RuntimeError is not always downcastable to the host error

[MaksymZavershynskyi]

Describe the bug

In Rust, sometimes wasmer_runtime::error::RuntimeError returned by Wasmer is not downcast-able to the error type that our host function returns to Wasmer.

• Here is we try to downcast it:
  https://github.com/nearprotocol/nearcore/blob/a08944db6672185618e2454fce5e7be0e327b47a/runtime/near-vm-runner/src/errors.rs#L59
• And here is the place where all host functions return only VMLogicError https://github.com/nearprotocol/nearcore/blob/05a82d8dd74531b21567623ab0e7e75946afea19/runtime/near-vm-runner/src/imports.rs#L7

Versions:

wasmer-runtime = { version = "0.11.0", features = ["default-backend-singlepass"], default-features = false }
wasmer-runtime-core = { version = "0.11.0", features = ["backend-singlepass"]}

Expected behavior

RuntimeError to be always downcastable to the error returned by the host functions.

Actual behavior

Sometimes we are getting error that cannot be downcasted.

[MarkMcCaskey]

Thanks for the bug report!

I believe RuntimeError is returned in other exceptional situations to avoid panicking or terminating, for example: in Func::call.

It seems that when an internal RuntimeError is returned, it's usually either a &'static str or a String. I'd be curious to know if the errors you're seeing can be downcast to either of those and if so, what the message is.

Additionally since, 0.14.0 it looks like we sometimes return an ExceptionCode this way.

[MaksymZavershynskyi]

Will try to reproduce