Fix #1457: Three incompatbilities with scalac

Two of these are unavoidable. I moved the tests to diabled/not-representable
and added in each case a comment to the main scala file detailing why there
is a deviation.

The last one (import-rewrite) is fixed.

5 files changed, 47 insertions, 0 deletions

diff --git a/tests/disabled/not-representable/hkt/compiler.error b/tests/disabled/not-representable/hkt/compiler.error
new file mode 100644
index 000000000..b31760891
--- /dev/null
+++ b/tests/disabled/not-representable/hkt/compiler.error
@@ -0,0 +1,6 @@
+$ scalac tests/pending/hkt/*.scala
+$ ./bin/dotc tests/pending/hkt/*.scala
+tests/pending/hkt/hkt.scala:14: error: method empty in object Child does not take type parameters
+  Child.empty[Int]
+             ^
+one error found
diff --git a/tests/disabled/not-representable/hkt/hkt.scala b/tests/disabled/not-representable/hkt/hkt.scala
new file mode 100644
index 000000000..1a9932d73
--- /dev/null
+++ b/tests/disabled/not-representable/hkt/hkt.scala
@@ -0,0 +1,18 @@
+// This one is unavoidable. Dotty does not allow several overloaded
+// parameterless methods, so it picks the one in the subclass.
+
+import scala.language.higherKinds
+// Minimal reproduction for:
+// scala.collection.mutable.ArrayStack.empty[Int]
+
+abstract class Super[C[_]] {
+  def empty[T]: C[T] = ???
+}
+
+class Child[T]
+
+object Child extends Super[Child] {
+  def empty: Child[Nothing] = new Child()
+
+  Child.empty[Int]
+}
diff --git a/tests/disabled/not-representable/naming-resolution/callsite.scala b/tests/disabled/not-representable/naming-resolution/callsite.scala
new file mode 100644
index 000000000..036803a26
--- /dev/null
+++ b/tests/disabled/not-representable/naming-resolution/callsite.scala
@@ -0,0 +1,10 @@
+// This one should be rejected according to spec. The import takes precedence
+// over the type in the same package because the typeis declared in a
+// different compilation unit. scalac does not conform to spec here.
+package naming.resolution
+
+import java.nio.file._ // Imports `Files`
+
+object Resolution {
+  def gimmeFiles: Files = Files.list(Paths.get("."))
+}
diff --git a/tests/disabled/not-representable/naming-resolution/compiler.error b/tests/disabled/not-representable/naming-resolution/compiler.error
new file mode 100644
index 000000000..81d6b3cfa
--- /dev/null
+++ b/tests/disabled/not-representable/naming-resolution/compiler.error
@@ -0,0 +1,8 @@
+$ scalac tests/pending/naming-resolution/*.scala
+$ ./bin/dotc tests/pending/naming-resolution/*.scala
+tests/pending/naming-resolution/callsite.scala:6: error: type mismatch:
+ found   : java.util.stream.Stream[java.nio.file.Path]
+ required: java.nio.file.Files
+  def gimmeFiles: Files = Files.list(Paths.get("."))
+                                    ^
+one error found
diff --git a/tests/disabled/not-representable/naming-resolution/package.scala b/tests/disabled/not-representable/naming-resolution/package.scala
new file mode 100644
index 000000000..f0e26ee95
--- /dev/null
+++ b/tests/disabled/not-representable/naming-resolution/package.scala
@@ -0,0 +1,5 @@
+package naming
+
+package object resolution {
+  type Files = java.util.stream.Stream[java.nio.file.Path]
+}