From 6973dec0ef46bb48c1c4227e03d3d01b6d9b410a Mon Sep 17 00:00:00 2001
From: Siegfried Pammer <siegfriedpammer@gmail.com>
Date: Wed, 15 Jan 2020 10:18:14 +0100
Subject: [PATCH] Fix #1906: RRs for default expressions of primitive types
 should use the correct constant value.

VB's `New Long()` is emitted as `initobj` whereas C#'s `default(long)` is emitted as `ldc.i4.0; conv.i8`.
---
 .../ICSharpCode.Decompiler.Tests.csproj                  | 2 ++
 .../TestCases/VBPretty/Issue1906.cs                      | 9 +++++++++
 .../TestCases/VBPretty/Issue1906.vb                      | 6 ++++++
 ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs       | 6 ++++++
 ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs       | 5 ++++-
 5 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.cs
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.vb

diff --git a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
index 888df6e51..358d3fbd8 100644
--- a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -82,6 +82,7 @@
     <Compile Include="DisassemblerPrettyTestRunner.cs" />
     <Compile Include="TestCases\Correctness\StringConcat.cs" />
     <Compile Include="TestCases\Ugly\NoLocalFunctions.cs" />
+    <Compile Include="TestCases\VBPretty\Issue1906.cs" />
     <Compile Include="TestCases\VBPretty\Select.cs" />
     <None Include="TestCases\ILPretty\WeirdEnums.cs" />
     <Compile Include="TestCases\ILPretty\ConstantBlobs.cs" />
@@ -93,6 +94,7 @@
     <Compile Include="TestCases\Ugly\NoForEachStatement.cs" />
     <None Include="TestCases\Ugly\NoExtensionMethods.Expected.cs" />
     <Compile Include="TestCases\Ugly\NoExtensionMethods.cs" />
+    <None Include="TestCases\VBPretty\Issue1906.vb" />
     <None Include="TestCases\VBPretty\Select.vb" />
     <None Include="TestCases\VBPretty\VBCompoundAssign.cs" />
     <Compile Include="TestCases\Pretty\ThrowExpressions.cs" />
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.cs b/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.cs
new file mode 100644
index 000000000..9d85ecd89
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.cs
@@ -0,0 +1,9 @@
+using System;
+
+public class Issue1906
+{
+	public void M()
+	{
+		Console.WriteLine(Math.Min(Math.Max(long.MinValue, default(long)), long.MaxValue));
+	}
+}
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.vb b/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.vb
new file mode 100644
index 000000000..70f2bbe3e
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/VBPretty/Issue1906.vb
@@ -0,0 +1,6 @@
+Imports System
+Public Class Issue1906
+	Public Sub M()
+		Console.WriteLine(Math.Min(Math.Max(Int64.MinValue, New Long), Int64.MaxValue))
+	End Sub
+End Class
\ No newline at end of file
diff --git a/ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs b/ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs
index d41f6aa70..6c1df2b1e 100644
--- a/ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs
+++ b/ICSharpCode.Decompiler.Tests/VBPrettyTestRunner.cs
@@ -78,6 +78,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run(options: options | CompilerOptions.Library);
 		}
 
+		[Test]
+		public void Issue1906([ValueSource(nameof(defaultOptions))] CompilerOptions options)
+		{
+			Run(options: options | CompilerOptions.Library);
+		}
+
 		void Run([CallerMemberName] string testName = null, CompilerOptions options = CompilerOptions.UseDebug, DecompilerSettings settings = null)
 		{
 			var vbFile = Path.Combine(TestCasePath, testName + ".vb");
diff --git a/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs b/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
index 08506d1ee..1a5a0b2da 100644
--- a/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
+++ b/ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs
@@ -536,14 +536,17 @@ namespace ICSharpCode.Decompiler.CSharp
 		{
 			Expression expr;
 			IType constantType;
+			object constantValue;
 			if (type.IsReferenceType == true || type.IsKnownType(KnownTypeCode.NullableOfT)) {
 				expr = new NullReferenceExpression();
 				constantType = SpecialType.NullType;
+				constantValue = null;
 			} else {
 				expr = new DefaultValueExpression(ConvertType(type));
 				constantType = type;
+				constantValue = CSharpResolver.GetDefaultValue(type);
 			}
-			return expr.WithRR(new ConstantResolveResult(constantType, null));
+			return expr.WithRR(new ConstantResolveResult(constantType, constantValue));
 		}
 		
 		protected internal override TranslatedExpression VisitSizeOf(SizeOf inst, TranslationContext context)