gccrs: Allow hashing Optional<T>

gcc/rust/ChangeLog:

	* util/rust-optional.h
	(struct std::hash<Optional<T>>): New.

Signed-off-by: Owen Avery <powerboat9.gamer@gmail.com>

diff --git a/gcc/rust/util/rust-optional.h b/gcc/rust/util/rust-optional.h
index 3b3f110b773ede5b82a2e6f769d54d231fdb240c..658d90faa87f30267139a54dc51f84dfd3db1b50 100644 (file)
--- a/gcc/rust/util/rust-optional.h
+++ b/gcc/rust/util/rust-optional.h
@@ -228,6 +228,18 @@ public:
 
 } // namespace Rust
 
+namespace std {
+
+template <typename T> struct hash<Rust::Optional<T>>
+{
+  size_t operator() (const Rust::Optional<T> &op) const
+  {
+    return op.is_some () ? std::hash<T> () (op.get ()) : 0;
+  }
+};
+
+} // namespace std
+
 #ifdef CHECKING_P
 
 void