add tests from scala/test/files/{pos,neg}

with explicit Unit return type

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/untried/pos/t4692.scala b/tests/untried/pos/t4692.scala
new file mode 100644
index 000000000..2ed98a6ee
--- /dev/null
+++ b/tests/untried/pos/t4692.scala
@@ -0,0 +1,27 @@
+class TypeAliasVsImplicitTest {
+
+    class For[m[_], a](x: m[a]) {
+       def map[b](y: a => b): m[b] = throw new Error
+    }
+    implicit def toFor[m[_], a](x: m[a]): For[m, a] = new For[m, a](x)
+
+    trait MyList[A]
+
+    def foo(xs: MyList[Int]) = xs.map(x => x) // compiles fine.
+
+    type MyListOfInt = MyList[Int]
+    def bar(xs: MyListOfInt) = xs.map(x => x) // doesn't compile: value map is not a member of TypeAliasVsImplicitTest.this.MyListOfInt
+}
+
+// minimal case -- the bug was in type constructor inference where `xs.type` needed to be widened *and* dealiased
+// in 2.8.1 implicit conversion search started with a widened type, so that combo never came up
+// object Test {
+//   class For[m[_], a](x: m[a])
+//   def toFor[m[_], a](x: m[a]): For[m, a] = new For[m, a](x)
+//
+//   trait MyList[A]
+//   type MyListOfInt = MyList[Int]
+//
+//   val xs: MyListOfInt = error("")
+//   toFor(xs : xs.type)
+// }