Compiler doesn't fully handle `return` statements in control flow

[Ferret-san]

Found this issue while compiling a predicate:
This compiles:

if let Result::Ok(address) = result_address {
        true
} else {
       false
}

However, this doesn't:

if let Result::Ok(address) = result_address {
        return true
} else {
        return false
}

Likewise, this doesn't compile either:

if let Result::Ok(address) = result_address {
        return true;
} else {
        return false;
};