Function extract_call_expression

src/completion/named_args.rs:236–315

Extract the call expression that precedes the opening paren at `open`. Handles: - `foo(` → `"foo"` - `$this->method(` → `"$this->method"` - `$var->method(` → `"$var->method"` - `ClassName::method(` → `"ClassName::method"` - `self::method(` / `static::method(` / `parent::method(` → as-is - `new ClassName(` → `"new ClassName"` - `(new Foo())->method(` → `"$this->method"` etc. — simplified

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

/// - `new ClassName(` → `"new ClassName"`
/// - `(new Foo())->method(` → `"$this->method"` etc. — simplified
pub fn extract_call_expression(chars: &[char], open: usize) -> Option<String> {
    if open == 0 {
        return None;
    }

    let mut i = open;

    // Skip whitespace before `(`
    while i > 0 && chars[i - 1] == ' ' {
        i -= 1;
    }

    if i == 0 {
        return None;
    }

    // ── If preceded by `)`, this is a chained call like `foo()->bar(`.
    // We won't try to resolve through call chains for named args — the
    // complexity is high and the user can rely on member completion.
    // But we DO need to handle `(new Foo)(` — skip for now.
    if chars[i - 1] == ')' {
        return None;
    }

    // ── Read the identifier (function/method name) ──────────────────
    let ident_end = i;
    while i > 0 && (chars[i - 1].is_alphanumeric() || chars[i - 1] == '_' || chars[i - 1] == '\\') {
        i -= 1;
    }
    if i == ident_end {
        return None;
    }
    let ident: String = chars[i..ident_end].iter().collect();

    // ── Check what precedes the identifier ──────────────────────────

    // Instance method: `->method(`
    if i >= 2 && chars[i - 2] == '-' && chars[i - 1] == '>' {
        let subject = extract_subject_before_arrow(chars, i - 2);
        if !subject.is_empty() {
            return Some(format!("{}->{}", subject, ident));
        }
        return None;
    }

    // Null-safe method: `?->method(`
    if i >= 3 && chars[i - 3] == '?' && chars[i - 2] == '-' && chars[i - 1] == '>' {
        let subject = extract_subject_before_arrow(chars, i - 3);
        if !subject.is_empty() {
            return Some(format!("{}->{}", subject, ident));
        }
        return None;
    }

    // Static method: `::method(`
    if i >= 2 && chars[i - 2] == ':' && chars[i - 1] == ':' {
        let class_name = extract_class_name_backward(chars, i - 2);
        if !class_name.is_empty() {