Derive HashStable for TokenKind.

Author: cjgillot

src/librustc/ich/impls_syntax.rs

@@ -3,12 +3,8 @@
 
 use crate::ich::StableHashingContext;
 
-use std::hash as std_hash;
-use std::mem;
-
 use syntax::ast;
 use syntax::feature_gate;
-use syntax::token;
 use syntax_pos::SourceFile;
 
 use crate::hir::def_id::{DefId, CrateNum, CRATE_DEF_INDEX};
@@ -65,68 +61,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for ast::Attribute {
     }
 }
 
-impl<'ctx> syntax::HashStableContext for StableHashingContext<'ctx> {
-    fn hash_stable_tokenkind(&mut self, tokenkind: &token::TokenKind, hasher: &mut StableHasher) {
-        mem::discriminant(tokenkind).hash_stable(self, hasher);
-        match *tokenkind {
-            token::Eq |
-            token::Lt |
-            token::Le |
-            token::EqEq |
-            token::Ne |
-            token::Ge |
-            token::Gt |
-            token::AndAnd |
-            token::OrOr |
-            token::Not |
-            token::Tilde |
-            token::At |
-            token::Dot |
-            token::DotDot |
-            token::DotDotDot |
-            token::DotDotEq |
-            token::Comma |
-            token::Semi |
-            token::Colon |
-            token::ModSep |
-            token::RArrow |
-            token::LArrow |
-            token::FatArrow |
-            token::Pound |
-            token::Dollar |
-            token::Question |
-            token::SingleQuote |
-            token::Whitespace |
-            token::Comment |
-            token::Eof => {}
-
-            token::BinOp(bin_op_token) |
-            token::BinOpEq(bin_op_token) => {
-                std_hash::Hash::hash(&bin_op_token, hasher);
-            }
-
-            token::OpenDelim(delim_token) |
-            token::CloseDelim(delim_token) => {
-                std_hash::Hash::hash(&delim_token, hasher);
-            }
-            token::Literal(lit) => lit.hash_stable(self, hasher),
-
-            token::Ident(name, is_raw) => {
-                name.hash_stable(self, hasher);
-                is_raw.hash_stable(self, hasher);
-            }
-            token::Lifetime(name) => name.hash_stable(self, hasher),
-
-            token::Interpolated(_) => {
-                bug!("interpolated tokens should not be present in the HIR")
-            }
-
-            token::DocComment(val) |
-            token::Shebang(val) |
-            token::Unknown(val) => val.hash_stable(self, hasher),
-        }
-    }
-}
+impl<'ctx> syntax::HashStableContext for StableHashingContext<'ctx> {}
 
 impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {

src/libsyntax/lib.rs

@@ -20,7 +20,6 @@
 #![recursion_limit="256"]
 
 pub use errors;
-use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::Lock;
 use rustc_index::bit_set::GrowableBitSet;
 pub use rustc_data_structures::thin_vec::ThinVec;
@@ -115,6 +114,4 @@ pub mod early_buffered_lints;
 /// Requirements for a `StableHashingContext` to be used in this crate.
 /// This is a hack to allow using the `HashStable_Generic` derive macro
 /// instead of implementing everything in librustc.
-pub trait HashStableContext: syntax_pos::HashStableContext {
-    fn hash_stable_tokenkind(&mut self, tokenkind: &token::TokenKind, hasher: &mut StableHasher);
-}
+pub trait HashStableContext: syntax_pos::HashStableContext {}

src/libsyntax/token.rs

@@ -19,6 +19,7 @@ use rustc_data_structures::sync::Lrc;
 use rustc_macros::HashStable_Generic;
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(HashStable_Generic)]
 pub enum BinOpToken {
     Plus,
     Minus,
@@ -192,7 +193,7 @@ fn ident_can_begin_type(name: ast::Name, span: Span, is_raw: bool) -> bool {
     ].contains(&name)
 }
 
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub enum TokenKind {
     /* Expression-operator symbols. */
     Eq,
@@ -264,14 +265,6 @@ pub enum TokenKind {
 #[cfg(target_arch = "x86_64")]
 rustc_data_structures::static_assert_size!(TokenKind, 16);
 
-impl<CTX> HashStable<CTX> for TokenKind
-    where CTX: crate::HashStableContext
-{
-    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
-        hcx.hash_stable_tokenkind(self, hasher)
-    }
-}
-
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, HashStable_Generic)]
 pub struct Token {
     pub kind: TokenKind,
@@ -735,3 +728,11 @@ impl fmt::Debug for Nonterminal {
         }
     }
 }
+
+impl<CTX> HashStable<CTX> for Nonterminal
+    where CTX: crate::HashStableContext
+{
+    fn hash_stable(&self, _hcx: &mut CTX, _hasher: &mut StableHasher) {
+        panic!("interpolated tokens should not be present in the HIR")
+    }
+}