Fix loop tuple unpacking in templates (#11174)

* Fix loop tuple unpacking in templates

* Add test

compiler/semtempl.nim

@@ -372,7 +372,11 @@ proc semTemplBody(c: var TemplCtx, n: PNode): PNode =
     openScope(c)
     n.sons[L-2] = semTemplBody(c, n.sons[L-2])
     for i in countup(0, L - 3):
-      addLocalDecl(c, n.sons[i], skForVar)
+      if n[i].kind == nkVarTuple:
+        for j in 0 ..< sonsLen(n[i])-1:
+          addLocalDecl(c, n[i][j], skForVar)
+      else:
+        addLocalDecl(c, n.sons[i], skForVar)
     openScope(c)
     n.sons[L-1] = semTemplBody(c, n.sons[L-1])
     closeScope(c)

tests/tuples/tfortupleunpack.nim

@@ -9,6 +9,7 @@ output: '''
 @[(88, 99, 11), (88, 99, 11)]
 @[(7, 6, -28), (7, 6, -28)]
 12
+110100
 '''
 """
 
@@ -41,3 +42,11 @@ proc test[n]() =
   for (a,b) in @[(1,2)]:
     echo a,b
 test[string]()
+
+iterator tuples: (int, (int, int)) = yield (1,(10, 100))
+
+template t11164 =
+  for i, (a, b) in tuples():
+    echo i, a , b
+
+t11164()