Implement typeref to demangle tree conversion for nested bound generics

Author: augusto2112

stdlib/public/Reflection/TypeRef.cpp

@@ -583,8 +583,35 @@ class DemanglingForTypeRef
     genericNode->addChild(unspecializedType, Dem);
     genericNode->addChild(genericArgsList, Dem);
 
-    if (auto parent = BG->getParent())
-      assert(false && "not implemented");
+    auto parent = BG->getParent();
+    if (!parent)
+      return genericNode;
+
+    auto parentNode = visit(parent);
+    if (!parentNode || !parentNode->hasChildren() ||
+        parentNode->getKind() != Node::Kind::Type ||
+        !unspecializedType->hasChildren())
+      return genericNode;
+
+    // Peel off the "Type" node.
+    parentNode = parentNode->getFirstChild();
+
+    auto nominalNode = unspecializedType->getFirstChild();
+
+    if (nominalNode->getNumChildren() != 2)
+      return genericNode;
+
+    // Save identifier for reinsertion later, we have to remove it
+    // so we can insert the parent node as the first child.
+    auto identifierNode = nominalNode->getLastChild();
+
+    // Remove all children.
+    nominalNode->removeChildAt(1);
+    nominalNode->removeChildAt(0);
+
+    // Add the parent we just visited back in, followed by the identifier.
+    nominalNode->addChild(parentNode, Dem);
+    nominalNode->addChild(identifierNode, Dem);
 
     return genericNode;
   }