Commit C# completion on colon

src/EditorFeatures/CSharpTest/Completion/CompletionProviders/NamedParameterCompletionProviderTests.cs

@@ -456,5 +456,55 @@ static void Main()
 ";
             await VerifyNoItemsExistAsync(markup);
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task CommitWithColonWordFullyTyped()
+        {
+            var markup = @"
+class Program
+{
+    static void Main(string[] args)
+    {
+        Main(args$$)
+    }
+}
+";
+
+            var expected = @"
+class Program
+{
+    static void Main(string[] args)
+    {
+        Main(args:)
+    }
+}
+";
+            await VerifyProviderCommitAsync(markup, "args:", expected, ':', "args");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task CommitWithColonWordPartiallyTyped()
+        {
+            var markup = @"
+class Program
+{
+    static void Main(string[] args)
+    {
+        Main(ar$$)
+    }
+}
+";
+
+            var expected = @"
+class Program
+{
+    static void Main(string[] args)
+    {
+        Main(args:)
+    }
+}
+";
+            await VerifyProviderCommitAsync(markup, "args:", expected, ':', "arg");
+        }
     }
 }

src/Features/CSharp/Portable/Completion/CompletionProviders/NamedParameterCompletionProvider.cs

@@ -22,6 +22,8 @@ namespace Microsoft.CodeAnalysis.CSharp.Completion.Providers
     internal partial class NamedParameterCompletionProvider : CommonCompletionProvider, IEqualityComparer<IParameterSymbol>
     {
         private const string ColonString = ":";
+        private static readonly CompletionItemRules CompletionItemRules = CompletionItemRules.Default
+            .WithFilterCharacterRule(CharacterSetModificationRule.Create(CharacterSetModificationKind.Remove, ':'));
 
         internal override bool IsInsertionTrigger(SourceText text, int characterPosition, OptionSet options)
         {
@@ -96,7 +98,7 @@ public override async Task ProvideCompletionsAsync(CompletionContext context)
                     symbol: parameter,
                     contextPosition: token.SpanStart,
                     filterText: escapedName,
-                    rules: CompletionItemRules.Default,
+                    rules: CompletionItemRules,
                     matchPriority: SymbolMatchPriority.PreferNamedArgument));
             }
         }