deprecate `do:` meaning `do ():` + misc cleanup (#20927)

* test disable do: block lambda lifting

* fix last test [skip ci]

* deprecate `do:` meaning `do ():` + misc cleanup

closes https://github.com/nim-lang/RFCs/issues/486

* oops

* fix

* no idea what could be causing nimsuggest failure other than this

* ensure ci works

3 files changed, 17 insertions, 8 deletions

diff --git a/tests/closure/tclosure.nim b/tests/closure/tclosure.nim
index 1bbe4cd0d..fa1f79ffe 100644
--- a/tests/closure/tclosure.nim
+++ b/tests/closure/tclosure.nim
@@ -239,19 +239,19 @@ block doNotation:
   b.onClick do (e: Event):
     echo "click at ", e.x, ",", e.y
 
-  b.onFocusLost:
+  b.onFocusLost do ():
     echo "lost focus 1"
 
-  b.onFocusLost do:
+  b.onFocusLost do ():
     echo "lost focus 2"
 
-  b.onUserEvent("UserEvent 1") do:
+  b.onUserEvent("UserEvent 1") do ():
     discard
 
-  b.onUserEvent "UserEvent 2":
+  onUserEvent(b, "UserEvent 2") do ():
     discard
 
-  b.onUserEvent("UserEvent 3"):
+  b.onUserEvent("UserEvent 3") do ():
     discard
 
   b.onUserEvent("UserEvent 4", () => echo "event 4")
diff --git a/tests/closure/tclosure_issues.nim b/tests/closure/tclosure_issues.nim
index 4688834de..b1a2d7c6b 100644
--- a/tests/closure/tclosure_issues.nim
+++ b/tests/closure/tclosure_issues.nim
@@ -71,12 +71,12 @@ block tissue7104:
   proc sp(cb: proc())=
       cb()
 
-  sp:
+  sp do ():
       var i = 0
       echo "ok ", i
-      sp():
+      sp do ():
           inc i
           echo "ok ", i
-          sp do:
+          sp do ():
               inc i
               echo "ok ", i
diff --git a/tests/closure/tstmtlist.nim b/tests/closure/tstmtlist.nim
new file mode 100644
index 000000000..6a1390617
--- /dev/null
+++ b/tests/closure/tstmtlist.nim
@@ -0,0 +1,9 @@
+discard """
+  action: compile
+"""
+
+proc foo(x: proc()) = x()
+foo: echo "a" #[tt.Warning
+     ^ statement list expression assumed to be anonymous proc; this is deprecated, use `do (): ...` or `proc () = ...` instead [StmtListLambda]]#
+foo do: echo "b" #[tt.Warning
+        ^ statement list expression assumed to be anonymous proc; this is deprecated, use `do (): ...` or `proc () = ...` instead [StmtListLambda]]#