Auto merge of #64751 - Centril:rollup-hpbmcfj, r=Centril

Rollup of 16 pull requests

Successful merges:

 - #63356 (Issue#63183: Add fs::read_dir() and ReadDir warning about iterator order + example)
 - #63934 (Fix coherence checking for impl trait in type aliases)
 - #64016 (Streamline `Compiler`)
 - #64296 (Document the unstable iter_order_by library feature)
 - #64443 (rustdoc: general cleanup)
 - #64622 (Add a cycle detector for generic `Graph`s and `mir::Body`s)
 - #64689 (Refactor macro by example)
 - #64698 (Recover on `const X = 42;` and infer type + Error Stash API)
 - #64702 (Remove unused dependencies)
 - #64717 (update mem::discriminant test to use assert_eq and assert_ne over comparison operators)
 - #64720 ( remove rtp.rs, and move rtpSpawn and RTP_ID_ERROR to libc)
 - #64721 (Fixed issue from #64447)
 - #64725 (fix one typo)
 - #64737 (fix several issues in String docs)
 - #64742 (relnotes: make compatibility section more sterile and fix rustc version)
 - #64748 (Fix #64744. Account for the Zero sub-pattern case.)

Failed merges:

r? @ghost

Author: bors

Diff for: Cargo.lock

@@ -3324,8 +3324,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_errors",
- "syntax",
  "syntax_pos",
 ]
 
@@ -3347,7 +3345,6 @@ dependencies = [
  "log",
  "memmap",
  "num_cpus",
- "parking_lot 0.9.0",
  "rustc",
  "rustc_apfloat",
  "rustc_codegen_utils",
@@ -3366,7 +3363,6 @@ dependencies = [
 name = "rustc_codegen_utils"
 version = "0.0.0"
 dependencies = [
- "flate2",
  "log",
  "punycode",
  "rustc",
@@ -3561,7 +3557,6 @@ name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
  "arena",
- "byteorder",
  "either",
  "graphviz",
  "log",
@@ -3614,7 +3609,6 @@ name = "rustc_plugin_impl"
 version = "0.0.0"
 dependencies = [
  "rustc",
- "rustc_errors",
  "rustc_metadata",
  "syntax",
  "syntax_pos",
@@ -3638,7 +3632,6 @@ version = "0.0.0"
 dependencies = [
  "arena",
  "bitflags",
- "indexmap",
  "log",
  "rustc",
  "rustc_data_structures",
@@ -3660,7 +3653,6 @@ dependencies = [
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_target",
- "rustc_typeck",
  "serde_json",
  "syntax",
  "syntax_pos",
@@ -3691,9 +3683,7 @@ checksum = "b725dadae9fabc488df69a287f5a99c5eaf5d10853842a8a3dfac52476f544ee"
 name = "rustc_traits"
 version = "0.0.0"
 dependencies = [
- "bitflags",
  "chalk-engine",
- "graphviz",
  "log",
  "rustc",
  "rustc_data_structures",
@@ -4056,7 +4046,6 @@ version = "0.0.0"
 dependencies = [
  "alloc",
  "backtrace",
- "cc",
  "cfg-if",
  "compiler_builtins",
  "core",
@@ -4241,7 +4230,6 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_lexer",
- "rustc_macros",
  "rustc_target",
  "scoped-tls",
  "serialize",
@@ -4257,7 +4245,6 @@ dependencies = [
  "log",
  "rustc_data_structures",
  "rustc_errors",
- "rustc_lexer",
  "rustc_target",
  "smallvec",
  "syntax",

Diff for: RELEASES.md

@@ -70,10 +70,10 @@ Misc
 
 Compatibility Notes
 -------------------
-- Unfortunately the [`x86_64-unknown-uefi` platform can not be built][62785]
-  with rustc 1.39.0.
-- The [`armv7-unknown-linux-gnueabihf` platform is also known to have
-  issues][62896] for certain crates such as libc.
+- The [`x86_64-unknown-uefi` platform can not be built][62785] with rustc
+  1.38.0.
+- The [`armv7-unknown-linux-gnueabihf` platform is known to have
+  issues][62896] with certain crates such as libc.
 
