fixes #24033; Yielding from var fails with pairs and destructuring (#…

…24046)

fixes #24033

compiler/transf.nim

@@ -410,9 +410,15 @@ proc transformYield(c: PTransf, n: PNode): PNode =
       result.add transform(c, v)
 
       for i in 0..<c.transCon.forStmt.len - 2:
-        let lhs = c.transCon.forStmt[i]
-        let rhs = transform(c, newTupleAccess(c.graph, tmp, i))
-        result.add(asgnTo(lhs, rhs))
+        if c.transCon.forStmt[i].kind == nkVarTuple:
+          for j in 0..<c.transCon.forStmt[i].len-1:
+            let lhs = c.transCon.forStmt[i][j]
+            let rhs = transform(c, newTupleAccess(c.graph, newTupleAccess(c.graph, tmp, i), j))
+            result.add(asgnTo(lhs, rhs))
+        else:
+          let lhs = c.transCon.forStmt[i]
+          let rhs = transform(c, newTupleAccess(c.graph, tmp, i))
+          result.add(asgnTo(lhs, rhs))
     else:
       for i in 0..<c.transCon.forStmt.len - 2:
         let lhs = c.transCon.forStmt[i]

tests/iter/titer_issues.nim

@@ -392,3 +392,19 @@ iterator tryFinally() {.closure.} =
 
 var x = tryFinally
 x()
+
+block: # bug #24033
+  type Query = ref object
+
+  iterator pairs(query: Query): (int, (string, float32)) =
+    var output: (int, (string, float32)) = (0, ("foo", 3.14))
+    for id in @[0, 1, 2]:
+      output[0] = id
+      yield output
+
+  var collections: seq[(int, string, string)]
+
+  for id, (str, num) in Query():
+    collections.add (id, str, $num)
+
+  doAssert collections[1] == (1, "foo", "3.14")