Trigger completion on space if object creation completion is available

src/OmniSharp.Abstractions/Models/v1/AutoComplete/AutoCompleteRequest.cs

@@ -51,5 +51,7 @@ public string WordToComplete
         /// Returns the kind (i.e Method, Property, Field)
         /// </summary>
         public bool WantKind { get; set; }
+
+        public string TriggerCharacter { get; set; }
     }
 }

src/OmniSharp.Roslyn.CSharp/Services/Intellisense/CompletionItemExtensions.cs

@@ -14,6 +14,7 @@ internal static class CompletionItemExtensions
     {
         private const string GetSymbolsAsync = nameof(GetSymbolsAsync);
         private const string InsertionText = nameof(InsertionText);
+        private const string ObjectCreationCompletionProvider = "Microsoft.CodeAnalysis.CSharp.Completion.Providers.ObjectCreationCompletionProvider";
         private const string NamedParameterCompletionProvider = "Microsoft.CodeAnalysis.CSharp.Completion.Providers.NamedParameterCompletionProvider";
         private const string OverrideCompletionProvider = "Microsoft.CodeAnalysis.CSharp.Completion.Providers.OverrideCompletionProvider";
         private const string ParitalMethodCompletionProvider = "Microsoft.CodeAnalysis.CSharp.Completion.Providers.PartialMethodCompletionProvider";
@@ -32,6 +33,12 @@ static CompletionItemExtensions()
             _getSymbolsAsync = symbolCompletionItemType.GetMethod(GetSymbolsAsync, BindingFlags.Public | BindingFlags.Static);
         }
 
+        public static bool IsObjectCreationCompletionItem(this CompletionItem item)
+        {
+            var properties = item.Properties;
+            return properties.TryGetValue(Provider, out var provider) && provider == ObjectCreationCompletionProvider;
+        }
+
         public static async Task<IEnumerable<ISymbol>> GetCompletionSymbolsAsync(this CompletionItem completionItem, IEnumerable<ISymbol> recommendedSymbols, Document document)
         {
             var properties = completionItem.Properties;

src/OmniSharp.Roslyn.CSharp/Services/Intellisense/IntellisenseService.cs

@@ -43,7 +43,13 @@ public async Task<IEnumerable<AutoCompleteResponse>> Handle(AutoCompleteRequest
 
                 if (completionList != null)
                 {
-                    // get recommened symbols to match them up later with SymbolCompletionProvider
+                    // Only trigger on space if Roslyn has object creation items
+                    if (request.TriggerCharacter == " " && !completionList.Items.Any(i => i.IsObjectCreationCompletionItem()))
+                    {
+                        return completions;
+                    }
+
+                    // get recommended symbols to match them up later with SymbolCompletionProvider
                     var semanticModel = await document.GetSemanticModelAsync();
                     var recommendedSymbols = await Recommender.GetRecommendedSymbolsAtPositionAsync(semanticModel, position, _workspace);
 

tests/OmniSharp.Roslyn.CSharp.Tests/AbstractAutoCompleteTestFixture.cs

@@ -16,7 +16,7 @@ protected AbstractAutoCompleteTestFixture(ITestOutputHelper output)
 
         protected override string EndpointName => OmniSharpEndpoints.AutoComplete;
 
-        protected async Task<IEnumerable<AutoCompleteResponse>> FindCompletionsAsync(string filename, string source, bool wantSnippet = false)
+        protected async Task<IEnumerable<AutoCompleteResponse>> FindCompletionsAsync(string filename, string source, bool wantSnippet = false, string triggerChar = null)
         {
             var testFile = new TestFile(filename, source);
             using (var host = CreateOmniSharpHost(testFile))
@@ -32,7 +32,8 @@ protected async Task<IEnumerable<AutoCompleteResponse>> FindCompletionsAsync(str
                     WordToComplete = GetPartialWord(testFile.Content),
                     WantMethodHeader = true,
                     WantSnippet = wantSnippet,
-                    WantReturnType = true
+                    WantReturnType = true,
+                    TriggerCharacter = triggerChar
                 };
 
                 var requestHandler = GetRequestHandler(host);

tests/OmniSharp.Roslyn.CSharp.Tests/IntellisenseFacts.cs

@@ -454,5 +454,39 @@ private void ContainsCompletions(IEnumerable<string> completions, params string[
 
             Assert.Equal(expected, completions.ToArray());
         }
+
+        [Theory]
+        [InlineData("dummy.cs")]
+        [InlineData("dummy.csx")]
+        public async Task TriggeredOnSpaceForObjectCreation(string filename)
+        {
+            const string input =
+@"public class Class1 {
+    public M()
+    {
+        Class1 c = new $$
+    }
+}";
+
+            var completions = await FindCompletionsAsync(filename, input, wantSnippet: true, triggerChar: " ");
+            Assert.NotEmpty(completions);
+        }
+
+        [Theory]
+        [InlineData("dummy.cs")]
+        [InlineData("dummy.csx")]
+        public async Task NotTriggeredOnSpaceWithoutObjectCreation(string filename)
+        {
+            const string input =
+@"public class Class1 {
+    public M()
+    {
+        $$
+    }
+}";
+
+            var completions = await FindCompletionsAsync(filename, input, wantSnippet: true, triggerChar: " ");
+            Assert.Empty(completions);
+        }
     }
 }