diff --git a/src/library/scala/collection/mutable/ArraySeq.scala b/src/library/scala/collection/mutable/ArraySeq.scala
index f64b26b05e6c..bc1e706e2c98 100644
--- a/src/library/scala/collection/mutable/ArraySeq.scala
+++ b/src/library/scala/collection/mutable/ArraySeq.scala
@@ -245,7 +245,7 @@ object ArraySeq extends StrictOptimizedClassTagSeqFactory[ArraySeq] { self =>
           while (i < len) {
             jsb.append(sep)
             jsb.append(array(i))
-            i += i
+            i += 1
           }
         }
       }
diff --git a/test/junit/scala/collection/mutable/ArraySeqTest.scala b/test/junit/scala/collection/mutable/ArraySeqTest.scala
index 4286e803858d..07b3aa8ec6c8 100644
--- a/test/junit/scala/collection/mutable/ArraySeqTest.scala
+++ b/test/junit/scala/collection/mutable/ArraySeqTest.scala
@@ -74,6 +74,13 @@ class ArraySeqTest {
     assertOfRef(Array(Int.box(65)), Array(Char.box('A')))
     assertOfRef(Array(Char.box('A')), Array(Int.box(65)))
   }
+
+  @Test
+  def t11583(): Unit = {
+    assertEquals("1 2 3 4 5 6 7", ArraySeq('1', '2', '3', '4', '5', '6', '7').mkString(" "))
+    // this wraps as `ArraySeq` via `Predef`
+    assertEquals("1 2 3 4 5 6 7", Array('1', '2', '3', '4', '5', '6', '7').mkString(" "))
+  }
 }
 
 /*