Cast seems to be missing support for legacy transactions on BSC

[0xca11]

When trying to make a function call to a contract on BSC using cast send, it fails with custom error: EIP-1559 not activated.

I've been able to deploy contracts to BSC using forge create --legacy, but that legacy parameter seems to be missing from cast.

Is there another way to send legacy, non-EIP-1559 transactions when using cast?

If not, I think it's a feature worth adding, as right now, cast doesn't automatically detect that BSC is being used and that it doesn't support EIP-1559.

[mattsse]

we already have

https://github.com/gakonst/foundry/blob/ff46022b58f6653ef4fc77536b0f8f6a3bb71f7e/cli/src/cmd/create.rs#L121-L132

but this is only in use for create rn

In send we're currently limited to Eip1559

https://github.com/gakonst/foundry/blob/9de25d1928da362cd3b185ebaccc0e3d00aee2c8/cast/src/lib.rs#L234

adding a similar is_legacy check should do the trick here as well

this leaves us with two tasks

• add BSC id to is_legacy
• check is_legacy is in build_tx (should perhaps return TypedTransaction?)