1 files changed, 15 insertions, 0 deletions
diff --git a/tests/effects/teffects14.nim b/tests/effects/teffects14.nim
new file mode 100644
index 000000000..6291d9569
--- /dev/null
+++ b/tests/effects/teffects14.nim
@@ -0,0 +1,15 @@
+discard """
+action: compile
+errormsg: "func1() has an illegal effect: IO"
+line: 15
+"""
+
+type IO = object ## input/output effect
+proc func1(): string {.tags: [IO].} = discard
+proc func2(): string = discard
+
+proc no_IO_please() {.forbids: [IO].} =
+  # this is OK because it didn't define any tag:
+  discard func2()
+  # the compiler prevents this:
+  let y = func1()