@ -485,12 +483,12 @@ macro_rules! implement_ty_decoder {
                     read_f64 -> f64;
                     read_f32 -> f32;
                     read_char -> char;
-                    read_str -> Cow<'_, str>;
+                    read_str -> &str;
                 }
 
                 #[inline]
-                fn read_raw_bytes_into(&mut self, bytes: &mut [u8]) {
-                    self.opaque.read_raw_bytes_into(bytes)
+                fn read_raw_bytes(&mut self, len: usize) -> &[u8] {
+                    self.opaque.read_raw_bytes(len)
                 }
             }
         }

Diff for: compiler/rustc_middle/src/ty/fast_reject.rs

@@ -17,7 +17,7 @@ pub type SimplifiedType = SimplifiedTypeGen<DefId>;
 /// because we sometimes need to use SimplifiedTypeGen values as stable sorting
 /// keys (in which case we use a DefPathHash as id-type) but in the general case
 /// the non-stable but fast to construct DefId-version is the better choice.
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, TyEncodable, TyDecodable)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, TyEncodable, TyDecodable)]
 pub enum SimplifiedTypeGen<D>
 where
     D: Copy + Debug + Eq,
@@ -124,7 +124,7 @@ pub fn simplify_type(
     }
 }
 
-impl<D: Copy + Debug + Ord + Eq> SimplifiedTypeGen<D> {
+impl<D: Copy + Debug + Eq> SimplifiedTypeGen<D> {
     pub fn def(self) -> Option<D> {
         match self {
             AdtSimplifiedType(d)
@@ -140,7 +140,7 @@ impl<D: Copy + Debug + Ord + Eq> SimplifiedTypeGen<D> {
     pub fn map_def<U, F>(self, map: F) -> SimplifiedTypeGen<U>
     where
         F: Fn(D) -> U,
-        U: Copy + Debug + Ord + Eq,
+        U: Copy + Debug + Eq,
     {
         match self {
             BoolSimplifiedType => BoolSimplifiedType,
@@ -171,7 +171,7 @@ impl<D: Copy + Debug + Ord + Eq> SimplifiedTypeGen<D> {
 
 impl<'a, D> HashStable<StableHashingContext<'a>> for SimplifiedTypeGen<D>
 where
-    D: Copy + Debug + Ord + Eq + HashStable<StableHashingContext<'a>>,
+    D: Copy + Debug + Eq + HashStable<StableHashingContext<'a>>,
 {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         mem::discriminant(self).hash_stable(hcx, hasher);

Diff for: compiler/rustc_serialize/src/opaque.rs

@@ -1,6 +1,5 @@
 use crate::leb128::{self, max_leb128_len};
-use crate::serialize::{self, Encoder as _};
-use std::borrow::Cow;
+use crate::serialize::{self, Decoder as _, Encoder as _};
 use std::convert::TryInto;
 use std::fs::File;
 use std::io::{self, Write};
@@ -549,25 +548,13 @@ impl<'a> Decoder<'a> {
     pub fn advance(&mut self, bytes: usize) {
         self.position += bytes;
     }
-
-    #[inline]
-    pub fn read_raw_bytes(&mut self, bytes: usize) -> &'a [u8] {
-        let start = self.position;
-        self.position += bytes;
-        &self.data[start..self.position]
-    }
 }
 
 macro_rules! read_leb128 {
     ($dec:expr, $fun:ident) => {{ leb128::$fun($dec.data, &mut $dec.position) }};
 }
 
 impl<'a> serialize::Decoder for Decoder<'a> {
-    #[inline]
-    fn read_unit(&mut self) -> () {
-        ()
-    }
-
     #[inline]
     fn read_u128(&mut self) -> u128 {
         read_leb128!(self, read_u128_leb128)
@@ -663,22 +650,22 @@ impl<'a> serialize::Decoder for Decoder<'a> {
     }
 
