Fix assertion with fields declared in an unresolved class type.

ICSharpCode.Decompiler/IL/ILReader.cs

@@ -1093,21 +1093,47 @@ namespace ICSharpCode.Decompiler.IL
 					return inst;
 				default:
 					Warn("Expected native int or pointer, but got " + inst.ResultType);
-					return inst;
+					return new Conv(inst, PrimitiveType.I, false, Sign.None);
 			}
 		}
 
 		ILInstruction PopFieldTarget(IField field)
 		{
-			return field.DeclaringType.IsReferenceType == true ? Pop(StackType.O) : PopPointer();
+			switch (field.DeclaringType.IsReferenceType) {
+				case true:
+					return Pop(StackType.O);
+				case false:
+					return PopPointer();
+				default:
+					// field in unresolved type
+					if (PeekStackType() == StackType.O)
+						return Pop();
+					else
+						return PopPointer();
+			}
 		}
 
+		/// <summary>
+		/// Like PopFieldTarget, but supports ldfld's special behavior for fields of temporary value types.
+		/// </summary>
 		ILInstruction PopLdFldTarget(IField field)
 		{
-			if (field.DeclaringType.IsReferenceType == true)
-				return Pop(StackType.O);
-
-			return PeekStackType() == StackType.O ? new AddressOf(Pop()) : PopPointer();
+			switch (field.DeclaringType.IsReferenceType) {
+				case true:
+					return Pop(StackType.O);
+				case false:
+					// field of value type: ldfld can handle temporaries
+					if (PeekStackType() == StackType.O)
+						return new AddressOf(Pop());
+					else
+						return PopPointer();
+				default:
+					// field in unresolved type
+					if (PeekStackType() == StackType.O)
+						return Pop(StackType.O);
+					else
+						return PopPointer();
+			}
 		}
 
 		private ILInstruction Return()

ICSharpCode.Decompiler/IL/Instructions/LdFlda.cs

@@ -25,7 +25,20 @@ namespace ICSharpCode.Decompiler.IL
 		internal override void CheckInvariant(ILPhase phase)
 		{
 			base.CheckInvariant(phase);
-			Debug.Assert(field.DeclaringType.IsReferenceType == true ? (target.ResultType == StackType.O) : (target.ResultType == StackType.I || target.ResultType == StackType.Ref));
+			switch (field.DeclaringType.IsReferenceType) {
+				case true:
+					Debug.Assert(target.ResultType == StackType.O,
+						"Class fields can only be accessed with an object on the stack");
+					break;
+				case false:
+					Debug.Assert(target.ResultType == StackType.I || target.ResultType == StackType.Ref,
+						"Struct fields can only be accessed with a pointer on the stack");
+					break;
+				case null:
+					// field of unresolved type
+					Debug.Assert(target.ResultType == StackType.O || target.ResultType == StackType.I || target.ResultType == StackType.Ref);
+					break;
+			}
 		}
 	}
 }