Adjust TemplateConstructableTypes to ensure that templates are present

- Previous logic worked except for types without methods (interfaces and structures) due to other rules that ensured the presence of a TemplateTypeLayout

Fixes #4860

[tfs-changeset: 1680445]

src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/NodeFactory.NativeLayout.cs

@@ -229,6 +229,13 @@ public IEnumerable<IDependencyNode> TemplateConstructableTypes(TypeDesc type)
  TypeDesc canonicalType = type.ConvertToCanonForm(CanonicalFormKind.Specific);
  yield return _factory.MaximallyConstructableType(canonicalType);
 
+ // Add a dependency on the template for this type, if the canonical type should be generated into this binary.
+ if (canonicalType.IsCanonicalSubtype(CanonicalFormKind.Any) && !_factory.NecessaryTypeSymbol(canonicalType).RepresentsIndirectionCell)
+ {
+ if (!_factory.TypeSystemContext.IsCanonicalDefinitionType(canonicalType, CanonicalFormKind.Any))
+ yield return _factory.NativeLayout.TemplateTypeLayout(canonicalType);
+ }
+
  foreach (TypeDesc instantiationType in type.Instantiation)
  {
  foreach (var dependency in TemplateConstructableTypes(instantiationType))