wip: make legacy global apis available on app instance as well

wip: fix v3 render fn detection regex

wip: defineReactive on instance with keys starting with $

wip: allow compatConfig mode to be a function

fix(hmr): don't remove __file key from component type

wip: expose configureCompat via named export

wip: make singleton mutations affect all app instances

wip: only generate non-scope slot flag when compatConfig is present

wip: remove v-if key warning as there are legit use cases

wip: relay compiler-core warnings in compiler-sfc with codeframe

wip: exclude legacy slots from $scopedSlots

wip: fix compiler dep externalization

wip: more private properties

wip: enable private vnode properties even for built-ins

wip: fix native template compat

wip: root instance $destroy before $mount

wip: vm._data for vuex compat

build(deps-dev): bump sass from 1.32.8 to 1.32.12

Bumps [sass](https://github.com/sass/dart-sass) from 1.32.8 to 1.32.12.
- [Release notes](https://github.com/sass/dart-sass/releases)
- [Changelog](https://github.com/sass/dart-sass/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sass/dart-sass/compare/1.32.8...1.32.12)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build(deps-dev): bump codemirror from 5.60.0 to 5.61.0

Bumps [codemirror](https://github.com/codemirror/CodeMirror) from 5.60.0 to 5.61.0.
- [Release notes](https://github.com/codemirror/CodeMirror/releases)
- [Changelog](https://github.com/codemirror/CodeMirror/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codemirror/CodeMirror/compare/5.60.0...5.61.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build(deps-dev): bump chalk from 4.1.0 to 4.1.1

Bumps [chalk](https://github.com/chalk/chalk) from 4.1.0 to 4.1.1.
- [Release notes](https://github.com/chalk/chalk/releases)
- [Commits](https://github.com/chalk/chalk/compare/v4.1.0...v4.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build(deps-dev): bump @types/node from 14.14.36 to 14.14.43

Bumps [@types/node](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/node) from 14.14.36 to 14.14.43.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/node)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

build(deps-dev): bump eslint from 7.22.0 to 7.25.0

Bumps [eslint](https://github.com/eslint/eslint) from 7.22.0 to 7.25.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v7.22.0...v7.25.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

chore: ignore compat entries for coverage

wip: compat test coverage

wip: test for global filter registration

wip: tests for compiler compat

wip: move compat test cases + filter tests

wip: test for v-model compat

wip: test for legacy component compat

wip: more tests for v2 compat

wip: test for instance and options compat

wip: fix isCustomElement

chore: Merge branch 'v2-compat'

wip: tests for global config compat

feat: support component-level `compilerOptions` when using runtime compiler

- The `delimiters` component option is deprecated.
  Use `compilerOptions.delimiters` instead.

fix(compiler-core): preserve comment content in production when comments option is enabled

chore: update IE11 support [ci skip]

wip: tests for global api compat

wip: ref v-for compat

wip: fix tests

wip: whitespace behavior compat

feat(config): support configuring runtime compiler via `app.config.compilerOptions`

- `config.isCustomElement` is deprecated - use `app.config.compilerOptions.isCustomElement` instead.

refactor(compiler): improve whitespace: 'preserve' behavior from #1600

- discard leading/ending whitespace inside an element
- condense preserved whitesapce into single space

feat(compiler-core): whitespace handling strategy

chore: fix typo in assertion

feat(devtools): improved KeepAlive support

This change allows the devtools to access the cached vnodes from the KeepAlive component in order to display them as inactive in the components tree

wip: add private api compat flag

wip: more compat tweaks

wip: more compat tweaks

wip: more compat tweaks

wip: class/style fallthrough compat

wip: treat compat model listener as already declared

perf: only trigger $attrs update when it has actually changed

chore: include component info in recursive update warning

wip: more compat progress

fix(watch): avoid traversing non-plain objects

wip: compat integration progress

chore: adjust the parameter order of the mountChildren function

wip: filters compat

wip: warn against `<template functional>`

wip: inline-template compat

wip: refactor

wip: plain template tag compat

perf(compiler): skip unncessary checks when parsing end tag

wip: warn v-bind object ordering

wip: remove unncessary deprecation messages

wip: default mode for compat build

wip: compiler should default to v3 behavior

wip: warn key usage of v-if branches

wip: warn v-if/v-for co-usage

wip: v-bind.sync compat

wip: invert compiler compat behavior default during tests

wip: support configuring compiler deprecations at runtime + warn invalid deprecation configs

wip: generate codeframe for compiler deprecations

wip: is usage compat

chore: fix typo in test case description

wip: compiler deprecation config

wip: refactor deprecations into a single file

feat: support casting plain element to component via is="vue:xxx"

In Vue 3's custom elements interop, we no longer process `is` usage on
known native elements as component casting. (ref:
https://v3.vuejs.org/guide/migration/custom-elements-interop.html)
This introduced the need for `v-is`. However, since it is a directive,
its value is considered a JavaScript expression. This makes it awkward
to use (e.g. `v-is="'foo'"`) when majority of casting is non-dynamic,
and also hinders static analysis when casting to built-in Vue
components, e.g. transition-group.

This commit adds the ability to cast a native element to a Vue component
by simply adding a `vue:` prefix:

```html
<button is="vue:my-button"></button>
<ul is="vue:transition-group" tag="ul"></ul>
```

wip: testing compiler deprecation warnings

chore: use isArray to keep the code consistency

wip: staticStyle and staticClass

wip: Vue.util compat

wip: fix render fn compat detection

wip: refactor compat check utils

wip: fix compat utils usage

wip: component v-model compat

wip: render function compat

wip: compat for legacy functional component

chore: fix dts

wip: support per-component compatConfig

wip: make tests pass again

wip: async component compat

wip: tweak warning dedupe logic

wip: $attrs class/style warning

wip: $scopedSlots compat

wip: vm.$listeners compat

wip: attr coersion compat

wip: transition group root compat

wip: apply compat enabled flags to currently implemented features