• Download ExtrudePull.py
• Open Blender Preferences.
• Click on 'Install add-on from file' and select this file.
• Enable the plugin 'Mesh: Extrude Pull':

[alt] + [e] in the Edit, Face select mode

or the menu Mesh → Extrude → Extrude Pull Geometry.

Note that a 'Boolean Modifier' is used and applied in the background. Unfortunatelly the current implementation doesn't work as expected, see the Boolean Modifier issues.

For best results, extrude in the normal direction. However, you can always use 'Undo' ([Ctrl] + [z]) and choose a different approach.

The add-on does not currently

• reliably remove duplicate vertices
• restore the object location and scale
• restore the 3D-cursor location

you must do that manually.

Note: The old "Remove Doubles" has been in v2.8x renamed to ([alt]+[m]) Merge by Distance:

• It would be now a waste of time trying to fix the issues on the Python side. Waiting until the new boolean operator get merged in Blender 2.8?. Design task: https://developer.blender.org/T67744

• Lock & Roll the 3D-Viewport: I have decided to maintain another useful Blender 2.8x addon!

Fast Carve: The other way around, not exactly user-friendly, but with more control over the shape of the Boolean Modifier.

'Destructive Extrude Operator' patch: https://developer.blender.org/D5336

Please report bugs and/or suggested solutions in the issues tab

Vladislav Kindushov – Technically better working 2.7x version.

https://blenderartists.org/u/theApe – Fixes for 2.80 API changes.

https://blenderartists.org/t/destructive-extrude-beta/678275 – The think tank 8-)