Improved NRE guards in formatters.

Resolves #267

2 files changed, 10 insertions, 2 deletions

diff --git a/mdoc/Mono.Documentation/Updater/Formatters/FSharpFormatter.cs b/mdoc/Mono.Documentation/Updater/Formatters/FSharpFormatter.cs
index 75155d61..0ab66627 100644
--- a/mdoc/Mono.Documentation/Updater/Formatters/FSharpFormatter.cs
+++ b/mdoc/Mono.Documentation/Updater/Formatters/FSharpFormatter.cs
@@ -228,9 +228,11 @@ namespace Mono.Documentation.Updater
 
             foreach (var interfaceImplementation in type.Interfaces)
             {
+                var resolvedInterface = interfaceImplementation.InterfaceType.Resolve ();
+
                 if (type.IsValueType
                     && ignoredValueTypeInterfaces.Any(i => interfaceImplementation.InterfaceType.FullName.StartsWith(i))
-                    || interfaceImplementation.InterfaceType.Resolve().IsNotPublic)
+                    || (resolvedInterface != null && resolvedInterface.IsNotPublic))
                     continue;
                 buf.Append($"{GetLineEnding()}{Consts.Tab}interface ");
                 AppendTypeName(buf, GetTypeName(interfaceImplementation.InterfaceType));
diff --git a/mdoc/Mono.Documentation/Updater/Formatters/MemberFormatter.cs b/mdoc/Mono.Documentation/Updater/Formatters/MemberFormatter.cs
index 14a2ddfe..b0e70667 100644
--- a/mdoc/Mono.Documentation/Updater/Formatters/MemberFormatter.cs
+++ b/mdoc/Mono.Documentation/Updater/Formatters/MemberFormatter.cs
@@ -106,6 +106,9 @@ namespace Mono.Documentation.Updater
 
         protected StringBuilder _AppendTypeName (StringBuilder buf, TypeReference type, DynamicParserContext context, bool appendGeneric = true)
         {
+            if (type == null)
+                return buf;
+            
             if (type is ArrayType)
             {
                 return AppendArrayTypeName(buf, type, context);
@@ -129,7 +132,9 @@ namespace Mono.Documentation.Updater
             {
                 try
                 {
-                    type = type.Resolve();
+                    var rtype = type.Resolve ();
+                    if (rtype != null)
+                        type = rtype;
                 }
                 catch (Exception)
                 {
@@ -138,6 +143,7 @@ namespace Mono.Documentation.Updater
                 }
             }
 
+
             if (type.GenericParameters.Count == 0 &&
                     (genInst == null ? true : genInst.GenericArguments.Count == 0))
             {