Fix "ref" parameter

src-examples/ProxyInterfaceConsumer/Person.cs

@@ -68,11 +68,13 @@ public void AddAddresses(params Address[] addresses)
         public void In_Out_Ref1(in int a, out int b, ref int c)
         {
             b = 1;
+            c++;
         }
 
         public int In_Out_Ref2(in Address a, out Address b, ref Address c)
         {
             b = new Address();
+            c.HouseNumber = 11;
             return 404;
         }
 

src/ProxyInterfaceSourceGenerator/Builders/MethodParameterBuilder.cs

@@ -13,7 +13,7 @@ public static string Build(IParameterSymbol parameterSymbol, string? type)
         {
             stringBuilder.Append(parameterSymbol.GetAttributesPrefix()); // "" or [NotNullWhen(true)]
             stringBuilder.Append(parameterSymbol.GetParamsPrefix()); // "" or "params "
-            stringBuilder.Append(parameterSymbol.GetRefPrefix()); // "" or "out "
+            stringBuilder.Append(parameterSymbol.GetRefKindPrefix()); // "" or "out "
             stringBuilder.AppendFormat("{0} ", type); // string or another type
         }
 

src/ProxyInterfaceSourceGenerator/Extensions/ParameterSymbolExtensions.cs

@@ -8,7 +8,12 @@ internal static class ParameterSymbolExtensions
 {
     private const string ParameterValueNull = "null";
 
-    public static string GetRefPrefix(this IParameterSymbol ps)
+    public static bool IsRef(this IParameterSymbol ps)
+    {
+        return ps.RefKind is RefKind.Ref or RefKind.RefReadOnly;
+    }
+
+    public static string GetRefKindPrefix(this IParameterSymbol ps)
     {
         return ps.RefKind switch
         {

src/ProxyInterfaceSourceGenerator/Extensions/StringExtensions.cs

@@ -4,6 +4,11 @@ namespace ProxyInterfaceSourceGenerator.Extensions;
 
 internal static class StringExtensions
 {
+    public static string IIf(this bool value, string valueTrue, string valueFalse = "")
+    {
+        return value ? valueTrue : valueFalse;
+    }
+
     // See https://andrewlock.net/why-is-string-gethashcode-different-each-time-i-run-my-program-in-net-core/
     public static string GetDeterministicHashCodeAsString(this string str)
     {

src/ProxyInterfaceSourceGenerator/FileGenerators/ProxyClassesGenerator.cs

@@ -208,7 +208,9 @@ private string GeneratePublicMethods(ClassSymbol targetClassSymbol, bool proxyBa
                 var type = GetParameterType(parameterSymbol, out _);
 
                 methodParameters.Add(MethodParameterBuilder.Build(parameterSymbol, type));
-                invokeParameters.Add($"{parameterSymbol.GetRefPrefix()}{parameterSymbol.GetSanitizedName()}_");
+
+                // Do not add the '_' for a 'ref' parameter.
+                invokeParameters.Add($"{parameterSymbol.GetRefKindPrefix()}{parameterSymbol.GetSanitizedName()}{(!parameterSymbol.IsRef()).IIf("_")}");
             }
 
             string overrideOrVirtual = string.Empty;
@@ -235,8 +237,9 @@ private string GeneratePublicMethods(ClassSymbol targetClassSymbol, bool proxyBa
             }
 
             str.AppendLine($"        public {overrideOrVirtual}{returnTypeAsString} {method.GetMethodNameWithOptionalTypeParameters()}({string.Join(", ", methodParameters)}){whereStatement}");
-            str.AppendLine("        {");
-            foreach (var ps in method.Parameters)
+            str.AppendLine(@"        {");
+
+            foreach (var ps in method.Parameters.Where(p => !p.IsRef()))
             {
                 var type = FixType(ps.Type.ToString());
                 string normalOrMap = $" = {ps.GetSanitizedName()}";

tests/ProxyInterfaceSourceGeneratorTests/Destination/ProxyInterfaceSourceGeneratorTests.Source.PersonExtendsProxy.g.cs

