Fix channel reference serialization in fifo instantiations.

PiperOrigin-RevId: 619694801

xls/ir/instantiation.cc

@@ -223,7 +223,7 @@ absl::StatusOr<InstantiationPort> FifoInstantiation::GetOutputPort(
 std::string FifoInstantiation::ToString() const {
   std::string channel_str;
   if (channel_name_.has_value()) {
-    channel_str = absl::StrFormat("channel=\"%s\", ", *channel_name_);
+    channel_str = absl::StrFormat("channel=%s, ", *channel_name_);
   }
 
   return absl::StrFormat(

xls/ir/ir_parser_test.cc

@@ -1795,6 +1795,36 @@ block my_block(x: bits[32]) {
   ParsePackageAndCheckDump(input);
 }
 
+TEST(IrParserTest, ParseInstantiationWithChannel) {
+  constexpr std::string_view input = R"(package test
+chan foo(bits[32], id=42, kind=streaming, ops=send_receive, flow_control=none, strictness=proven_mutually_exclusive, fifo_depth=0, metadata="""""")
+
+proc placeholder_channel_user(tok: token, init={}) {
+  recv_out: (token, bits[32]) = receive(tok, channel=foo, id=1)
+  recv_tok: token = tuple_index(recv_out, index=0, id=2)
+  recv_data: bits[32] = tuple_index(recv_out, index=1, id=3)
+  send_out: token = send(recv_tok, recv_data, channel=foo, id=4)
+  next (send_out)
+}
+
+block sub_block(in: bits[32], out: bits[32]) {
+  in: bits[32] = input_port(name=in, id=5)
+  zero: bits[32] = literal(value=0, id=6)
+  out: () = output_port(zero, name=out, id=7)
+}
+
+block my_block(x: bits[32], y: bits[32]) {
+  instantiation foo_inst(data_type=bits[32], depth=0, bypass=true, channel=foo, kind=fifo)
+  instantiation bar(block=sub_block, kind=block)
+  x: bits[32] = input_port(name=x, id=8)
+  x_in: () = instantiation_input(x, instantiation=bar, port_name=in, id=9)
+  x_out: bits[32] = instantiation_output(instantiation=bar, port_name=out, id=10)
+  y: () = output_port(x_out, name=y, id=11)
+}
+)";
+  ParsePackageAndCheckDump(input);
+}
+
 TEST(IrParserTest, ParseArrayIndex) {
   const std::string input = R"(
 fn foo(x: bits[32][6]) -> bits[32] {