LLVM assert with "put break"

[jruderman]

iter x() -> int {
    while true { put break; }
}
fn main() {}

Assertion failed: ((i >= FTy->getNumParams() || FTy->getParamType(i) == Args[i]->getType()) && "Invoking a function with a bad signature!"), function init, file Instructions.cpp, line 531.