Merge pull request #3669 from adriaanm/rebase-3667

SI-8460 Fix regression in implicit divergence recovery

2 files changed, 30 insertions, 1 deletions

diff --git a/test/files/neg/divergent-implicit.check b/test/files/neg/divergent-implicit.check
index 60d876409f..d4a3ddfc71 100644
--- a/test/files/neg/divergent-implicit.check
+++ b/test/files/neg/divergent-implicit.check
@@ -3,6 +3,10 @@ divergent-implicit.scala:4: error: type mismatch;
  required: String
   val x1: String = 1
                    ^
+divergent-implicit.scala:5: error: diverging implicit expansion for type Int => String
+starting with method $conforms in object Predef
+  val x2: String = cast[Int, String](1)
+                                    ^
 divergent-implicit.scala:14: error: type mismatch;
  found   : Test2.Foo
  required: Test2.Bar
@@ -13,4 +17,4 @@ divergent-implicit.scala:15: error: type mismatch;
  required: Test2.Bar
   val y: Bar = new Baz
                ^
-three errors found
+four errors found
diff --git a/test/files/pos/t8460.scala b/test/files/pos/t8460.scala
new file mode 100644
index 0000000000..10d2ed432c
--- /dev/null
+++ b/test/files/pos/t8460.scala
@@ -0,0 +1,25 @@
+object tan extends UFunc {
+  implicit def ImplDouble: Impl[Double, Double] = ???
+}
+
+trait UFunc {
+  trait TC[+A]
+  type Impl[V, VR] = UFunc.UImpl[this.type, V, VR]
+}
+
+object UFunc {
+  class UImpl[A, B, C]
+  implicit def implicitDoubleUTag[Tag, V, VR](implicit conv: V=>Double, impl: UImpl[Tag, Double, VR]):UImpl[Tag, V, VR] = ???
+
+}
+
+object Test {
+  implicitly[tan.Impl[Double, Double]]
+  // we should discard the one and only divergent implicit (`implicitDoubleUTag`)
+  // This is done under `scalac-hash v2.10.4 test.scala`, but not under
+  // `scalac-hash v2.10.4 -Xdivergence211 test.scala`
+  //
+  // This seems to be because the companion implicits contain redundant entries
+  //
+
+}