Fix #982: ILSpy should ignore the parameter name of property setter and always use "value" instead in C#

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

@@ -61,6 +61,7 @@
     <Compile Include="TestCases\Correctness\ExpressionTrees.cs" />
     <Compile Include="TestCases\Correctness\LINQRaytracer.cs" />
     <Compile Include="TestCases\Correctness\MiniJSON.cs" />
+    <Compile Include="TestCases\ILPretty\Issue982.cs" />
     <Compile Include="TestCases\Pretty\ExpressionTrees.cs" />
     <None Include="TestCases\ILPretty\Issue959.cs" />
     <None Include="TestCases\ILPretty\FSharpLoops_Debug.cs" />
@@ -141,6 +142,7 @@
   <ItemGroup>
     <None Include="TestCases\ILPretty\Issue646.il" />
     <None Include="TestCases\ILPretty\Issue379.il" />
+    <None Include="TestCases\ILPretty\Issue982.il" />
     <None Include="TestCases\Pretty\Readme.txt" />
   </ItemGroup>
 

ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs

@@ -48,6 +48,12 @@ namespace ICSharpCode.Decompiler.Tests
 			Run();
 		}
 
+		[Test]
+		public void Issue982()
+		{
+			Run();
+		}
+
 		[Test]
 		public void FSharpUsing_Debug()
 		{

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue982.cs

@@ -0,0 +1,27 @@
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	internal class Issue982
+	{
+		private string textStr;
+
+		private string textStr2;
+
+		public string Text {
+			get {
+				return this.textStr;
+			}
+			set {
+				this.textStr = value;
+			}
+		}
+
+		public string this[int index] {
+			get {
+				return this.textStr2;
+			}
+			set {
+				this.textStr2 = value;
+			}
+		}
+	}
+}

ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue982.il

@@ -0,0 +1,125 @@
+
+//  Microsoft (R) .NET Framework IL Disassembler.  Version 3.5.30729.1
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+
+
+
+// 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 extern System
+{
+  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+  .ver 4:0:0:0
+}
+.assembly extern Microsoft.VisualBasic
+{
+  .publickeytoken = (B0 3F 5F 7F 11 D5 0A 3A )                         // .?_....:
+  .ver 10:0:0:0
+}
+.assembly ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+  .hash algorithm 0x00008004
+  .ver 1:0:0:0
+}
+
+.module Issue982.exe
+// MVID: {1DAED9CF-459B-4BA6-A091-CB3BDEF963F8}
+.imagebase 0x00400000
+.file alignment 0x00000200
+.stackreserve 0x00100000
+.subsystem 0x0003       // WINDOWS_CUI
+.corflags 0x00020003    //  ILONLY 32BITREQUIRED
+// Image base: 0x06E80000
+
+
+// =============== CLASS MEMBERS DECLARATION ===================
+
+.class private auto ansi ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982
+       extends [mscorlib]System.Object
+{
+  .custom instance void [mscorlib]System.Reflection.DefaultMemberAttribute::.ctor(string) = ( 01 00 05 54 65 78 74 32 00 00 )                   // ...Text2..
+  .field private string textStr
+  .field private string textStr2
+  .method public specialname rtspecialname 
+          instance void  .ctor() cil managed
+  {
+    // Code size       7 (0x7)
+    .maxstack  8
+    IL_0000:  ldarg.0
+    IL_0001:  call       instance void [mscorlib]System.Object::.ctor()
+    IL_0006:  ret
+  } // end of method Issue982::.ctor
+
+  .method public specialname instance string 
+          get_Text() cil managed
+  {
+    // Code size       12 (0xc)
+    .maxstack  1
+    .locals init ([0] string Text)
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  ldfld      string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::textStr
+    IL_0007:  stloc.0
+    IL_0008:  br.s       IL_000a
+
+    IL_000a:  ldloc.0
+    IL_000b:  ret
+  } // end of method Issue982::get_Text
+
+  .method public specialname instance void 
+          set_Text(string str) cil managed
+  {
+    // Code size       9 (0x9)
+    .maxstack  8
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  ldarg.1
+    IL_0003:  stfld      string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::textStr
+    IL_0008:  ret
+  } // end of method Issue982::set_Text
+
+  .method public specialname instance string 
+          get_Text2(int32 index) cil managed
+  {
+    // Code size       12 (0xc)
+    .maxstack  1
+    .locals init ([0] string Text2)
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  ldfld      string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::textStr2
+    IL_0007:  stloc.0
+    IL_0008:  br.s       IL_000a
+
+    IL_000a:  ldloc.0
+    IL_000b:  ret
+  } // end of method Issue982::get_Text2
+
+  .method public specialname instance void 
+          set_Text2(int32 index,
+                    string str) cil managed
+  {
+    // Code size       9 (0x9)
+    .maxstack  8
+    IL_0000:  nop
+    IL_0001:  ldarg.0
+    IL_0002:  ldarg.2
+    IL_0003:  stfld      string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::textStr2
+    IL_0008:  ret
+  } // end of method Issue982::set_Text2
+
+  .property instance string Text()
+  {
+    .get instance string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::get_Text()
+    .set instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::set_Text(string)
+  } // end of property Issue982::Text
+  .property instance string Text2(int32)
+  {
+    .get instance string ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::get_Text2(int32)
+    .set instance void ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982::set_Text2(int32,
+                                                      string)
+  } // end of property Issue982::Text2
+} // end of class ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue982

