1 files changed, 23 insertions, 6 deletions
diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim
index 0a9de674b..75dea069f 100644
--- a/compiler/sempass2.nim
+++ b/compiler/sempass2.nim
@@ -9,9 +9,12 @@
 
 import
   intsets, ast, astalgo, msgs, renderer, magicsys, types, idents, trees,
-  wordrecg, strutils, options, guards, writetracking, lineinfos,
+  wordrecg, strutils, options, guards, lineinfos, semfold,
   modulegraphs
 
+when not defined(leanCompiler):
+  import writetracking
+
 when defined(useDfa):
   import dfa
 
@@ -48,10 +51,12 @@ type
     tags: PNode # list of tags
     bottom, inTryStmt: int
     owner: PSym
+    owner_module: PSym
     init: seq[int] # list of initialized variables
     guards: TModel # nested guards
     locked: seq[PNode] # locked locations
     gcUnsafe, isRecursive, isToplevel, hasSideEffect, inEnforcedGcSafe: bool
+    inEnforcedNoSideEffects: bool
     maxLockLevel, currLockLevel: TLockLevel
     config: ConfigRef
     graph: ModuleGraph
@@ -190,10 +195,10 @@ proc markGcUnsafe(a: PEffects; reason: PNode) =
 
 when true:
   template markSideEffect(a: PEffects; reason: typed) =
-    a.hasSideEffect = true
+    if not a.inEnforcedNoSideEffects: a.hasSideEffect = true
 else:
   template markSideEffect(a: PEffects; reason: typed) =
-    a.hasSideEffect = true
+    if not a.inEnforcedNoSideEffects: a.hasSideEffect = true
     markGcUnsafe(a, reason)
 
 proc listGcUnsafety(s: PSym; onlyWarning: bool; cycleCheck: var IntSet; conf: ConfigRef) =
@@ -562,8 +567,10 @@ proc trackOperand(tracked: PEffects, n: PNode, paramType: PType) =
   if op != nil and op.kind == tyProc and n.skipConv.kind != nkNilLit:
     internalAssert tracked.config, op.n.sons[0].kind == nkEffectList
     var effectList = op.n.sons[0]
-    let s = n.skipConv
-    if s.kind == nkSym and s.sym.kind in routineKinds:
+    var s = n.skipConv
+    if s.kind == nkCast and s[1].typ.kind == tyProc:
+      s = s[1]
+    if s.kind == nkSym and s.sym.kind in routineKinds and isNoEffectList(effectList):
       propagateEffects(tracked, n, s.sym)
     elif isNoEffectList(effectList):
       if isForwardedProc(n):
@@ -709,9 +716,13 @@ proc track(tracked: PEffects, n: PNode) =
     for i in 0 ..< safeLen(n):
       track(tracked, n.sons[i])
   of nkCallKinds:
+    if getConstExpr(tracked.owner_module, n, tracked.graph) != nil:
+      return
     # p's effects are ours too:
-    let a = n.sons[0]
+    var a = n.sons[0]
     let op = a.typ
+    if a.kind == nkCast and a[1].typ.kind == tyProc:
+      a = a[1]
     # XXX: in rare situations, templates and macros will reach here after
     # calling getAst(templateOrMacro()). Currently, templates and macros
     # are indistinguishable from normal procs (both have tyProc type) and
@@ -836,15 +847,20 @@ proc track(tracked: PEffects, n: PNode) =
     let oldLocked = tracked.locked.len
     let oldLockLevel = tracked.currLockLevel
     var enforcedGcSafety = false
+    var enforceNoSideEffects = false
     for i in 0 ..< pragmaList.len:
       let pragma = whichPragma(pragmaList.sons[i])
       if pragma == wLocks:
         lockLocations(tracked, pragmaList.sons[i])
       elif pragma == wGcSafe:
         enforcedGcSafety = true
+      elif pragma == wNosideeffect:
+        enforceNoSideEffects = true
     if enforcedGcSafety: tracked.inEnforcedGcSafe = true
+    if enforceNoSideEffects: tracked.inEnforcedNoSideEffects = true
     track(tracked, n.lastSon)
     if enforcedGcSafety: tracked.inEnforcedGcSafe = false
+    if enforceNoSideEffects: tracked.inEnforcedNoSideEffects = false
     setLen(tracked.locked, oldLocked)
     tracked.currLockLevel = oldLockLevel
   of nkTypeSection, nkProcDef, nkConverterDef, nkMethodDef, nkIteratorDef,
@@ -934,6 +950,7 @@ proc initEffects(g: ModuleGraph; effects: PNode; s: PSym; t: var TEffects) =
   t.exc = effects.sons[exceptionEffects]
   t.tags = effects.sons[tagEffects]
   t.owner = s
+  t.owner_module = s.getModule
   t.init = @[]
   t.guards.s = @[]
   t.guards.o = initOperators(g)