Rust: Take derive macros into account in is{In,From}MacroExpansion

[hvitved]

#19824 follow-up.

[Copilot]

Pull Request Overview

This PR refactors the macro-expansion checks to use a unified root node and adds support for derive-macro expansions in isInMacroExpansion, updating the corresponding isFromMacroExpansion predicate to match the new signature.

• Changed isInMacroExpansion to accept a generic AstNode root and handle derive-macro expansions.
• Updated isFromMacroExpansion to call the revised predicate and adjust the token-tree check accordingly.

Reviewed Changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 1 comment.

File	Description
rust/ql/lib/codeql/rust/elements/internal/MacroCallImpl.qll	Refactored isInMacroExpansion signature and added getDeriveMacroExpansion branch
rust/ql/lib/codeql/rust/elements/internal/AstNodeImpl.qll	Updated isFromMacroExpansion to use new isInMacroExpansion(AstNode,…) and adjusted cast for token-tree check

Comments suppressed due to low confidence (3)

rust/ql/lib/codeql/rust/elements/internal/MacroCallImpl.qll:17

• [nitpick] The parameter name root is quite generic; consider renaming it to something more descriptive like expansionRoot to clarify its role.

  predicate isInMacroExpansion(AstNode root, AstNode n) {

rust/ql/lib/codeql/rust/elements/internal/MacroCallImpl.qll:20

• Add unit tests to verify that isInMacroExpansion correctly recognizes nodes produced by derive macros, ensuring the new branch is covered.

    n = root.(Adt).getDeriveMacroExpansion(_)

rust/ql/lib/codeql/rust/elements/internal/AstNodeImpl.qll:73

• [nitpick] For consistency with MacroCallImpl.qll, consider renaming this root parameter to expansionRoot so its purpose remains clear.

      exists(AstNode root |

[Copilot]

[nitpick] Instead of using the wildcard _ for the derive expansion, bind it to a named variable (e.g. getDeriveMacroExpansion(deriveExp)) to improve readability.

Suggested change

	n = root.(Adt).getDeriveMacroExpansion(_)
	or
	isInMacroExpansion(root, n.getParentNode())
	}
	n = root.(Adt).getDeriveMacroExpansion(deriveExp)
	or
	isInMacroExpansion(root, n.getParentNode())
	}
	AstNode deriveExp;

[geoffw0]

Looks good, thanks for fixing this!