Flatten removes "pragma experimental ABIEncoderV2;"

[sakulstra]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (44f3a4b 2022-07-18T00:10:06.735136619Z)

What command(s) is the bug in?

forge flatten

Operating System

Linux

Describe the bug

forge flatten will remove pragma experimental ABIEncoderV2; from the code and thus break it.

To reproduce I can run cast etherscan-source -d etherscan/0x7b2a3cf972c3193f26cdec6217d27379b6417bd0 0x7b2a3cf972c3193f26cdec6217d27379b6417bd0 to download https://etherscan.io/address/0x7b2a3cf972c3193f26cdec6217d27379b6417bd0#code
The ILendingPool.sol will correctly contain pragma experimental ABIEncoderV2;.

If you now run:

forge flatten ./etherscan/0x7b2a3cf972c3193f26cdec6217d27379b6417bd0/AToken/@aave/protocol-v2/contracts/protocol/tokenization/AToken.sol --output ./etherscan/0x7b2a3cf972c3193f26cdec6217d27379b6417bd0/Flattened.sol

The code will be flattened, but pragma experimental ABIEncoderV2; will be lost, breaking the code.