fixes #3144

tests/metatype/tstatic_ones.nim

@@ -0,0 +1,28 @@
+discard """
+  output: "@[2, 2, 2, 2, 2]"
+"""
+
+# bug #3144
+
+type IntArray[N: static[int]] = array[N, int]
+
+proc `$`(a: IntArray): string = $(@(a))
+
+proc `+=`[N: static[int]](a: var IntArray[N], b: IntArray[N]) =
+  for i in 0 .. < N:
+    a[i] += b[i]
+
+proc zeros(N: static[int]): IntArray[N] =
+  for i in 0 .. < N:
+    result[i] = 0
+
+proc ones(N: static[int]): IntArray[N] =
+  for i in 0 .. < N:
+    result[i] = 1
+
+proc sum[N: static[int]](vs: seq[IntArray[N]]): IntArray[N] =
+  result = zeros(N)
+  for v in vs:
+    result += v
+
+echo sum(@[ones(5), ones(5)])