From f75bf972a5d8789e2e8c05301067c4f3a0b9ee5a Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Tue, 4 Jun 2024 22:51:47 +0800
Subject: [PATCH] implements rfc #435; Better effect tracking for inner
 routines

---
 compiler/ast.nim      |  3 ++-
 compiler/semdata.nim  |  2 ++
 compiler/sempass2.nim | 17 ++++++++++++++++-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/compiler/ast.nim b/compiler/ast.nim
index 4de277ba9a..cb9567c7aa 100644
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -331,7 +331,7 @@ type
     nfOpenSym # node is a captured sym but can be overriden by local symbols
 
   TNodeFlags* = set[TNodeFlag]
-  TTypeFlag* = enum   # keep below 32 for efficiency reasons (now: 47)
+  TTypeFlag* = enum   # keep below 32 for efficiency reasons (now: 48)
     tfVarargs,        # procedure has C styled varargs
                       # tyArray type represeting a varargs list
     tfNoSideEffect,   # procedure type does not allow side effects
@@ -403,6 +403,7 @@ type
     tfIsOutParam
     tfSendable
     tfImplicitStatic
+    tfTrackedProc     # used for delayedEffects
 
   TTypeFlags* = set[TTypeFlag]
 
diff --git a/compiler/semdata.nim b/compiler/semdata.nim
index 12930fecad..b74999b31f 100644
--- a/compiler/semdata.nim
+++ b/compiler/semdata.nim
@@ -168,6 +168,8 @@ type
     inUncheckedAssignSection*: int
     importModuleLookup*: Table[int, seq[int]] # (module.ident.id, [module.id])
     skipTypes*: seq[PNode] # used to skip types between passes in type section. So far only used for inheritance, sets and generic bodies.
+    delayedEffects*: Table[ItemId, seq[PSym]]
+    delayedEffectsInverted*: Table[ItemId, ItemId]
   TBorrowState* = enum
     bsNone, bsReturnNotMatch, bsNoDistinct, bsGeneric, bsNotSupported, bsMatch
 
diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim
index f611ee8fe1..1f1f130df3 100644
--- a/compiler/sempass2.nim
+++ b/compiler/sempass2.nim
@@ -1024,7 +1024,14 @@ proc trackCall(tracked: PEffects; n: PNode) =
         else:
           if laxEffects notin tracked.c.config.legacyFeatures and a.kind == nkSym and
               a.sym.kind in routineKinds:
-            propagateEffects(tracked, n, a.sym)
+            if tfTrackedProc in a.sym.typ.flags:
+              propagateEffects(tracked, n, a.sym)
+            else:
+              if a.sym.typ.itemId notin tracked.c.delayedEffects:
+                tracked.c.delayedEffects[a.sym.typ.itemId] = @[tracked.owner]
+              else:
+                tracked.c.delayedEffects[a.sym.typ.itemId].add tracked.owner
+              tracked.c.delayedEffectsInverted[tracked.owner.typ.itemId] = a.sym.typ.itemId
       else:
         mergeRaises(tracked, effectList[exceptionEffects], n)
         mergeTags(tracked, effectList[tagEffects], n)
@@ -1728,6 +1735,14 @@ proc trackProc*(c: PContext; s: PSym, body: PNode) =
   if strictNotNil in c.features and s.kind in {skProc, skFunc, skMethod, skConverter}:
     checkNil(s, body, g.config, c.idgen)
 
+  if s.typ.itemId notin c.delayedEffectsInverted:
+    s.typ.flags.incl tfTrackedProc
+
+  if s.typ.itemId in c.delayedEffects:
+    for sym in c.delayedEffects[s.typ.itemId]:
+      trackProc(c, sym, sym.ast[bodyPos])
+    # todo call track delayedEffects recursively
+
 proc trackStmt*(c: PContext; module: PSym; n: PNode, isTopLevel: bool) =
   case n.kind
   of {nkPragma, nkMacroDef, nkTemplateDef, nkProcDef, nkFuncDef,