From 2a2474d395afb58ef71897530ff334f4725514b4 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Sun, 11 Aug 2024 16:12:00 +0800
Subject: [PATCH] fixes #23902; Compiler infers sink in return type from auto
 (#23904)

fixes #23902
---
 compiler/semexprs.nim      | 6 +++---
 tests/destructor/tsink.nim | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 54a8440351..c1e74b4575 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -2003,7 +2003,7 @@ proc semAsgn(c: PContext, n: PNode; mode=asgnNormal): PNode =
         if rhsTyp.kind in tyUserTypeClasses and rhsTyp.isResolvedUserTypeClass:
           rhsTyp = rhsTyp.last
         if lhs.sym.typ.kind == tyAnything:
-          rhsTyp = rhsTyp.skipIntLit(c.idgen)
+          rhsTyp = rhsTyp.skipTypes({tySink}).skipIntLit(c.idgen)
         if cmpTypes(c, lhs.typ, rhsTyp) in {isGeneric, isEqual}:
           internalAssert c.config, c.p.resultSym != nil
           # Make sure the type is valid for the result variable
@@ -2825,7 +2825,7 @@ proc semTupleFieldsConstr(c: PContext, n: PNode, flags: TExprFlags; expectedType
       n[i][1].typ = errorType(c)
 
     var f = newSymS(skField, n[i][0], c)
-    f.typ = skipIntLit(n[i][1].typ, c.idgen)
+    f.typ = skipIntLit(n[i][1].typ.skipTypes({tySink}), c.idgen)
     f.position = i
     rawAddSon(typ, f.typ)
     typ.n.add newSymNode(f)
@@ -2851,7 +2851,7 @@ proc semTuplePositionsConstr(c: PContext, n: PNode, flags: TExprFlags; expectedT
       # `const foo = [(1, {}), (2, {false})]`,
       # `const foo = if true: (0, nil) else: (1, new(int))`
       n[i] = fitNode(c, expectedElemType, n[i], n[i].info)
-    addSonSkipIntLit(typ, n[i].typ, c.idgen)
+    addSonSkipIntLit(typ, n[i].typ.skipTypes({tySink}), c.idgen)
   result.typ = typ
 
 include semobjconstr
diff --git a/tests/destructor/tsink.nim b/tests/destructor/tsink.nim
index 82cbdfbe5d..e214e4cca3 100644
--- a/tests/destructor/tsink.nim
+++ b/tests/destructor/tsink.nim
@@ -14,3 +14,11 @@ proc foo = # bug #23359
   doAssert bar.value == 42
 
 foo()
+
+block: # bug #23902
+  proc foo(a: sink string): auto = (a, a)
+
+  proc bar(a: sink int): auto = return a
+
+  proc foo(a: sink string) =
+    var x = (a, a)