 [60260]: https://github.com/rust-lang/rust/pull/60260/
 [61457]: https://github.com/rust-lang/rust/pull/61457/

Diff for: src/liballoc/string.rs

@@ -429,7 +429,7 @@ impl String {
 
     /// Converts a vector of bytes to a `String`.
     ///
-    /// A string slice ([`&str`]) is made of bytes ([`u8`]), and a vector of bytes
+    /// A string ([`String`]) is made of bytes ([`u8`]), and a vector of bytes
     /// ([`Vec<u8>`]) is made of bytes, so this function converts between the
     /// two. Not all byte slices are valid `String`s, however: `String`
     /// requires that it is valid UTF-8. `from_utf8()` checks to ensure that
@@ -446,7 +446,7 @@ impl String {
     /// If you need a [`&str`] instead of a `String`, consider
     /// [`str::from_utf8`].
     ///
-    /// The inverse of this method is [`as_bytes`].
+    /// The inverse of this method is [`into_bytes`].
     ///
     /// # Errors
     ///
@@ -480,11 +480,11 @@ impl String {
     /// with this error.
     ///
     /// [`from_utf8_unchecked`]: struct.String.html#method.from_utf8_unchecked
-    /// [`&str`]: ../../std/primitive.str.html
+    /// [`String`]: struct.String.html
     /// [`u8`]: ../../std/primitive.u8.html
     /// [`Vec<u8>`]: ../../std/vec/struct.Vec.html
     /// [`str::from_utf8`]: ../../std/str/fn.from_utf8.html
-    /// [`as_bytes`]: struct.String.html#method.as_bytes
+    /// [`into_bytes`]: struct.String.html#method.into_bytes
     /// [`FromUtf8Error`]: struct.FromUtf8Error.html
     /// [`Err`]: ../../std/result/enum.Result.html#variant.Err
     #[inline]

Diff for: src/libcore/iter/traits/iterator.rs

@@ -2581,7 +2581,7 @@ pub trait Iterator {
     /// assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (x * x).cmp(&y)), Ordering::Equal);
     /// assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (2 * x).cmp(&y)), Ordering::Greater);
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn cmp_by<I, F>(mut self, other: I, mut cmp: F) -> Ordering
     where
         Self: Sized,
@@ -2664,7 +2664,7 @@ pub trait Iterator {
     ///     Some(Ordering::Greater)
     /// );
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn partial_cmp_by<I, F>(mut self, other: I, mut partial_cmp: F) -> Option<Ordering>
     where
         Self: Sized,
@@ -2729,7 +2729,7 @@ pub trait Iterator {
     ///
     /// assert!(xs.iter().eq_by(&ys, |&x, &y| x * x == y));
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn eq_by<I, F>(mut self, other: I, mut eq: F) -> bool
     where
         Self: Sized,

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

@@ -818,9 +818,9 @@ impl<T> fmt::Debug for Discriminant<T> {
 ///
 /// enum Foo { A(&'static str), B(i32), C(i32) }
 ///
-/// assert!(mem::discriminant(&Foo::A("bar")) == mem::discriminant(&Foo::A("baz")));
-/// assert!(mem::discriminant(&Foo::B(1))     == mem::discriminant(&Foo::B(2)));
-/// assert!(mem::discriminant(&Foo::B(3))     != mem::discriminant(&Foo::C(3)));
+/// assert_eq!(mem::discriminant(&Foo::A("bar")), mem::discriminant(&Foo::A("baz")));
+/// assert_eq!(mem::discriminant(&Foo::B(1)), mem::discriminant(&Foo::B(2)));
+/// assert_ne!(mem::discriminant(&Foo::B(3)), mem::discriminant(&Foo::C(3)));
 /// ```
 #[stable(feature = "discriminant_value", since = "1.21.0")]
 pub fn discriminant<T>(v: &T) -> Discriminant<T> {

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

@@ -262,6 +262,12 @@ impl<'tcx> Body<'tcx> {
         dominators(self)
     }
 
+    /// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
+    /// `START_BLOCK`.
+    pub fn is_cfg_cyclic(&self) -> bool {
+        graph::is_cyclic(self)
+    }
+
     #[inline]
     pub fn local_kind(&self, local: Local) -> LocalKind {
         let index = local.as_usize();

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

@@ -321,6 +321,7 @@ impl Session {
     }
     pub fn compile_status(&self) -> Result<(), ErrorReported> {
         if self.has_errors() {
+            self.diagnostic().emit_stashed_diagnostics();
             Err(ErrorReported)
         } else {
             Ok(())

