Fix handling of null constants in portable pdbs

3 files changed, 19 insertions, 2 deletions

diff --git a/Mono.Cecil/AssemblyReader.cs b/Mono.Cecil/AssemblyReader.cs
index 43926c0..654bf48 100644
--- a/Mono.Cecil/AssemblyReader.cs
+++ b/Mono.Cecil/AssemblyReader.cs
@@ -2986,13 +2986,13 @@ namespace Mono.Cecil {
 					value = Encoding.Unicode.GetString (bytes, 0, bytes.Length);
 				} else
 					value = null;
-			} else if (type.etype == ElementType.Object) {
-				value = null;
 			} else if (type.IsTypeOf ("System", "Decimal")) {
 				var b = signature.ReadByte ();
 				value = new decimal (signature.ReadInt32 (), signature.ReadInt32 (), signature.ReadInt32 (), (b & 0x80) != 0, (byte) (b & 0x7f));
 			} else if (type.IsTypeOf ("System", "DateTime")) {
 				value = new DateTime (signature.ReadInt64());
+			} else if (type.etype == ElementType.Object || type.etype == ElementType.None || type.etype == ElementType.Class) {
+				value = null;
 			} else
 				value = signature.ReadConstantSignature (type.etype);
 
diff --git a/Mono.Cecil/AssemblyWriter.cs b/Mono.Cecil/AssemblyWriter.cs
index 4cd79a3..cf08434 100644
--- a/Mono.Cecil/AssemblyWriter.cs
+++ b/Mono.Cecil/AssemblyWriter.cs
@@ -2146,6 +2146,7 @@ namespace Mono.Cecil {
 			case ElementType.SzArray:
 			case ElementType.Class:
 			case ElementType.Object:
+			case ElementType.None:
 			case ElementType.Var:
 			case ElementType.MVar:
 				signature.WriteInt32 (0);
diff --git a/Test/Mono.Cecil.Tests/PortablePdbTests.cs b/Test/Mono.Cecil.Tests/PortablePdbTests.cs
index 107b537..1b4c5ec 100644
--- a/Test/Mono.Cecil.Tests/PortablePdbTests.cs
+++ b/Test/Mono.Cecil.Tests/PortablePdbTests.cs
@@ -388,6 +388,22 @@ namespace Mono.Cecil.Tests {
 		}
 
 		[Test]
+		public void NullClassConstant ()
+		{
+			TestModule ("xattr.dll", module => {
+				var type = module.GetType ("Library");
+				var method = type.GetMethod ("NullXAttributeConstant");
+				var symbol = method.DebugInformation;
+
+				Assert.IsNotNull (symbol);
+				Assert.AreEqual(1, symbol.Scope.Constants.Count);
+
+				var a = symbol.Scope.Constants [0];
+				Assert.AreEqual ("a", a.Name);
+			}, symbolReaderProvider: typeof (PortablePdbReaderProvider), symbolWriterProvider: typeof (PortablePdbWriterProvider));
+		}
+
+		[Test]
 		public void PortablePdbLineInfo  ()
 		{
 			TestModule ("line.exe", module => {