Fix #19224 For loops over a hardcoded empty array crash the compiler (#20476)

* Fix #11684 For loops over a hardcoded empty array crash the compiler

* Update t19224.nim

(cherry picked from commit 567c3f055d)

compiler/semstmts.nim

@@ -767,6 +767,9 @@ proc semForVars(c: PContext, n: PNode; flags: TExprFlags): PNode =
   var iterAfterVarLent = iter.skipTypes({tyGenericInst, tyAlias, tyLent, tyVar})
   # n.len == 3 means that there is one for loop variable
   # and thus no tuple unpacking:
+  if iterAfterVarLent.kind == tyEmpty:
+    localError(c.config, n[^2].info, "cannot infer element type of $1" %
+               renderTree(n[^2], {renderNoComments}))
   if iterAfterVarLent.kind != tyTuple or n.len == 3:
     if n.len == 3:
       if n[0].kind == nkVarTuple:

tests/errmsgs/t19224.nim

@@ -0,0 +1,12 @@
+discard """
+cmd: "nim check --hints:off $file"
+errormsg: ""
+nimout: '''
+t19224.nim(10, 10) Error: cannot infer element type of items([])
+t19224.nim(12, 10) Error: cannot infer element type of items(@[])
+'''
+"""
+
+for _ in []: discard
+
+for _ in @[]: discard