Protect against [InternalsVisibleTo] stack overflow and fixed a possible cause for that stack overflow

ICSharpCode.NRefactory.CSharp/TypeSystem/CSharpAssembly.cs

@@ -18,9 +18,9 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading;
-
 using ICSharpCode.NRefactory.TypeSystem;
 using ICSharpCode.NRefactory.TypeSystem.Implementation;
 using ICSharpCode.NRefactory.Utils;
@@ -151,13 +151,19 @@ namespace ICSharpCode.NRefactory.CSharp.TypeSystem
 			if (result != null) {
 				return result;
 			} else {
-				internalsVisibleTo = (
-					from attr in this.AssemblyAttributes
-					where attr.AttributeType.Name == "InternalsVisibleToAttribute"
-					&& attr.AttributeType.Namespace == "System.Runtime.CompilerServices"
-					&& attr.PositionalArguments.Count == 1
-					select GetShortName(attr.PositionalArguments.Single().ConstantValue as string)
-				).ToArray();
+				using (var busyLock = BusyManager.Enter(this)) {
+					Debug.Assert(busyLock.Success);
+					if (!busyLock.Success) {
+						return new string[0];
+					}
+					internalsVisibleTo = (
+						from attr in this.AssemblyAttributes
+						where attr.AttributeType.Name == "InternalsVisibleToAttribute"
+						&& attr.AttributeType.Namespace == "System.Runtime.CompilerServices"
+						&& attr.PositionalArguments.Count == 1
+						select GetShortName(attr.PositionalArguments.Single().ConstantValue as string)
+					).ToArray();
+				}
 				return internalsVisibleTo;
 			}
 		}

ICSharpCode.NRefactory/TypeSystem/Implementation/MergedNamespace.cs

@@ -129,9 +129,13 @@ namespace ICSharpCode.NRefactory.TypeSystem.Implementation
 			foreach (var ns in namespaces) {
 				ITypeDefinition typeDef = ns.GetTypeDefinition(name, typeParameterCount);
 				if (typeDef != null) {
-					if (typeDef.IsPublic || (typeDef.IsInternal && typeDef.ParentAssembly.InternalsVisibleTo(compilation.MainAssembly))) {
+					if (typeDef.IsPublic) {
 						// Prefer accessible types over non-accessible types.
 						return typeDef;
+						// || (typeDef.IsInternal && typeDef.ParentAssembly.InternalsVisibleTo(...))
+						// We can't call InternalsVisibleTo() here as we don't know the correct 'current' assembly,
+						// and using the main assembly can cause a stack overflow if there
+						// are internal assembly attributes.
 					}
 					anyTypeDef = typeDef;
 				}