.forbids pragma: defining forbidden tags (#20050)

* .forbids pragma: defining illegal effects for proc types

This patch intends to define the opposite of the .tags pragma: a way to define effects which are not allowed in a proc.

* updated documentation and changelogs for the forbids pragma

* renamed notTagEffects to forbiddenEffects

* corrected issues of forbids pragma

the forbids pragma didn't handle simple restrictions properly and it also had issues with subtyping

* removed incorrect character from changelog

* added test to cover the interaction of methods and the forbids pragma

* covering the interaction of the tags and forbids pragmas

* updated manual about the forbids pragma

* removed useless statement

* corrected the subtyping of proc types using the forbids pragma

* updated manual for the forbids pragma

* updated documentations for forbids pragma

* updated nim docs

* updated docs with rsttester.nim

* regenerated documentation

* updated rst docs

* Update changelog.md

Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>

* updated changelog

* corrected typo

Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/tests/effects/teffects12.nim b/tests/effects/teffects12.nim
new file mode 100644
index 000000000..5f5499c38
--- /dev/null
+++ b/tests/effects/teffects12.nim
@@ -0,0 +1,52 @@
+discard """
+action: compile
+"""
+
+import std/locks
+
+type
+  Test2Effect* = object
+  Test2* = object
+    value2*: int
+  Test1Effect* = object
+  Test1* = object
+    value1*: int
+  Main* = object
+    test1Lock: Lock
+    test1: Test1
+    test2Lock: Lock
+    test2: Test2
+
+proc `=copy`(obj1: var Test2, obj2: Test2) {.error.}
+proc `=copy`(obj1: var Test1, obj2: Test1) {.error.}
+proc `=copy`(obj1: var Main, obj2: Main) {.error.}
+
+proc withTest1(main: var Main,
+               fn: proc(test1: var Test1) {.gcsafe, forbids: [Test1Effect].}) {.gcsafe, tags: [Test1Effect, RootEffect].} =
+  withLock(main.test1Lock):
+    fn(main.test1)
+
+proc withTest2(main: var Main,
+               fn: proc(test1: var Test2) {.gcsafe, forbids: [Test2Effect].}) {.gcsafe, tags: [Test2Effect, RootEffect].} =
+  withLock(main.test2Lock):
+    fn(main.test2)
+
+proc newMain(): Main =
+  var test1lock: Lock
+  initLock(test1Lock)
+  var test2lock: Lock
+  initLock(test2Lock)
+  var main = Main(test1Lock: move(test1Lock), test1: Test1(value1: 1),
+                  test2Lock: move(test2Lock), test2: Test2(value2: 2))
+  main.withTest1(proc(test1: var Test1) = test1.value1 += 1)
+  main.withTest2(proc(test2: var Test2) = test2.value2 += 1)
+  move main
+
+var main = newMain()
+main.withTest1(proc(test1: var Test1) =
+  test1.value1 += 1
+  main.withTest2(proc(test2: var Test2) = test2.value2 += 1)
+)
+
+main.withTest1(proc(test1: var Test1) {.tags: [].} = echo $test1.value1)
+main.withTest2(proc(test2: var Test2) {.tags: [].} = echo $test2.value2)