Kotlin: parsing-layer coverage gaps (8 findings)

[magyargergo]

Parent epic: #1919
Enabled by: #1920 (node-type validator) — closes F50 · #1921 (heritage helper) — closes F46

8 verified findings. Each box is a discrete fix unit. Legend: ✅ confirmed · 🟡 partial.

• ✅ F45 [MEDIUM] Kotlin default/optional parameters are never detected — requiredParameterCount always equals parameterCount
• ✅ F46 [MEDIUM] Interface delegation heritage (class Foo : Bar by baz) is silently dropped
• ✅ F47 [MEDIUM] Kotlin callable references (::method, Type::new, obj::m) are never captured
• ✅ F48 [MEDIUM] Secondary constructors are not extracted as member definitions
• ✅ F49 [LOW] Infix-call query emits spurious @call captures for both operands, not just the operator
• 🟡 F50 [LOW] Dead literal node-type names line_string_literal / multi_line_string_literal in arg-type inference
• ✅ F51 [LOW] Destructuring declarations (multi_variable_declaration) not captured as properties or loop bindings
• ✅ F52 [LOW] Companion-object properties are not indexed as fields

Verified against main @ a93ecee0. Finding IDs use an F prefix to avoid colliding with unrelated issue/PR numbers.

[magyargergo]

Partial overlap with PR #1956 (fix #1951)

Finding	#1956 impact
Heritage worker-path regression	Solved — Kotlin @reference.inherits synth from heritage clauses; legacy @heritage gated off for registry-primary languages; worker-forced test asserts exact EXTENDS/IMPLEMENTS set.
F46 [MEDIUM] Interface delegation (class Foo : Bar by baz)	Not solved — delegation syntax not in synth scope.
F45, F47–F52	Not addressed by #1956 (F50 dead-branch class was #1920 / PR #1937)
(perf)	Fixed — O(n²) findNodeAtRange in Kotlin scope-capture (2.78→0.84); Kotlin added to bench.

Why: Kotlin was registry-primary but inheritance still came from legacy @heritage, which worker mode drops — same root cause as #1951. #1956 routes normal class/interface inheritance through scope-resolution; delegation and the other parsing gaps remain for this ticket.

[magyargergo]

Coverage vs origin/main @ 7691abf7

3/8 done · 0 in flight · 5 open

Finding	Severity	Status	Evidence
F45	MEDIUM	Open	Default/optional param detection — no Kotlin scope regression proving requiredParameterCount < parameterCount
F46	MEDIUM	Done	#1940 — interface delegation (: Bar by baz) via explicit_delegation synth
F47	MEDIUM	Open	Callable references (::method, Type::new) not captured
F48	MEDIUM	Open	Secondary constructors not in scope @declaration.*
F49	LOW	Open	Infix-call spurious @call on both operands
F50	LOW	Done	#1937 — dead string-literal node types gated/removed
F51	LOW	Open	multi_variable_declaration not captured
F52	LOW	Open	Companion-object properties not indexed as fields

[magyargergo]

Coverage vs origin/main @ 7cbc5442

3/8 done · 0 in flight · 5 open. Parent epic #1919.

Finding	Severity	Status	PR
F45	HIGH	Open	—
F46	MEDIUM	Done	#1940
F47–F49	mixed	Open	—
F50	LOW	Done	#1937
F51–F52	LOW	Open	—

[azizur100389]

I can take the scoped F45 follow-up: Kotlin default/optional parameter detection so requiredParameterCount excludes parameters with defaults. I’ll keep it focused on the registry-primary parsing/scope-resolution surface with exact function, method, and constructor fixtures, and leave F47-F49/F51-F52 separate.