test #25849

compiler/vmgen.nim

@@ -1842,6 +1842,8 @@ proc genArrAccessOpcode(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
   if dest < 0: dest = c.getTemp(n.typ)
   if opc in {opcLdArrAddr, opcLdStrIdxAddr} and gfNodeAddr in flags:
     c.gABC(n, opc, dest, a, b)
+    if c.prc.regInfo[a].kind >= slotTempUnknown:
+      c.prc.regInfo[a].kind = slotTempPerm
   elif needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opc, cc, a, b)
@@ -1858,6 +1860,8 @@ proc genObjAccessAux(c: PCtx; n: PNode; a, b: int, dest: var TDest; flags: TGenF
   if dest < 0: dest = c.getTemp(n.typ)
   if {gfNodeAddr} * flags != {}:
     c.gABC(n, opcLdObjAddr, dest, a, b)
+    if a < c.prc.regInfo.len and c.prc.regInfo[a].kind >= slotTempUnknown:
+      c.prc.regInfo[a].kind = slotTempPerm
   elif needsRegLoad():
     var cc = c.getTemp(n.typ)
     c.gABC(n, opcLdObj, cc, a, b)

lib/system/iterators.nim

@@ -37,7 +37,7 @@ iterator mitems*[T](a: var openArray[T]): var T {.inline.} =
     yield a[i]
     unCheckedInc(i)
 
-iterator items*[IX, T](a: array[IX, T]): T {.inline.} =
+iterator items*[IX, T](a: array[IX, T]): lent2 T {.inline.} =
   ## Iterates over each item of `a`.
   when a.len > 0:
     var i = low(IX)

tests/lent/titems_array_lent.nim

@@ -0,0 +1,38 @@
+discard """
+  targets: "c cpp js"
+"""
+
+template sameAddress(a, b): bool =
+  when defined(js):
+    a == b
+  else:
+    a.unsafeAddr == b.unsafeAddr
+
+proc main() =
+  block:
+    let a = [10, 11, 12]
+    for ai in items(a):
+      doAssert sameAddress(ai, a[0])
+      break
+
+  block:
+    let a = [[1, 2], [1, 2], [1, 2]]
+    for ai in items(a):
+      doAssert sameAddress(ai[0], a[0][0])
+      break
+
+  block:
+    let s = @[(1, 2), (3, 4), (5, 6)]
+    doAssert (3, 4) in s
+
+main()
+
+static:
+  main()
+
+block: # issue #25849
+  static:
+    const key = "NIM_TESTS_TOSENV_KEY"
+    for val in ["val", "", "\xc3\x86"]:
+      let s = @[(key, "val"), (key, ""), (key, "\xc3\x86")]
+      doAssert (key, val) in s