Add IL tests for basic isinst patterns. Undo change mentioned in 54ff546221 (commitcomment-32359757)

ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -67,6 +67,7 @@
 
   <ItemGroup>
     <Compile Include="DisassemblerPrettyTestRunner.cs" />
+    <Compile Include="TestCases\ILPretty\Issue1389.cs" />
     <Compile Include="TestCases\Pretty\MultidimensionalArray.cs" />
     <Compile Include="Output\CSharpAmbienceTests.cs" />
     <Compile Include="Semantics\ConversionTests.cs" />
@@ -81,6 +82,7 @@
     <Compile Include="TestCases\Pretty\EnumTests.cs" />
     <Compile Include="TestCases\Pretty\TypeMemberTests.cs" />
     <Compile Include="TestCases\Pretty\ValueTypes.cs" />
+    <None Include="TestCases\ILPretty\Issue1389.il" />
     <None Include="TestCases\ILPretty\SequenceOfNestedIfs.cs" />
     <Compile Include="TestCases\Pretty\ConstructorInitializers.cs" />
     <None Include="TestCases\ILPretty\SequenceOfNestedIfs.il" />

ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs

@@ -82,6 +82,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run();
 		}
 
+		[Test]
+		public void Issue1389()
+		{
+			Run();
+		}
+
 		[Test]
 		public void FSharpUsing_Debug()
 		{

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue1389.cs

@@ -0,0 +1,28 @@
+// Issue1389.Program
+using System;
+
+namespace Issue1389
+{
+	public class Program
+	{
+		private static object GetObject()
+		{
+			throw null;
+		}
+
+		private static void UnusedResultOfIsinst()
+		{
+			bool flag = GetObject() is TypeCode;
+		}
+
+		private static bool BoolResultOfIsinst()
+		{
+			return GetObject() is TypeCode;
+		}
+
+		private static object EnumResultOfIsinst(object A_0)
+		{
+			return (A_0 is TypeCode) ? A_0 : null;
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue1389.il

@@ -0,0 +1,74 @@
+.assembly extern mscorlib
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )
+  .ver 4:0:0:0
+}
+.assembly Issue1389
+{
+  .hash algorithm 0x00008004
+  .ver 1:0:4059:39717
+}
+.module Issue1389.dll
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00000003    //  ILONLY 32BITREQUIRED
+
+.class public auto ansi beforefieldinit Issue1389.Program
+	extends [mscorlib]System.Object
+{
+	// Methods
+	.method /* 06000001 */ private hidebysig static 
+		object GetObject () cil managed 
+	{
+		// Method begins at RVA 0x2050
+		// Code size 2 (0x2)
+		.maxstack 8
+
+		IL_0000: ldnull
+		IL_0001: throw
+	} // end of method Program::GetObject
+
+	.method /* 06000002 */ private hidebysig static 
+		void UnusedResultOfIsinst () cil managed 
+	{
+		// Method begins at RVA 0x2053
+		// Code size 12 (0xc)
+		.maxstack 8
+
+		IL_0000: call object Issue1389.Program::GetObject() /* 06000001 */
+		IL_0005: isinst [mscorlib]System.TypeCode /* 01000002 */
+		IL_000a: pop
+		IL_000b: ret
+	} // end of method Program::UnusedResultOfIsinst
+
+	.method /* 06000003 */ private hidebysig static 
+		bool BoolResultOfIsinst () cil managed 
+	{
+		// Method begins at RVA 0x2060
+		// Code size 14 (0xe)
+		.maxstack 8
+
+		IL_0000: call object Issue1389.Program::GetObject() /* 06000001 */
+		IL_0005: isinst [mscorlib]System.TypeCode /* 01000002 */
+		IL_000a: ldnull
+		IL_000b: cgt.un
+		IL_000d: ret
+	} // end of method Program::BoolResultOfIsinst
+
+	.method /* 06000004 */ private hidebysig static 
+		object EnumResultOfIsinst (
+			object A_0
+		) cil managed 
+	{
+		// Method begins at RVA 0x206f
+		// Code size 7 (0x7)
+		.maxstack 8
+
+		IL_0000: ldarg.0
+		IL_0001: isinst [mscorlib]System.TypeCode /* 01000002 */
+		IL_0006: ret
+	} // end of method Program::EnumResultOfIsinst
+
+} // end of class Issue1389.Program

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -266,7 +266,6 @@ namespace ICSharpCode.Decompiler.CSharp
 		protected internal override TranslatedExpression VisitIsInst(IsInst inst, TranslationContext context)
 		{
 			var arg = Translate(inst.Argument);
-			arg = UnwrapBoxingConversion(arg);
 			if (inst.Type.IsReferenceType == false) {
 				// isinst with a value type results in an expression of "boxed value type",
 				// which is not supported in C#.
@@ -286,6 +285,7 @@ namespace ICSharpCode.Decompiler.CSharp
 					return ErrorExpression("isinst with value type is only supported in some contexts");
 				}
 			}
+			arg = UnwrapBoxingConversion(arg);
 			return new AsExpression(arg.Expression, ConvertType(inst.Type))
 				.WithILInstruction(inst)
 				.WithRR(new ConversionResolveResult(inst.Type, arg.ResolveResult, Conversion.TryCast));