fixes #11958 (#12013)

tests/misc/tlocals.nim

@@ -1,5 +1,7 @@
 discard """
-  output: '''(x: "string here", a: 1)'''
+  output: '''(x: "string here", a: 1)
+b is 5
+x is 12'''
 """
 
 proc simple[T](a: T) =
@@ -28,3 +30,35 @@ proc test(baz: int, qux: var int): int =
 
 var x1 = 456
 discard test(123, x1)
+
+# bug #11958
+proc foo() =
+  var a = 5
+  proc bar() {.nimcall.} =
+    var b = 5
+    for k, v in fieldpairs(locals()):
+      echo k, " is ", v
+
+  bar()
+foo()
+
+
+proc foo2() =
+  var a = 5
+  proc bar2() {.nimcall.} =
+    for k, v in fieldpairs(locals()):
+      echo k, " is ", v
+
+  bar2()
+foo2()
+
+
+proc foo3[T](y: T) =
+  var a = 5
+  proc bar2[T](x: T) {.nimcall.} =
+    for k, v in fieldpairs(locals()):
+      echo k, " is ", v
+
+  bar2(y)
+
+foo3(12)