From 2c68d993365051b9eb7cca237d62ef125b350eed Mon Sep 17 00:00:00 2001
From: Siegfried Pammer <siegfriedpammer@gmail.com>
Date: Thu, 2 Nov 2017 23:31:54 +0100
Subject: [PATCH] Fix #959: Crash in CSharp.StatementBuilder.TranslateSwitch
 (due to empty sequence)

---
 .../ICSharpCode.Decompiler.Tests.csproj       |  2 ++
 .../ILPrettyTestRunner.cs                     |  6 ++++
 .../TestCases/ILPretty/Issue959.cs            | 12 +++++++
 .../TestCases/ILPretty/Issue959.il            | 36 +++++++++++++++++++
 .../CSharp/StatementBuilder.cs                |  2 +-
 5 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.cs
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.il

diff --git a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
index a722b7b70..e5e3b7b8f 100644
--- a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -59,6 +59,7 @@
   <ItemGroup>
     <Compile Include="DataFlowTest.cs" />
     <Compile Include="TestCases\Correctness\LINQRaytracer.cs" />
+    <Compile Include="TestCases\ILPretty\Issue959.cs" />
     <None Include="TestCases\ILPretty\FSharpLoops_Debug.cs" />
     <None Include="TestCases\ILPretty\FSharpLoops_Release.cs" />
     <Compile Include="TestCases\Pretty\DelegateConstruction.cs" />
@@ -79,6 +80,7 @@
     <Compile Include="TestCases\Pretty\FixProxyCalls.cs" />
     <Compile Include="TestCases\Pretty\UnsafeCode.cs" />
     <Compile Include="TestCases\Pretty\InitializerTests.cs" />
+    <None Include="TestCases\ILPretty\Issue959.il" />
     <None Include="TestCases\ILPretty\Issue646.cs" />
     <Compile Include="TestCases\Pretty\Async.cs" />
     <Compile Include="TestCases\Pretty\CheckedUnchecked.cs" />
diff --git a/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs b/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
index 05ff2be06..1ddfb26d5 100644
--- a/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
+++ b/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
@@ -42,6 +42,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run();
 		}
 
+		[Test]
+		public void Issue959()
+		{
+			Run();
+		}
+
 		[Test]
 		public void FSharpUsing_Debug()
 		{
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.cs b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.cs
new file mode 100644
index 000000000..c9fc8ee2a
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.cs
@@ -0,0 +1,12 @@
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	internal class Issue959
+	{
+		public void Test(bool arg)
+		{
+			switch (arg) {
+
+			}
+		}
+	}
+}
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.il b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.il
new file mode 100644
index 000000000..754593da2
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue959.il
@@ -0,0 +1,36 @@
+// Metadata version: v4.0.30319
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly ConsoleApp11
+{
+  .ver 1:0:0:0
+}
+.module ConsoleApp11.exe
+// MVID: {B973FCD6-A9C4-48A9-8291-26DDC248E208}
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00020003    //  ILONLY 32BITPREFERRED
+// Image base: 0x000001C4B6C90000
+
+.class private auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue959
+       extends [mscorlib]System.Object
+{
+.method public hidebysig instance void  Test(
+            bool arg
+        ) cil managed
+{
+  // Code size 18 (0x12)
+  .maxstack  8
+	IL_0000: ldarg.1
+	IL_0001: brfalse IL_000b
+	IL_0006: br IL_0011
+	IL_000b: ldarg.1
+	IL_000c: brtrue IL_0011
+	IL_0011: ret
+} // end of method Program::Test
+}
\ No newline at end of file
diff --git a/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs b/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
index 995b7a247..52b85f519 100644
--- a/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
+++ b/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
@@ -186,7 +186,7 @@ namespace ICSharpCode.Decompiler.CSharp
 						break;
 				}
 			}
-			if (switchContainer != null) {
+			if (switchContainer != null && stmt.SwitchSections.Count > 0) {
 				// Translate any remaining blocks:
 				var lastSectionStatements = stmt.SwitchSections.Last().Statements;
 				foreach (var block in switchContainer.Blocks.Skip(1)) {