Fix up galc and add some comments

Author: SeeminglyScience

src/ClassExplorer/ALCPoly.cs

@@ -80,7 +80,7 @@ public static string SafeGetName(AssemblyLoadContext alc)
             {
             }
 
-            return name ?? alc.GetType().FullName;
+            return name ?? alc.GetType().FullName ?? "<Unnamed>";
         }
 
         public static void AssertSupported(PSCmdlet cmdlet)
@@ -104,7 +104,7 @@ public static IEnumerable<AssemblyLoadContext> GetAll()
 #endif
         }
 
-        public static AssemblyLoadContext GetLoadContext(Assembly assembly)
+        public static AssemblyLoadContext? GetLoadContext(Assembly assembly)
         {
 #if NETFRAMEWORK
             return AssemblyLoadContext.Default;

src/ClassExplorer/Commands/GetAssemblyCommand.cs

@@ -2,6 +2,7 @@
 using System.Linq;
 using System.Management.Automation;
 using System.Reflection;
+using System.Runtime.Loader;
 
 namespace ClassExplorer.Commands
 {
@@ -94,6 +95,12 @@ protected override void ProcessRecord()
                 return;
             }
 
+            if (InputObject.BaseObject is AssemblyLoadContext alc)
+            {
+                WriteObject(ALC.SafeGetAssemblies(alc), enumerateCollection: true);
+                return;
+            }
+
             WriteObject(InputObject.BaseObject.GetType().Assembly, enumerateCollection: false);
         }
     }

src/ClassExplorer/Commands/GetAssemblyLoadContextCommand.cs

@@ -7,6 +7,7 @@ namespace ClassExplorer.Commands;
 
 [Cmdlet(VerbsCommon.Get, "AssemblyLoadContext")]
 [Alias("galc")]
+[OutputType(typeof(AssemblyLoadContext))]
 public sealed class GetAssemblyLoadContextCommand : PSCmdlet
 {
     [Parameter(Position = 0)]
@@ -49,7 +50,12 @@ protected override void ProcessRecord()
             return;
         }
 
-        AssemblyLoadContext alc = ALC.GetLoadContext(assembly);
+        AssemblyLoadContext? alc = ALC.GetLoadContext(assembly);
+        if (alc is null)
+        {
+            return;
+        }
+
         if (!(_processedAlcs ??= new()).Add(alc))
         {
             return;

src/ClassExplorer/Commands/InvokeMemberCommand.cs

@@ -6,7 +6,7 @@
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using ClassExplorer.Internal;
-
+using ClassExplorer.Signatures;
 using PSAllowNull = System.Management.Automation.AllowNullAttribute;
 
 namespace ClassExplorer.Commands;
@@ -33,6 +33,19 @@ public sealed class InvokeMemberCommand : PSCmdlet
     [Parameter]
     public SwitchParameter SkipPSObjectUnwrap { get; set; }
 
+    protected override void BeginProcessing()
+    {
+        if (SessionState.LanguageMode is not PSLanguageMode.FullLanguage)
+        {
+            ThrowTerminatingError(
+                new ErrorRecord(
+                    new PSInvalidOperationException(SR.InvalidLanguageMode),
+                    nameof(SR.InvalidLanguageMode),
+                    ErrorCategory.InvalidOperation,
+                    targetObject: null));
+        }
+    }
+
     protected override unsafe void ProcessRecord()
     {
         Poly.Assert(InputObject is not null);
@@ -82,8 +95,6 @@ protected override unsafe void ProcessRecord()
             }
         }
 
-
-
         if (InputObject is not MethodBase methodBase)
         {
             ThrowTerminatingError(
@@ -166,11 +177,17 @@ protected override unsafe void ProcessRecord()
             return;
         }
 
+        // Go through refs and remove any that link to a `PSReference` or are for a `in` parameter.
         for (int i = refs.Count - 1; i >= 0; i--)
         {
             RefInfo info = refs[i];
             if (info.PSRef is null)
             {
+                if (info.Parameter?.IsDecoratedReadOnly() ?? false)
+                {
+                    refs.RemoveAt(i);
+                }
+
                 continue;
             }
 

src/ClassExplorer/Internal/_Format.cs

@@ -61,6 +61,19 @@ public static string FullType(Type value, int maxLength = -1)
             .ToString();
     }
 
