Fix ReadCodeMappingInfo for lambdas compiled with mcs.

ICSharpCode.Decompiler/CSharp/CSharpDecompiler.cs

@@ -613,7 +613,7 @@ namespace ICSharpCode.Decompiler.CSharp
 						// deal with ldftn instructions, i.e., lambdas
 						token = MetadataTokenHelpers.EntityHandleOrNil(blob.ReadInt32());
 						if (!token.IsNil && token.Kind == HandleKind.MethodDefinition) {
-							if (((MethodDefinitionHandle)token).IsCompilerGenerated(module.Metadata))
+							if (((MethodDefinitionHandle)token).IsCompilerGeneratedOrIsInCompilerGeneratedClass(module.Metadata))
 								connectedMethods.Enqueue((MethodDefinitionHandle)token);
 						}
 						break;

ICSharpCode.Decompiler/SRMExtensions.cs

@@ -291,6 +291,17 @@ namespace ICSharpCode.Decompiler
 			return metadata.GetMethodDefinition(handle).IsCompilerGenerated(metadata);
 		}
 
+		public static bool IsCompilerGeneratedOrIsInCompilerGeneratedClass(this MethodDefinitionHandle handle, MetadataReader metadata)
+		{
+			MethodDefinition method = metadata.GetMethodDefinition(handle);
+			if (method.IsCompilerGenerated(metadata))
+				return true;
+			TypeDefinitionHandle declaringTypeHandle = method.GetDeclaringType();
+			if (!declaringTypeHandle.IsNil && declaringTypeHandle.IsCompilerGenerated(metadata))
+				return true;
+			return false;
+		}
+
 		public static bool IsCompilerGenerated(this MethodDefinition method, MetadataReader metadata)
 		{
 			return method.GetCustomAttributes().HasKnownAttribute(metadata, KnownAttribute.CompilerGenerated);