Description:
I have a document which includes two Fields side-by-side, e.g.
---
<Field1> <Field2>
---
If they are inside a table cell and my database contains an entry where both of
those fields are empty, if I do something like "Edit Individual Documents" or
"Save Merged Documents", LibreOffice exits unexpectedly.

This only happens when the option in Tools > Options > LibreOffice Writer >
Compatibility > "Hide paragraphs of database fields (e.g., mail merge) with an
empty value" is selected.

It does NOT happen when that option is unselected but the "Suppress lines with
just empty fields" option in the Mail Merge Wizard is selected.

Also, it only happens if there is one or more newlines before the table.

I have a crash report:
https://crashreport.libreoffice.org/stats/crash_details/a5eceb8e-23a4-4287-8fe5-052fe12dc69d

Steps to Reproduce:
Easiest way of reproducing (probably...) is using the Mail Merge Wizard, as it
puts the Address Block in a table.
1. Create a new Writer document
2. Go to Tools > Options > LibreOffice Writer > Compatibility and check that "Hide paragraphs of database fields..." is ticked. Tick it if not and click OK.
3. Select Tools > Mail Merge Wizard...
4. Check radio button "Use current document" and click Next.
5. Check radio button "Letter" and click Next.
6. Click "Select Different Address List...", click Add and select the attached spreadsheet. Highlight the newly added spreadsheet and press OK.
7. Make sure "This document shall contain an address block" is ticked. Click More and then click New.
8. Add two address elements, "<First Name>" and "<Last Name>" on the same line (attached screenshot showing what I mean). Click OK and then OK again.
9. Click "Match Fields..." and check that "<First Name>" and "<Last Name>" are matched to the fields "First Name" and "Last Name" respectively. Do so if not. Click OK and then Next.
10. Untick (if it is not already unselected) "This document should contain a salutation" (I do not think it makes a difference). Click Next and then Finish.
11. Then click something like "Edit Individual Documents" or "Save Merged Documents".

Possibly also happens if you Print or Email, but I have not tried.

Can also reproduce this by adding Fields via Insert > Field > More Fields >
Database, and inserting fields into a table. Just remember to place the table
not at the very top of the document, but add one or more newlines before it.

Actual Results:
LibreOffice will exit unexpectedly/crash.

Expected Results:
Not crash.


Reproducible: Always


User Profile Reset: Yes



Additional Info:
Version: 6.1.0.1
Build ID: 378e26bd4f22a135cef5fa17afd5d4171d8da21a
CPU threads: 2; OS: Linux 3.16; UI render: default; VCL: gtk2; 
Locale: en-GB (en_GB.UTF-8); Calc: group threaded

Also reproduced on:
Version: 6.1.0.1.0+
Build ID: 4e5248f32d8fdfd4655bd15bd60d83e9a0c6e540
CPU threads: 2; OS: Linux 3.16; UI render: default; VCL: gtk2; 
TinderBox: Linux-rpm_deb-x86_64@70-TDF, Branch:libreoffice-6-1, Time: 2018-07-19_00:36:46
Locale: en-GB (en_GB.UTF-8); Calc: group threaded

My system is Debian 8.11.