[Fix] External struct equality

[evan-schott]

Resolves #27900

[evan-schott]

The parsing of composite types will always be ambiguous in the sense that there is no way to know whether it is a struct or a record. This PR makes it so that all composites are parsed as having no program of origin. The ambiguity is resolved because after ST creator pass no two composites can share the same name, even if one is a record and the other is a struct. This means that the ST lookup_struct function can search again with program name set to the local program if it fails to find a record because the type indicated that its program of origin is None. @d0cd lmk if you think there is a better way to do this.

[d0cd]

Fairly large PR so reviewing in stages for manageability.

My main questions are:

• do we need all of the additional clones?
• why is does the program name need to be removed?
• is see a number of files where the generated bytecode has changed. Is this expected?

One immediate TODO is add back in the removed errors and regen expectations. This will reduce a lot of the files changed.

[codecov]

Codecov Report

Attention: Patch coverage is 86.91099% with 25 lines in your changes are missing coverage. Please review.

Project coverage is 77.06%. Comparing base (8056874) to head (88b57be).
Report is 2 commits behind head on testnet3.

Files	Patch %	Lines
compiler/passes/src/flattening/flatten_program.rs	64.28%	5 Missing ⚠️
compiler/ast/src/stub/function_stub.rs	73.33%	4 Missing ⚠️
compiler/passes/src/type_checking/checker.rs	89.47%	4 Missing ⚠️
compiler/ast/src/mapping/mod.rs	0.00%	3 Missing ⚠️
compiler/ast/src/stub/finalize_stub.rs	25.00%	3 Missing ⚠️
compiler/passes/src/common/graph/mod.rs	50.00%	3 Missing ⚠️
...mpiler/passes/src/code_generation/visit_program.rs	83.33%	2 Missing ⚠️
compiler/ast/src/types/type_.rs	90.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           testnet3   #27902      +/-   ##
============================================
+ Coverage     76.95%   77.06%   +0.10%     
============================================
  Files           205      204       -1     
  Lines          7200     7158      -42     
  Branches       7200     7158      -42     
============================================
- Hits           5541     5516      -25     
+ Misses         1659     1642      -17     

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

[evan-schott]

@d0cd

do we need all of the additional clones?

get_output_type() and Output::type_() cloned them in previous version, so these are not additional clones.

why is does the program name need to be removed?

I initially made this choice to allow the ST to compare struct equality using eq_flat. Looking back, since I had to define eq_flat_relax_struct in type_.rs anyways, it makes more sense to have all composites be labeled with the local program, even though through the lens of snarkVM structs are technically not attached to a program.

is see a number of files where the generated bytecode has changed. Is this expected?

All of these changes are because the records and structs defined are unused. I am going to change the tests so that the composites are used, since the point of those tests is to test behavior of composites. Another possibility is to only remove unused structs when DCE is on. Or to default remove redefinitions of unused external structs, and adhere to the DCE flag otherwise.

[d0cd]

LGTM! Nice work!