Cryptic error on a wat file with floats

[gabriel-fallen]

Running wasmtime --invoke=test wasmtime_bug.wat produces puzzling error message:

Error: failed to process main module `wasmtime_bug.wat`

Caused by:
    0: failed to invoke `test`
    1: unsupported outgoing binding expr As(OutgoingBindingExpressionAs { ty: Scalar(UnrestrictedFloat), idx: 0 })

wasmtime_bug.wat contains this:

(module
  (func $test (result f32)
f32.const 42.0
f32.const 8.0
f32.const 10.0
f32.sub
f32.div
)
  (export "test" (func $test)))

wat2wasm seems to process this file fine. At least the error message might be more enlightening I think. :)

[alexcrichton]

Thanks for the report! This is due to the wasmtime-interface-types crate not having support yet for the "unrestricted float" type, but that can actually be trivially fixed by adding a new case there. The interface types support is currently being overhauled, though, so it may be best to wait for the dust to settle a bit.

[alexcrichton]

I'm going to close this in favor of #677 since I think it's unlikely we'll support the old webidl bindings spec for much longer.