Invalid input causes segfault

[wintered]

[510] % z3 small.smt2
(error "line 1 column 38: invalid recursive function definition, '(' expected")
Segmentation fault
[511] % z3release small.smt2
(error "line 1 column 38: invalid recursive function definition, '(' expected")
Segmentation fault
[512] % z3san small.smt2
(error "line 1 column 38: invalid recursive function definition, '(' expected")
ASAN:DEADLYSIGNAL
=================================================================
==8280==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000004 (pc 0x562d164cd8dd bp 0x7ffebfe9e100 sp 0x7ffebfe9e0d0 T0)
==8280==The signal is caused by a READ memory access.
==8280==Hint: address points to the zero page.
  #0 0x562d164cd8dc in ast::get_kind() const ../src/ast/ast.h:504
  #1 0x562d164cd8dc in is_app(ast const*) ../src/ast/ast.h:914
  #2 0x562d164cd8dc in is_ground(expr const*) ../src/ast/ast.h:1378
  #3 0x562d164cd8dc in var_subst::operator()(expr*, unsigned int, expr* const*) ../src/ast/rewriter/var_subst.cpp:28
  #4 0x562d1644373d in recfun_rewriter::mk_app_core(func_decl*, unsigned int, expr* const*, obj_ref<expr, ast_manager>&) ../src/ast/rewriter/recfun_rewriter.cpp:31
  #5 0x562d16416c73 in reduce_app_core ../src/ast/rewriter/th_rewriter.cpp:225
  #6 0x562d16416c73 in reduce_app ../src/ast/rewriter/th_rewriter.cpp:620
  #7 0x562d1642052a in process_app<false> ../src/ast/rewriter/rewriter_def.h:298
  #8 0x562d1642052a in resume_core<false> ../src/ast/rewriter/rewriter_def.h:769
  #9 0x562d1643057a in main_loop<false> ../src/ast/rewriter/rewriter_def.h:728
  #10 0x562d1643057a in operator() ../src/ast/rewriter/rewriter_def.h:800
  #11 0x562d1643057a in th_rewriter::operator()(expr*, obj_ref<expr, ast_manager>&, obj_ref<app, ast_manager>&) ../src/ast/rewriter/th_rewriter.cpp:860
  #12 0x562d14dca2cb in asserted_formulas::assert_expr(expr*, app*) ../src/smt/asserted_formulas.cpp:158
  #13 0x562d148b5c4c in smt::context::assert_expr_core(expr*, app*) ../src/smt/smt_context.cpp:2901
  #14 0x562d148b5c4c in smt::context::assert_expr(expr*, app*) ../src/smt/smt_context.cpp:2913
  #15 0x562d148b5c4c in smt::context::assert_expr(expr*) ../src/smt/smt_context.cpp:2908
  #16 0x562d15fe8e5c in solver::assert_expr(expr*) ../src/solver/solver.cpp:210
  #17 0x562d15fe8e5c in solver::assert_expr(expr*) ../src/solver/solver.cpp:210
  #18 0x562d15f1f788 in cmd_context::assert_expr(expr*) ../src/cmd_context/cmd_context.cpp:1319
  #19 0x562d15e81618 in smt2::parser::parse_assert() ../src/parsers/smt2/smt2parser.cpp:2571
  #20 0x562d15e87db7 in smt2::parser::parse_cmd() ../src/parsers/smt2/smt2parser.cpp:2926
  #21 0x562d15e87db7 in smt2::parser::operator()() ../src/parsers/smt2/smt2parser.cpp:3130
  #22 0x562d15e3f245 in parse_smt2_commands(cmd_context&, std::istream&, bool, params_ref const&, char const*) ../src/parsers/smt2/smt2parser.cpp:3179
  #23 0x562d134d10b6 in read_smtlib2_commands(char const*) ../src/shell/smtlib_frontend.cpp:89
  #24 0x562d134a994e in main ../src/shell/main.cpp:352
  #25 0x7f341d1cfb96 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)
  #26 0x562d134bd729 in _start (/home/suz/software/z3san/build-04262020232942-a0de244/z3+0x1f7729)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV ../src/ast/ast.h:504 in ast::get_kind() const
==8280==ABORTING
[513] %
[513] % cat small.smt2
(define-funs-rec ((a ((b Int)) Bool)))
(assert (a 0))
(check-sat)
[514] %

OS: Ubuntu 18.04
Commit: a0de244