GOTO conversion: Declaration hops must not invalidate incomplete gotos

[tautschnig]

Declaration hops are built as part of finish_gotos, and must not invalidate goto-instructions that are yet to be finished. To accomplish this, collect all instructions that are to be inserted and do the insertion after having finished all gotos.

Bug was observed when invoking CBMC from Kani.

• 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.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 3 lines in your changes missing coverage. Please review.

Project coverage is 78.12%. Comparing base (50bfa4e) to head (fd6c193).
Report is 4 commits behind head on develop.

Files	Patch %	Lines
src/ansi-c/goto-conversion/goto_convert.cpp	85.71%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #8349      +/-   ##
===========================================
- Coverage    78.15%   78.12%   -0.04%     
===========================================
  Files         1726     1726              
  Lines       188862   188967     +105     
  Branches     18403    18435      +32     
===========================================
+ Hits        147613   147622       +9     
- Misses       41249    41345      +96     

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[peterschrammel]

Any test that triggered this?

[tautschnig]

Any test that triggered this?

I'm having a hard time come up with a C code example that does this. Kani (well, really, MIR) appears to have loads of these.