Empty and non-empty lines

```
Errors encountered when parsing cabal file ./tree-diff.cabal:

tree-diff.cabal:102:7:
unexpected 'n'
expecting space, "&&", white space, "||", comma or end of input

   98 |       void               >=0.7.2    && <0.8
   99 |
  100 |       -- space and comments
  101 |
  102 |       nats               >=1.1.1    && <1.2,
      |       ^

tree-diff.cabal:86:48: version with tags

   85 |     tagged               >=0.8.5    && <0.9,
   86 |     text                 >=1.2.2.2  && <1.3-foo,
      |                                                ^

```