Bizzare macro error

[dawkot]

    for i, node in toSeq(prc.getType)[2..^1]: #error
            
            let isRef = node.kind == nnkBracketExpr and $node[0] == "ref"
            
            let isServer = node.kind == nnkBracketExpr and $node[0] == "ref" 
and (
                serverKind == ServerKind.Tcp and $node[1] == 
"TcpServer:ObjectType" or
                serverKind == ServerKind.Udp and $node[1] == 
"UdpServer:ObjectType"
            )
    

Full error message:

_type mismatch: got (char)_

_but expected one of:_

_proc myProc(a: string; b: TcpServer)_

Removing either isRef or isServer gets a rid of the error.

Writing it in a different way to get the same result returns the same error.

Any idea how to make it work? I don't think the rest of code matters in this 
case.