ICE when defining multiple Yul functions with the same name but different arguments/returns in inline assembly

[cameel]

Description

If a Yul function with the same name is defined again with different parameters and/or return parameters in a completely different scope in inline assembly, the compiler throws an ICE.

It happens only with the new code generator and I did not manage to reproduce it with optimizer enabled.

It's probably related to #12090, but this one can be triggered using inline assembly rather than pure Yul. The solution should also probably be different - the compiler can just give these functions different names internally instead of completely disabling named labels (which is the solution in #12139).

Steps to Reproduce

contract.sol:

contract C {
    function f() external {
        assembly {
            {
                function x() -> a {}
            }
            {
                function x() {}
            }
        }
    }
}

solc --bin --experimental-via-ir contract.sol

Exception during compilation: /solidity/libevmasm/Assembly.cpp(350): Throw in function solidity::evmasm::AssemblyItem solidity::evmasm::Assembly::namedTag(const string&, size_t, size_t, std::optional<long unsigned int>)
Dynamic exception type: boost::wrapexcept<solidity::evmasm::AssemblyException>
std::exception::what:
[solidity::util::tag_comment*] =

The result is the same even if the functions are defined in separate assembly blocks, even if these blocks are inside different Solidity functions:

contract C {
    function f() external {
        assembly {
            function x() -> a {}
        }
    }
    function g() external {
        assembly {
            function x() {}
        }
    }
}

Note that, unlike in #12090, just giving functions the same name is not enough to trigger this. For example this compiles fine:

contract C {
    function f() external {
        assembly {
            function x() { mstore(0, 0) }
        }
    }
    function g() external {
        assembly {
            function x() { mstore(1, 1) }
        }
    }
}

Environment

• Compiler version: 0.8.9