diff --git a/packages/core/src/warning.ts b/packages/core/src/warning.ts
index 80f9ad31..4d42ddca 100644
--- a/packages/core/src/warning.ts
+++ b/packages/core/src/warning.ts
@@ -1,20 +1,88 @@
-import { MountedComponent, ComponentType } from './component'
+import { ComponentType, ComponentClass, FunctionalComponent } from './component'
+import { EMPTY_OBJ } from './utils'
 
-let currentComponent: MountedComponent | null = null
-let currentComponentDefinition: ComponentType | null = null
+// TODO push vnodes instead
+// component vnodes get a new property (contextVNode) which points to the
+// parent component (stateful or functional)
+// this way we can use any component vnode to construct a trace that inludes
+// functional and stateful components.
 
-export function setCurrentComponent(c: MountedComponent) {
-  currentComponent = c
+// in createRenderer, parentComponent should be replced by ctx
+// $parent logic should also accomodate
+
+let stack: ComponentType[] = []
+
+export function pushComponent(c: ComponentType) {
+  stack.push(c)
 }
 
-export function unsetCurrentComponent() {
-  currentComponent = null
+export function popComponent() {
+  stack.pop()
 }
 
-export function setCurrentComponentDefinition(d: ComponentType) {
-  currentComponentDefinition = d
+export function warn(msg: string) {
+  // TODO warn handler?
+  console.warn(`[Vue warn]: ${msg}${getComponentTrace()}`)
 }
 
-export function unsetCurrentComponentDefinition() {
-  currentComponentDefinition = null
+function getComponentTrace(): string {
+  const current = stack[stack.length - 1]
+  if (!current) {
+    return ''
+  }
+  // we can't just use the stack itself, because it will be incomplete
+  // during updates
+  // check recursive
+  const normlaizedStack: Array<{
+    type: ComponentType
+    recurseCount: number
+  }> = []
+  stack.forEach(c => {
+    const last = normlaizedStack[normlaizedStack.length - 1]
+    if (last && last.type === c) {
+      last.recurseCount++
+    } else {
+      normlaizedStack.push({ type: c, recurseCount: 0 })
+    }
+  })
+  return (
+    `\n\nfound in\n\n` +
+    normlaizedStack
+      .map(({ type, recurseCount }, i) => {
+        const padding = i === 0 ? '---> ' : ' '.repeat(5 + i * 2)
+        const postfix =
+          recurseCount > 0 ? `... (${recurseCount} recursive calls)` : ``
+        return padding + formatComponentName(type) + postfix
+      })
+      .join('\n')
+  )
+}
+
+const classifyRE = /(?:^|[-_])(\w)/g
+const classify = (str: string): string =>
+  str.replace(classifyRE, c => c.toUpperCase()).replace(/[-_]/g, '')
+
+function formatComponentName(c: ComponentType, includeFile?: boolean): string {
+  let name: string
+  let file: string | null = null
+
+  if (c.prototype.render) {
+    const cc = c as ComponentClass
+    const options = cc.options || EMPTY_OBJ
+    name = options.displayName || cc.name
+    file = options.__file
+  } else {
+    const fc = c as FunctionalComponent
+    name = fc.displayName || fc.name
+  }
+
+  if (file && name === 'AnonymousComponent') {
+    const match = file.match(/([^/\\]+)\.vue$/)
+    if (match) {
+      name = match[1]
+    }
+  }
+
+  const filePostfix = file && includeFile !== false ? ` at ${file}` : ''
+  return `<${classify(name)}>` + filePostfix
 }