[shayyz-code]

Summary

Adds 21 conformance cases under tests/conformance/structs/ that record how v0.1.11 handles structs and methods, so the upcoming refactor changes them on purpose. The cases cover declarations with typed fields, pub, construction with Name::{...}, field access, construction errors, impl { } and impl Target { } methods, self, Self return types, and inherits. No interpreter or harness changes.

Current behaviour (blessed, 12 cases): field_access, pub_modifier_not_enforced, field_type_mismatch, missing_field, undefined_struct, unknown_field_access, method_reads_self, method_with_argument, impl_target_block, method_returns_self_type, static_method_call_rejected, inherits_parent_method.

Known failures (9 cases, hand-written intended output plus .ignore):

Case	Issue	Today
unknown_field_rejected	#64	Point::{x, y, z} is accepted silently
struct_typed_field	#64	a Point value for a Point field is rejected (expected Map({...}) but got Map({}))
vec_typed_field	#63	parse error Unexpected token: TInt. The case returns the vector instead of indexing it, because indexing after a field access is a separate defect (#107)
field_assignment	#106	c.count = 2; on a mut binding fails with Unexpected token: Assignment, expected: SemiColon; there is no field assignment syntax yet
method_returns_int_field	#50	self.x is typed String, so >> int fails with "Return type mismatch"
method_result_binding	#50	poo n <: p.get_name(); fails with "Undefined method 'get_name' for object of type Map(...)" (inference panic caught by the hook)
method_mutates_self	#65	self.count = 0; does not parse at all (Unexpected token: Assignment, see #106), so the case fails before the lost-mutation bug can show
inherits_parent_without_impl	#57	Runtime error: called Option::unwrap() on a None value (exit 1, because the panic hook turns the panic into an error)
print_struct	#69	prints Rust Debug of the backing map, e.g. {"x": Int(1), "y": Int(2), "__prototypes__": Map({})}, in a different key order from run to run. With methods, it also dumps the method AST. It does not panic as #69 says

Not included: override resolution (#56). A child overriding a parent method returned the child's result in 20 of 60 runs and the parent's in the other 40. A case expecting the child to win would pass about one run in three, and the harness fails the run when an ignored case passes, so it would make CI flaky. #56 stays without a corpus case until the lookup is deterministic.

Recorded as they are now, decision still open:

• pub_modifier_not_enforced: pub is parsed, but fields without pub can still be read from outside the struct.
• missing_field: a missing field is rejected with the confusing message Mismatched key 'y' on struct compound - 'Point'.
• unknown_field_access: reading an unknown field says Value for key z does not exist in the map, which talks about a map, not a struct.
• static_method_call_rejected: Point::origin() fails with Expected struct compound after namespace access. Methods can only be called on an instance, so a >> Self constructor can't be called without one.

Defects found while writing these cases: #106 (struct field assignment does not parse), #107 (indexing after a field access), and #109 (impl Other { } naming a struct that doesn't exist is accepted, and its methods attach to the enclosing struct; no case here).

Also seen: type-mismatch messages for struct-typed fields print the expected Map({...}) in random key order, so .error files must not include that part.

Issue

Closes #87

Verification

• BLESS=1 POO_CASE=structs/ cargo test --test conformance, then checked every blessed .stdout and .error by hand.
• First commit: ran cargo test --test conformance 5 times, each conformance: 17 passed, 9 known failures, 0 failed; POO_CASE=structs/ 20 more times, each 13 passed, 8 known failures, 0 failed (21 matched).
• After the review commits: ran cargo test --test conformance 3 times on the branch tip, each conformance: 16 passed, 10 known failures, 0 failed (structs: 12 passed, 9 known failures, 21 matched). The middle commit alone gives 17 passed, 9 known failures, 0 failed.
• Before writing the cases, ran each candidate program 30 times with the poo binary. Every recorded output was the same on all 30 runs.
• just check passes on the branch tip.
• Each commit is a self-contained Conventional Commit and passes just check

Documentation and Visual Impact

None. The only changes are test files under tests/conformance/structs/.

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