From 057d5789ba6cf7e1f0cef681ffba77b0c4788110 Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Sat, 7 Oct 2017 22:17:16 +0300
Subject: [PATCH] fix #6277

---
 compiler/ccgexprs.nim        |  2 +-
 tests/concepts/titerable.nim | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 tests/concepts/titerable.nim

diff --git a/compiler/ccgexprs.nim b/compiler/ccgexprs.nim
index dd526c5fb..da92b281e 100644
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
@@ -849,7 +849,7 @@ proc genArrayElem(p: BProc, n, x, y: PNode, d: var TLoc) =
   var a, b: TLoc
   initLocExpr(p, x, a)
   initLocExpr(p, y, b)
-  var ty = skipTypes(skipTypes(a.t, abstractVarRange), abstractPtrs)
+  var ty = skipTypes(a.t, abstractVarRange + abstractPtrs + tyUserTypeClasses)
   var first = intLiteral(firstOrd(ty))
   # emit range check:
   if optBoundsCheck in p.options and tfUncheckedArray notin ty.flags:
diff --git a/tests/concepts/titerable.nim b/tests/concepts/titerable.nim
new file mode 100644
index 000000000..b18658b2a
--- /dev/null
+++ b/tests/concepts/titerable.nim
@@ -0,0 +1,20 @@
+discard """
+  nimout: "int\nint"
+  output: 15
+"""
+
+import typetraits
+
+type
+  Iterable[T] = concept x
+    for value in x:
+      type(value) is T
+
+proc sum*[T](iter: Iterable[T]): T =
+  static: echo T.name
+  for element in iter:
+    static: echo element.type.name
+    result += element
+
+echo sum([1, 2, 3, 4, 5])
+