Copilot 1c8b6cfdb8 scanner: emit ERROR_TOKEN on I/O failure instead of silent EOF (#10294) ... `scanner::scan()` was returning `EOF_TOKEN` when the underlying stream had `badbit` set, making a failed read (EIO, ENOSPC, etc.) indistinguishable from a clean end-of-file. Z3 would silently produce no output with exit code 0. ## Root cause `std::istream::gcount()` returns 0 for both normal EOF and I/O failure. `read_char()` returned -1 in both cases, and `scan()`'s `-1` handler unconditionally set `EOF_TOKEN`. ## Fix ### `src/parsers/util/scanner.cpp` Check `m_stream.bad()` in the `-1` case; emit an error message and `ERROR_TOKEN` on failure: ```cpp case static_cast<char>(-1): if (m_stream.bad()) { m_err << "ERROR: I/O failure while reading input stream.\n"; m_state = ERROR_TOKEN; } else { m_state = EOF_TOKEN; } break; ``` ### `src/test/scanner_io.cpp` (new) Regression test (ported from the `io_test` branch) verifying: 1. A good stream scans to completion (`n > 0` tokens). 2. A stream with `badbit` pre-set produces `ERROR_TOKEN` or a non-empty error message rather than silent EOF. ### `src/test/main.cpp` + `src/test/CMakeLists.txt` Register `tst_scanner_io` in the `FOR_EACH_ALL_TEST` macro and add `scanner_io.cpp` to the build. --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com> Co-authored-by: Nikolaj Bjorner <nikolaj@cs.stanford.edu>		2026-07-29 14:00:42 -07:00
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smt2	Remove unnecessary semicolons (Attempt 2) (#10020)	2026-07-02 12:47:29 -07:00
util	scanner: emit ERROR_TOKEN on I/O failure instead of silent EOF (#10294)	2026-07-29 14:00:42 -07:00