[backport] Handle nkOpenSymChoice for nkAccQuoted in considerQuotedIdent (#20578)

* Handle nkOpenSymChoice for nkAccQuoted in considerQuotedIdent

* Add test

* Update compiler/lookups.nim

Co-authored-by: SirOlaf <a>
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

compiler/lookups.nim

@@ -48,6 +48,11 @@ proc considerQuotedIdent*(c: PContext; n: PNode, origin: PNode = nil): PIdent =
         case x.kind
         of nkIdent: id.add(x.ident.s)
         of nkSym: id.add(x.sym.name.s)
+        of nkSymChoices:
+          if x[0].kind == nkSym:
+            id.add(x[0].sym.name.s)
+          else:
+            handleError(n, origin)
         of nkLiterals - nkFloatLiterals: id.add(x.renderTree)
         else: handleError(n, origin)
       result = getIdent(c.cache, id)

tests/template/template_various.nim

@@ -353,3 +353,18 @@ block gensym3:
   echo a ! b ! c ! d
   echo a ! b ! c ! d ! e
   echo x,y,z
+
+
+block identifier_construction_with_overridden_symbol:
+  # could use add, but wanna make sure it's an override no matter what
+  func examplefn = discard
+  func examplefn(x: int) = discard
+
+  # the function our template wants to use
+  func examplefn1 = discard
+
+  template exampletempl(n) =
+    # attempt to build a name using the overridden symbol "examplefn"
+    `examplefn n`()
+
+  exampletempl(1)