Taint detection does not work for global functions in a namespace due to id not including namespace

[TysonAndre]

I see that the graph that was built has an edge with a from_id of identity#1, but elsewhere, there's an edge to ns\identity#1 with a prefix of ns\

It also looks like there might be potential problems normalizing the case of namespace (should be consistently lowercased or uppercased to properly uniquely track?), but the lack of the prefix seems to be the main problem.

Using https://github.com/TysonAndre/psalm/compare/taint-debug?targetBranch=master to print debugging info about sources/edges

Expected: Should emit TaintedInput
Observed: Does not

<?php

namespace ns {

function identity($s) {
    return $s;
}

echo namespace\identity($_GET['userinput']);

}
/*

Sources:
$_GET:src/namespaced_taint.php:89
Edges:
From identity#1  -- this is the $from_id
-> ns\identity
From $_GET:src/namespaced_taint.php:89
-> $_GET['userinput']-src/namespaced_taint.php:89-93
From call to NS\identity-src/namespaced_taint.php:89-106
-> ns\identity#1   -- this is the $to_id
From $_GET['userinput']-src/namespaced_taint.php:89-93
-> call to NS\identity-src/namespaced_taint.php:89-106
From call to echo-src/namespaced_taint.php:70-107
-> echo#1-src/namespaced_taint.php:65
From ns\identity
-> call to echo-src/namespaced_taint.php:70-107
Sinks:
echo#1-src/namespaced_taint.php:65
 */