+    [Hidden, EditorBrowsable(EditorBrowsableState.Never)]
+    public static string FullType(string value, int maxLength = -1)
+    {
+        SignatureWriter w = GetWriter(maxLength);
+        int lastPeriod = value.LastIndexOf('.');
+        if (lastPeriod is -1 || lastPeriod == value.Length - 1)
+        {
+            return w.TypeInfo(value).ToString();
+        }
+
+        return w.Namespace(value[..lastPeriod]).Dot().TypeInfo(value[(lastPeriod + 1)..]).ToString();
+    }
+
     [Hidden, EditorBrowsable(EditorBrowsableState.Never)]
     public static string Namespace(string value, int maxLength = -1)
     {

src/ClassExplorer/PipelineEmitter.cs

@@ -51,22 +51,25 @@ static PipelineEmitter()
 
     public PipelineEmitter(PSCmdlet cmdlet) => _cmdlet = cmdlet;
 
-    public void Invoke(T value) => _cmdlet.WriteObject(value, enumerateCollection: false);
-
-    public void Invoke(T value, object? instance)
+    private static PSObject AsPSObject(object obj, bool storeTypeNameAndInstanceMembersLocally)
     {
-        PSObject pso;
-        if (s_asPSObject is null || s_setHidden is null)
+        if (s_asPSObject is null)
         {
-            pso = PSObject.AsPSObject(value);
-            pso.Properties.Add(new PSNoteProperty("__ce_Instance", instance));
-            _cmdlet.WriteObject(pso, enumerateCollection: false);
-            return;
+            return PSObject.AsPSObject(obj);
         }
 
-        pso = s_asPSObject(value, true);
+        return s_asPSObject(obj, storeTypeNameAndInstanceMembersLocally);
+    }
+
+    public void Invoke(T value) => _cmdlet.WriteObject(value, enumerateCollection: false);
+
+    public void Invoke(T value, object? instance)
+    {
+        // Avoid saving to the PSObject member resurrection table if possible as
+        // .NET caches `MemberInfo` objects.
+        PSObject pso = AsPSObject(value!, storeTypeNameAndInstanceMembersLocally: true);
         PSNoteProperty instanceProp = new("__ce_Instance", instance);
-        s_setHidden(instanceProp);
+        s_setHidden?.Invoke(instanceProp);
         pso.Properties.Add(instanceProp);
         _cmdlet.WriteObject(pso, enumerateCollection: false);
     }

src/ClassExplorer/SR.resx

@@ -191,4 +191,7 @@ Message: {0}</value>
   <data name="UnexpectedSignatureKind" xml:space="preserve">
     <value>Expected signature of kind "{0}" but found a "{1}" signature.</value>
   </data>
+  <data name="InvalidLanguageMode" xml:space="preserve">
+    <value>The 'Invoke-Member' command cannot be used outside of 'PSLanguageMode.FullLanguage'.</value>
+  </data>
 </root>

src/ClassExplorer/Signatures/RefSignature.cs

@@ -33,14 +33,14 @@ private static bool DoesRefKindMatch(RefKind kind, ParameterInfo parameter)
                 return kind is RefKind.Out;
             }
 
-            if (parameter.IsDefined("System.Runtime.CompilerServices.IsReadOnlyAttribute"))
+            if (parameter.IsDecoratedReadOnly())
             {
                 return kind is RefKind.In;
             }
 
             if (parameter.Position is -1)
             {
-                if (parameter.IsDefined("System.Runtime.CompilerServices.IsReadOnlyAttribute"))
+                if (parameter.IsDecoratedReadOnly())
                 {
                     return kind is RefKind.In;
                 }

src/ClassExplorer/Signatures/SignatureExtensions.cs

@@ -47,6 +47,11 @@ public static bool IsDefined(this MemberInfo member, string fullName)
             return member.IsDefined(type, true);
         }
 
+        public static bool IsDecoratedReadOnly(this ParameterInfo parameter)
+        {
+            return parameter.IsDefined("System.Runtime.CompilerServices.IsReadOnlyAttribute");
+        }
+
         public static bool IsDefined(this ParameterInfo parameter, string fullName)
         {
             Type? type = parameter.Member.Module.GetType(fullName) ?? Type.GetType(fullName);