use control flow graph for sink params

1 files changed, 7 insertions, 3 deletions

diff --git a/tests/destructor/tmatrix.nim b/tests/destructor/tmatrix.nim
index 6ae38fc29..b89b41a4c 100644
--- a/tests/destructor/tmatrix.nim
+++ b/tests/destructor/tmatrix.nim
@@ -52,6 +52,8 @@ proc matrix*(m, n: int, s: float): Matrix =
   for i in 0 ..< m * n:
     result.data[i] = s
 
+proc len(m: Matrix): int = m.n * m.m
+
 proc `[]`*(m: Matrix, i, j: int): float {.inline.} =
   ## Get a single element.
   m.data[i * m.n + j]
@@ -73,7 +75,8 @@ proc `-`*(m: sink Matrix): Matrix =
 
 proc `+`*(a: sink Matrix; b: Matrix): Matrix =
   ## ``C = A + B``
-  assert(b.m == a.m and b.n == a.n, "Matrix dimensions must agree.")
+  doAssert(b.m == a.m and b.n == a.n, "Matrix dimensions must agree.")
+  doAssert(a.len == b.len) # non destructive use before sink is ok
   result = a
   for i in 0 ..< result.m:
     for j in 0 ..< result.n:
@@ -82,9 +85,10 @@ proc `+`*(a: sink Matrix; b: Matrix): Matrix =
 proc `-`*(a: sink Matrix; b: Matrix): Matrix =
   ## ``C = A - B``
   assert(b.m == a.m and b.n == a.n, "Matrix dimensions must agree.")
+  doAssert(a.len == b.len) # non destructive use before sink is ok
   result = a
-  for i in 0 ..< a.m:
-     for j in 0 ..< a.n:
+  for i in 0 ..< result.m:
+     for j in 0 ..< result.n:
         result[i, j] = a[i, j] - b[i, j]
 
 proc info =