diff --git a/src/cast.c b/src/cast.c
index 788f7a366974..b4b581fa5880 100644
--- a/src/cast.c
+++ b/src/cast.c
@@ -2934,6 +2934,12 @@ int typeMerge(Scope *sc, Expression *e, Type **pt, Expression **pe1, Expression
         e1 = e1->castTo(sc, t);
         e2 = e2->castTo(sc, t);
     }
+    else if (t1->ty == Tvector && t2->ty == Tvector)
+    {
+        // Bugzilla 13841, all vector types should have no common types between
+        // different vectors, even though their sizes are same.
+        goto Lincompatible;
+    }
     else if (t1->ty == Tvector && t2->ty != Tvector &&
              e2->implicitConvTo(t1))
     {
diff --git a/test/runnable/testxmm.d b/test/runnable/testxmm.d
index 68688bac350a..96cd9aa8aff2 100644
--- a/test/runnable/testxmm.d
+++ b/test/runnable/testxmm.d
@@ -7,6 +7,8 @@ import core.simd;
 import core.stdc.string;
 import std.stdio;
 
+alias TypeTuple(T...) = T;
+
 /*****************************************/
 
 void test1()
@@ -1208,6 +1210,32 @@ void test9449_2()
     assert(m[1][3] == 8);
 }
 
+/*****************************************/
+// 13841
+
+void test13841()
+{
+    alias Vector16s = TypeTuple!(
+        void16,  byte16,  short8,  int4,  long2,
+                ubyte16, ushort8, uint4, ulong2, float4, double2);
+    foreach (V1; Vector16s)
+    {
+        foreach (V2; Vector16s)
+        {
+            V1 v1 = void;
+            V2 v2 = void;
+            static if (is(V1 == V2))
+            {
+                static assert( is(typeof(true ? v1 : v2) == V1));
+            }
+            else
+            {
+                static assert(!is(typeof(true ? v1 : v2)));
+            }
+        }
+    }
+}
+
 /*****************************************/
 
 int main()