Consider this source code:
-----
package test;

public class LambdaLNT {
    public static void main(String... args) {
        Runnable r = () -> {
            int i = args.length;
        };
        r.run();
    }
}
-----

When compiled with -g, the LineNumberTable for the lambda method looks like this:
      LineNumberTable:
        line 1: 0
        line 7: 3

That is undoubtedly wrong: the first statement of the lambda does not start at line 1. As a consequence, debuggers would likely misbehave.

This appears to be caused by a missing TreeMaker.at in LambdaToMethod.visitVarDef.