closes #3777.

no review

2 files changed, 18 insertions, 8 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Types.scala b/src/compiler/scala/tools/nsc/symtab/Types.scala
index 057bf45107..7aed4cd648 100644
--- a/src/compiler/scala/tools/nsc/symtab/Types.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Types.scala
@@ -2244,14 +2244,17 @@ A type's typeSymbol should never be inspected directly.
         if(params.isEmpty) { // type var has kind *
           addBound(tp)
           true
-        } else // higher-kinded type var with same arity as tp
-          (typeArgs.length == tp.typeArgs.length) && {
-            // register type constructor (the type without its type arguments) as bound
-            addBound(tp.typeConstructor)
-            // check subtyping of higher-order type vars
-            // use variances as defined in the type parameter that we're trying to infer (the result is sanity-checked later)
-            checkArgs(tp.typeArgs, typeArgs, params)
-          }
+        } else { // higher-kinded type var with same arity as tp
+          def unifyHK(tp: Type) =
+            (typeArgs.length == tp.typeArgs.length) && {
+              // register type constructor (the type without its type arguments) as bound
+              addBound(tp.typeConstructor)
+              // check subtyping of higher-order type vars
+              // use variances as defined in the type parameter that we're trying to infer (the result is sanity-checked later)
+              checkArgs(tp.typeArgs, typeArgs, params)
+            }
+          unifyHK(tp) || unifyHK(tp.dealias)
+        }
       }
     }
 
diff --git a/test/files/pos/t3777.scala b/test/files/pos/t3777.scala
new file mode 100644
index 0000000000..165eeebfdb
--- /dev/null
+++ b/test/files/pos/t3777.scala
@@ -0,0 +1,7 @@
+object Test {
+  type Point = Map[Symbol, String]
+  type Points = IndexedSeq[Point]
+
+  def makePoints2: Points = IndexedSeq[Point]()
+  val spoints2 = util.Random.shuffle(makePoints2)
+}