     #[inline]
-    fn read_str(&mut self) -> Cow<'_, str> {
+    fn read_str(&mut self) -> &'a str {
         let len = self.read_usize();
         let sentinel = self.data[self.position + len];
         assert!(sentinel == STR_SENTINEL);
         let s = unsafe {
             std::str::from_utf8_unchecked(&self.data[self.position..self.position + len])
         };
         self.position += len + 1;
-        Cow::Borrowed(s)
+        s
     }
 
     #[inline]
-    fn read_raw_bytes_into(&mut self, s: &mut [u8]) {
+    fn read_raw_bytes(&mut self, bytes: usize) -> &'a [u8] {
         let start = self.position;
-        self.position += s.len();
-        s.copy_from_slice(&self.data[start..self.position]);
+        self.position += bytes;
+        &self.data[start..self.position]
     }
 }
 
@@ -746,10 +733,10 @@ impl<'a> serialize::Decodable<Decoder<'a>> for IntEncodedWithFixedSize {
     fn decode(decoder: &mut Decoder<'a>) -> IntEncodedWithFixedSize {
         let _start_pos = decoder.position();
         let bytes = decoder.read_raw_bytes(IntEncodedWithFixedSize::ENCODED_SIZE);
+        let value = u64::from_le_bytes(bytes.try_into().unwrap());
         let _end_pos = decoder.position();
         debug_assert_eq!((_end_pos - _start_pos), IntEncodedWithFixedSize::ENCODED_SIZE);
 
-        let value = u64::from_le_bytes(bytes.try_into().unwrap());
         IntEncodedWithFixedSize(value)
     }
 }

Diff for: compiler/rustc_serialize/src/serialize.rs

@@ -181,7 +181,6 @@ pub trait Encoder {
 // concise.
 pub trait Decoder {
     // Primitive types:
-    fn read_unit(&mut self) -> ();
     fn read_usize(&mut self) -> usize;
     fn read_u128(&mut self) -> u128;
     fn read_u64(&mut self) -> u64;
@@ -198,8 +197,8 @@ pub trait Decoder {
     fn read_f64(&mut self) -> f64;
     fn read_f32(&mut self) -> f32;
     fn read_char(&mut self) -> char;
-    fn read_str(&mut self) -> Cow<'_, str>;
-    fn read_raw_bytes_into(&mut self, s: &mut [u8]);
+    fn read_str(&mut self) -> &str;
+    fn read_raw_bytes(&mut self, len: usize) -> &[u8];
 }
 
 /// Trait for types that can be serialized
@@ -313,7 +312,7 @@ impl<S: Encoder> Encodable<S> for String {
 
 impl<D: Decoder> Decodable<D> for String {
     fn decode(d: &mut D) -> String {
-        d.read_str().into_owned()
+        d.read_str().to_owned()
     }
 }
 
@@ -324,9 +323,7 @@ impl<S: Encoder> Encodable<S> for () {
 }
 
 impl<D: Decoder> Decodable<D> for () {
-    fn decode(d: &mut D) -> () {
-        d.read_unit()
-    }
+    fn decode(_: &mut D) -> () {}
 }
 
 impl<S: Encoder, T> Encodable<S> for PhantomData<T> {
@@ -336,8 +333,7 @@ impl<S: Encoder, T> Encodable<S> for PhantomData<T> {
 }
 
 impl<D: Decoder, T> Decodable<D> for PhantomData<T> {
-    fn decode(d: &mut D) -> PhantomData<T> {
-        d.read_unit();
+    fn decode(_: &mut D) -> PhantomData<T> {
         PhantomData
     }
 }

Diff for: compiler/rustc_target/src/spec/riscv32imc_esp_espidf.rs

@@ -18,11 +18,11 @@ pub fn target() -> Target {
             cpu: "generic-rv32".to_string(),
 
