Don't show enum completion if text is typed after dot (#18577)

Don't show enum completion if text is typed after dot

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

@@ -488,6 +488,33 @@ enum E
         B,
     }
 }
+";
+            await VerifyNoItemsExistAsync(markup);
+        }
+
+        [WorkItem(18359, "https://github.com/dotnet/roslyn/issues/18359")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task NotAfterDotWithTextTyped()
+        {
+            var markup =
+@"namespace ConsoleApplication253
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            M(E.a$$)
+        }
+
+        static void M(E e) { }
+    }
+
+    enum E
+    {
+        A,
+        B,
+    }
+}
 ";
             await VerifyNoItemsExistAsync(markup);
         }

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

@@ -9077,5 +9077,34 @@ Action<int> Local(string x, ref var @class, params Func<int, string> f)
     }
 }", "Local", "Action<int> Local(string x, ref var @class, params Func<int, string> f)");
         }
+
+        [WorkItem(18359, "https://github.com/dotnet/roslyn/issues/18359")]
+        [Fact, Trait(Traits.Feature, Traits.Features.Completion)]
+        public async Task EnumMemberAfterDot()
+        {
+            var markup =
+@"namespace ConsoleApplication253
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            M(E.$$)
+        }
+
+        static void M(E e) { }
+    }
+
+    enum E
+    {
+        A,
+        B,
+    }
+}
+";
+            // VerifyItemExistsAsync also tests with the item typed.
+            await VerifyItemExistsAsync(markup, "A");
+            await VerifyItemExistsAsync(markup, "B");
+        }
     }
 }
\ No newline at end of file

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

@@ -52,7 +52,9 @@ public override async Task ProvideCompletionsAsync(CompletionContext context)
                     return;
                 }
 
-                var token = tree.FindTokenOnLeftOfPosition(position, cancellationToken);
+                var token = tree.FindTokenOnLeftOfPosition(position, cancellationToken)
+                                .GetPreviousTokenIfTouchingWord(position);
+
                 if (token.IsMandatoryNamedParameterPosition())
                 {
                     return;
@@ -61,6 +63,7 @@ public override async Task ProvideCompletionsAsync(CompletionContext context)
                 // Don't show up within member access
                 // This previously worked because the type inferrer didn't work
                 // in member access expressions.
+                // The regular SymbolCompletionProvider will handle completion after .
                 if (token.IsKind(SyntaxKind.DotToken))
                 {
                     return;