Expose as a new entrypoint a Compilation-accepting version

I'm not sure why this ever took an INamespaceSymbol in the first place,
but we either have code working around it, or having an (old) comment
saying the code was wrong.

Author: jasonmalinowski

src/VisualStudio/CSharp/Impl/ProjectSystemShim/CSharpEntryPointFinder.cs

@@ -18,8 +18,7 @@ public static IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilat
     {
         // This differs from the VB implementation
         // (Microsoft.VisualStudio.LanguageServices.VisualBasic.ProjectSystemShim.EntryPointFinder) because we don't
-        // ever consider forms entry points. Technically, this is wrong but it just doesn't matter since the ref
-        // assemblies are unlikely to have a random Main() method that matches
+        // ever consider forms entry points.
         var visitor = new CSharpEntryPointFinder(compilation);
         visitor.Visit(compilation.SourceModule.GlobalNamespace);
         return visitor.EntryPoints;

src/VisualStudio/CSharp/Impl/ProjectSystemShim/CSharpEntryPointFinderService.cs

@@ -16,6 +16,6 @@ namespace Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim;
 [method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
 internal sealed class CSharpEntryPointFinderService() : AbstractEntryPointFinderService
 {
-    protected override IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilation, bool findFormsOnly)
+    public override IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilation, bool findFormsOnly)
         => CSharpEntryPointFinder.FindEntryPoints(compilation);
 }

src/VisualStudio/Core/Def/ProjectSystem/AbstractEntryPointFinderService.cs

@@ -9,7 +9,7 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
 
 internal abstract class AbstractEntryPointFinderService : IEntryPointFinderService
 {
-    protected abstract IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilation, bool findFormsOnly);
+    public abstract IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilation, bool findFormsOnly);
 
     public IEnumerable<INamedTypeSymbol> FindEntryPoints(INamespaceSymbol symbol, bool findFormsOnly)
         => symbol is { ContainingCompilation: Compilation compilation }

src/VisualStudio/Core/Def/ProjectSystem/IEntryPointFinderService.cs

@@ -19,4 +19,11 @@ internal interface IEntryPointFinderService : ILanguageService
     /// <param name="symbol">The namespace to search.</param>
     /// <param name="findFormsOnly">Restrict the search to only Windows Forms classes. Note that this is only implemented for VisualBasic</param>
     IEnumerable<INamedTypeSymbol> FindEntryPoints(INamespaceSymbol symbol, bool findFormsOnly);
+
+    /// <summary>
+    /// Finds the types that contain entry points like the Main method in a given compilation.
+    /// </summary>
+    /// <param name="compilation">The compilation to search.</param>
+    /// <param name="findFormsOnly">Restrict the search to only Windows Forms classes. Note that this is only implemented for VisualBasic</param>
+    IEnumerable<INamedTypeSymbol> FindEntryPoints(Compilation compilation, bool findFormsOnly);
 }

src/VisualStudio/VisualBasic/Impl/ProjectSystemShim/VisualBasicEntryPointFinderService.vb

@@ -17,7 +17,7 @@ Namespace Microsoft.VisualStudio.LanguageServices.VisualBasic.ProjectSystemShim
         Public Sub New()
         End Sub
 
-        Protected Overrides Function FindEntryPoints(compilation As Compilation, findFormsOnly As Boolean) As IEnumerable(Of INamedTypeSymbol)
+        Public Overrides Function FindEntryPoints(compilation As Compilation, findFormsOnly As Boolean) As IEnumerable(Of INamedTypeSymbol)
             Return VisualBasicEntryPointFinder.FindEntryPoints(compilation, findFormsOnly)
         End Function
     End Class