1 files changed, 31 insertions, 0 deletions
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index 40f00aaa5d8..6de9a0fb070 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -16,6 +16,7 @@
 use crate::token::{self, DelimToken, Token, TokenKind};
 
 use syntax_pos::{Span, DUMMY_SP};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::sync::Lrc;
 use smallvec::{SmallVec, smallvec};
 
@@ -51,6 +52,26 @@ where
     TokenStream: Send + Sync,
 {}
 
+impl<CTX> HashStable<CTX> for TokenTree
+    where CTX: crate::StableHashingContextLike
+{
+    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+        mem::discriminant(self).hash_stable(hcx, hasher);
+        match *self {
+            TokenTree::Token(ref token) => {
+                token.hash_stable(hcx, hasher);
+            }
+            TokenTree::Delimited(span, delim, ref tts) => {
+                span.hash_stable(hcx, hasher);
+                std::hash::Hash::hash(&delim, hasher);
+                for sub_tt in tts.trees() {
+                    sub_tt.hash_stable(hcx, hasher);
+                }
+            }
+        }
+    }
+}
+
 impl TokenTree {
     /// Checks if this TokenTree is equal to the other, regardless of span information.
     pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
@@ -115,6 +136,16 @@ impl TokenTree {
     }
 }
 
+impl<CTX> HashStable<CTX> for TokenStream
+    where CTX: crate::StableHashingContextLike
+{
+    fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
+        for sub_tt in self.trees() {
+            sub_tt.hash_stable(hcx, hasher);
+        }
+    }
+}
+
 /// A `TokenStream` is an abstract sequence of tokens, organized into `TokenTree`s.
 ///
 /// The goal is for procedural macros to work with `TokenStream`s and `TokenTree`s