Improved IDE support for conditional access operators

 (changeset 1251701)

Src/Workspaces/CSharp/Formatting/Rules/TokenBasedFormattingRule.cs

@@ -354,6 +354,11 @@ public override AdjustSpacesOperation GetAdjustSpacesOperation(SyntaxToken previ
                 return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpacesIfOnSingleLine);
             }
 
+            if (previousToken.CSharpKind() == SyntaxKind.IdentifierToken && currentToken.CSharpKind() == SyntaxKind.QuestionToken && currentToken.Parent.IsKind(SyntaxKind.ConditionalAccessExpression))
+            {
+                return CreateAdjustSpacesOperation(0, AdjustSpacesOption.ForceSpacesIfOnSingleLine);
+            }
+
             return nextOperation.Invoke();
         }
     }

Src/Workspaces/CSharp/Recommendations/CSharpRecommendationService.cs

@@ -121,6 +121,11 @@ internal class CSharpRecommendationService : AbstractRecommendationService
             {
                 return GetSymbolsOffOffAlias(context, ((AliasQualifiedNameSyntax)node).Alias, cancellationToken);
             }
+            else if (node.CSharpKind() == SyntaxKind.MemberBindingExpression)
+            {
+                var parentConditionalAccess = node.GetAncestor<ConditionalAccessExpressionSyntax>();
+                return GetSymbolsOffOfExpression(context, parentConditionalAccess.Expression, cancellationToken);
+            }
             else
             {
                 return SpecializedCollections.EmptyEnumerable<ISymbol>();

Src/Workspaces/CSharpTest/Formatting/FormattingTests.cs

@@ -5281,5 +5281,40 @@ public void Method()
 
             AssertFormat(expected, code, changedOptionSet: options);
         }
+
+        public void ConditionalMemberAccess()
+        {
+            var code = @"
+class A
+{
+    public A a;
+}
+
+class Program
+{
+    static void Main()
+    {
+        A a = null;
+        A ?.a = null;
+    }
+}";
+
+            var expected = @"
+class A
+{
+    public A a;
+}
+
+class Program
+{
+    static void Main()
+    {
+        A a = null;
+        A?.a = null;
+    }
+}";
+
+            AssertFormat(expected, code);
+        }
     }
 }