unified: Declare exposed fields on supertypes

[asgerf]

Supertypes in ast_nodes.yml can now have a list of fields to expose in the generated QL class. This replaces the previous rule from #22507 where fields that were common among all subtypes were automatically hoisted to supertypes.

Compared to automatic hoisting, manually-declared supertype fields work better in a few scenarios:

• There are some subtypes where the field has a more precise type thus failing an exact signature match
• Adding a new subtype that lacks a previously-common field can cause a breaking AST change.
• Sometimes it's just nice to have getters for fields that are present in the common case, but some subtypes are lacking it.

This PR uses the feature for the callable supertype:

  callable:
    subtypes:
      - top_level
      - function_expr
      - function_declaration
      - constructor_declaration
      - destructor_declaration
      - accessor_declaration
      - initializer_declaration
    fields:
      parameter*: parameter
      body?: block

Previously the body field was hoisted automatically, but not parameter, because some callables can't have parameters (like top-level).

[Copilot]

Copilot review overview

🟡 Changes recommended

The generated unified Callable now declares abstract parameter accessors, but some concrete Callable subtypes don’t implement them, and the generator change likely breaks supertypes that have subtypes but no declared fields.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review tier: Lite
Findings: 1 · 1

New issues introduced by this change (2)

Severity	Finding
	unified/​ql/​lib/​codeql/​unified/​internal/​Ast.qll — Callable now declares getParameter/getAParameter as abstract, but several concrete…
	shared/​tree-sitter-extractor/​src/​generator/​ql_gen.rs — compute_exposed_predicates now makes union (supertype) classes expose only the predicates derived…

What changed in this PR

This PR extends the Yeast/unified AST schema format so supertypes can explicitly declare a set of exposed fields, and updates the tree-sitter QL generator and unified AST output to surface those fields (notably callable.parameter) on the generated supertype class.

Changes:

• Add a “detailed” supertypes YAML form supporting subtypes + fields, with JSON round-tripping and tests.
• Update tree-sitter extractor data structures and QL generator to carry/emit supertype-declared field predicates.
• Regenerate unified Ast.qll so Callable exposes parameter accessors and members override them.

File	Description
unified/​ql/​lib/​codeql/​unified/​internal/​Ast.qll	Regenerated unified AST QL classes; adds Callable.getParameter/getAParameter and marks member implementations as override.
unified/​extractor/​tests/​corpus_tests.rs	Minor Rust formatting cleanup for Bazel RUNFILES_DIR handling.
unified/​extractor/​ast_types.yml	Switch callable supertype to detailed form and declare exposed parameter* and body? fields.
shared/​yeast/​doc/​node-types-yaml.md	Document the new detailed supertype syntax and field semantics.
shared/​yeast-schema/​src/​schema.rs	Formatting-only refactor of field_types accessor signature.
shared/​yeast-schema/​src/​node_types_yaml.rs	Parse/convert detailed supertypes, factor field conversion, add YAML↔JSON round-trip tests for supertype fields.
shared/​tree-sitter-extractor/​src/​node_types.rs	Extend union (supertype) entries to retain declared fields/children for codegen.
shared/​tree-sitter-extractor/​src/​generator/​ql_gen.rs	Change how exposed predicates are computed/hoisted, and add tests for “expose only declared supertype fields”.
shared/​tree-sitter-extractor/​src/​generator/​mod.rs	Update pattern matches for the expanded EntryKind::Union shape.
shared/​tree-sitter-extractor/​src/​extractor/​mod.rs	Update pattern matches for the expanded EntryKind::Union shape in type matching.

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[Copilot]

Copilot review overview

🟡 Changes recommended

Nested inheritance, refined return overrides, and in-memory schema registration are currently incomplete.

Get a fresh assessment by requesting another Copilot review.

Review effort: Balanced
Findings: 2

Open (2)

• Propagate inherited field predicates through nested supertypes · New
• Support refined return types when detecting predicate overrides · New

Resolved since last review (2)

• Callable now declares getParameter/getAParameter as abstract, but several concrete…
• compute_exposed_predicates now makes union (supertype) classes expose only the predicates derived…

[Copilot]

Copilot review overview

🔵 Needs a closer look

Detailed supertype fields are omitted from schemas created directly from YAML.

Review effort: Balanced
Findings: None

Resolved since last review (2)

• Support refined return types when detecting predicate overrides
• Propagate inherited field predicates through nested supertypes

Previously missed (1)

In code that hasn't changed since last review

Register detailed supertype fields in Schema

shared/​yeast-schema/​src/​node_types_yaml.rs:380

Detailed supertype fields are not applied to Schema: this loop records only members, while the field registration/type/cardinality loop below visits only yaml.named. As a result, schema_from_yaml/extend_schema_from_yaml return a schema where has_field("callable", Some("parameter")) is false and no declared type or cardinality is available, despite these public helpers documenting that they register all YAML fields. Apply the same field metadata logic to definition.fields() and add a schema-path assertion to the new test.