feat(node): Add utility methods for AST traversal

[marlon-costa-dc]

Summary

This PR adds utility methods to the Node struct and Search trait for improved AST traversal capabilities:

• has_ancestor() - Check if any ancestor node matches a predicate
• all_occurrences() - Find all descendant nodes matching a predicate (extends Search trait)

Origin

These methods were developed to support more complex AST analysis patterns, particularly for:

• Checking node context by examining ancestors (e.g., "is this node inside a class?")
• Collecting all nodes of a certain type for batch processing

What it does

has_ancestor<F: Fn(&Node) -> bool>(&self, pred: F) -> bool

Traverses up the tree from the current node's parent to the root, returning true if any ancestor satisfies the given predicate.

// Example: Check if node is inside a function
let in_function = node.has_ancestor(|n| n.kind_id() == FunctionDeclaration);

all_occurrences(&self, pred: fn(u16) -> bool) -> Vec<Node<'a>>

Starting from the current node, finds all descendant nodes (including self) that match the predicate. Uses depth-first traversal.

// Example: Find all function calls in a subtree
let calls = node.all_occurrences(|id| id == CallExpression);

Implementation decisions

1. has_ancestor uses a generic closure (F: Fn(&Node) -> bool) instead of fn(u16) -> bool to allow more flexible predicates that can inspect the full node, not just the kind_id.

2. all_occurrences uses fn(u16) -> bool to match the existing first_occurrence signature in the Search trait, maintaining API consistency.

3. Both methods are non-recursive using explicit stacks to avoid stack overflow on deeply nested ASTs.

Test plan

• Code compiles without errors
• Existing tests pass
• New methods are ready for use by downstream implementations

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🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds two utility methods for AST traversal: has_ancestor() for checking if any ancestor node matches a predicate, and all_occurrences() for finding all descendant nodes matching a predicate. These methods support more complex AST analysis patterns by enabling upward and comprehensive downward tree traversal.

Changes:

• Added has_ancestor() method to the Node struct using a generic closure for flexible ancestor checking
• Added all_occurrences() method to the Search trait for collecting all matching descendant nodes
• Both methods use non-recursive implementations with explicit stacks to avoid stack overflow on deep ASTs

Reviewed changes

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

File	Description
src/traits.rs	Added all_occurrences signature to the Search trait interface
src/node.rs	Implemented has_ancestor on Node and all_occurrences in the Search trait implementation

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