Auto merge of #66460 - cjgillot:hashstable_generic, r=Zoxc

Add a proc-macro to derive HashStable in librustc dependencies

A second proc-macro is added to derive HashStable for crates librustc depends on.
This proc-macro HashStable_Generic (to bikeshed) allows to decouple code and some librustc's boilerplate.

Not everything is migrated, because `Span` and `TokenKind` require to be placed inside librustc.
Types using them stay there too.

Split out of #66279
r? @Zoxc

4 files changed, 36 insertions, 27 deletions

diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index d96b5b7a3dd..dff23076c82 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -20,5 +20,6 @@ errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_index = { path = "../librustc_index" }
 rustc_lexer = { path = "../librustc_lexer" }
+rustc_macros = { path = "../librustc_macros" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc_error_codes = { path = "../librustc_error_codes" }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index bbf00825acb..a9f03e4af5b 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -37,6 +37,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_index::vec::Idx;
 use rustc_serialize::{self, Decoder, Encoder};
+use rustc_macros::HashStable_Generic;
 
 use std::fmt;
 
@@ -722,9 +723,8 @@ pub enum PatKind {
     Mac(Mac),
 }
 
-#[derive(
-    Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug, Copy,
-)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash,
+         RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
 pub enum Mutability {
     Mutable,
     Immutable,
@@ -1328,7 +1328,7 @@ pub struct QSelf {
 }
 
 /// A capture clause used in closures and `async` blocks.
-#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum CaptureBy {
     /// `move |x| y + x`.
     Value,
@@ -1339,7 +1339,7 @@ pub enum CaptureBy {
 /// The movability of a generator / closure literal:
 /// whether a generator contains self-references, causing it to be `!Unpin`.
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash,
-         RustcEncodable, RustcDecodable, Debug, Copy)]
+         RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
 pub enum Movability {
     /// May contain self-references, `!Unpin`.
     Static,
@@ -1400,7 +1400,7 @@ impl MacroDef {
 }
 
 // Clippy uses Hash and PartialEq
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, PartialEq)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy, Hash, PartialEq, HashStable_Generic)]
 pub enum StrStyle {
     /// A regular string, like `"foo"`.
     Cooked,
@@ -1451,7 +1451,7 @@ impl StrLit {
 
 // Clippy uses Hash and PartialEq
 /// Type of the integer literal based on provided suffix.
-#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq, HashStable_Generic)]
 pub enum LitIntType {
     /// e.g. `42_i32`.
     Signed(IntTy),
@@ -1462,7 +1462,7 @@ pub enum LitIntType {
 }
 
 /// Type of the float literal based on provided suffix.
-#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
+#[derive(Clone, Copy, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq, HashStable_Generic)]
 pub enum LitFloatType {
     /// A float literal with a suffix (`1f32` or `1E10f32`).
     Suffixed(FloatTy),
@@ -1474,7 +1474,7 @@ pub enum LitFloatType {
 ///
 /// E.g., `"foo"`, `42`, `12.34`, or `bool`.
 // Clippy uses Hash and PartialEq
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq)]
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug, Hash, PartialEq, HashStable_Generic)]
 pub enum LitKind {
     /// A string literal (`"foo"`).
     Str(Symbol, StrStyle),
@@ -1609,7 +1609,8 @@ pub enum ImplItemKind {
     Macro(Mac),
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable_Generic,
+         RustcEncodable, RustcDecodable, Debug)]
 pub enum FloatTy {
     F32,
     F64,
@@ -1638,7 +1639,8 @@ impl FloatTy {
     }
 }
 
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable_Generic,
+         RustcEncodable, RustcDecodable, Debug)]
 pub enum IntTy {
     Isize,
     I8,
@@ -1690,7 +1692,8 @@ impl IntTy {
     }
 }
 
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, Copy, Debug)]
+#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable_Generic,
+         RustcEncodable, RustcDecodable, Copy, Debug)]
 pub enum UintTy {
     Usize,
     U8,
@@ -1863,7 +1866,7 @@ pub enum TraitObjectSyntax {
 /// Inline assembly dialect.
 ///
 /// E.g., `"intel"` as in `asm!("mov eax, 2" : "={eax}"(result) : : : "intel")`.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
 pub enum AsmDialect {
     Att,
     Intel,
@@ -2021,14 +2024,14 @@ impl FnDecl {
 }
 
