Speculate on DejaFu: `speculate: could not find Listable Thread D1 D1`

[rudymatela]

The attached file (Main.hs.txt) applies Speculate to DejaFu. When it is run, Speculate reports an error:

speculate: could not find Listable Thread D1 D1
CallStack (from HasCallStack):
  error, called at src/Test/Speculate/Expr/Instance.hs:194:27 in speculate-0.2.9-...

See full log here.

That definitely seems like a bug.

Thanks to @barrucadu for discovering this.