ICSharpCode.Decompiler/IL/Transforms/AssignVariableNames.cs

@@ -63,8 +63,54 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 			loopCounters = CollectLoopCounters(function);
 			foreach (var f in function.Descendants.OfType<ILFunction>()) {
 				if (f.Method != null) {
-					foreach (var p in f.Method.Parameters)
-						AddExistingName(reservedVariableNames, p.Name);
+					if (f.Method.IsAccessor && f.Method.Parameters.Count > 0) {
+						for (int i = 0; i < f.Method.Parameters.Count - 1; i++) {
+							AddExistingName(reservedVariableNames, f.Method.Parameters[i].Name);
+						}
+						var lastParameter = f.Method.Parameters.Last();
+						switch (f.Method.AccessorOwner) {
+							case IProperty prop:
+								if (prop.Setter == f.Method) {
+									if (prop.Parameters.Any(p => p.Name == "value")) {
+										f.Warnings.Add("Parameter named \"value\" already present in property signature!");
+										break;
+									}
+									var variableForLastParameter = f.Variables.FirstOrDefault(v => v.Function == f
+										&& v.Kind == VariableKind.Parameter
+										&& v.Index == f.Method.Parameters.Count - 1);
+									if (variableForLastParameter == null) {
+										AddExistingName(reservedVariableNames, lastParameter.Name);
+									} else {
+										if (variableForLastParameter.Name != "value") {
+											variableForLastParameter.Name = "value";
+										}
+										AddExistingName(reservedVariableNames, variableForLastParameter.Name);
+									}
+								}
+								break;
+							case IEvent ev:
+								if (f.Method != ev.InvokeAccessor) {
+									var variableForLastParameter = f.Variables.FirstOrDefault(v => v.Function == f
+										&& v.Kind == VariableKind.Parameter
+										&& v.Index == f.Method.Parameters.Count - 1);
+									if (variableForLastParameter == null) {
+										AddExistingName(reservedVariableNames, lastParameter.Name);
+									} else {
+										if (variableForLastParameter.Name != "value") {
+											variableForLastParameter.Name = "value";
+										}
+										AddExistingName(reservedVariableNames, variableForLastParameter.Name);
+									}
+								}
+								break;
+							default:
+								AddExistingName(reservedVariableNames, lastParameter.Name);
+								break;
+						}
+					} else {
+						foreach (var p in f.Method.Parameters)
+							AddExistingName(reservedVariableNames, p.Name);
+					}
 				} else {
 					foreach (var p in f.Variables.Where(v => v.Kind == VariableKind.Parameter))
 						AddExistingName(reservedVariableNames, p.Name);