fix(semantic-tokens): filter ineligible highlight references

[Myriad-Dreamin]

Add a reusable declaration-name eligibility helper that mirrors clangd's canHighlightName, use it to suppress unsupported reference tokens in the semantic-token collector, and cover the change with focused semantic-token regression tests plus a constructor/destructor positive case.

Summary by CodeRabbit

• Bug Fixes

  • Enhanced semantic token filtering to prevent certain declaration references from being highlighted when they cannot be properly highlighted, while maintaining support for constructors and destructors.

• Tests

  • Added test coverage for operator reference suppression and constructor/destructor name highlighting behavior.

• Chores

  • Updated .gitignore configuration.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR adds suppression logic for semantic tokens on references with non-highlightable declaration names. A new utility function classifies declaration names (Identifiers, constructors, destructors) that can be highlighted. The semantic token collector now early-returns for references with non-highlightable names, preventing token emission.

Changes

Cohort / File(s)	Summary
Configuration .gitignore	Updated ignore patterns to ignore .codex and removed -openspec/ entry.
Utility Functions src/semantic/ast_utility.h, src/semantic/ast_utility.cpp	Added new can_highlight_name() function that classifies declaration name kinds, returning true for Identifiers, constructors, and destructors; false for operators, conversion functions, and other ineligible kinds. Includes exhaustiveness check via std::unreachable().
Feature Implementation src/feature/semantic_tokens.cpp	Added early-return in handleDeclOccurrence when relation indicates a reference and the referenced declaration name cannot be highlighted, preventing token emission for ineligible references.
Tests tests/unit/feature/semantic_tokens_tests.cpp	Added EXPECT_NO_TOKEN() assertion helper and two test cases: IneligibleOperatorReferenceIsSuppressed validates operator references are skipped; ConstructorAndDestructorNamesRemainHighlighted verifies constructor/destructor identifiers retain semantic tokens with appropriate modifiers.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• feat: classify dependent-name semantic token modifier #387 — Both PRs modify SemanticTokensCollector::handleDeclOccurrence in src/feature/semantic_tokens.cpp, affecting suppression and modifier computation for references.
• feat: classify more semantic token modifiers #395 — Both PRs modify SemanticTokensCollector::handleDeclOccurrence with early-return logic and are directly related through expansion of modifier classification.

Suggested reviewers

• 16bit-ykiko

Poem

🐰 A filter for tokens, so spry and so bright,
We highlight what matters and hide what's not right,
Constructors shine golden, operators take flight—
Now references filter with surgical might! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: filtering ineligible highlight references in semantic tokens, which is the primary objective evident from the code changes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch requests/highlight-name-filter/d9eec958-acd5-4df7-92cc--c074498e6e1badd9/a1-proposal-1

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[coderabbitai]

🧹 Nitpick comments (1)

tests/unit/feature/semantic_tokens_tests.cpp (1)

285-307: Add a constructor reference case to exercise the new guard.

Line 303 and Line 305 assert constructor declaration/definition tokens, but the new filter only runs for references. If CXXConstructorName were accidentally removed from can_highlight_name, these constructor assertions would still pass. Add a constructor-call/reference assertion alongside the destructor reference.

Suggested coverage addition

 void use(S* value) {
+    (void)@ctor_ref[S]();
     value->@dtor_ref[~]S();
 }
 )cpp");
@@
     EXPECT_TOKEN("ctor_decl", SymbolKind::Method, declaration | special_member);
     EXPECT_TOKEN("dtor_decl", SymbolKind::Method, declaration | special_member);
     EXPECT_TOKEN("ctor_def", SymbolKind::Method, definition | special_member);
+    EXPECT_TOKEN("ctor_ref", SymbolKind::Method, special_member);
     EXPECT_TOKEN("dtor_ref", SymbolKind::Method, special_member);
 }

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@tests/unit/feature/semantic_tokens_tests.cpp` around lines 285 - 307, Add a
constructor-reference case in the ConstructorAndDestructorNamesRemainHighlighted
test by inserting a constructor call annotated like new `@ctor_ref`[S](); (or
equivalent call site) inside the run_utf8 sample, and then add an assertion
EXPECT_TOKEN("ctor_ref", SymbolKind::Method, special_member) alongside the
existing dtor_ref assertion; this ensures the new guard that runs only for
references (can_highlight_name) is exercised for constructors as well. Ensure
you use the same modifier_mask special_member and the unique token name
"ctor_ref" so the test locates the annotation and validates the constructor
reference highlighting.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@tests/unit/feature/semantic_tokens_tests.cpp`:
- Around line 285-307: Add a constructor-reference case in the
ConstructorAndDestructorNamesRemainHighlighted test by inserting a constructor
call annotated like new `@ctor_ref`[S](); (or equivalent call site) inside the
run_utf8 sample, and then add an assertion EXPECT_TOKEN("ctor_ref",
SymbolKind::Method, special_member) alongside the existing dtor_ref assertion;
this ensures the new guard that runs only for references (can_highlight_name) is
exercised for constructors as well. Ensure you use the same modifier_mask
special_member and the unique token name "ctor_ref" so the test locates the
annotation and validates the constructor reference highlighting.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 58aa4fe0-cee0-48a2-ab29-e854b9931069

📥 Commits

Reviewing files that changed from the base of the PR and between 17e6801 and f1c2841.

📒 Files selected for processing (5)

• .gitignore
• src/feature/semantic_tokens.cpp
• src/semantic/ast_utility.cpp
• src/semantic/ast_utility.h
• tests/unit/feature/semantic_tokens_tests.cpp