Description of problem:
attempted to tab-complete a variable name

Version-Release number of selected component:
gdb-headless-7.12.1-41.fc25

Additional info:
reporter:       libreport-2.8.0
backtrace_rating: 4
cmdline:        gdb --args build/SC2BuildSimulator rush marine 360
crash_function: add_symtab_completions
executable:     /usr/libexec/gdb
global_pid:     28480
kernel:         4.9.7-201.fc25.x86_64
pkg_fingerprint: 4089 D8F2 FDB1 9C98
pkg_vendor:     Fedora Project
runlevel:       N 5
type:           CCpp
uid:            1000

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 add_symtab_completions at ../../gdb/symtab.c:5272
 #1 psym_expand_symtabs_matching at ../../gdb/psymtab.c:1453
 #2 expand_symtabs_matching at ../../gdb/symfile.c:3887
 #3 default_make_symbol_completion_list_break_on_1 at ../../gdb/symtab.c:5431
 #4 default_make_symbol_completion_list_break_on at ../../gdb/symtab.c:5525
 #5 linespec_location_completer at ../../gdb/completer.c:287
 #6 location_completer at ../../gdb/completer.c:525
 #7 expression_completer at ../../gdb/completer.c:650
 #8 complete_line_internal at ../../gdb/completer.c:958
 #9 complete_line at ../../gdb/completer.c:1067