Add test for #1877

tests/static/tmatrix.nim

@@ -0,0 +1,19 @@
+discard """
+  output: "111"
+"""
+
+type Matrix[M,N: static[int]] = array[M, array[N, float]]
+
+let a = [[1.0,  1.0,  1.0,   1.0],
+         [2.0,  4.0,  8.0,  16.0],
+         [3.0,  9.0, 27.0,  81.0],
+         [4.0, 16.0, 64.0, 256.0]]
+
+proc `$`(m: Matrix): string =
+  result = ""
+
+proc `*`[M,N,M2,N2](a: Matrix[M,N2]; b: Matrix[M2,N]): Matrix[M,N] =
+  discard
+
+echo a * a
+