The following errors were reported by 4.7.1-rc, but not by 4.6.4

vuejs/vue

2 of 5 projects failed to build with the old tsc

tsconfig.json

• error TS2774: This condition will always return true since this function is always defined. Did you mean to call it instead?
  • src/core/util/perf.ts#L11
  • src/core/util/perf.ts#L12
  • src/core/util/perf.ts#L14