Auto merge of rust-lang#59967 - Centril:rollup-bdqq7ux, r=Centril

Rollup of 7 pull requests

Successful merges:

 - rust-lang#59856 (update polonius-engine)
 - rust-lang#59877 (HirIdify hir::Def)
 - rust-lang#59896 (Remove duplicated redundant spans)
 - rust-lang#59900 (Remove [mut] syntax in pin docs)
 - rust-lang#59906 (Make BufWriter use get_mut instead of manipulating inner in Write implementation)
 - rust-lang#59936 (Fix cross-crate visibility of fictive variant constructors)
 - rust-lang#59957 (Add missing backtick to Symbol documentation.)

Failed merges:

r? @ghost

Author: bors

Cargo.lock

@@ -1906,7 +1906,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "polonius-engine"
-version = "0.6.2"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "datafrog 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2341,7 +2341,7 @@ dependencies = [
  "measureme 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "polonius-engine 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polonius-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon-core 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_apfloat 0.0.0",
@@ -2841,7 +2841,7 @@ dependencies = [
  "graphviz 0.0.0",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "log_settings 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "polonius-engine 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polonius-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_apfloat 0.0.0",
  "rustc_data_structures 0.0.0",
@@ -4164,7 +4164,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum phf_generator 0.7.22 (registry+https://github.com/rust-lang/crates.io-index)" = "05a079dd052e7b674d21cb31cbb6c05efd56a2cd2827db7692e2f1a507ebd998"
 "checksum phf_shared 0.7.22 (registry+https://github.com/rust-lang/crates.io-index)" = "c2261d544c2bb6aa3b10022b0be371b9c7c64f762ef28c6f5d4f1ef6d97b5930"
 "checksum pkg-config 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)" = "676e8eb2b1b4c9043511a9b7bea0915320d7e502b0a079fb03f9635a5252b18c"
-"checksum polonius-engine 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2490c396085801abf88df91758bad806b0890354f0875d624e62ecf0579a8145"
+"checksum polonius-engine 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8b24942fee141ea45628484a453762bb7e515099c3ec05fbeb76b7bf57b1aeed"
 "checksum precomputed-hash 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "925383efa346730478fb4838dbe9137d2a47675ad789c546d150a6e1dd4ab31c"
 "checksum pretty_assertions 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a029430f0d744bc3d15dd474d591bed2402b645d024583082b9f63bb936dac6"
 "checksum pretty_env_logger 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df8b3f4e0475def7d9c2e5de8e5a1306949849761e107b360d03e98eafaffd61"

src/libcore/pin.rs

@@ -158,28 +158,32 @@
 //! is called *even if your type was previously pinned*! It is as if the
 //! compiler automatically called `get_unchecked_mut`.
 //!
-//! This can never cause a problem in safe code because implementing a type that relies on pinning
-//! requires unsafe code, but be aware that deciding to make use of pinning
-//! in your type (for example by implementing some operation on `Pin<&[mut] Self>`)
-//! has consequences for your `Drop` implementation as well: if an element
-//! of your type could have been pinned, you must treat Drop as implicitly taking
-//! `Pin<&mut Self>`.
+//! This can never cause a problem in safe code because implementing a type that
+//! relies on pinning requires unsafe code, but be aware that deciding to make
+//! use of pinning in your type (for example by implementing some operation on
+//! `Pin<&Self>` or `Pin<&mut Self>`) has consequences for your `Drop`
+//! implementation as well: if an element of your type could have been pinned,
+//! you must treat Drop as implicitly taking `Pin<&mut Self>`.
 //!
 //! In particular, if your type is `#[repr(packed)]`, the compiler will automatically
 //! move fields around to be able to drop them. As a consequence, you cannot use
 //! pinning with a `#[repr(packed)]` type.
 //!
 //! # Projections and Structural Pinning
 //!
-//! One interesting question arises when considering the interaction of pinning and
-//! the fields of a struct. When can a struct have a "pinning projection", i.e.,
-//! an operation with type `fn(Pin<&[mut] Struct>) -> Pin<&[mut] Field>`?
-//! In a similar vein, when can a generic wrapper type (such as `Vec<T>`, `Box<T>`, or `RefCell<T>`)
-//! have an operation with type `fn(Pin<&[mut] Wrapper<T>>) -> Pin<&[mut] T>`?
+//! One interesting question arises when considering the interaction of pinning
+//! and the fields of a struct. When can a struct have a "pinning projection",
+//! i.e., an operation with type `fn(Pin<&Struct>) -> Pin<&Field>`?  In a
+//! similar vein, when can a generic wrapper type (such as `Vec<T>`, `Box<T>`,
+//! or `RefCell<T>`) have an operation with type `fn(Pin<&Wrapper<T>>) ->
+//! Pin<&T>`?
+//!
+//! Note: For the entirety of this discussion, the same applies for mutable references as it
+//! does for shared references.
 //!
 //! Having a pinning projection for some field means that pinning is "structural":
 //! when the wrapper is pinned, the field must be considered pinned, too.
-//! After all, the pinning projection lets us get a `Pin<&[mut] Field>`.
+//! After all, the pinning projection lets us get a `Pin<&Field>`.
 //!
 //! However, structural pinning comes with a few extra requirements, so not all
 //! wrappers can be structural and hence not all wrappers can offer pinning projections:

