message: explicit sourceFile
diff: @@ -68,7 +68,7 @@ export default function tracer(
  function getTrace(node: ts.Node, pos: "start" | "end") {
  const nodeStart = sourceFile.getLineAndCharacterOfPosition(
  - pos === "start" ? node.getStart() : node.getEnd()
  + pos === "start" ? node.getStart(sourceFile) : node.getEnd()
  )
  return factory.createBinaryExpression(
  fileVar,
  @@ -97,18 +97,12 @@ export default function tracer(
  function visitor(node: ts.Node): ts.VisitResult<ts.Node> {
  if (ts.isCallExpression(node)) {
  - let isTracing = false
  -
  - try {
  const nodeStart = sourceFile.getLineAndCharacterOfPosition(
  - node.expression.getEnd()
  + node.expression.getStart(sourceFile)
  )
  - isTracing =
  + const isTracing =
  tracingOn && checkRegionAt(regions, nodeStart.line, nodeStart.character)
  - } catch {
  - isTracing = false
  - }
  if (isTracing) {
  const trace = getTrace(node.expression, "end")
  