From c14427dbf38ffe573c838a452b9187c44d063145 Mon Sep 17 00:00:00 2001
From: Andreas Rumpf <rumpf_a@web.de>
Date: Sat, 8 May 2021 16:47:06 +0200
Subject: [PATCH] ORC: cursor inference bugfix (#17973)

* fixed a .cursor inference bug

* added a test case
---
 compiler/varpartitions.nim   |  4 +--
 lib/pure/asyncfutures.nim    |  4 +--
 tests/arc/topt_no_cursor.nim | 47 +++++++++++++++++++++++++++++++++++-
 3 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/compiler/varpartitions.nim b/compiler/varpartitions.nim
index 7bb626c0a..810ce8586 100644
--- a/compiler/varpartitions.nim
+++ b/compiler/varpartitions.nim
@@ -695,7 +695,7 @@ proc traverse(c: var Partitions; n: PNode) =
               # 'paramType[0]' is still a view type, this is not a typo!
               if directViewType(paramType[0]) == noView and classifyViewType(paramType[0]) != noView:
                 borrowingCall(c, paramType[0], n, i)
-        elif borrowChecking in c.goals and m == mNone:
+        elif m == mNone:
           potentialMutationViaArg(c, n[i], parameters)
 
   of nkAddr, nkHiddenAddr:
@@ -921,4 +921,4 @@ proc computeCursors*(s: PSym; n: PNode; g: ModuleGraph) =
         discard "cannot cursor into a graph that is mutated"
       else:
         v.sym.flags.incl sfCursor
-        #echo "this is now a cursor ", v.sym, " ", par.s[rid].flags, " ", config $ v.sym.info
+        #echo "this is now a cursor ", v.sym, " ", par.s[rid].flags, " ", g.config $ v.sym.info
diff --git a/lib/pure/asyncfutures.nim b/lib/pure/asyncfutures.nim
index fd62b2703..0178ee4d6 100644
--- a/lib/pure/asyncfutures.nim
+++ b/lib/pure/asyncfutures.nim
@@ -362,9 +362,9 @@ proc read*[T](future: Future[T] | FutureVar[T]): T =
   ##
   ## If the result of the future is an error then that error will be raised.
   when future is Future[T]:
-    let fut = future
+    let fut {.cursor.} = future
   else:
-    let fut = Future[T](future)
+    let fut {.cursor.} = Future[T](future)
   if fut.finished:
     if fut.error != nil:
       injectStacktrace(fut)
diff --git a/tests/arc/topt_no_cursor.nim b/tests/arc/topt_no_cursor.nim
index f1eb8575a..06cc4eda8 100644
--- a/tests/arc/topt_no_cursor.nim
+++ b/tests/arc/topt_no_cursor.nim
@@ -8,7 +8,7 @@ doing shady stuff...
 192.168.0.1
 192.168.0.1
 192.168.0.1'''
-  cmd: '''nim c --gc:arc --expandArc:newTarget --expandArc:delete --expandArc:p1 --expandArc:tt --hint:Performance:off --assertions:off --expandArc:extractConfig $file'''
+  cmd: '''nim c --gc:arc --expandArc:newTarget --expandArc:delete --expandArc:p1 --expandArc:tt --hint:Performance:off --assertions:off --expandArc:extractConfig --expandArc:mergeShadowScope $file'''
   nimout: '''--expandArc: newTarget
 
 var
@@ -108,6 +108,25 @@ try:
           `=destroy`(splitted)
 finally:
   `=destroy_1`(lan_ip)
+--expandArc: mergeShadowScope
+
+var shadowScope
+`=copy`(shadowScope, c.currentScope)
+rawCloseScope(c)
+block :tmp:
+  var sym
+  var i = 0
+  let L = len(shadowScope.symbols)
+  block :tmp_1:
+    while i < L:
+      var :tmpD
+      sym = shadowScope.symbols[i]
+      addInterfaceDecl(c):
+        wasMoved(:tmpD)
+        `=copy_1`(:tmpD, sym)
+        :tmpD
+      inc(i, 1)
+`=destroy`(shadowScope)
 -- end of expandArc ------------------------'''
 """
 
@@ -277,3 +296,29 @@ proc extractConfig() =
     echo splitted[1] # Without this line everything works
 
 extractConfig()
+
+
+type
+  Symbol = ref object
+    name: string
+
+  Scope = ref object
+    parent: Scope
+    symbols: seq[Symbol]
+
+  PContext = ref object
+    currentScope: Scope
+
+proc rawCloseScope(c: PContext) =
+  c.currentScope = c.currentScope.parent
+
+proc addInterfaceDecl(c: PContext; s: Symbol) =
+  c.currentScope.symbols.add s
+
+proc mergeShadowScope*(c: PContext) =
+  let shadowScope = c.currentScope
+  c.rawCloseScope
+  for sym in shadowScope.symbols:
+    c.addInterfaceDecl(sym)
+
+mergeShadowScope(PContext(currentScope: Scope(parent: Scope())))