make tests green again

tests/effects/teffects3.nim

@@ -9,7 +9,7 @@ type
     a, b, c: string
     fn: proc (): int {.tags: [].}
 
-  EIO2 = ref object of EIO
+
 
 proc raiser(): int {.tags: [TObj, WriteIoEffect].} =
   writeLine stdout, "arg"

tests/effects/teffects4.nim

@@ -9,7 +9,7 @@ type
     a, b, c: string
     fn: proc (): int {.tags: [ReadIOEffect].}
 
-  EIO2 = ref object of EIO
+
 
 proc q() {.tags: [IoEffect].} =
   discard

tests/effects/teffects6.nim

@@ -20,8 +20,8 @@ proc noRaise(x: proc()) {.raises: [].} =
   # unknown call that might raise anything, but valid:
   x()
 
-proc doRaise() {.raises: [EIO].} =
-  raise newException(EIO, "IO")
+proc doRaise() {.raises: [IoError].} =
+  raise newException(IoError, "IO")
 
 proc use*() =
   noRaise(doRaise)