Function inferCppReceiverType

src/resolution/name-matcher.ts:687–748

(
  receiverName: string,
  ref: UnresolvedRef,
  context: ResolutionContext,
  depth = 0,
)

}

function inferCppReceiverType(
  receiverName: string,
  ref: UnresolvedRef,
  context: ResolutionContext,
  depth = 0,
): string | null {
  // Per-file lines cache when available — this runs per `receiver->method()`
  // ref and re-splitting the file each time is the same quadratic as the
  // shared inferrer's (#1122).
  const lines = context.getFileLines
    ? context.getFileLines(ref.filePath)
    : (context.readFile(ref.filePath)?.split(/\r?\n/) ?? null);
  if (!lines || lines.length === 0) return null;

  const callLineIndex = Math.max(0, Math.min(lines.length - 1, ref.line - 1));
  const escapedReceiver = receiverName.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
  const receiverPattern = new RegExp(`\\b${escapedReceiver}\\b`);
  const declaratorRegex = buildDeclaratorRegex(escapedReceiver);

  for (let i = callLineIndex; i >= 0; i--) {
    const line = lines[i];
    if (!line || !receiverPattern.test(line)) continue;

    const declaratorMatch = line.match(declaratorRegex);
    if (declaratorMatch) {
      const normalized = normalizeCppTypeName(declaratorMatch[1] ?? '');
      if (normalized === 'auto') {
        // `auto x = Foo::instance();` — the declared type is deduced; recover it
        // from the initializer (call return type / construction) (#645).
        const initType = inferCppAutoInitializerType(line, receiverName, ref, context, depth);
        if (initType) return initType;
        // No usable initializer on this line — keep scanning earlier ones.
      } else if (normalized) {
        return normalized;
      }
    }
  }

  const headerCandidates = [
    ref.filePath.replace(/\.(?:c|cc|cpp|cxx)$/i, '.h'),
    ref.filePath.replace(/\.(?:c|cc|cpp|cxx)$/i, '.hpp'),
    ref.filePath.replace(/\.(?:c|cc|cpp|cxx)$/i, '.hxx'),
  ].filter((candidate, index, arr) => arr.indexOf(candidate) === index && candidate !== ref.filePath);

  for (const headerPath of headerCandidates) {
    if (!context.fileExists(headerPath)) continue;
    const headerLines = context.getFileLines
      ? context.getFileLines(headerPath)
      : (context.readFile(headerPath)?.split(/\r?\n/) ?? null);
    if (!headerLines) continue;

    for (const line of headerLines) {
      if (!receiverPattern.test(line)) continue;
      const declaratorMatch = line.match(declaratorRegex);
      if (!declaratorMatch) continue;
      const normalized = normalizeCppTypeName(declaratorMatch[1] ?? '');
      if (normalized && normalized !== 'auto') return normalized;
    }