This fixes a regression about where we report errors:
echo error(here
old: ^
fixed: ^
Commit 0c22f67bd (Remove the old parser bits, 2020-07-02) removed
uses of "error_offset_within_token" so we always report errors at
token start. Add it back, hopefully restoring the 3.1.2 behavior.
Note that for cases like
echo "$("
we report "unbalanced quotes" because we treat the $( as double
quote. Giving a better error seems hard because of the ambguity -
we don't know if quote is meant to be inside or outside the command
substitution.
Like the $status commit, this would add the offset to already existing
errors, so
```fish
(foo)
(bar)
something
```
would see the "(foo)" error, store the correct error location, then
see the "(bar)" error, and *add the offset of (bar)* to the "(foo)"
error location.
Solve this by making a new error list and appending it to the existing
ones.
There's a few other ways to solve this, including:
- Stopping after the first error (we only display the first anyway, I
think?)
- Making it so the source location has an "absolute" flag that shows
the offset has already been added (but do we ever need to add two offsets?)
I went with the simpler fix.
This would break the location of any prior errors without doing
anything of value.
E.g.
```fish
echo foo | exec grep # this exec is not allowed!
$status
somethingelse # The error might be found here!
```
Would apply the offset of `$status` to the offset of `exec`, locating
the error for `exec` somewhere after $status!