 /// Is the trait definition an auto trait?
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum IsAuto {
     Yes,
     No,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash,
-         RustcEncodable, RustcDecodable, Debug)]
+         RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum Unsafety {
     Unsafe,
     Normal,
@@ -2085,7 +2088,7 @@ impl IsAsync {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum Constness {
     Const,
     NotConst,
@@ -2093,13 +2096,13 @@ pub enum Constness {
 
 /// Item defaultness.
 /// For details see the [RFC #2532](https://github.com/rust-lang/rfcs/pull/2532).
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum Defaultness {
     Default,
     Final,
 }
 
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable_Generic)]
 pub enum ImplPolarity {
     /// `impl Trait for Type`
     Positive,
@@ -2233,7 +2236,7 @@ impl UseTree {
 /// Distinguishes between `Attribute`s that decorate items and Attributes that
 /// are contained as statements within items. These two cases need to be
 /// distinguished for pretty-printing.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, HashStable_Generic)]
 pub enum AttrStyle {
     Outer,
     Inner,
@@ -2331,7 +2334,7 @@ impl PolyTraitRef {
     }
 }
 
-#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum CrateSugar {
     /// Source is `pub(crate)`.
     PubCrate,
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index 767fcabc017..c10541c8c7e 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -9,6 +9,7 @@ use errors::{Applicability, Handler};
 use std::num::NonZeroU32;
 use syntax_pos::hygiene::Transparency;
 use syntax_pos::{symbol::Symbol, symbol::sym, Span};
+use rustc_macros::HashStable_Generic;
 
 use super::{mark_used, MetaItemKind};
 
@@ -141,7 +142,8 @@ pub fn find_unwind_attr(diagnostic: Option<&Handler>, attrs: &[Attribute]) -> Op
 }
 
 /// Represents the #[stable], #[unstable], #[rustc_{deprecated,const_unstable}] attributes.
-#[derive(RustcEncodable, RustcDecodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(RustcEncodable, RustcDecodable, Copy, Clone, Debug,
+         PartialEq, Eq, Hash, HashStable_Generic)]
 pub struct Stability {
     pub level: StabilityLevel,
     pub feature: Symbol,
@@ -157,7 +159,8 @@ pub struct Stability {
 }
 
 /// The available stability levels.
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Copy, Clone, Debug, Eq, Hash)]
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd,
+         Copy, Clone, Debug, Eq, Hash, HashStable_Generic)]
 pub enum StabilityLevel {
     // Reason for the current stability level and the relevant rust-lang issue
     Unstable { reason: Option<Symbol>, issue: Option<NonZeroU32>, is_soft: bool },
@@ -181,7 +184,8 @@ impl StabilityLevel {
     }
 }
 
-#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd, Copy, Clone, Debug, Eq, Hash)]
+#[derive(RustcEncodable, RustcDecodable, PartialEq, PartialOrd,
+         Copy, Clone, Debug, Eq, Hash, HashStable_Generic)]
 pub struct RustcDeprecation {
     pub since: Symbol,
     pub reason: Symbol,
@@ -636,7 +640,7 @@ pub fn eval_condition<F>(cfg: &ast::MetaItem, sess: &ParseSess, eval: &mut F)
     }
 }
 
-#[derive(RustcEncodable, RustcDecodable, Clone)]
+#[derive(RustcEncodable, RustcDecodable, Clone, HashStable_Generic)]
 pub struct Deprecation {
     pub since: Option<Symbol>,
     pub note: Option<Symbol>,
@@ -763,7 +767,7 @@ pub enum ReprAttr {
     ReprAlign(u32),
 }
 
-#[derive(Eq, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone)]
+#[derive(Eq, PartialEq, Debug, RustcEncodable, RustcDecodable, Copy, Clone, HashStable_Generic)]
 pub enum IntType {
     SignedInt(ast::IntTy),
     UnsignedInt(ast::UintTy)
diff --git a/src/libsyntax/token.rs b/src/libsyntax/token.rs
index ab798e93d67..fd1623384a4 100644
--- a/src/libsyntax/token.rs
+++ b/src/libsyntax/token.rs
@@ -15,6 +15,7 @@ use syntax_pos::{self, Span, DUMMY_SP};
 use std::fmt;
 use std::mem;
 use rustc_data_structures::sync::Lrc;
+use rustc_macros::HashStable_Generic;
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum BinOpToken {
@@ -53,7 +54,7 @@ impl DelimToken {
     }
 }
 
-#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum LitKind {
     Bool, // AST only, must never appear in a `Token`
     Byte,
@@ -68,7 +69,7 @@ pub enum LitKind {
 }
 
 /// A literal token.
-#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, Copy, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub struct Lit {
     pub kind: LitKind,
     pub symbol: Symbol,