[dhcp_interop] Deny unused results

Bug: 73468
Change-Id: I90a4942532477d75825a03d0a18c13db3b685c16
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/515023
Commit-Queue: Ghanan Gowripalan <ghanan@google.com>
Reviewed-by: Jay Zhuang <jayzhuang@google.com>
Reviewed-by: Tamir Duberstein <tamird@google.com>
diff --git a/build/config/rust/BUILD.gn b/build/config/rust/BUILD.gn
index 8992d65..0645992 100644
--- a/build/config/rust/BUILD.gn
+++ b/build/config/rust/BUILD.gn
@@ -147,7 +147,6 @@
     "//src/connectivity/network/netstack/*",
     "//src/connectivity/network/netstack3/*",
     "//src/connectivity/network/tests/connect/*",
-    "//src/connectivity/network/tests/dhcp_interop/*",
     "//src/connectivity/network/tools/*",
     "//src/connectivity/openthread/*",
     "//src/connectivity/overnet/*",
diff --git a/src/connectivity/network/tests/dhcp_interop/dhcp_validity/BUILD.gn b/src/connectivity/network/tests/dhcp_interop/dhcp_validity/BUILD.gn
index a28caa1..f2220d7 100644
--- a/src/connectivity/network/tests/dhcp_interop/dhcp_validity/BUILD.gn
+++ b/src/connectivity/network/tests/dhcp_interop/dhcp_validity/BUILD.gn
@@ -25,6 +25,8 @@
   ]
 
   sources = [ "src/main.rs" ]
+
+  configs -= [ "//build/config/rust:allow_unused_results" ]
 }
 
 rustc_library("lib") {
@@ -51,4 +53,6 @@
   ]
 
   sources = [ "src/lib.rs" ]
+
+  configs -= [ "//build/config/rust:allow_unused_results" ]
 }