Looping string concatenation

[mbenke]

With #391, this seems to loop:

import std.{*};
contract Cat {
   function main() -> word {
     let e : empty = empty(1);
     
     let b : memory(bytes) = concat(e,concat(e,to_bytes(e)));
     return 42;
     //return uint256(MemoryAttributes.len(e));
   }
}

$ ./runsol.sh tmp/cat2.solc
Processing: tmp/cat2.solc
Compiling to hull...
Emitting hull for contract Cat
Writing to output1.hull
Generating Yul...
writing output to /home/ben/work/review/build/cat2.yul
Compiling to bytecode...
Hex output: /home/ben/work/review/build/cat2.hex
Executing...
Creation successful
returndata: 0x6022601e...5b604c56
Executing...
Execution failed: gas uint64 overflow
returndata: 0x

[axic]

As I said this is not a concat issue, since test cases in the PR passes this -- concat_nested_empty as well as the above if I rename it to main2. It is a problem of main causing some miscompilation (more of the thread here and hence why I opened #440).

[mbenke]

Yes, this is on me :)