Fixes #8243 (#8904)

compiler/closureiters.nim

@@ -712,6 +712,25 @@ proc lowerStmtListExprs(ctx: var Ctx, n: PNode, needsSplit: var bool): PNode =
 
       result.add(n)
 
+  of nkBracketExpr:
+    var lhsNeedsSplit = false
+    var rhsNeedsSplit = false
+    n[0] = ctx.lowerStmtListExprs(n[0], lhsNeedsSplit)
+    n[1] = ctx.lowerStmtListExprs(n[1], rhsNeedsSplit)
+    if lhsNeedsSplit or rhsNeedsSplit:
+      needsSplit = true
+      result = newNodeI(nkStmtListExpr, n.info)
+      if lhsNeedsSplit:
+        let (st, ex) = exprToStmtList(n[0])
+        result.add(st)
+        n[0] = ex
+
+      if rhsNeedsSplit:
+        let (st, ex) = exprToStmtList(n[1])
+        result.add(st)
+        n[1] = ex
+      result.add(n)
+
   of nkWhileStmt:
     var ns = false
 

tests/iter/tyieldintry.nim

@@ -416,5 +416,28 @@ block: #8851
 
   test(it, 1)
 
+block: # 8243
+  iterator it(): int {.closure.} =
+    template yieldAndSeq: seq[int] =
+      yield 1
+      @[123, 5, 123]
+
+    checkpoint(yieldAndSeq[1])
+
+  test(it, 1, 5)
+
+block:
+  iterator it(): int {.closure.} =
+    template yieldAndSeq: seq[int] =
+      yield 1
+      @[123, 5, 123]
+
+    template yieldAndNum: int =
+      yield 2
+      1
+
+    checkpoint(yieldAndSeq[yieldAndNum])
+
+  test(it, 1, 2, 5)
 
 echo "ok"