[WIP] GenAPI: a work around for a generation an explicit interface implementation indexer.

src/GenAPI/Microsoft.DotNet.GenAPI/CSharpFileBuilder.cs

@@ -222,15 +222,27 @@ private SyntaxNode Visit(SyntaxNode namedTypeNode, INamedTypeSymbol namedType)
 
             foreach (ISymbol member in members.Order())
             {
+                IMethodSymbol? method = member as IMethodSymbol;
                 // If the method is ExplicitInterfaceImplementation and is derived from an interface that was filtered out, we must filter out it either.
-                if (member is IMethodSymbol method &&
+                if (method != null &&
                     method.MethodKind == MethodKind.ExplicitInterfaceImplementation &&
                     method.ExplicitInterfaceImplementations.Any(m => !_symbolFilter.Include(m.ContainingSymbol) ||
                         // if explicit interface implementation method has inaccessible type argument
                         m.ContainingType.HasInaccessibleTypeArgument(_symbolFilter)))
                 {
                     continue;
                 }
+
+                // TODO: a work around for the https://github.com/dotnet/sdk/issues/31570 issue.
+                // if the symbol is a method and if it is an explicit interface implementation getter or setter of an indexer property (get_Item or set_Item).
+                if (method != null && method.MethodKind == MethodKind.ExplicitInterfaceImplementation &&
+                    method.ExplicitInterfaceImplementations.Length == 1 &&
+                    method.ExplicitInterfaceImplementations.ElementAt(0) is IMethodSymbol explicitMethod &&
+                    (explicitMethod.MethodKind == MethodKind.PropertyGet || explicitMethod.MethodKind == MethodKind.PropertySet))
+                {
+                    continue;
+                }
+
                 // If the property is derived from an interface that was filter out, we must filtered out it either.
                 if (member is IPropertySymbol property && !property.ExplicitInterfaceImplementations.IsEmpty &&
                     property.ExplicitInterfaceImplementations.Any(m => !_symbolFilter.Include(m.ContainingSymbol)))

src/GenAPI/Microsoft.DotNet.GenAPI/SyntaxGeneratorExtensions.cs

@@ -92,6 +92,16 @@ public static SyntaxNode DeclarationExt(this SyntaxGenerator syntaxGenerator, IS
                 }
             }
 
+            // TODO: a work around for the https://github.com/dotnet/sdk/issues/31570 issue.
+            // if the symbol is a property (not an indexer) and if it is an explicit interface implementation of an indexer property.
+            if (symbol is IPropertySymbol propertySymbol &&
+                !propertySymbol.IsIndexer && propertySymbol.ExplicitInterfaceImplementations.Length == 1 &&
+                propertySymbol.ExplicitInterfaceImplementations.ElementAt(0) is IPropertySymbol explicitProperty &&
+                explicitProperty.IsIndexer)
+            {
+                return syntaxGenerator.IndexerDeclaration(propertySymbol);
+            }
+
             try
             {
                 return syntaxGenerator.Declaration(symbol);