Use implicit package reference for ILC build package

Author: sbomer

src/Tasks/Microsoft.NET.Build.Tasks/ProcessFrameworkReferences.cs

@@ -104,6 +104,9 @@ public class ProcessFrameworkReferences : TaskBase
         [Output]
         public ITaskItem[] TargetILCompilerPacks { get; set; }
 
+        [Output]
+        public ITaskItem[] ImplicitPackageReferences { get; set; }
+
         //  Runtime packs which aren't available for the specified RuntimeIdentifier
         [Output]
         public ITaskItem[] UnavailableRuntimePacks { get; set; }
@@ -621,6 +624,9 @@ private bool AddAotOrR2RRuntimePackage(AotPackageType packageType, Version norma
             else
             {
                 HostILCompilerPacks = new[] { newItem };
+                var ilCompilerBuildPackageReference = new TaskItem(knownPack.ItemSpec);
+                ilCompilerBuildPackageReference.SetMetadata(MetadataKeys.Version, packVersion);
+                ImplicitPackageReferences = new[] { ilCompilerBuildPackageReference };
                 // ILCompiler supports cross target compilation. If there is a cross-target request, we need to download that package as well
                 // We expect RuntimeIdentifier to be defined during publish but can allow during build
                 if (RuntimeIdentifier != null)
@@ -643,7 +649,7 @@ private bool AddAotOrR2RRuntimePackage(AotPackageType packageType, Version norma
                         TargetILCompilerPacks = new[] { newItem2 };
                     }
                 }
-            }            
+            }
 
             return true;
         }

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.FrameworkReferenceResolution.targets

@@ -1,4 +1,4 @@
-<!--
+<!--
 ***********************************************************************************************
 Microsoft.NET.Sdk.FrameworkReferenceResolution.targets
 
@@ -123,6 +123,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <Output TaskParameter="HostILCompilerPacks" ItemName="HostILCompilerPack" />
       <Output TaskParameter="TargetILCompilerPacks" ItemName="TargetILCompilerPack" />
       <Output TaskParameter="UnavailableRuntimePacks" ItemName="UnavailableRuntimePack" />
+      <Output TaskParameter="ImplicitPackageReferences" ItemName="_ImplicitPackageReference" />
 
     </ProcessFrameworkReferences>
 
@@ -175,6 +176,15 @@ Copyright (c) .NET Foundation. All rights reserved.
                         PrivateAssets="all"
                         ExcludeAssets="all" />
     </ItemGroup>
+
+    <!-- Add implicit package references that don't already exist in PackageReference. -->
+    <Message Importance="High" Text="Sven was here" />
+    <ItemGroup>
+      <_ImplicitPackageReference Remove="@(PackageReference)" />
+      <PackageReference Include="@(_ImplicitPackageReference)"
+                        IsImplicitlyDefined="true"
+                        PrivateAssets="all" />
+    </ItemGroup>
   </Target>
 
   <!--