Fix warning CA1062#AsyncRateLimitPolicy

src/Polly/RateLimit/AsyncRateLimitPolicy.cs

@@ -4,7 +4,6 @@ namespace Polly.RateLimit;
 /// <summary>
 /// A rate-limit policy that can be applied to asynchronous delegates.
 /// </summary>
-#pragma warning disable CA1062 // Validate arguments of public methods
 public class AsyncRateLimitPolicy : AsyncPolicy, IRateLimitPolicy
 {
     private readonly IRateLimiter _rateLimiter;
@@ -14,9 +13,25 @@ internal AsyncRateLimitPolicy(IRateLimiter rateLimiter) =>
 
     /// <inheritdoc/>
     [DebuggerStepThrough]
-    protected override Task<TResult> ImplementationAsync<TResult>(Func<Context, CancellationToken, Task<TResult>> action, Context context, CancellationToken cancellationToken,
-        bool continueOnCapturedContext) =>
-        AsyncRateLimitEngine.ImplementationAsync(_rateLimiter, null, action, context, continueOnCapturedContext, cancellationToken);
+    protected override Task<TResult> ImplementationAsync<TResult>(
+        Func<Context, CancellationToken, Task<TResult>> action,
+        Context context,
+        CancellationToken cancellationToken,
+        bool continueOnCapturedContext)
+    {
+        if (action is null)
+        {
+            throw new ArgumentNullException(nameof(action));
+        }
+
+        return AsyncRateLimitEngine.ImplementationAsync(
+            _rateLimiter,
+            null,
+            action,
+            context,
+            continueOnCapturedContext,
+            cancellationToken);
+    }
 }
 
 /// <summary>
@@ -38,7 +53,23 @@ internal AsyncRateLimitPolicy(
 
     /// <inheritdoc/>
     [DebuggerStepThrough]
-    protected override Task<TResult> ImplementationAsync(Func<Context, CancellationToken, Task<TResult>> action, Context context, CancellationToken cancellationToken,
-        bool continueOnCapturedContext) =>
-        AsyncRateLimitEngine.ImplementationAsync(_rateLimiter, _retryAfterFactory, action, context, continueOnCapturedContext, cancellationToken);
+    protected override Task<TResult> ImplementationAsync(
+        Func<Context, CancellationToken, Task<TResult>> action,
+        Context context,
+        CancellationToken cancellationToken,
+        bool continueOnCapturedContext)
+    {
+        if (action is null)
+        {
+            throw new ArgumentNullException(nameof(action));
+        }
+
+        return AsyncRateLimitEngine.ImplementationAsync(
+            _rateLimiter,
+            _retryAfterFactory,
+            action,
+            context,
+            continueOnCapturedContext,
+            cancellationToken);
+    }
 }

test/Polly.Specs/NoOp/NoOpSpecs.cs

@@ -18,7 +18,8 @@ public void Should_throw_when_action_is_null()
 
         var exceptionAssertions = func.Should().Throw<TargetInvocationException>();
         exceptionAssertions.And.Message.Should().Be("Exception has been thrown by the target of an invocation.");
-        exceptionAssertions.WithInnerException<ArgumentNullException>("action");
+        exceptionAssertions.And.InnerException.Should().BeOfType<ArgumentNullException>()
+            .Which.ParamName.Should().Be("action");
     }
 
     [Fact]

test/Polly.Specs/NoOp/NoOpTResultAsyncSpecs.cs

@@ -17,7 +17,8 @@ public void Should_throw_when_action_is_null()
 
         var exceptionAssertions = func.Should().Throw<TargetInvocationException>();
         exceptionAssertions.And.Message.Should().Be("Exception has been thrown by the target of an invocation.");
-        exceptionAssertions.WithInnerException<ArgumentNullException>("action");
+        exceptionAssertions.And.InnerException.Should().BeOfType<ArgumentNullException>()
+            .Which.ParamName.Should().Be("action");
     }
 
     [Fact]

test/Polly.Specs/RateLimit/AsyncRateLimitPolicySpecs.cs

@@ -31,4 +31,30 @@ protected override (bool, TimeSpan) TryExecuteThroughPolicy(IRateLimitPolicy pol
             throw new InvalidOperationException("Unexpected policy type in test construction.");
         }
     }
+
+    [Fact]
+    public void Should_throw_when_action_is_null()
+    {
+        var flags = BindingFlags.NonPublic | BindingFlags.Instance;
+        Func<Context, CancellationToken, Task<EmptyStruct>> action = null!;
+        IRateLimiter rateLimiter = RateLimiterFactory.Create(TimeSpan.FromSeconds(1), 1);
+
+        var instance = Activator.CreateInstance(
+            typeof(AsyncRateLimitPolicy),
+            flags,
+            null,
+            [rateLimiter],
+            null)!;
+        var instanceType = instance.GetType();
+        var methods = instanceType.GetMethods(flags);
+        var methodInfo = methods.First(method => method is { Name: "ImplementationAsync", ReturnType.Name: "Task`1" });
+        var generic = methodInfo.MakeGenericMethod(typeof(EmptyStruct));
+
+        var func = () => generic.Invoke(instance, [action, new Context(), CancellationToken.None, false]);
+
+        var exceptionAssertions = func.Should().Throw<TargetInvocationException>();
+        exceptionAssertions.And.Message.Should().Be("Exception has been thrown by the target of an invocation.");
+        exceptionAssertions.And.InnerException.Should().BeOfType<ArgumentNullException>()
+            .Which.ParamName.Should().Be("action");
+    }
 }

test/Polly.Specs/RateLimit/AsyncRateLimitPolicyTResultSpecs.cs

@@ -47,4 +47,30 @@ protected override TResult TryExecuteThroughPolicy<TResult>(IRateLimitPolicy<TRe
             throw new InvalidOperationException("Unexpected policy type in test construction.");
         }
     }
+
+    [Fact]
+    public void Should_throw_when_action_is_null()
+    {
+        var flags = BindingFlags.NonPublic | BindingFlags.Instance;
+        Func<Context, CancellationToken, Task<EmptyStruct>> action = null!;
+        IRateLimiter rateLimiter = RateLimiterFactory.Create(TimeSpan.FromSeconds(1), 1);
+        Func<TimeSpan, Context, EmptyStruct>? retryAfterFactory = null!;
+
+        var instance = Activator.CreateInstance(
+            typeof(AsyncRateLimitPolicy<EmptyStruct>),
+            flags,
+            null,
+            [rateLimiter, retryAfterFactory],
+            null)!;
+        var instanceType = instance.GetType();
+        var methods = instanceType.GetMethods(flags);
+        var methodInfo = methods.First(method => method is { Name: "ImplementationAsync", ReturnType.Name: "Task`1" });
+
+        var func = () => methodInfo.Invoke(instance, [action, new Context(), CancellationToken.None, false]);
+
+        var exceptionAssertions = func.Should().Throw<TargetInvocationException>();
+        exceptionAssertions.And.Message.Should().Be("Exception has been thrown by the target of an invocation.");
+        exceptionAssertions.And.InnerException.Should().BeOfType<ArgumentNullException>()
+            .Which.ParamName.Should().Be("action");
+    }
 }