src/librustc/Cargo.toml

@@ -19,7 +19,7 @@ lazy_static = "1.0.0"
 num_cpus = "1.0"
 scoped-tls = "1.0"
 log = { version = "0.4", features = ["release_max_level_info", "std"] }
-polonius-engine = "0.6.2"
+polonius-engine = "0.7.0"
 rustc-rayon = "0.1.2"
 rustc-rayon-core = "0.1.2"
 rustc_apfloat = { path = "../librustc_apfloat" }

src/librustc/hir/def.rs

@@ -2,10 +2,12 @@ use crate::hir::def_id::DefId;
 use crate::util::nodemap::{NodeMap, DefIdMap};
 use syntax::ast;
 use syntax::ext::base::MacroKind;
+use syntax::ast::NodeId;
 use syntax_pos::Span;
 use rustc_macros::HashStable;
 use crate::hir;
 use crate::ty;
+use std::fmt::Debug;
 
 use self::Namespace::*;
 
@@ -43,7 +45,7 @@ pub enum NonMacroAttrKind {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, HashStable)]
-pub enum Def {
+pub enum Def<Id = hir::HirId> {
     // Type namespace
     Mod(DefId),
     /// `DefId` refers to the struct itself, `Def::Ctor` refers to its constructor if it exists.
@@ -78,8 +80,8 @@ pub enum Def {
     Method(DefId),
     AssociatedConst(DefId),
 
-    Local(ast::NodeId),
-    Upvar(ast::NodeId,  // `NodeId` of closed over local
+    Local(Id),
+    Upvar(Id,           // `HirId` of closed over local
           usize,        // index in the `freevars` list of the closure
           ast::NodeId), // expr node that creates the closure
     Label(ast::NodeId),
@@ -108,22 +110,22 @@ pub enum Def {
 /// ```
 #[derive(Copy, Clone, Debug)]
 pub struct PathResolution {
-    base_def: Def,
+    base_def: Def<NodeId>,
     unresolved_segments: usize,
 }
 
 impl PathResolution {
-    pub fn new(def: Def) -> Self {
+    pub fn new(def: Def<NodeId>) -> Self {
         PathResolution { base_def: def, unresolved_segments: 0 }
     }
 
-    pub fn with_unresolved_segments(def: Def, mut unresolved_segments: usize) -> Self {
+    pub fn with_unresolved_segments(def: Def<NodeId>, mut unresolved_segments: usize) -> Self {
         if def == Def::Err { unresolved_segments = 0 }
         PathResolution { base_def: def, unresolved_segments: unresolved_segments }
     }
 
     #[inline]
-    pub fn base_def(&self) -> Def {
+    pub fn base_def(&self) -> Def<NodeId> {
         self.base_def
     }
 
