From 9c6de08db074dfd41ef4671f99086c1b53a8b540 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Sat, 31 Aug 2013 16:45:10 +0200
Subject: [PATCH] fixes #516

---
 compiler/semcall.nim            |  9 ++++++---
 tests/reject/tinvalidborrow.nim | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)
 create mode 100644 tests/reject/tinvalidborrow.nim

diff --git a/compiler/semcall.nim b/compiler/semcall.nim
index 735e6fac8e..a29efcd8ac 100644
--- a/compiler/semcall.nim
+++ b/compiler/semcall.nim
@@ -207,11 +207,14 @@ proc SearchForBorrowProc(c: PContext, startScope: PScope, fn: PSym): PSym =
   # New approach: generate fn(x, y, z) where x, y, z have the proper types
   # and use the overloading resolution mechanism:
   var call = newNode(nkCall)
+  var hasDistinct = false
   call.add(newIdentNode(fn.name, fn.info))
   for i in 1.. <fn.typ.n.len:
     let param = fn.typ.n.sons[i]
     let t = skipTypes(param.typ, abstractVar-{tyTypeDesc})
+    if t.kind == tyDistinct or param.typ.kind == tyDistinct: hasDistinct = true
     call.add(newNodeIT(nkEmpty, fn.info, t.baseOfDistinct))
-  var resolved = semOverloadedCall(c, call, call, {fn.kind})
-  if resolved != nil:
-    result = resolved.sons[0].sym
+  if hasDistinct:
+    var resolved = semOverloadedCall(c, call, call, {fn.kind})
+    if resolved != nil:
+      result = resolved.sons[0].sym
diff --git a/tests/reject/tinvalidborrow.nim b/tests/reject/tinvalidborrow.nim
new file mode 100644
index 0000000000..9ab9e8d645
--- /dev/null
+++ b/tests/reject/tinvalidborrow.nim
@@ -0,0 +1,17 @@
+discard """
+  line: 11
+  errormsg: "no symbol to borrow from found"
+"""
+
+# bug #516
+
+type
+  TAtom = culong
+
+proc `==`*(a, b: TAtom): bool {.borrow.}
+
+var
+  d, e: TAtom
+
+echo( $(d == e) )
+