Diff for: src/librustc/traits/coherence.rs

@@ -432,7 +432,7 @@ fn orphan_check_trait_ref<'tcx>(
 }
 
 fn uncovered_tys<'tcx>(tcx: TyCtxt<'_>, ty: Ty<'tcx>, in_crate: InCrate) -> Vec<Ty<'tcx>> {
-    if ty_is_local_constructor(ty, in_crate) {
+    if ty_is_local_constructor(tcx, ty, in_crate) {
         vec![]
     } else if fundamental_ty(ty) {
         ty.walk_shallow()
@@ -451,7 +451,7 @@ fn is_possibly_remote_type(ty: Ty<'_>, _in_crate: InCrate) -> bool {
 }
 
 fn ty_is_local(tcx: TyCtxt<'_>, ty: Ty<'_>, in_crate: InCrate) -> bool {
-    ty_is_local_constructor(ty, in_crate) ||
+    ty_is_local_constructor(tcx, ty, in_crate) ||
         fundamental_ty(ty) && ty.walk_shallow().any(|t| ty_is_local(tcx, t, in_crate))
 }
 
@@ -472,7 +472,7 @@ fn def_id_is_local(def_id: DefId, in_crate: InCrate) -> bool {
     }
 }
 
-fn ty_is_local_constructor(ty: Ty<'_>, in_crate: InCrate) -> bool {
+fn ty_is_local_constructor(tcx: TyCtxt<'_>, ty: Ty<'_>, in_crate: InCrate) -> bool {
     debug!("ty_is_local_constructor({:?})", ty);
 
     match ty.sty {
@@ -504,6 +504,15 @@ fn ty_is_local_constructor(ty: Ty<'_>, in_crate: InCrate) -> bool {
 
         ty::Adt(def, _) => def_id_is_local(def.did, in_crate),
         ty::Foreign(did) => def_id_is_local(did, in_crate),
+        ty::Opaque(did, _) => {
+            // Check the underlying type that this opaque
+            // type resolves to.
+            // This recursion will eventually terminate,
+            // since we've already managed to successfully
+            // resolve all opaque types by this point
+            let real_ty = tcx.type_of(did);
+            ty_is_local_constructor(tcx, real_ty, in_crate)
+        }
 
         ty::Dynamic(ref tt, ..) => {
             if let Some(principal) = tt.principal() {
@@ -518,8 +527,7 @@ fn ty_is_local_constructor(ty: Ty<'_>, in_crate: InCrate) -> bool {
         ty::UnnormalizedProjection(..) |
         ty::Closure(..) |
         ty::Generator(..) |
-        ty::GeneratorWitness(..) |
-        ty::Opaque(..) => {
+        ty::GeneratorWitness(..) => {
             bug!("ty_is_local invoked on unexpected type: {:?}", ty)
         }
     }

Diff for: src/librustc/traits/specialize/specialization_graph.rs

@@ -395,7 +395,7 @@ impl<'tcx> Graph {
     /// The parent of a given impl, which is the `DefId` of the trait when the
     /// impl is a "specialization root".
     pub fn parent(&self, child: DefId) -> DefId {
-        *self.parent.get(&child).unwrap()
+        *self.parent.get(&child).unwrap_or_else(|| panic!("Failed to get parent for {:?}", child))
     }
 }
 

Diff for: src/librustc_ast_borrowck/Cargo.toml

@@ -12,11 +12,9 @@ doctest = false
 
 [dependencies]
 log = "0.4"
-syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 # for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
 # refers to the borrowck-specific graphviz adapter traits.
 dot = { path = "../libgraphviz", package = "graphviz" }
 rustc = { path = "../librustc" }
-errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }

Diff for: src/librustc_codegen_ssa/Cargo.toml

@@ -17,7 +17,6 @@ memmap = "0.6"
 log = "0.4.5"
 libc = "0.2.44"
 jobserver = "0.1.11"
-parking_lot = "0.9"
 tempfile = "3.1"
 
 rustc_serialize = { path = "../libserialize", package = "serialize" }

Diff for: src/librustc_codegen_utils/Cargo.toml

@@ -10,7 +10,6 @@ path = "lib.rs"
 test = false
 
 [dependencies]
-flate2 = "1.0"
 log = "0.4"
 punycode = "0.4.0"
 rustc-demangle = "0.1.16"