allow replacing captured syms in macro calls in generics (#23091)

fixes #22605, separated from #22744

This marks symbol captures in macro calls in generic contexts as
`nfOpenSym`, which means if there is a new symbol in the local
instantiatied body during instantiation time, this symbol replaces the
captured symbol. We have to be careful not to consider symbols outside
of the instantiation body during instantiation, because this will leak
symbols from the instantiation context scope rather than the original
declaration scope. This is done by checking if the local context owner
(maybe should be the symbol of the proc currently getting instantiated
instead? not sure how to get this) is the same as or a parent owner of
the owner of the replacement candidate symbol.

This solution is distinct from the symchoice mechanisms which we
originally assumed had to be related, if this assumption was wrong it
would explain why this solution took so long to arrive at.

1 files changed, 6 insertions, 4 deletions

diff --git a/compiler/ic/ic.nim b/compiler/ic/ic.nim
index e85621910..c9f546c76 100644
--- a/compiler/ic/ic.nim
+++ b/compiler/ic/ic.nim
@@ -433,11 +433,11 @@ proc addModuleRef(n: PNode; ir: var PackedTree; c: var PackedEncoder; m: var Pac
   let info = n.info.toPackedInfo(c, m)
   if n.typ != n.sym.typ:
     ir.addNode(kind = nkModuleRef, operand = 3.int32, # spans 3 nodes in total
-               info = info,
+               info = info, flags = n.flags,
                typeId = storeTypeLater(n.typ, c, m))
   else:
     ir.addNode(kind = nkModuleRef, operand = 3.int32, # spans 3 nodes in total
-              info = info)
+              info = info, flags = n.flags)
   ir.addNode(kind = nkNone, info = info,
              operand = toLitId(n.sym.itemId.module.FileIndex, c, m).int32)
   ir.addNode(kind = nkNone, info = info,
@@ -829,7 +829,8 @@ proc loadNodes*(c: var PackedDecoder; g: var PackedModuleGraph; thisModule: int;
     result.ident = getIdent(c.cache, g[thisModule].fromDisk.strings[n.litId])
   of nkSym:
     result.sym = loadSym(c, g, thisModule, PackedItemId(module: LitId(0), item: tree[n].soperand))
-    if result.typ == nil: result.typ = result.sym.typ
+    if result.typ == nil and nfOpenSym notin result.flags:
+      result.typ = result.sym.typ
   of externIntLit:
     result.intVal = g[thisModule].fromDisk.numbers[n.litId]
   of nkStrLit..nkTripleStrLit:
@@ -842,7 +843,8 @@ proc loadNodes*(c: var PackedDecoder; g: var PackedModuleGraph; thisModule: int;
     assert n2.kind == nkNone
     transitionNoneToSym(result)
     result.sym = loadSym(c, g, thisModule, PackedItemId(module: n1.litId, item: tree[n2].soperand))
-    if result.typ == nil: result.typ = result.sym.typ
+    if result.typ == nil and nfOpenSym notin result.flags:
+      result.typ = result.sym.typ
   else:
     for n0 in sonsReadonly(tree, n):
       result.addAllowNil loadNodes(c, g, thisModule, tree, n0)