1 files changed, 26 insertions, 0 deletions
diff --git a/tests/generics/tbadcache.nim b/tests/generics/tbadcache.nim
new file mode 100644
index 000000000..33e65be3a
--- /dev/null
+++ b/tests/generics/tbadcache.nim
@@ -0,0 +1,26 @@
+# issue #16128
+
+import std/[tables, hashes]
+
+type
+  NodeId*[L] = object
+    isSource: bool
+    index: Table[NodeId[L], seq[NodeId[L]]]
+
+func hash*[L](id: NodeId[L]): Hash = discard
+func `==`[L](a, b: NodeId[L]): bool = discard
+
+proc makeIndex*[T, L](tree: T) =
+  var parent = NodeId[L]()
+  var tmp: Table[NodeId[L], seq[NodeId[L]]]
+  tmp[parent] = @[parent]
+
+proc simpleTreeDiff*[T, L](source, target: T) =
+  # Swapping these two lines makes error disappear
+  var m: Table[NodeId[L], NodeId[L]]
+  makeIndex[T, L](target)
+
+var tmp: Table[string, seq[string]] # removing this forward declaration also removes error
+
+proc diff(x1, x2: string): auto =
+  simpleTreeDiff[int, string](12, 12)