Change record status: 
Project: 
Introduced in branch: 
8.x
Description: 

The _theme() function now casts the result to a string to ensure that drupal_render() can always deal with it. _theme() returns FALSE when no matching theme implementation is found.

Impacts: 
Module developers
Themers
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done