closes #2416.

this patch introduces a new subclass of TypeTree: TypeTreeWithDeferredRefCheck, which tracks the type args and type params of a type application when it was beta-reduced during typing without checking that the application was well-kinded -- that check must wait until refchecks, but was never performed since the application had been beta-reduced away

caveat discovered while working on the fix: adapt turned all trees for
which _.isType holds into TypeTree's

review by odersky

2 files changed, 24 insertions, 0 deletions

diff --git a/test/files/neg/t2416.check b/test/files/neg/t2416.check
new file mode 100644
index 0000000000..0899ad09d5
--- /dev/null
+++ b/test/files/neg/t2416.check
@@ -0,0 +1,10 @@
+t2416.scala:3: error: type arguments [Int] do not conform to trait A's type parameter bounds [X <: Double]
+  def x : A[Int]#B = 10 // no you won't
+          ^
+t2416.scala:8: error: type arguments [Boolean] do not conform to type B's type parameter bounds [Y <: Double]
+  def x : A#B[Boolean] = 10 // seriously?
+            ^
+t2416.scala:13: error: type arguments [String] do not conform to type B's type parameter bounds [Z <: Double]
+  type C[Z <: A] = Z#B[String] // nuh-uh!
+                     ^
+three errors found
diff --git a/test/files/neg/t2416.scala b/test/files/neg/t2416.scala
new file mode 100644
index 0000000000..6bb57a984b
--- /dev/null
+++ b/test/files/neg/t2416.scala
@@ -0,0 +1,14 @@
+object t2416a {
+  trait A[X <: Double] { type B = X }
+  def x : A[Int]#B = 10 // no you won't
+}
+
+object t2416b {
+  trait A{type B[Y <: Double] = Int}
+  def x : A#B[Boolean] = 10 // seriously?
+}
+
+object t2416c {
+  trait A{type B[Z <: Double] = Int}
+  type C[Z <: A] = Z#B[String] // nuh-uh!
+}
\ No newline at end of file