core/array: fix implementation of naive copy_to to avoid overwriting

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/core/collection/array.nit b/lib/core/collection/array.nit
index 0896bab..e8f57c0 100644 (file)
--- a/lib/core/collection/array.nit
+++ b/lib/core/collection/array.nit
@@ -112,10 +112,18 @@ abstract class AbstractArrayRead[E]
        fun copy_to(start: Int, len: Int, dest: AbstractArray[E], new_start: Int)
        do
                # TODO native one
-               var i = len
-               while i > 0 do
-                       i -= 1
-                       dest[new_start+i] = self[start+i]
+               if start < new_start then
+                       var i = len
+                       while i > 0 do
+                               i -= 1
+                               dest[new_start+i] = self[start+i]
+                       end
+               else
+                       var i = 0
+                       while i < len do
+                               dest[new_start+i] = self[start+i]
+                               i += 1
+                       end
                end
        end