FieldPath::push clones the entire vector on every call

[eikopf]

Location

crates/gnomon-db/src/eval/interned.rs:50-53

Description

FieldPath::push clones the entire Vec<PathSegment> to produce a new FieldPath:

pub fn push(&self, segment: PathSegment<'db>) -> Self {
    let mut segments = self.0.clone();
    segments.push(segment);
    Self(segments)
}

For deeply nested record structures, this results in O(n^2) total allocation where n is the nesting depth, since each level clones all previous segments.

Suggested Fix

Consider using Rc<[PathSegment]> for structural sharing, pre-allocating capacity, or switching to a mutable-push API where the path is built incrementally and rolled back.

[eikopf]

Fixed by #91 without using Rc.