             // While the RiscV32IMC architecture does not natively support atomics, ESP-IDF does support
-            // the __atomic* and __sync* GCC builtins, so setting `max_atomic_width` to `Some(32)`
+            // the __atomic* and __sync* GCC builtins, so setting `max_atomic_width` to `Some(64)`
             // and `atomic_cas` to `true` will cause the compiler to emit libcalls to these builtins.
             //
             // Support for atomics is necessary for the Rust STD library, which is supported by the ESP-IDF framework.
-            max_atomic_width: Some(32),
+            max_atomic_width: Some(64),
             atomic_cas: true,
 
             features: "+m,+c".to_string(),

Diff for: library/core/src/array/iter.rs

@@ -93,7 +93,7 @@ impl<T, const N: usize> IntoIter<T, N> {
     ///
     /// - The `buffer[initialized]` elements must all be initialized.
     /// - The range must be canonical, with `initialized.start <= initialized.end`.
-    /// - The range must in in-bounds for the buffer, with `initialized.end <= N`.
+    /// - The range must be in-bounds for the buffer, with `initialized.end <= N`.
     ///   (Like how indexing `[0][100..100]` fails despite the range being empty.)
     ///
     /// It's sound to have more elements initialized than mentioned, though that

Diff for: library/core/src/ops/control_flow.rs

@@ -134,7 +134,6 @@ impl<B, C> ControlFlow<B, C> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(control_flow_enum)]
     /// use std::ops::ControlFlow;
     ///
     /// assert!(ControlFlow::<i32, String>::Break(3).is_break());
@@ -151,7 +150,6 @@ impl<B, C> ControlFlow<B, C> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(control_flow_enum)]
     /// use std::ops::ControlFlow;
     ///
     /// assert!(!ControlFlow::<i32, String>::Break(3).is_continue());

Diff for: library/std/src/io/error.rs

@@ -141,6 +141,19 @@ struct Custom {
 /// It is used with the [`io::Error`] type.
 ///
 /// [`io::Error`]: Error
+///
+/// # Handling errors and matching on `ErrorKind`
+///
+/// In application code, use `match` for the `ErrorKind` values you are
+/// expecting; use `_` to match "all other errors".
+///
+/// In comprehensive and thorough tests that want to verify that a test doesn't
+/// return any known incorrect error kind, you may want to cut-and-paste the
+/// current full list of errors from here into your test code, and then match
+/// `_` as the correct case. This seems counterintuitive, but it will make your
+/// tests more robust. In particular, if you want to verify that your code does
+/// produce an unrecognized error kind, the robust solution is to check for all
+/// the recognized error kinds and fail in those cases.
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[allow(deprecated)]

Diff for: src/test/debuginfo/basic-types.rs

@@ -104,7 +104,8 @@
 // cdb-check:b                : false [Type: bool]
 // cdb-command:dx i
 // cdb-check:i                : -1 [Type: [...]]
-// The variable 'c' doesn't appear for some reason...
+// cdb-command:dx c
+// cdb-check:c                : 0x61 'a' [Type: char32_t]
 // cdb-command:dx i8
 // cdb-check:i8               : 68 [Type: char]
 // cdb-command:dx i16

Diff for: src/test/debuginfo/borrowed-basic.rs

@@ -14,8 +14,7 @@
 // gdb-check:$2 = -1
 
 // gdb-command:print *char_ref
-// gdbg-check:$3 = 97
-// gdbr-check:$3 = 97 'a'
+// gdb-check:$3 = 97
 
 // gdb-command:print *i8_ref
 // gdbg-check:$4 = 68 'D'

Diff for: src/test/debuginfo/borrowed-unique-basic.rs

@@ -16,8 +16,7 @@
 // gdb-check:$2 = -1
 
 // gdb-command:print *char_ref
-// gdbg-check:$3 = 97
-// gdbr-check:$3 = 97 'a'
+// gdb-check:$3 = 97
 
 // gdb-command:print/d *i8_ref
 // gdb-check:$4 = 68