System Information
Operating system: Ubuntu LTS 4.19.17-041917-generic x86_64
Graphics card: Nvidia Geforce GTX 1070 Ti

Blender Version
Broken: 2.80, 957b4547aeeb, blender2.8, 2019-01-28, as found on splash screen

Applying Detailed Flood Fill in Dyntopo Sculpt mode using Constant Detail deletes object mesh data.

Steps to reproduce:

1. Create a new file using General or Sculpting startup file.
2. Delete default mesh object.
3. Add new mesh object.
4. Switch to sculpt mode and enable Dyntopo.
5. Select 'Constant Detail' in Detailing.
6. Under remesh, apply 'Detail Flood Fill'.

Result:

• Object mesh data is deleted.
• Object name remains in Outliner.
• Bottom right status bar confirms no mesh data - it shows "Cube | Verts: 0 | Tris: 0" (replace "Cube" with whatever mesh you had created)