fixes #2257

tests/parallel/tarray_of_channels.nim

@@ -0,0 +1,26 @@
+# bug #2257
+import threadpool
+
+type StringChannel = TChannel[string]
+var channels: array[1..3, StringChannel]
+
+type
+  MyObject[T] = object
+    x: T
+
+var global: MyObject[string]
+var globalB: MyObject[float]
+
+proc consumer(ix : int) {.thread.} =
+  echo channels[ix].recv() ###### not GC-safe: 'channels'
+  echo globalB
+
+proc main =
+  for ix in 1..3: channels[ix].open()
+  for ix in 1..3: spawn consumer(ix)
+  for ix in 1..3: channels[ix].send("test")
+  sync()
+  for ix in 1..3: channels[ix].close()
+
+when isMainModule:
+  main()

tests/parallel/tgc_unsafe.nim

@@ -0,0 +1,32 @@
+discard """
+  errormsg: "'consumer' is not GC-safe"
+  line: 19
+"""
+
+# bug #2257
+import threadpool
+
+type StringChannel = TChannel[string]
+var channels: array[1..3, StringChannel]
+
+type
+  MyObject[T] = object
+    x: T
+
+var global: MyObject[string]
+var globalB: MyObject[float]
+
+proc consumer(ix : int) {.thread.} =
+  echo channels[ix].recv() ###### not GC-safe: 'channels'
+  echo global
+  echo globalB
+
+proc main =
+  for ix in 1..3: channels[ix].open()
+  for ix in 1..3: spawn consumer(ix)
+  for ix in 1..3: channels[ix].send("test")
+  sync()
+  for ix in 1..3: channels[ix].close()
+
+when isMainModule:
+  main()