@@ -215,25 +217,36 @@ pub type DefMap = NodeMap<PathResolution>;
 
 /// This is the replacement export map. It maps a module to all of the exports
 /// within.
-pub type ExportMap = DefIdMap<Vec<Export>>;
+pub type ExportMap<Id> = DefIdMap<Vec<Export<Id>>>;
 
 /// Map used to track the `use` statements within a scope, matching it with all the items in every
 /// namespace.
 pub type ImportMap = NodeMap<PerNS<Option<PathResolution>>>;
 
 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct Export {
+pub struct Export<Id> {
     /// The name of the target.
     pub ident: ast::Ident,
     /// The definition of the target.
-    pub def: Def,
+    pub def: Def<Id>,
     /// The span of the target definition.
     pub span: Span,
     /// The visibility of the export.
     /// We include non-`pub` exports for hygienic macros that get used from extern crates.
     pub vis: ty::Visibility,
 }
 
+impl<Id> Export<Id> {
+    pub fn map_id<R>(self, map: impl FnMut(Id) -> R) -> Export<R> {
+        Export {
+            ident: self.ident,
+            def: self.def.map_id(map),
+            span: self.span,
+            vis: self.vis,
+        }
+    }
+}
+
 impl CtorKind {
     pub fn from_ast(vdata: &ast::VariantData) -> CtorKind {
         match *vdata {
@@ -264,9 +277,12 @@ impl NonMacroAttrKind {
     }
 }
 
-impl Def {
+impl<Id> Def<Id> {
     /// Return the `DefId` of this `Def` if it has an id, else panic.
-    pub fn def_id(&self) -> DefId {
+    pub fn def_id(&self) -> DefId
+    where
+        Id: Debug,
+    {
         self.opt_def_id().unwrap_or_else(|| {
             bug!("attempted .def_id() on invalid def: {:?}", self)
         })
@@ -358,4 +374,43 @@ impl Def {
             _ => "a",
         }
     }
+
+    pub fn map_id<R>(self, mut map: impl FnMut(Id) -> R) -> Def<R> {
+        match self {
+            Def::Fn(id) => Def::Fn(id),
+            Def::Mod(id) => Def::Mod(id),
+            Def::Static(id, is_mutbl) => Def::Static(id, is_mutbl),
+            Def::Enum(id) => Def::Enum(id),
+            Def::Variant(id) => Def::Variant(id),
+            Def::Ctor(a, b, c) => Def::Ctor(a, b, c),
+            Def::Struct(id) => Def::Struct(id),
+            Def::Existential(id) => Def::Existential(id),
+            Def::TyAlias(id) => Def::TyAlias(id),
+            Def::TraitAlias(id) => Def::TraitAlias(id),
+            Def::AssociatedTy(id) => Def::AssociatedTy(id),
+            Def::AssociatedExistential(id) => Def::AssociatedExistential(id),
+            Def::SelfCtor(id) => Def::SelfCtor(id),
+            Def::Union(id) => Def::Union(id),
+            Def::Trait(id) => Def::Trait(id),
+            Def::ForeignTy(id) => Def::ForeignTy(id),
+            Def::Method(id) => Def::Method(id),
+            Def::Const(id) => Def::Const(id),
+            Def::AssociatedConst(id) => Def::AssociatedConst(id),
+            Def::TyParam(id) => Def::TyParam(id),
+            Def::ConstParam(id) => Def::ConstParam(id),
+            Def::PrimTy(id) => Def::PrimTy(id),
+            Def::Local(id) => Def::Local(map(id)),
+            Def::Upvar(id, index, closure) => Def::Upvar(
+                map(id),
+                index,
+                closure
+            ),
+            Def::Label(id) => Def::Label(id),
+            Def::SelfTy(a, b) => Def::SelfTy(a, b),
+            Def::Macro(id, macro_kind) => Def::Macro(id, macro_kind),
+            Def::ToolMod => Def::ToolMod,
+            Def::NonMacroAttr(attr_kind) => Def::NonMacroAttr(attr_kind),
+            Def::Err => Def::Err,
+        }
+    }
 }