Add support for serialization of ImmutableHashSet

Author: someone-with-default-username

Nitra/Nitra.Compiler/Generation/Serialization/CollectionTypeSerializationBuilder.n

@@ -61,6 +61,12 @@ namespace Nitra.Serialization
                         buffer.Add($readItem); ]>);
           body.Add(<[ buffer.MoveToImmutable() ]>);
 
+        | ImmutableHashSet =>
+          body.Add(<[ def buffer = System.Collections.Immutable.ImmutableHashSet.CreateBuilder(); ]>);
+          body.Add(<[ repeat (count)
+                        buffer.Add($readItem); ]>);
+          body.Add(<[ buffer.MoveToImmutable() ]>);
+
         | NemerleList         with result = <[ Nemerle.Collections.NList.FromArray(buffer) ]>
         | IReadOnlyCollection with result = <[ System.Collections.ObjectModel.ReadOnlyCollection(buffer) ]>
         | IReadOnlyList       with result = <[ System.Collections.ObjectModel.ReadOnlyCollection(buffer) ]>

Nitra/Nitra.Compiler/Generation/Serialization/DefaultTypeSerializationFactory.n

@@ -24,6 +24,7 @@ namespace Nitra.Serialization
       | IImmutableList
       | IReadOnlyCollection
       | IReadOnlyList
+      | ImmutableHashSet
     }
 
     public override CreateBuilder(compiler : SerializationCompiler, type : FixedType) : TypeSerializationBuilder
@@ -37,6 +38,7 @@ namespace Nitra.Serialization
         | Class(ti, [itemType]) when ti.Equals(typeCatalog.Generic_IList_tc)           => CreateCollectionBuilder(compiler, CollectionType.IList,               type, itemType)
         | Class(ti, [itemType]) when ti.Equals(typeCatalog.Generic_ICollection_tc)     => CreateCollectionBuilder(compiler, CollectionType.ICollection,         type, itemType)
         | Class(ti, [itemType]) when ti.Equals(typeCatalog.Generic_IEnumerable_tc)     => CreateCollectionBuilder(compiler, CollectionType.IEnumerable,         type, itemType)
+        | Class(ti, [itemType]) when EqualsOption(ti, compiler.ImmutableHashSetOpt)    => CreateCollectionBuilder(compiler, CollectionType.ImmutableHashSet,    type, itemType)
         | Class(ti, [itemType]) when EqualsOption(ti, compiler.ImmutableArrayOpt)      => CreateCollectionBuilder(compiler, CollectionType.ImmutableArray,      type, itemType)
         | Class(ti, [itemType]) when EqualsOption(ti, compiler.IImmutableListOpt)      => CreateCollectionBuilder(compiler, CollectionType.IImmutableList,      type, itemType)
         | Class(ti, [itemType]) when EqualsOption(ti, compiler.IReadOnlyCollectionOpt) => CreateCollectionBuilder(compiler, CollectionType.IReadOnlyCollection, type, itemType)

Nitra/Nitra.Compiler/Generation/Serialization/NitraTypeSerializationFactory.n

@@ -143,6 +143,7 @@ namespace Nitra.Serialization
       {
         | NemerleList    => <[ Nemerle.Collections.NCollectionsExtensions.NToList($expr) ]>
         | ImmutableArray => <[ System.Collections.Immutable.ImmutableArray.Create($expr) ]>
+        | ImmutableHashSet => <[ System.Collections.Immutable.ImmutableHashSet.Create($expr) ]>
         | _              => expr
       }
     }

Nitra/Nitra.Compiler/Generation/Serialization/SerializationCompiler.n

@@ -48,6 +48,18 @@ namespace Nitra.Serialization
       }
     }
 
+    public ImmutableHashSetOpt : option[TypeInfo]
+    {
+      mutable _immutableHashSetOpt : option[TypeInfo];
+      get
+      {
+        when (_immutableHashSetOpt : object == null)
+          _immutableHashSetOpt = Manager.NameTree.LookupExactType("System.Collections.Immutable.ImmutableHashSet", 1);
+        _immutableHashSetOpt
+      }
+    }
+
+    
     public ImmutableArrayOpt : option[TypeInfo]
     {
       mutable _immutableArrayOpt : option[TypeInfo];