This adjusts prior behavior that would error to now allow keys that
are marked; those marks are removed in evaluation in order to give
a valid string for the map key, but the resulting object or tuple
is marked as a whole with whatever mark the key contained, ensuring
marks are maintained.
Using marked values in a for expression conditional expression would
previously panic due to calling `.False()` on the result of the
expression.
This commit makes two changes:
- Unmark the conditional expression value before testing if it is false;
- Merge any marks from the conditional into the resulting marks for the
for expression.
When evaluating an HCL expression attempting
to use a marked value as an object key,
return an error rather than falling through
to the cty panic. The error style mimics similar
errors in the area.
Functions which accept multiple parameters can be called with the
expansion operator, `...`. When doing so, we must unmark the expanded
argument value before transforming it into a collection of function
arguments. To ensure that any marks applied to the collection are
preserved, we transfer the collection marks to the individual elements
as we build the argument list.
The rules for the splat operator call for it to return an empty tuple
when its operand is null, but this rule was previously being
overridden by another rule that a value whose type is unknown
causes the operator to return an unknown value of unknown
type.
This was initially reported and discussed in Terraform, under
hashicorp/terraform#26746.
Previously functions such as concat() would result in a panic if there
was a null element and a sequence, as in the included test. This PR adds
a check if the error index is outside of the range of arguments and
crafts an error that references the entire function instead of the null
argument.
Our error message for the ambiguous situation recommends doing this, but
the parser didn't actually previously allow it. Now we'll accept the form
that the error message recommends.
As before, we also accept a template with an interpolation sequence as
a disambiguation, but the error message doesn't mention that because it's
no longer idiomatic to use an inline string template containing just a
single interpolation sequence.
