Addressing feedback from Chuck. Handle scenario where input isn't ref assembly. Hook assembly redirect.

Author: Julien Couvreur

src/Compilers/CSharp/Portable/CommandLine/CSharpCommandLineParser.cs

@@ -1178,7 +1178,7 @@ internal sealed override CommandLineArguments CommonParse(IEnumerable<string> ar
                 AddDiagnostic(diagnostics, diagnosticOptions, ErrorCode.ERR_NoRefOutWhenRefOnly);
             }
 
-            if (metadataReferences.Any(r => r.Properties.EmbedInteropTypes) && (refOnly || outputRefFilePath != null))
+            if ((refOnly || outputRefFilePath != null) && metadataReferences.Any(r => r.Properties.EmbedInteropTypes))
             {
                 AddDiagnostic(diagnostics, diagnosticOptions, ErrorCode.ERR_NoEmbeddedTypeWhenRefOutOrRefOnly);
             }

src/Compilers/Core/MSBuildTask/CopyRefAssembly.cs

@@ -20,6 +20,11 @@ public sealed class CopyRefAssembly : Task
         [Required]
         public string DestinationPath { get; set; }
 
+        static CopyRefAssembly()
+        {
+            AssemblyResolution.Install();
+        }
+
         public CopyRefAssembly()
         {
             TaskResources = ErrorString.ResourceManager;
@@ -45,20 +50,27 @@ public override bool Execute()
                     Log.LogMessageFromResources(MessageImportance.High, "CopyRefAssembly_BadSource3", SourcePath, e.Message, e.StackTrace);
                 }
 
-                try
+                if (source.Equals(Guid.Empty))
+                {
+                    Log.LogMessageFromResources(MessageImportance.High, "CopyRefAssembly_SourceNotRef1", SourcePath);
+                }
+                else
                 {
-                    Guid destination = ExtractMvid(DestinationPath);
+                    try
+                    {
+                        Guid destination = ExtractMvid(DestinationPath);
 
-                    if (source.Equals(destination))
+                        if (!source.Equals(Guid.Empty) && source.Equals(destination))
+                        {
+                            Log.LogMessageFromResources(MessageImportance.Low, "CopyRefAssembly_SkippingCopy1", DestinationPath);
+                            return true;
+                        }
+                    }
+                    catch (Exception)
                     {
-                        Log.LogMessageFromResources(MessageImportance.Low, "CopyRefAssembly_SkippingCopy1", DestinationPath);
-                        return true;
+                        Log.LogMessageFromResources(MessageImportance.High, "CopyRefAssembly_BadDestination1", DestinationPath);
                     }
                 }
-                catch (Exception)
-                {
-                    Log.LogMessageFromResources(MessageImportance.High, "CopyRefAssembly_BadDestination1", DestinationPath);
-                }
             }
 
             return Copy();

src/Compilers/Core/MSBuildTask/ErrorString.Designer.cs

@@ -154,6 +154,9 @@
   <data name="CopyRefAssembly_SkippingCopy1" xml:space="preserve">
     <value>Reference assembly "{0}" already has latest information. Leaving it untouched.</value>
   </data>
+  <data name="CopyRefAssembly_SourceNotRef1" xml:space="preserve">
+    <value>Could not extract the MVID from "{0}". Are you sure it is a reference assembly?</value>
+  </data>
   <data name="CopyRefAssembly_BadSource3" xml:space="preserve">
     <value>Failed to check the content hash of the source ref assembly '{0}': {1}
 {2}</value>

src/Compilers/Core/MSBuildTask/ErrorString.resx

@@ -1203,7 +1203,7 @@ lVbRuntimePlus:
                 AddDiagnostic(diagnostics, ERRID.ERR_NoRefOutWhenRefOnly)
             End If
 
-            If metadataReferences.Any(Function(r) r.Properties.EmbedInteropTypes) AndAlso (refOnly OrElse outputRefFileName IsNot Nothing) Then
+            If (refOnly OrElse outputRefFileName IsNot Nothing) AndAlso metadataReferences.Any(Function(r) r.Properties.EmbedInteropTypes) Then
                 AddDiagnostic(diagnostics, ERRID.ERR_NoEmbeddedTypeWhenRefOutOrRefOnly)
             End If
 

src/Compilers/VisualBasic/Portable/CommandLine/VisualBasicCommandLineParser.vb

@@ -5472,7 +5472,7 @@
     <value>Do not use refout when using refonly.</value>
   </data>
   <data name="ERR_NoEmbeddedTypeWhenRefOutOrRefOnly" xml:space="preserve">
-    <value>Cannot compile embed types when using /refout or /refonly.</value>
+    <value>Cannot embed types when using /refout or /refonly.</value>
   </data>
   <data name="ERR_NoNetModuleOutputWhenRefOutOrRefOnly" xml:space="preserve">
     <value>Cannot compile net modules when using /refout or /refonly.</value>