Overlay: Add QL for QL query to warn about possible non-inlining across overlay frontier

[kaspersv]

This PR adds a QL-for-QL query to warn about possible non-inlining across the overlay frontier for possibly local non-private inline predicates. It will be used in tandem with a script to automatically add overlay annotations to files without existing overlay annotations. Once locality annotations have been added to a file, this query takes over responsibility for warning about possible non-inlining.

Due to a limitation of the tree-sitter-ql grammar with respect to annotations on file-level module declarations (i.e., module;), the heuristic for determining whether an inline predicate might be local is very crude: if the file contains any overlay[local] or overlay[local?] annotations.

For https://github.com/github/codeql-core/issues/4951.

[Copilot]

Pull Request Overview

Adds a CodeQL query to warn when local inline predicates lack an overlay[caller] annotation and the supporting AST classes to recognize new overlay annotations.

• Introduces InlineOverlayCaller.ql to flag non-private inline predicates in files with overlay[local]/overlay[local?] annotations.
• Extends the AST model in Ast.qll with new AnnotationArg and Annotation subclasses for overlay[caller], overlay[local], and overlay[local?].

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
ql/ql/src/queries/overlay/InlineOverlayCaller.ql	New query to detect and warn about inline predicates crossing an overlay frontier.
ql/ql/src/codeql_ql/ast/Ast.qll	Added CallerArg, LocalArg, LocalQArg and corresponding OverlayCaller, OverlayLocal, OverlayLocalQ classes.

Comments suppressed due to low confidence (1)

ql/ql/src/codeql_ql/ast/Ast.qll:2541

• [nitpick] The class name CallerArg is generic. Consider renaming it to OverlayCallerArg (and similarly LocalArg to OverlayLocalArg, LocalQArg to OverlayLocalQArg) for clarity and consistency.

private class CallerArg extends AnnotationArg {

[hvitved]

Would have been nice with a few tests as well.