fixes #6992

compiler/semstmts.nim

@@ -692,6 +692,12 @@ proc implicitIterator(c: PContext, it: string, arg: PNode): PNode =
     result.add arg
   result = semExprNoDeref(c, result, {efWantIterator})
 
+proc isTrivalStmtExpr(n: PNode): bool =
+  for i in 0 .. n.len-2:
+    if n[i].kind notin {nkEmpty, nkCommentStmt}:
+      return false
+  result = true
+
 proc semFor(c: PContext, n: PNode): PNode =
   result = n
   checkMinSonsLen(n, 3)
@@ -699,6 +705,9 @@ proc semFor(c: PContext, n: PNode): PNode =
   openScope(c)
   n.sons[length-2] = semExprNoDeref(c, n.sons[length-2], {efWantIterator})
   var call = n.sons[length-2]
+  if call.kind == nkStmtListExpr and isTrivalStmtExpr(call):
+    call = call.lastSon
+    n.sons[length-2] = call
   let isCallExpr = call.kind in nkCallKinds
   if isCallExpr and call[0].kind == nkSym and
       call[0].sym.magic in {mFields, mFieldPairs, mOmpParFor}:

tests/iter/titer2.nim

@@ -2,7 +2,12 @@ discard """
   output: '''true
 3
 4
-5'''
+5
+0
+1
+2
+3
+4'''
   cmd: "nim $target --gc:none --hints:on --warnings:off $options $file"
 """
 
@@ -55,3 +60,7 @@ echo "true"
 # bug #1560
 for i in @[3, 4, 5]:
   echo($i)
+
+# bug #6992
+for i in 0 ..< 5u32:
+  echo i