fixes #14079 [backport:1.2] (#14163)

compiler/sempass2.nim

@@ -854,7 +854,8 @@ proc track(tracked: PEffects, n: PNode) =
     when false: cstringCheck(tracked, n)
     if tracked.owner.kind != skMacro:
       createTypeBoundOps(tracked, n[0].typ, n.info)
-    checkForSink(tracked.config, tracked.owner, n[1])
+    if n[0].kind != nkSym or not isLocalVar(tracked, n[0].sym):
+      checkForSink(tracked.config, tracked.owner, n[1])
   of nkVarSection, nkLetSection:
     for child in n:
       let last = lastSon(child)

compiler/sigmatch.nim

@@ -548,7 +548,8 @@ proc allowsNilDeprecated(c: TCandidate, f: PType): TTypeRelation =
     result = isNone
 
 proc inconsistentVarTypes(f, a: PType): bool {.inline.} =
-  result = f.kind != a.kind and (f.kind in {tyVar, tyLent} or a.kind in {tyVar, tyLent})
+  result = f.kind != a.kind and
+    (f.kind in {tyVar, tyLent, tySink} or a.kind in {tyVar, tyLent, tySink})
 
 proc procParamTypeRel(c: var TCandidate, f, a: PType): TTypeRelation =
   ## For example we have:

compiler/sinkparameter_inference.nim

@@ -48,8 +48,7 @@ proc checkForSink*(config: ConfigRef; owner: PSym; arg: PNode) =
         # we only report every potential 'sink' parameter only once:
         incl arg.sym.flags, sfWasForwarded
         message(config, arg.info, hintPerformance,
-          ("could not turn '$1' to a sink parameter " &
-          "because '$2' was forward declared") % [arg.sym.name.s, owner.name.s])
+          "could not turn '$1' to a sink parameter" % [arg.sym.name.s])
       #echo config $ arg.info, " candidate for a sink parameter here"
   of nkStmtList, nkStmtListExpr, nkBlockStmt, nkBlockExpr:
     if not isEmptyType(arg.typ):