Historical development case comparison

Historical development evidence. See the current v0.2.0 evaluation case comparison for the independently reviewed, immutable result. These cases remain useful regression evidence but are not part of that evaluation denominator.

This page expands the 131 cases scoreable by both sides in the corrected 24 July development run. Exact means complete token ranges, no unallowed extras, and the one reviewed navigation target. A language-server disagreement is a contract result, not an automatic defect verdict.

Import, re-export, and export-metadata bindings are optional. They remain visible in reports but do not make an otherwise exact case non-exact.

The PHP row predates the PHP ground-truth audit

This page reports PHP as ten shared cases with nine exact for both sides and none exact for the language server alone, which reads as Bifrost satisfying every PHP case. That cannot describe the corpus as it stands.

The PHP human ground-truth audit landed on 22 July 2026, two days before this run, and rewrote php-property-access and php-parity-static-property-access to expect sigil-inclusive ranges ($last, $sent). No Bifrost version contemporary with this run satisfied them: both failed under v0.10.1, and php-parity-static-property-access still failed under v0.10.5, which corrected the declaration side but not the static usage side. Both pass from v0.10.6, which is later than anything this page could describe.

So this row reflects a corpus state from before that audit, or a shared denominator that excluded those two cases for a reason this page does not record. Either way it is not evidence that Bifrost passed them, and it should not be used to date a regression — doing exactly that produced a false regression hypothesis that took a source-level check across two Bifrost tags to disprove.

Shared-case overview

Language	Shared	Both exact	Bifrost only	LSP only	Neither
C++	15	11	1	1	2
C#	16	11	3	2	0
Go	6	5	0	1	0
Java	11	4	7	0	0
JavaScript	8	3	3	2	0
TypeScript	9	8	1	0	0
PHP	10	9	1	0	0
Python	13	10	0	3	0
Ruby	16	5	10	0	1
Rust	15	11	3	1	0
Scala	12	8	2	1	1
Total	131	85	31	11	4

Exact only for Bifrost

These 31 cases satisfy the reviewed contract in Bifrost but not in the reference LSP. Nine LSP results are position_unverified; the remaining 22 are hard disagreements.

Language	Separating cases	Current distinction
C++	cpp-parity-concrete-override-method-call	clangd expands the implementation family beyond the concrete receiver.
C#	csharp-parity-interface-receiver-method-call, csharp-parity-concrete-implementation-method-call, csharp-parity-buffer-implementation-method-call	Roslyn returns related interface/implementation-family calls beyond the reviewed static identity.
Java	java-service-method-call, java-nested-class-constructor, java-parity-static-import-method-call, java-parity-interface-receiver-method-call, java-parity-concrete-implementation-method-call, java-lambda-body-member-call, java-static-qualified-method-call	JDT LS returns every expected usage site. Five cases use broader containing ranges and two group interface and override-family calls.
JavaScript	js-class-construction, js-parity-commonjs-destructured-function-call, js-commonjs-barrel-class-construction	TypeScript LS broadens constructor navigation in one case and omits two CommonJS edges.
TypeScript	ts-default-class-import-and-construction	TypeScript LS reaches the expected class plus an enclosing constructor-body range, so strict singleton navigation is position-unverified.
PHP	php-class-construction	Intelephense returns both the class and explicit constructor; Bifrost returns the reviewed class target alone.
Ruby	ruby-relative-nested-constant, ruby-include-instance-mixin, ruby-prepend-method-precedence, ruby-top-level-implicit-self-method-call, ruby-singleton-method-dispatch, ruby-class-variable-access, ruby-parity-autoload-constant-definition, ruby-parity-attr-reader-method-call, ruby-parity-alias-method-call, ruby-factory-return-member-call	Ruby LSP spans range, declaration-inclusion, mixin, alias, generated-reader, singleton, and factory-return boundaries. No single approximation label explains the group.
Rust	rust-parity-associated-type-definition-no-movement, rust-parity-associated-type-use-definition, rust-ufcs-trait-method-through-barrel	Bifrost keeps associated-type owner identity and the UFCS trait member narrower than rust-analyzer.
Scala	scala-class-construction, scala-object-apply-call	Bifrost separates class/companion identity and connects the visible application to the authored apply member.

Exact only for the language server

These 11 cases are the clearest current Bifrost parity backlog.

Language	Separating cases	Current Bifrost gap
C++	cpp-parity-function-like-macro-expanded-call	Does not navigate the visible macro argument to the expanded function definition.
C#	csharp-parity-namespace-alias-constructor, csharp-parity-extension-method-call	Navigates the alias to the namespace surface and does not resolve the extension receiver.
Go	go-dot-import-concrete-receiver-call	Misclassifies both imported concrete member selectors as shadowed local bindings.
JavaScript	js-parity-computed-string-literal-method-call, js-commonjs-barrel-member-call	Misses the computed string-literal call and the member immediately following new Client() through a destructured barrel.
Python	python-module-import, python-parity-reexported-class-alias-classmethod, python-barrel-inherited-member-call	Misses module declaration navigation, one alias-site usage, and a narrow inherited-member contract.
Rust	rust-parity-macro-generated-function-reference	Does not expand the declarative macro to recover the generated declaration and call.
Scala	scala-parity-case-class-generated-construction-and-copy	Handles construction but cannot resolve the generated copy receiver.

Exact for neither

Language	Case	Current distinction
C++	cpp-class-reference	Bifrost misses a required class usage; clangd adds constructor-family tokens.
C++	cpp-parity-using-alias-constructor	Bifrost navigates declaration identity to the underlying class and lacks C++ type lookup; clangd misses the alias usage and adds constructor-family locations.
Ruby	ruby-require-relative-class-construction	Bifrost misses the class self-construction; Ruby LSP reaches the expected lines but not exact token ranges.
Scala	scala-parity-trait-method-implementation	Bifrost over-expands to a concrete call while Metals omits the reviewed implementation edge.

Capability boundary

Twenty-three cases are unsupported by the corresponding LSP profile because the authored operation is not advertised: 6 Go, 5 JavaScript/TypeScript, 4 PHP, 4 Ruby, 3 Scala, and 1 C++. Bifrost exactly satisfies 17 of them, is non-exact on 4, and shares the unsupported boundary on 2 configured-build cases.

Four runtime-driven cases are not planned for either side: one JavaScript, two Python, and one Ruby case.

What to isolate next

The highest-value additions are:

1. More compiler-generated and configured-project controls where LSPs should lead: macros, source generators, SDK symbols, conditional compilation, and synthetic members.
2. Interface-family minimal pairs with multiple implementations and receiver contexts, separating intentional symbol-family grouping from receiver sensitivity.
3. Alias and barrel chains with direct, one-hop, and two-hop controls.
4. Future competitor runners evaluated against these same frozen source contracts, without tool-specific scoring exceptions.