goto-symex: support struct-keyed arrays (maps) in value materialisation

[tautschnig]

Field-sensitivity and the value-set assume array indices are integer-typed. For arrays keyed by a struct (used to model heaps as Map Ref Struct), the from_integer-based index construction aborts. Gate is_divisible/get_fields to integer/bitvector/enum index types, and relax value_sett::assign array type-equality to allow arrays with the same element type but differing size (unbounded heap maps).

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[Copilot]

Pull request overview

Note

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This PR updates goto-symex field sensitivity and pointer-analysis value materialisation to support “map-like” arrays keyed by non-integer types (e.g., struct references), avoiding invalid integer-index enumeration and relaxing array type matching to ignore size differences.

Changes:

• Treat arrays with non-scalar index types monolithically (skip element enumeration / field decomposition).
• Relax value_sett::assign array type invariant to allow differing array sizes when element types match.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/pointer-analysis/value_set.cpp	Allows assigning arrays with same element type but different sizes (for unbounded heap-map models).
src/goto-symex/field_sensitivity.cpp	Prevents field-splitting / enumeration for arrays whose index types can’t be constructed via from_integer.

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[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 80.68%. Comparing base (7483d0d) to head (c996a37).

Files with missing lines	Patch %	Lines
src/goto-symex/field_sensitivity.cpp	85.71%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #9065   +/-   ##
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  Coverage    80.68%   80.68%           
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  Files         1714     1714           
  Lines       189593   189600    +7     
  Branches        73       73           
========================================
+ Hits        152979   152988    +9     
+ Misses       36614    36612    -2     

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