diff --git a/CHANGELOG.md b/CHANGELOG.md
index 184f703870..175c78ecbd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,11 @@
 # Changelog
 All changes to the project will be documented in this file.
 
+## [1.29.1] - Not Yet Released
+* Fixed duplicate diagnostics in C# ([omnisharp-vscode#1830](https://github.com/OmniSharp/omnisharp-vscode/issues/1830), PR: [#1107](https://github.com/OmniSharp/omnisharp-roslyn/pull/1107))
+
 ## [1.29.0] - 2018-1-29
-* Updated to Roslyn 2.6.1 packages - C# 7.2 support, (PR: [#1055](https://github.com/OmniSharp/omnisharp-roslyn/pull/1055))
+* Updated to Roslyn 2.6.1 packages - C# 7.2 support (PR: [#1055](https://github.com/OmniSharp/omnisharp-roslyn/pull/1055))
 * Shipped Language Server Protocol support in box.  (PR: [#969](https://github.com/OmniSharp/omnisharp-roslyn/pull/969))
   - Additional information and features tracked at [#968](https://github.com/OmniSharp/omnisharp-roslyn/issues/968)
 * Fixed locating Visual Studio with more than one installation (PR: [#1063](https://github.com/OmniSharp/omnisharp-roslyn/pull/1063))
diff --git a/src/OmniSharp.Cake/Services/RequestHandlers/CakeRequestHandler.cs b/src/OmniSharp.Cake/Services/RequestHandlers/CakeRequestHandler.cs
index 3bfd8b5a62..848afae35a 100644
--- a/src/OmniSharp.Cake/Services/RequestHandlers/CakeRequestHandler.cs
+++ b/src/OmniSharp.Cake/Services/RequestHandlers/CakeRequestHandler.cs
@@ -54,11 +54,15 @@ public virtual async Task<TResponse> Handle(TRequest request)
 
             request = await TranslateRequestAsync(request);
 
-            var response = await service.Handle(request);
+            var response = IsValid(request)
+                ? await service.Handle(request)
+                : default(TResponse);
 
             return await TranslateResponse(response, request);
         }
 
+        public virtual bool IsValid(TRequest request) => true;
+
         protected virtual async Task<TRequest> TranslateRequestAsync(TRequest req)
         {
             var request = req as Request;
diff --git a/src/OmniSharp.Cake/Services/RequestHandlers/Diagnostics/CodeCheckHandler.cs b/src/OmniSharp.Cake/Services/RequestHandlers/Diagnostics/CodeCheckHandler.cs
index 8a857b9422..930f36a6e3 100644
--- a/src/OmniSharp.Cake/Services/RequestHandlers/Diagnostics/CodeCheckHandler.cs
+++ b/src/OmniSharp.Cake/Services/RequestHandlers/Diagnostics/CodeCheckHandler.cs
@@ -1,4 +1,5 @@
 using System.Composition;
+using System.Threading.Tasks;
 using OmniSharp.Mef;
 using OmniSharp.Models;
 using OmniSharp.Models.CodeCheck;
@@ -14,5 +15,8 @@ public CodeCheckHandler(
             : base(workspace)
         {
         }
+
+        public override bool IsValid(CodeCheckRequest request) =>
+            !string.IsNullOrEmpty(request.FileName);
     }
 }
diff --git a/tests/OmniSharp.Cake.Tests/CodeCheckFacts.cs b/tests/OmniSharp.Cake.Tests/CodeCheckFacts.cs
new file mode 100644
index 0000000000..79d28d7b66
--- /dev/null
+++ b/tests/OmniSharp.Cake.Tests/CodeCheckFacts.cs
@@ -0,0 +1,72 @@
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using OmniSharp.Cake.Services.RequestHandlers.Diagnostics;
+using OmniSharp.Models;
+using OmniSharp.Models.CodeCheck;
+using OmniSharp.Models.UpdateBuffer;
+using TestUtility;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace OmniSharp.Cake.Tests
+{
+    public class CodeCheckFacts : CakeSingleRequestHandlerTestFixture<CodeCheckHandler>
+    {
+        private readonly ILogger _logger;
+
+        public CodeCheckFacts(ITestOutputHelper testOutput) : base(testOutput)
+        {
+            _logger = LoggerFactory.CreateLogger<AutoCompleteFacts>();
+        }
+
+        protected override string EndpointName => OmniSharpEndpoints.CodeCheck;
+
+        [Fact]
+        public async Task ShouldProvideDiagnosticsIfRequestContainsCakeFileName()
+        {
+            const string input = @"zzz";
+
+            var diagnostics = await FindDiagnostics(input, includeFileName: true);
+            Assert.NotEmpty(diagnostics.QuickFixes);
+        }
+
+        [Fact]
+        public async Task ShouldNotCallCodeCheckServiceIfRequestDoesNotSpecifyFileName()
+        {
+            const string input = @"zzz$$";
+
+            var diagnostics = await FindDiagnostics(input, includeFileName: false);
+            Assert.Null(diagnostics);
+        }
+        
+        private async Task<QuickFixResponse> FindDiagnostics(string contents, bool includeFileName)
+        {
+            using (var testProject = await TestAssets.Instance.GetTestProjectAsync("CakeProject", shadowCopy : false))
+            using (var host = CreateOmniSharpHost(testProject.Directory))
+            {
+                var testFile = new TestFile(Path.Combine(testProject.Directory, "build.cake"), contents);
+
+                var request = new CodeCheckRequest
+                {
+                    FileName = includeFileName ? testFile.FileName : string.Empty,
+                };
+
+                var updateBufferRequest = new UpdateBufferRequest
+                {
+                    Buffer = testFile.Content.Code,
+                    Column = request.Column,
+                    FileName = testFile.FileName,
+                    Line = request.Line,
+                    FromDisk = false
+                };
+
+                await GetUpdateBufferHandler(host).Handle(updateBufferRequest);
+
+                var requestHandler = GetRequestHandler(host);
+
+                return await requestHandler.Handle(request);
+            }
+        }
+    }
+}