Fix NullReferenceException when decompiling an automatic property within a generic class.

ICSharpCode.Decompiler/Ast/Transforms/ConvertConstructorCallIntoInitializer.cs

@@ -62,7 +62,7 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 					if (m == null)
 						break;
 					
-					FieldDefinition fieldDef = m.Get("fieldAccess").Single().Annotation<FieldDefinition>();
+					FieldDefinition fieldDef = m.Get("fieldAccess").Single().Annotation<FieldReference>().ResolveWithinSameModule();
 					if (fieldDef == null)
 						break;
 					AttributedNode fieldOrEventDecl = typeDeclaration.Members.FirstOrDefault(f => f.Annotation<FieldDefinition>() == fieldDef);
@@ -106,7 +106,7 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 						AssignmentExpression assignment = es.Expression as AssignmentExpression;
 						if (assignment == null || assignment.Operator != AssignmentOperatorType.Assign)
 							break;
-						FieldDefinition fieldDef = assignment.Left.Annotation<FieldDefinition>();
+						FieldDefinition fieldDef = assignment.Left.Annotation<FieldReference>().ResolveWithinSameModule();
 						if (fieldDef == null || !fieldDef.IsStatic)
 							break;
 						FieldDeclaration fieldDecl = typeDeclaration.Members.OfType<FieldDeclaration>().FirstOrDefault(f => f.Annotation<FieldDefinition>() == fieldDef);

ICSharpCode.Decompiler/Ast/Transforms/PatternStatementTransform.cs

@@ -334,7 +334,7 @@ namespace ICSharpCode.Decompiler.Ast.Transforms
 					continue;
 				Match m = automaticPropertyPattern.Match(property);
 				if (m != null) {
-					FieldDefinition field = m.Get("fieldReference").Single().Annotation<FieldDefinition>();
+					FieldDefinition field = m.Get("fieldReference").Single().Annotation<FieldReference>().ResolveWithinSameModule();
 					if (field.IsCompilerGenerated()) {
 						RemoveCompilerGeneratedAttribute(property.Getter.Attributes);
 						RemoveCompilerGeneratedAttribute(property.Setter.Attributes);

ICSharpCode.Decompiler/CecilExtensions.cs

@@ -159,9 +159,25 @@ namespace ICSharpCode.Decompiler
 			return accessorMethods;
 		}
 		
+		public static FieldDefinition ResolveWithinSameModule(this FieldReference field)
+		{
+			if (field != null && field.DeclaringType.GetElementType().Module == field.Module)
+				return field.Resolve();
+			else
+				return null;
+		}
+		
+		public static MethodDefinition ResolveWithinSameModule(this MethodReference method)
+		{
+			if (method != null && method.DeclaringType.GetElementType().Module == method.Module)
+				return method.Resolve();
+			else
+				return null;
+		}
+		
 		public static bool IsCompilerGenerated(this ICustomAttributeProvider provider)
 		{
-			if (provider.HasCustomAttributes) {
+			if (provider != null && provider.HasCustomAttributes) {
 				foreach (CustomAttribute a in provider.CustomAttributes) {
 					if (a.AttributeType.FullName == "System.Runtime.CompilerServices.CompilerGeneratedAttribute")
 						return true;

ICSharpCode.Decompiler/ILAst/YieldReturnDecompiler.cs

@@ -130,18 +130,12 @@ namespace ICSharpCode.Decompiler.ILAst
 		
 		static FieldDefinition GetFieldDefinition(FieldReference field)
 		{
-			if (field != null && field.DeclaringType.IsGenericInstance)
-				return field.Resolve();
-			else
-				return field as FieldDefinition;
+			return CecilExtensions.ResolveWithinSameModule(field);
 		}
 		
 		static MethodDefinition GetMethodDefinition(MethodReference method)
 		{
-				if (method != null && method.DeclaringType.IsGenericInstance)
-				return method.Resolve();
-			else
-				return method as MethodDefinition;
+			return CecilExtensions.ResolveWithinSameModule(method);
 		}
 		
 		bool MatchEnumeratorCreationNewObj(ILExpression expr, out MethodDefinition ctor)