Better name generation while extracting nullables. In ConditionalAccess...

Better name generation while extracting nullables. In ConditionalAccess Expression ?. if we have a member binding expression, we now use that to get a smart name. If nothing else works and if the original definition is a nullable, we give back the default parameter name (v) we use in for built in types. (changeset 1394509)

Src/Workspaces/CSharp/Portable/Extensions/ISemanticModelExtensions.cs

@@ -222,6 +222,14 @@ private static bool CanBindToken(SyntaxToken token)
                 {
                     return ((MemberAccessExpressionSyntax)current).Name.Identifier.ValueText.ToCamelCase();
                 }
+                else if (current is MemberBindingExpressionSyntax)
+                {
+                    return ((MemberBindingExpressionSyntax)current).Name.Identifier.ValueText.ToCamelCase();
+                }
+                else if (current is ConditionalAccessExpressionSyntax)
+                {
+                    current = ((ConditionalAccessExpressionSyntax)current).WhenNotNull;
+                }
                 else if (current is CastExpressionSyntax)
                 {
                     current = ((CastExpressionSyntax)current).Expression;

Src/Workspaces/Core/Portable/Shared/Extensions/ITypeSymbolExtensions.cs

@@ -559,7 +559,7 @@ private static string GetParameterName(ITypeSymbol type)
                 return DefaultParameterName;
             }
 
-            if (type.IsSpecialType())
+            if (type.IsSpecialType() || type.OriginalDefinition.SpecialType == SpecialType.System_Nullable_T)
             {
                 return DefaultBuiltInParameterName;
             }