@@ -76,10 +76,8 @@ public int DefaultValue(int x = 100)
 
         public void In_Out_Ref1(in int a, out int b, ref int c)
         {
-            int a_ = a;
             int b_;
-            int c_ = c;
-            _Instance.In_Out_Ref1(in a_, out b_, ref c_);
+            _Instance.In_Out_Ref1(in a, out b_, ref c);
             b = b_;
         }
 

tests/ProxyInterfaceSourceGeneratorTests/Destination/ProxyInterfaceSourceGeneratorTests.Source.PersonProxy.g.cs

@@ -103,10 +103,8 @@ public int DefaultValue(int x = 100)
 
         public void In_Out_Ref1(in int a, out int b, ref int c)
         {
-            int a_ = a;
             int b_;
-            int c_ = c;
-            _Instance.In_Out_Ref1(in a_, out b_, ref c_);
+            _Instance.In_Out_Ref1(in a, out b_, ref c);
             b = b_;
         }
 

tests/ProxyInterfaceSourceGeneratorTests/ProxyInterfaceSourceGeneratorTest.GenerateFiles_ForClassWithArray_Should_GenerateCorrectFiles.verified.txt

@@ -1,6 +1,6 @@
 [
   {
-    HintName: ProxyInterfaceGenerator.ProxyAttribute.g.cs,
+    HintName: ProxyInterfaceGenerator.Extra.g.cs,
     Source:
 //----------------------------------------------------------------------------------------
 // <auto-generated>
@@ -16,7 +16,7 @@ using System;
 namespace ProxyInterfaceGenerator
 {
     [AttributeUsage(AttributeTargets.Interface)]
-    public class ProxyAttribute : Attribute
+    internal sealed class ProxyAttribute : Attribute
     {
         public Type Type { get; }
         public bool ProxyBaseClasses { get; }

tests/ProxyInterfaceSourceGeneratorTests/ProxyInterfaceSourceGeneratorTest.cs

@@ -273,7 +273,7 @@ public void GenerateFiles_When_MixedVisibility_Should_GenerateCorrectFiles()
     public void GenerateFiles_ForSingleClass_Should_GenerateCorrectFiles()
     {
         // Arrange
-        var attributeFilename = "ProxyInterfaceGenerator.ProxyAttribute.g.cs";
+        var attributeFilename = "ProxyInterfaceGenerator.Extra.g.cs";
         var interfaceFilename = "ProxyInterfaceSourceGeneratorTests.Source.IPersonExtends.g.cs";
         var proxyClassFilename = "ProxyInterfaceSourceGeneratorTests.Source.PersonExtendsProxy.g.cs";
 
@@ -364,7 +364,7 @@ public void GenerateFiles_ForSingleClass_AsInternal_Should_GenerateCorrectFiles(
     public void GenerateFiles_ForTwoClasses_Should_GenerateCorrectFiles()
     {
         // Arrange
-        var attributeFilename = "ProxyInterfaceGenerator.ProxyAttribute.g.cs";
+        var attributeFilename = "ProxyInterfaceGenerator.Extra.g.cs";
         var interfaceHumanFilename = "ProxyInterfaceSourceGeneratorTests.Source.IHuman.g.cs";
         var proxyClassHumanFilename = "ProxyInterfaceSourceGeneratorTests.Source.HumanProxy.g.cs";
         var interfacePersonFilename = "ProxyInterfaceSourceGeneratorTests.Source.IPerson.g.cs";
@@ -440,5 +440,12 @@ public void GenerateFiles_ForTwoClasses_Should_GenerateCorrectFiles()
         var proxyCode = proxyClassPerson.ToString();
         if (Write) File.WriteAllText($"../../../Destination/{proxyClassPersonFilename}", proxyCode);
         proxyCode.Should().NotBeNullOrEmpty().And.Be(File.ReadAllText($"../../../Destination/{proxyClassPersonFilename}"));
+
+        var personProxy = new PersonProxy(new Person());
+
+        int c = 100;
+        personProxy.In_Out_Ref1(1, out var b, ref c);
+
+        c.Should().Be(101);
     }
 }

tests/ProxyInterfaceSourceGeneratorTests/Source/Person.cs

@@ -83,6 +83,7 @@ public int DefaultValue(int x = 100)
         public void In_Out_Ref1(in int a, out int b, ref int c)
         {
             b = 1;
+            c++;
         }
 
         public double[,] Out_MultiDimensionIssue54(out double[,] x)