1 files changed, 175 insertions, 0 deletions
diff --git a/tests/discard/tdiscardable.nim b/tests/discard/tdiscardable.nim
new file mode 100644
index 000000000..84b669ed8
--- /dev/null
+++ b/tests/discard/tdiscardable.nim
@@ -0,0 +1,175 @@
+discard """
+output: '''
+tdiscardable
+1
+1
+something defered
+something defered
+hi
+'''
+"""
+
+echo "tdiscardable"
+
+# Test the discardable pragma
+
+proc p(x, y: int): int {.discardable.} =
+  return x + y
+
+# test that it is inherited from generic procs too:
+proc q[T](x, y: T): T {.discardable.} =
+  return x + y
+
+
+p(8, 2)
+q[float](0.8, 0.2)
+
+# bug #942
+
+template maybeMod(x: SomeInteger, module: Natural): untyped =
+  if module > 0: x mod module
+  else: x
+
+proc foo(b: int):int =
+  var x = 1
+  result = x.maybeMod(b) # Works fine
+
+proc bar(b: int):int =
+  result = 1
+  result = result.maybeMod(b) # Error: value returned by statement has to be discarded
+
+echo foo(0)
+echo bar(0)
+
+# bug #9726
+
+proc foo: (proc: int) =
+  proc bar: int = 1
+  return bar
+
+discard foo()
+
+# bug #10842
+
+proc myDiscardable(): int {.discardable.} =
+  discard
+
+proc main1() =
+  defer:
+    echo "something defered"
+  discard myDiscardable()
+
+proc main2() =
+  defer:
+    echo "something defered"
+  myDiscardable()
+
+main1()
+main2()
+
+block: # bug #13583
+  block:
+    proc hello(): int {.discardable.} = 12
+
+    iterator test(): int {.closure.} =
+      while true:
+        hello()
+
+    let t = test
+
+  block:
+    proc hello(): int {.discardable.} = 12
+
+    iterator test(): int {.closure.} =
+      while true:
+        block:
+          yield 12
+          hello()
+
+    let t = test
+    doAssert t() == 12
+
+  block:
+    proc hello(): int {.discardable.} = 12
+
+    iterator test(): int {.closure.} =
+      while true:
+        yield 12
+        hello()
+
+    let t = test
+    doAssert t() == 12
+
+block:
+  proc bar(): string {.discardable.} =
+    "15"
+
+  proc foo(): int =
+    while true:
+      raise newException(ValueError, "check")
+    12
+
+  doAssertRaises(ValueError):
+    doAssert foo() == 12
+
+block: # issue #10440
+  proc x(): int {.discardable.} = discard
+  try:
+    x()
+  finally:
+    echo "hi"
+
+import macros
+
+block: # issue #14665
+  macro test(): untyped =   
+    let b = @[1, 2, 3, 4]
+
+    result = nnkStmtList.newTree()
+    var i = 0
+    while i < b.len:
+      if false:
+        # this quote do is mandatory, removing it fixes the problem
+        result.add quote do:
+          let testtest = 5
+      else:
+        result.add quote do:
+          let test = 6
+        inc i
+        # removing this continue fixes the problem too
+        continue
+      inc i
+  test()
+
+block: # bug #23775
+  proc retInt(): int {.discardable.} =
+    42
+
+  proc retString(): string {.discardable.} =
+    "text"
+
+  type
+    Enum = enum
+      A, B, C, D
+
+  proc doStuff(msg: Enum) =
+    case msg:
+    of A:
+      retString()
+    of B:
+      retInt()
+    of C:
+      discard retString()
+    else:
+      let _ = retString()
+
+  doStuff(C)
+
+block:
+  proc test(): (int, int) {.discardable.} =
+    discard
+
+  if true:
+    test()
+  else:
+    quit()