[522] % z3release t1.smt2 
Segmentation fault
[523] % z3debug t1.smt2 
Segmentation fault
[524] % z3san t1.smt2 
ASAN:DEADLYSIGNAL
=================================================================
==25122==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000004 (pc 0x5566c7d7fcc2 bp 0x7ffd4eddfe60 sp 0x7ffd4eddfd10 T0)
==25122==The signal is caused by a READ memory access.
==25122==Hint: address points to the zero page.
    #0 0x5566c7d7fcc1 in ast::get_kind() const ../src/ast/ast.h:508
    #1 0x5566c7d7fcc1 in is_app(ast const*) ../src/ast/ast.h:921
    #2 0x5566c7d7fcc1 in is_ground(expr const*) ../src/ast/ast.h:1382
    #3 0x5566c7d7fcc1 in smt2::parser::push_local(smt2::parser::local const&) ../src/parsers/smt2/smt2parser.cpp:1738
    #4 0x5566c7da4624 in smt2::parser::pop_app_frame(smt2::parser::app_frame*) ../src/parsers/smt2/smt2parser.cpp:1900
    #5 0x5566c7da4624 in smt2::parser::pop_expr_frame() ../src/parsers/smt2/smt2parser.cpp:2065
    #6 0x5566c7da4624 in smt2::parser::parse_expr() ../src/parsers/smt2/smt2parser.cpp:2101
    #7 0x5566c7dac5f2 in smt2::parser::parse_assert() ../src/parsers/smt2/smt2parser.cpp:2563
    #8 0x5566c7db7297 in smt2::parser::parse_cmd() ../src/parsers/smt2/smt2parser.cpp:2935
    #9 0x5566c7db7297 in smt2::parser::operator()() ../src/parsers/smt2/smt2parser.cpp:3139
    #10 0x5566c7d6c935 in parse_smt2_commands(cmd_context&, std::istream&, bool, params_ref const&, char const*) ../src/parsers/smt2/smt2parser.cpp:3188
    #11 0x5566c50fb96f in read_smtlib2_commands(char const*) ../src/shell/smtlib_frontend.cpp:142
    #12 0x5566c50a6357 in main ../src/shell/main.cpp:372
    #13 0x7ff10c685b96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
    #14 0x5566c50bc109 in _start (/local/suz-local/software/z3san/build-05022021104022-51a4db8/z3+0x206109)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV ../src/ast/ast.h:508 in ast::get_kind() const
==25122==ABORTING
[525] % 
[525] % cat t1.smt2 
(assert (let ((a (= 0))) (a true)))
[526] %