diff --git a/ICSharpCode.Decompiler/FlowAnalysis/ReachingDefinitions.cs b/ICSharpCode.Decompiler/FlowAnalysis/ReachingDefinitions.cs
new file mode 100644
index 000000000..4b223da8a
--- /dev/null
+++ b/ICSharpCode.Decompiler/FlowAnalysis/ReachingDefinitions.cs
@@ -0,0 +1,34 @@
+// Copyright (c) 2016 Daniel Grunwald
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+
+namespace ICSharpCode.Decompiler.FlowAnalysis
+{
+	/// <summary>
+	/// Implements the "reaching defintions" analysis.
+	/// 
+	/// https://en.wikipedia.org/wiki/Reaching_definition
+	/// </summary>
+	public class ReachingDefinitions
+	{
+		public ReachingDefinitions()
+		{
+		}
+	}
+}
diff --git a/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj b/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
index 4c1a8fa78..004ba8419 100644
--- a/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
+++ b/ICSharpCode.Decompiler/ICSharpCode.Decompiler.csproj
@@ -50,8 +50,9 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
-    <Reference Include="System.Collections.Immutable">
-      <HintPath>..\packages\Microsoft.Bcl.Immutable.1.1.22-beta\lib\portable-net45+win8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\System.Collections.Immutable.1.2.0-rc2-24027\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <Private>True</Private>
     </Reference>
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
@@ -83,6 +84,7 @@
     <Compile Include="CSharp\Transforms\ReplaceMethodCallsWithOperators.cs" />
     <Compile Include="FlowAnalysis\ControlFlowNode.cs" />
     <Compile Include="FlowAnalysis\Dominance.cs" />
+    <Compile Include="FlowAnalysis\ReachingDefinitions.cs" />
     <Compile Include="IL\ControlFlow\ConditionDetection.cs" />
     <Compile Include="IL\ControlFlow\ControlFlowSimplification.cs" />
     <Compile Include="IL\ControlFlow\IntroduceExitPoints.cs" />
@@ -187,11 +189,7 @@
     <Service Include="{508349B6-6B84-4DF5-91F0-309BEEBAD82D}" />
   </ItemGroup>
   <ItemGroup>
-    <Folder Include="FlowAnalysis" />
-    <Folder Include="ILAst" />
-    <Folder Include="IL\ControlFlow" />
-    <Folder Include="IL\Transforms" />
-    <Folder Include="TypeSystem" />
+    <Folder Include="ILAst\" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.Targets" />
   <Target Name="BeforeBuild">
diff --git a/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
index 058bbcf7a..642d850c5 100644
--- a/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -66,10 +66,6 @@
       <HintPath>..\..\packages\NUnit.2.6.3\lib\nunit.framework.dll</HintPath>
     </Reference>
     <Reference Include="System" />
-    <Reference Include="System.Collections.Immutable, Version=1.1.22.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\..\packages\Microsoft.Bcl.Immutable.1.1.22-beta\lib\portable-net45+win8+wpa81\System.Collections.Immutable.dll</HintPath>
-    </Reference>
     <Reference Include="nunit.util, Version=2.6.4.14350, Culture=neutral, PublicKeyToken=96d09a1eb7f44a77, processorArchitecture=MSIL">
       <HintPath>..\..\packages\NUnitTestAdapter.2.0.0\lib\nunit.util.dll</HintPath>
       <Private>False</Private>
@@ -79,6 +75,10 @@
       <Private>False</Private>
     </Reference>
     <Reference Include="System" />
+    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Collections.Immutable.1.2.0-rc2-24027\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
diff --git a/ICSharpCode.Decompiler/Tests/packages.config b/ICSharpCode.Decompiler/Tests/packages.config
index f0730487d..5b3d94163 100644
--- a/ICSharpCode.Decompiler/Tests/packages.config
+++ b/ICSharpCode.Decompiler/Tests/packages.config
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="DiffLib" version="1.0.0.55" />
-  <package id="Microsoft.Bcl.Immutable" version="1.1.22-beta" targetFramework="net45" />
   <package id="NUnit" version="2.6.3" targetFramework="net45" />
   <package id="NUnitTestAdapter" version="2.0.0" targetFramework="net45" />
+  <package id="System.Collections.Immutable" version="1.2.0-rc2-24027" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/ICSharpCode.Decompiler/packages.config b/ICSharpCode.Decompiler/packages.config
index aeafe728e..412c0517d 100644
--- a/ICSharpCode.Decompiler/packages.config
+++ b/ICSharpCode.Decompiler/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Microsoft.Bcl.Immutable" version="1.1.22-beta" targetFramework="net45" />
+  <package id="System.Collections.Immutable" version="1.2.0-rc2-24027" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/ILSpy/ILSpy.csproj b/ILSpy/ILSpy.csproj
index 55fda9711..efdbfa814 100644
--- a/ILSpy/ILSpy.csproj
+++ b/ILSpy/ILSpy.csproj
@@ -80,9 +80,9 @@
       <RequiredTargetFramework>3.0</RequiredTargetFramework>
     </Reference>
     <Reference Include="System" />
-    <Reference Include="System.Collections.Immutable, Version=1.1.22.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\packages\Microsoft.Bcl.Immutable.1.1.22-beta\lib\portable-net45+win8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\System.Collections.Immutable.1.2.0-rc2-24027\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <Private>True</Private>
     </Reference>
     <Reference Include="System.ComponentModel.Composition">
       <RequiredTargetFramework>4.0</RequiredTargetFramework>
diff --git a/ILSpy/packages.config b/ILSpy/packages.config
index 171ede54c..ef7dda2d8 100644
--- a/ILSpy/packages.config
+++ b/ILSpy/packages.config
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="AvalonEdit" version="5.0.3" targetFramework="net45" />
-  <package id="Microsoft.Bcl.Immutable" version="1.1.22-beta" targetFramework="net45" />
+  <package id="System.Collections.Immutable" version="1.2.0-rc2-24027" targetFramework="net45" />
 </packages>
\ No newline at end of file