Parser crashes when old-style character literals are encountered

Repro: foo := !x

Result:

[140215052543816 frontend/lex/lex.cc:186] Assertion failed
    Expected: buffer[cursor + Offset(1)] == '\''
         LHS: x
         RHS: '
*** SIGABRT received at time=1643046913 on cpu 0 ***
PC: @     0x7f865c701808  (unknown)  pthread_kill
    @          0x1542260         64  absl::WriteFailureInfo()
    @          0x1541f44        224  absl::AbslFailureSignalHandler()
    @     0x7f865c6ad520  (unknown)  (unknown)
Aborted (core dumped

asoffer / Icarus

Parser crashes when old-style character literals are encountered #109