Trailing comma after deleting two adjacent nodes in a list

[ghost]

TypeScript Version: 2.9.0-dev.20180516

Code

/// <reference path='fourslash.ts' />

////function f(t, u, v) { return t; }

verify.codeFixAll({
    fixId: "unusedIdentifier_delete",
    fixAllDescription: "Delete all unused declarations",
    newFileContent:
`function f(t) { return t; }`,
});

Expected behavior:

Test passes.

Actual behavior:

     Error: verifyFileContent failed:
Expected:
function f(t) { return t; }
Actual:
function f(t, ) { return t; }