[tautschnig]

The SAT back end (boolbv_typecast) treated all c_enum values as signed
when extending to wider types: integer-to-integer, integer-to-fixedbv,
and integer-to-float conversions all used sign extension for c_enum
sources. This is wrong for enums whose underlying type is unsigned
(e.g., enums with values > INT_MAX or packed enums with values > 127).

Fix: check the c_enum underlying type signedness in all three places
instead of unconditionally treating IS_C_ENUM as signed.

Fixes #9206

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

An organization owner can choose the repository organization as the billing source for reviews requested by members with a paid Copilot license. Learn about Copilot code review billing. Review the Copilot code review billing settings.

[codecov]

Codecov Report

❌ Patch coverage is 16.66667% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.90%. Comparing base (266f438) to head (5c81988).

Files with missing lines	Patch %	Lines
src/solvers/flattening/boolbv_typecast.cpp	16.66%	10 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9227      +/-   ##
===========================================
- Coverage    80.91%   80.90%   -0.02%     
===========================================
  Files         1718     1718              
  Lines       190266   190275       +9     
  Branches        73       73              
===========================================
- Hits        153952   153937      -15     
- Misses       36314    36338      +24     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.