impossible-assertion

Availability: default; no policy required. Severity medium, confidence high for modeled universal rejection.

Reports a nonliteral-false assertion that fails on every modeled path reaching its source site, with complete caller coverage. It can also report a completely analyzed entrypoint with no successful path, without duplicating an entry already explained by an assertion finding.

Example and review scenario#

The compiler-qualified owned fixture requires flag and then its negation. The correction keeps compatible checks. Review contradictory validation when an intended entrypoint appears unusable; inspect the preceding constraints as well as the reported assertion.

Recommendation: preserve guards that reject invalid inputs while allowing the intended inputs to succeed. Correct contradictory operands or document an intentionally disabled entrypoint. Checked arithmetic and casts may also explain an entrypoint-level rejection.

False positives and limitations#

Deliberately disabled entrypoints can match. Ordinary rejecting guards are quiet if some reaching invocation passes, even if that caller aborts later. Literal assert(false) revert sites are suppressed as assertion findings; nonliteral constant-false expressions remain reportable. Incomplete or unselected potential callers block universal assertion claims. A finding concerns modeled invocation constraints, not cross-transaction reachability or a successful state change. Unknown effects and exhausted budgets remain incomplete.

Source examples#

These short regression examples are included here for installed-package readers. Rule-specific policy requirements and limits above still apply.

Example 1#

Fixture (source: tests/corpus/vulnerable/contradictory-assertion.compact).

pragma language_version >= 0.26.0;
export circuit verify(flag: Boolean): [] {
  assert(flag, "flag required");
  assert(!flag, "flag forbidden");
}

Example 2#

Correction (source: tests/corpus/safe/contradictory-assertion.compact).

pragma language_version >= 0.26.0;
export circuit verify(flag: Boolean): [] {
  assert(flag, "flag required");
  assert(flag, "flag still required");
}