From 5d96a9594d4b072ca35becd48bda367ce4958558 Mon Sep 17 00:00:00 2001
From: Carl de Billy <carl.debilly@gmail.com>
Date: Sat, 16 Feb 2019 17:02:46 -0500
Subject: [PATCH] Added support for readonly immutable fields

---
 .../Given_ImmutableEntity.Fields.cs           | 35 +++++++++++++++++++
 src/Uno.CodeGen/ImmutableGenerator.cs         | 15 +++++---
 2 files changed, 46 insertions(+), 4 deletions(-)
 create mode 100644 src/Uno.CodeGen.Tests/Given_ImmutableEntity.Fields.cs

diff --git a/src/Uno.CodeGen.Tests/Given_ImmutableEntity.Fields.cs b/src/Uno.CodeGen.Tests/Given_ImmutableEntity.Fields.cs
new file mode 100644
index 0000000..daf9f3d
--- /dev/null
+++ b/src/Uno.CodeGen.Tests/Given_ImmutableEntity.Fields.cs
@@ -0,0 +1,35 @@
+// ******************************************************************
+// Copyright � 2015-2018 nventive inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ******************************************************************
+using System.Collections.Generic;
+
+namespace Uno.CodeGen.Tests
+{
+	[GeneratedImmutable]
+	internal partial class MyEntityWithFields
+	{
+		private readonly IReadOnlyDictionary<string, string> _readonlyField;
+
+		public MyEntityWithFields(IReadOnlyDictionary<string, string> readonlyField)
+		{
+			_readonlyField = readonlyField;
+		}
+	}
+
+	partial class Given_ImmutableEntity
+	{
+	}
+}
diff --git a/src/Uno.CodeGen/ImmutableGenerator.cs b/src/Uno.CodeGen/ImmutableGenerator.cs
index 86c542c..32d7979 100644
--- a/src/Uno.CodeGen/ImmutableGenerator.cs
+++ b/src/Uno.CodeGen/ImmutableGenerator.cs
@@ -951,10 +951,17 @@ $@"public sealed class {symbolName}BuilderJsonConverterTo{symbolName}{genericArg
 
 				if (!field.IsStatic)
 				{
-					Error(
-						builder,
-						$"Immutable type {symbolNames.SymbolNameWithGenerics} cannot "
-						+ $"have the non-static field {field.Name}. You must remove it for immutable generation or make it static.");
+					if (field.IsReadOnly)
+					{
+						CheckTypeImmutable(field.Type, $"Field {field.Name}");
+					}
+					else
+					{
+						Error(
+							builder,
+							$"Immutable type {symbolNames.SymbolNameWithGenerics} cannot "
+							+ $"have the non-static field {field.Name}. You must either remove it, make it readonly or static to allow for immutable generation.");
+					}
 				}
 			}
 		}