From f19433c8eebcff318035e057a1c2a74bf4a861d8 Mon Sep 17 00:00:00 2001
From: Pierre-Marie Dartus <p.dartus@salesforce.com>
Date: Wed, 19 Jan 2022 10:48:22 +0100
Subject: [PATCH] chore: add back dev assertions

---
 .../@lwc/engine-core/src/framework/api.ts     | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/packages/@lwc/engine-core/src/framework/api.ts b/packages/@lwc/engine-core/src/framework/api.ts
index 22ab69c219..ef7e137d37 100644
--- a/packages/@lwc/engine-core/src/framework/api.ts
+++ b/packages/@lwc/engine-core/src/framework/api.ts
@@ -81,6 +81,17 @@ function h(sel: string, data: VElementData, children: VNodes): VElement {
                 vmBeingRendered
             );
         }
+        forEach.call(children, (childVnode: VNode | null | undefined) => {
+            if (childVnode != null) {
+                assert.isTrue(
+                    'type' in childVnode &&
+                        'sel' in childVnode &&
+                        'elm' in childVnode &&
+                        'key' in childVnode,
+                    `${childVnode} is not a vnode.`
+                );
+            }
+        });
     }
 
     let elm;
@@ -182,6 +193,19 @@ function c(
                 vmBeingRendered
             );
         }
+        if (arguments.length === 4) {
+            forEach.call(children, (childVnode: VNode | null | undefined) => {
+                if (childVnode != null) {
+                    assert.isTrue(
+                        'type' in childVnode &&
+                            'sel' in childVnode &&
+                            'elm' in childVnode &&
+                            'key' in childVnode,
+                        `${childVnode} is not a vnode.`
+                    );
+                }
+            });
+        }
     }
     const { key } = data;
     let elm;