Clearer ssr error message 11902#11966

Merged

gaearon merged 4 commits intofacebook:masterfrom

HeroProtagonist:clearer-ssr-error-message-11902

Feb 5, 2018

Commits on Feb 2, 2018

Match error message to one in `ReactFiber.js`
HeroProtagonist
committed

Commits on Feb 3, 2018

Add undefined/null guard and tests
HeroProtagonist
committed

Commits on Feb 5, 2018