Function extract_arrow_subject

src/subject_extraction.rs:291–487

Extract the subject expression before an arrow operator (`->`). `chars` is the line as a char slice. `arrow_pos` is the index of the `-` character (i.e. `chars[arrow_pos] == '-'` and `chars[arrow_pos + 1] == '>'`). Handles: - `$this->`, `$var->` (simple variable) - `$this->prop->` (property chain) - `$this?->prop->` (nullsafe property chain) - `app()->` (function call) - `$this->getService()->`

(chars: &[char], arrow_pos: usize)

///   - `Status::Active->` (enum case access)
///   - `tryFrom($int)?->` (nullsafe after call)
fn extract_arrow_subject(chars: &[char], arrow_pos: usize) -> String {
    // Position just before the `->`
    let mut end = arrow_pos;

    // Skip whitespace
    let mut i = end;
    while i > 0 && chars[i - 1] == ' ' {
        i -= 1;
    }

    // Skip the `?` of the nullsafe `?->` operator so that the rest
    // of the extraction logic sees the expression before the `?`
    // (e.g. the `)` of a call expression like `tryFrom($int)?->`,
    // or a simple variable like `$var?->`).
    if i > 0 && chars[i - 1] == '?' {
        i -= 1;
    }

    // Update `end` so the fallback `extract_simple_variable` at the
    // bottom of this function also starts from the correct position
    // (past any `?` and whitespace).
    end = i;

    // ── Array access: detect `]` ──
    // e.g. `$admins[0]->`, `$admins[$key]->`, `$config['key']->`
    // Also handles chained access: `$response['items'][0]->`
    //
    // Walk backward through one or more balanced `[…]` pairs, collecting
    // each bracket segment.  The segments are stored innermost-first and
    // reversed at the end so the final subject reads left-to-right.
    if i > 0 && chars[i - 1] == ']' {
        let mut segments: Vec<String> = Vec::new();
        // Track the raw bracket ranges so we can reconstruct the
        // array literal base when there is no `$var` prefix.
        let mut bracket_ranges: Vec<(usize, usize)> = Vec::new();
        let mut pos = i;

        while pos > 0
            && chars[pos - 1] == ']'
            && let Some(bracket_open) = skip_balanced_brackets_back(chars, pos)
        {
            let inner: String = chars[bracket_open + 1..pos - 1].iter().collect();
            let inner_trimmed = inner.trim();
            // Quoted string key → preserve it so the resolver can look
            // up the specific key in an array shape type annotation.
            if (inner_trimmed.starts_with('\'') && inner_trimmed.ends_with('\''))
                || (inner_trimmed.starts_with('"') && inner_trimmed.ends_with('"'))
            {
                segments.push(format!("[{}]", inner_trimmed));
            } else {
                // Generic / numeric index → strip to `[]`.
                segments.push("[]".to_string());
            }
            bracket_ranges.push((bracket_open, pos));
            pos = bracket_open;
        }

        if !segments.is_empty() {