From 43bfaba7e013ea2f1998e50ec6acab10528ebe33 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maximilian=20Schm=C3=B6cker?= <m.schmoecker@brickfire.eu>
Date: Wed, 6 Aug 2025 21:37:30 +0200
Subject: [PATCH] Add ExpandParamsArguments DecompilerSettings

---
 .../ICSharpCode.Decompiler.Tests.csproj       |  1 +
 .../PrettyTestRunner.cs                       |  6 ++++++
 .../Pretty/ExpandParamsArgumentsDisabled.cs   | 17 +++++++++++++++++
 ICSharpCode.Decompiler/CSharp/CallBuilder.cs  |  2 +-
 ICSharpCode.Decompiler/DecompilerSettings.cs  | 19 +++++++++++++++++++
 ILSpy/Properties/Resources.Designer.cs        |  9 +++++++++
 ILSpy/Properties/Resources.resx               |  3 +++
 7 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/Pretty/ExpandParamsArgumentsDisabled.cs

diff --git a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
index 0282f9d00..2851e3eea 100644
--- a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -146,6 +146,7 @@
     <Compile Include="TestCases\ILPretty\Issue3442.cs" />
     <Compile Include="TestCases\ILPretty\Issue3466.cs" />
     <Compile Include="TestCases\ILPretty\Issue3524.cs" />
+    <Compile Include="TestCases\Pretty\ExpandParamsArgumentsDisabled.cs" />
     <Compile Include="TestCases\Pretty\ExtensionProperties.cs" />
     <None Include="TestCases\ILPretty\Issue3504.cs" />
     <Compile Include="TestCases\ILPretty\MonoFixed.cs" />
diff --git a/ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs b/ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs
index d67877e72..d28edc76a 100644
--- a/ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs
+++ b/ICSharpCode.Decompiler.Tests/PrettyTestRunner.cs
@@ -617,6 +617,12 @@ namespace ICSharpCode.Decompiler.Tests
 			await RunForLibrary(cscOptions: cscOptions);
 		}
 
+		[Test]
+		public async Task ExpandParamsArgumentsDisabled([ValueSource(nameof(defaultOptions))] CompilerOptions cscOptions)
+		{
+			await RunForLibrary(cscOptions: cscOptions, configureDecompiler: settings => settings.ExpandParamsArguments = false);
+		}
+
 		[Test]
 		public async Task Issue1080([ValueSource(nameof(roslynOnlyOptions))] CompilerOptions cscOptions)
 		{
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/Pretty/ExpandParamsArgumentsDisabled.cs b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/ExpandParamsArgumentsDisabled.cs
new file mode 100644
index 000000000..86d168df6
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/Pretty/ExpandParamsArgumentsDisabled.cs
@@ -0,0 +1,17 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
+{
+	public class ExpandParamsArgumentsDisabled
+	{
+		public void Test()
+		{
+			MethodWithParams(Array.Empty<int>());
+			MethodWithParams(new int[1] { 5 });
+		}
+
+		public void MethodWithParams(params int[] b)
+		{
+		}
+	}
+}
diff --git a/ICSharpCode.Decompiler/CSharp/CallBuilder.cs b/ICSharpCode.Decompiler/CSharp/CallBuilder.cs
index 2ff1ce4d1..f4fa1fb03 100644
--- a/ICSharpCode.Decompiler/CSharp/CallBuilder.cs
+++ b/ICSharpCode.Decompiler/CSharp/CallBuilder.cs
@@ -969,7 +969,7 @@ namespace ICSharpCode.Decompiler.CSharp
 				{
 					firstOptionalArgumentIndex = -2;
 				}
-				if (parameter.IsParams && i + 1 == callArguments.Count && argumentToParameterMap == null)
+				if (expressionBuilder.settings.ExpandParamsArguments && parameter.IsParams && i + 1 == callArguments.Count && argumentToParameterMap == null)
 				{
 					// Parameter is marked params
 					// If the argument is an array creation, inline all elements into the call and add missing default values.
diff --git a/ICSharpCode.Decompiler/DecompilerSettings.cs b/ICSharpCode.Decompiler/DecompilerSettings.cs
index 0abb9a2fb..1b8684d99 100644
--- a/ICSharpCode.Decompiler/DecompilerSettings.cs
+++ b/ICSharpCode.Decompiler/DecompilerSettings.cs
@@ -1703,6 +1703,25 @@ namespace ICSharpCode.Decompiler
 			}
 		}
 
+		bool expandParamsArguments = true;
+
+		/// <summary>
+		/// Gets/Sets whether to expand <c>params</c> arguments by replacing explicit array creation
+		/// with individual values in method calls.
+		/// </summary>
+		[Category("C# 1.0 / VS .NET")]
+		[Description("DecompilerSettings.ExpandParamsArguments")]
+		public bool ExpandParamsArguments {
+			get { return expandParamsArguments; }
+			set {
+				if (expandParamsArguments != value)
+				{
+					expandParamsArguments = value;
+					OnPropertyChanged();
+				}
+			}
+		}
+
 		bool localFunctions = true;
 
 		/// <summary>
diff --git a/ILSpy/Properties/Resources.Designer.cs b/ILSpy/Properties/Resources.Designer.cs
index e6308d83e..6c08ae8e7 100644
--- a/ILSpy/Properties/Resources.Designer.cs
+++ b/ILSpy/Properties/Resources.Designer.cs
@@ -1017,6 +1017,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Expand params arguments by removing explicit array creation.
+        /// </summary>
+        public static string DecompilerSettings_ExpandParamsArguments {
+            get {
+                return ResourceManager.GetString("DecompilerSettings.ExpandParamsArguments", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use file-scoped namespace declarations.
         /// </summary>
diff --git a/ILSpy/Properties/Resources.resx b/ILSpy/Properties/Resources.resx
index 65d7471aa..f14786326 100644
--- a/ILSpy/Properties/Resources.resx
+++ b/ILSpy/Properties/Resources.resx
@@ -360,6 +360,9 @@ Are you sure you want to continue?</value>
   <data name="DecompilerSettings.DoWhileStatement" xml:space="preserve">
     <value>Transform to do-while, if possible</value>
   </data>
+  <data name="DecompilerSettings.ExpandParamsArguments" xml:space="preserve">
+	  <value>Expand params arguments by removing explicit array creation</value>
+  </data>
   <data name="DecompilerSettings.FSpecificOptions" xml:space="preserve">
     <value>F#-specific options</value>
   </data>