Bug#696396: This seems to be caused by gtksourceview3.

[h-kubo at geisya.or.jp]

Hi.

I set a breakpoint where the assertion occurred,
and investigated the variables.

Here is the source code aroud gtksourcecontextengine.c:2859,
where the breakpoint is set:

2856		if (line->start_at + start_pos < state->start_at)
2857			g_critical ("%s: oops", G_STRLOC);
2858		else if (line->start_at + end_pos != state->end_at)
2859			g_critical ("%s: oops", G_STRLOC);
2860		else
2861			state->end_len = state->end_at - line->start_at - start_pos;
2862	}

And the variables:

line->start_at  = 10
end_pos = 0
state->end_at = 14
line->text  = (gchar *) 0x84effd0 "][\302\236\303\240\\\"}]"


This seems to be a mismatch of the recognition about the
line length between 'line' variable and 'state' variable.

It seems that the real prolem is about  gtksourceview3 
package. Why don't you change the object to it?
---
Kubo Hiroshi