Add support for parsing empty tuple patterns.

gcc/rust/ChangeLog:

	* parse/rust-parse-impl.h
	(Parser::parse_grouped_or_tuple_pattern): Add support for empty tuple patterns.

gcc/testsuite/ChangeLog:

	* rust/compile/parse_empty_tuple_pattern.rs: New test.

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

2 files changed, 12 insertions, 0 deletions

diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 4ceb978..cc5436c 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -10926,6 +10926,15 @@ Parser<ManagedTokenSource>::parse_grouped_or_tuple_pattern ()
       return std::unique_ptr<AST::TuplePattern> (
 	new AST::TuplePattern (std::move (items), paren_locus));
     }
+  else if (lexer.peek_token ()->get_id () == RIGHT_PAREN)
+    {
+      skip_token (RIGHT_PAREN);
+      auto items = std::unique_ptr<AST::TuplePatternItemsMultiple> (
+	new AST::TuplePatternItemsMultiple (
+	  std::vector<std::unique_ptr<AST::Pattern>> ()));
+      return std::unique_ptr<AST::TuplePattern> (
+	new AST::TuplePattern (std::move (items), paren_locus));
+    }
 
   // parse initial pattern (required)
   std::unique_ptr<AST::Pattern> initial_pattern = parse_pattern ();
diff --git a/gcc/testsuite/rust/compile/parse_empty_tuple_pattern.rs b/gcc/testsuite/rust/compile/parse_empty_tuple_pattern.rs
new file mode 100644
index 0000000..d974d31
--- /dev/null
+++ b/gcc/testsuite/rust/compile/parse_empty_tuple_pattern.rs
@@ -0,0 +1,3 @@
+fn main() {
+    let () = ();
+}