A stackless generator called after a later generator seeds the wrong slots

function G(a, b, c: Integer): Integer; generator; stackless;
begin yield a; yield b; yield c; end;
function H(k: Integer): Integer; generator; stackless;
var x: Integer;
begin x := k; yield x; end;
...
for v in G(1, 2, 3) do WriteLn(v);   // 1 3 0

Delete H and it prints 1 2 3. H does not have to be called.

Mechanism

With PXXDBG=a.slslot, the call site shows each argument's slot being looked up through SymGenSlot[Procs[G].Params[k].SymIdx]. By then G's scope had closed and H had reused those symbol indices, so SymGenSlot was either -1 (the fallback offset 40, inside the instance header) or H's own slot number.

Fix

AssignStacklessSlots records each declared parameter's offset per proc in ProcGenArgOff. GenArgSlotOff reads that record, and falls back to the symbol only when nothing was recorded.

Test

test/test_stackless_generator_called_after_a_later_generator.pas: a row in test-core and rows in the three cross targets. It prints 1 3 0 with v446 on x86-64, i386, aarch64 and arm32.