Enable warnings as errors (#100)

Motivation:

It's generally helpful to avoid warnings. Currently there are zero
warnings, we can avoid regressing this by enabling warnings as errors in
CI.

Modifications:

- Enable warnings as errors

Result:

Harder to introduce warnings

.github/workflows/main.yml

@@ -13,10 +13,10 @@ jobs:
     with:
       linux_5_9_enabled: false
       linux_5_10_enabled: false
-      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
 
   construct-integration-tests-matrix:
     name: Construct integration matrix

.github/workflows/pull_request.yml

@@ -22,10 +22,10 @@ jobs:
     with:
       linux_5_9_enabled: false
       linux_5_10_enabled: false
-      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
-      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_6_1_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_nightly_next_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -warnings-as-errors"
 
   construct-integration-tests-matrix:
     name: Construct integration matrix

Tests/GRPCNIOTransportHTTP2Tests/HTTP2TransportTLSEnabledTests.swift

@@ -590,7 +590,9 @@ struct HTTP2TransportTLSEnabledTests {
     let input = ControlInput.with { $0.numberOfMessages = 1 }
     let request = ClientRequest(message: input)
     try await control.unary(request: request) { response in
-      #expect(throws: Never.self) { try response.message }
+      _ = #expect(throws: Never.self) {
+        try response.message
+      }
     }
   }
 }