lcov reporting errors with nyc@7.0.0-alpha3 in a ES2015+ babel project with ava

nyc@7.0.0-alpha3.txt

> NODE_ENV=test nyc -r lcov -r text-summary -i babel-register ava


   4 passed
/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-reports/lib/lcovonly/index.js:32
        writer.println('FN:' + [meta.decl.start.line, meta.name].join(','));
                                         ^

TypeError: Cannot read property 'start' of undefined
    at /Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-reports/lib/lcovonly/index.js:32:42
    at Array.forEach (native)
    at LcovOnlyReport.onDetail (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-reports/lib/lcovonly/index.js:30:28)
    at LcovReport.(anonymous function) [as onDetail] (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-reports/lib/lcov/index.js:21:24)
    at Visitor.(anonymous function) [as onDetail] (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-lib-report/lib/tree.js:34:30)
    at ReportNode.Node.visit (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-lib-report/lib/tree.js:123:17)
    at /Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-lib-report/lib/tree.js:116:23
    at Array.forEach (native)
    at visitChildren (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-lib-report/lib/tree.js:115:32)
    at ReportNode.Node.visit (/Users/Jason/git/spomodoro/node_modules/nyc/node_modules/istanbul-lib-report/lib/tree.js:126:5)