Fix "ref" parameter (#61)

src/ProxyInterfaceSourceGenerator/Builders/MethodParameterBuilder.cs

@@ -13,7 +13,7 @@ internal static class MethodParameterBuilder
         {
             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 @@ using System;
                 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 @@ using System;
             }
 
             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()}";