~VAR[][n] (without a name) generates invalid HDL

[leonschoorl]

Using a ~VAR[][n] without providing an explicit name breaks code generation.

{-# LANGUAGE QuasiQuotes #-}
module TestPrim where

import           Clash.Annotations.Primitive
import           Clash.Prelude
import           Data.String.Interpolate      (i)
import           Data.String.Interpolate.Util (unindent)

{-# ANN double (InlineYamlPrimitive [VHDL] $ unindent [i|
 BlackBox:
   kind: Expression
   name: TestPrim.double
   template: |-
     (~VAR[foo][0] + ~VAR[][0])
|]) #-}
{-# NOINLINE double #-}
double :: Int -> Int
double = (*2)

topEntity x = double (x+1)

generates

  ccase_alt <= (\c$foo\ + ;

Notice the missing ).
It doesn't just use an empty string for a name, but completely stops generating code for the blackbox at that point.
Also when you do fill in a name other then foo clash will just ignore it and use the first name you gave to that argument position.

I'd like clash to come up with a name when I can't be bothered.
Or it could report an error,

[leonschoorl]

This is caused by the blackbox parser failing to parse ~VAR[].
And a bug where a parse failure caused the parser to return succes for everything it had parsed so far, and just dropping any unparsed input leftover.

[martijnbastiaan]

We've released v1.6.4, which includes a fix for this issue.