Segfault (exit 139) when an import resolves into the KerML standard library via -I #1

Version / pin

• sysml2 built from commit 130e2d3085affa36998838aa9d0736a11821ca1d
  (2026年02月04日 21:23:44 +0100, subject: "import fixes")
• Source: https://github.com/zbigniewsobiecki/sysml2.git
• Platform: macOS Darwin 25.5.0 arm64, locally built binary

Summary

sysml2 crashes with a segfault (exit code 139, no diagnostics emitted) whenever
validation is run with -I pointing at a directory containing KerML
standard-library files and the validated file's import resolves into that
directory.

Minimal reproduction

1. Create a library directory containing ScalarValues.kerml and Base.kerml
   (from the OMG KerML 20250201 standard-library release; in our setup these
   files are provisioned on disk under .sysand/lib/ via sysand 0.1.7).
2. Take any SysML file whose import resolves into that directory, e.g. a file
   containing private import ScalarValues::*;.
3. Run validation with the library path, e.g. sysml2 -I lib/ test.sysml.

Observed: immediate segfault, exit 139, before any diagnostics are emitted.
The same crash chain reproduces when VectorValues.kerml is placed in the
-I directory.

Expected behavior

Validation completes successfully with standard-library names resolved from
the -I path.

What works as workaround baseline

Without -I, the same binary runs deterministically on our project slice:
exit 0 when clean, exit 2 with diagnostics. Parsing is clean (zero syntax
errors), semantic validation runs fully on the model's internal
cross-references, and the only diagnostics reported are the expected
standard-library-absence family: E3003 on the ScalarValues / ISQ / SI
namespaces and E3001 on names that only the standard library defines (e.g.
String, ISQ::* references) — 16 such diagnostics on our current 7-file
validation slice. The crash is specific to standard-library resolution, not
general operation.

Impact

This blocks full standard-library validation for any model that imports
standard namespaces — effectively all SysML v2 models using ScalarValues,
ISQ, or SI. Running without -I is viable only because the resulting
standard-library-absence diagnostics are treated as expected; that expected
family could mask a genuine diagnostic of the same codes.

Revisit trigger

We re-test on any published fix or newer commit that passes the minimal
reproduction above; on success we re-enable -I and require the diagnostics
on our validation slice to drop to zero. A separate, lower-priority tooling
issue (tracked by us as U-2) is on hold and parked; it will be revisited at
our Phase 4 boundary review.