From e3dfe1a074855065c915924fc4987edae3bd629a Mon Sep 17 00:00:00 2001
From: Timothee Cour <timothee.cour2@gmail.com>
Date: Fri, 26 Mar 2021 10:11:24 -0700
Subject: [PATCH] items(array) now returns lent T

---
 lib/system/iterators.nim |  2 +-
 tests/types/tlent.nim    | 67 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 tests/types/tlent.nim

diff --git a/lib/system/iterators.nim b/lib/system/iterators.nim
index d8af4eed56045..5c5bd8947a7f6 100644
--- a/lib/system/iterators.nim
+++ b/lib/system/iterators.nim
@@ -27,7 +27,7 @@ iterator mitems*[T](a: var openArray[T]): var T {.inline.} =
     yield a[i]
     inc(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`.
   var i = low(IX)
   if i <= high(IX):
diff --git a/tests/types/tlent.nim b/tests/types/tlent.nim
new file mode 100644
index 0000000000000..7fae4c3852d08
--- /dev/null
+++ b/tests/types/tlent.nim
@@ -0,0 +1,67 @@
+discard """
+  targets: "c cpp js"
+"""
+
+#[
+xxx move at least some of those tests to here:
+tests/lent/tbasic_lent_check.nim
+tests/lent/tlent_from_var.nim
+tests/lent/tnot_allowed_lent.nim
+tests/lent/tnot_allowed_lent2.nim
+tests/types/tlent.nim
+tests/types/tlent_var.nim
+]#
+
+type Foo = object
+  f0: int
+  f1: int
+
+proc fn1(a: auto): lent int = a[0]
+proc fn2(a: Foo): lent int = a.f0
+
+iterator it3(a: Foo): lent int =
+  yield a.f0
+
+template sameAddr(a, b): bool = 
+  when defined(js):
+    # we could probably do something smarter here
+    a == b
+  else:
+    let pa = cast[int](a.unsafeAddr)
+    let pb = cast[int](b.unsafeAddr)
+    pa == pb
+
+template main() = 
+  block:
+    let a = @[10,11,12]
+    doAssert sameAddr(a[0], fn1(a))
+  block:
+    let a = [10,11,12]
+    doAssert sameAddr(a[0], fn1(a))
+  block:
+    let a = Foo(f0: 10)
+    doAssert sameAddr(a.f0, fn2(a))
+
+  block:
+    let a = @[10,11,12]
+    for ai in items(a):
+      doAssert sameAddr(a[0], ai)
+      break
+  block:
+    let a = [10,11,12]
+    for ai in items(a):
+      doAssert sameAddr(a[0], ai)
+      break
+  block:
+    let a = [[1,2],[1,2],[1,2]]
+    for ai in items(a):
+      doAssert sameAddr(a[0][0], ai[0])
+      break
+  block:
+    let a = Foo(f0: 10)
+    for ai in it3(a):
+      doAssert sameAddr(a.f0, ai)
+      break
+
+static: main()
+main()