SI-7783 Don't issue deprecation warnings for inferred TypeTrees

Deprecation checks in RefChecks were looking into all TypeTrees
to find references to deprecated type aliases. However, when the
compiler infers a type argument or type of a member it creates
a TypeTree (with a null original) that was also leading to warnings.

I ran into this problem often when upgrading a build from SBT 0.12
to 0.13: a plugin I was using used the deprecated type alias, and I
suffered transitively when I used methods from its API.

This commit disables the checks for inferred TypeTree-s.

5 files changed, 33 insertions, 10 deletions

diff --git a/test/files/neg/classmanifests_new_deprecations.check b/test/files/neg/classmanifests_new_deprecations.check
index 12428c7626..4ad4a12b3e 100644
--- a/test/files/neg/classmanifests_new_deprecations.check
+++ b/test/files/neg/classmanifests_new_deprecations.check
@@ -7,9 +7,6 @@ classmanifests_new_deprecations.scala:3: error: type ClassManifest in object Pre
 classmanifests_new_deprecations.scala:4: error: type ClassManifest in object Predef is deprecated: Use scala.reflect.ClassTag instead
   val cm3: ClassManifest[Int] = null
            ^
-classmanifests_new_deprecations.scala:4: error: type ClassManifest in object Predef is deprecated: Use scala.reflect.ClassTag instead
-  val cm3: ClassManifest[Int] = null
-      ^
 classmanifests_new_deprecations.scala:6: error: type ClassManifest in package reflect is deprecated: Use scala.reflect.ClassTag instead
   def rcm1[T: scala.reflect.ClassManifest] = ???
             ^
@@ -19,13 +16,10 @@ classmanifests_new_deprecations.scala:7: error: type ClassManifest in package re
 classmanifests_new_deprecations.scala:8: error: type ClassManifest in package reflect is deprecated: Use scala.reflect.ClassTag instead
   val rcm3: scala.reflect.ClassManifest[Int] = null
                           ^
-classmanifests_new_deprecations.scala:8: error: type ClassManifest in package reflect is deprecated: Use scala.reflect.ClassTag instead
-  val rcm3: scala.reflect.ClassManifest[Int] = null
-      ^
 classmanifests_new_deprecations.scala:10: error: type ClassManifest in object Predef is deprecated: Use scala.reflect.ClassTag instead
   type CM[T] = ClassManifest[T]
                ^
 classmanifests_new_deprecations.scala:15: error: type ClassManifest in package reflect is deprecated: Use scala.reflect.ClassTag instead
   type RCM[T] = scala.reflect.ClassManifest[T]
                               ^
-10 errors found
+8 errors found
diff --git a/test/files/neg/t7783.check b/test/files/neg/t7783.check
new file mode 100644
index 0000000000..f489b3c8fd
--- /dev/null
+++ b/test/files/neg/t7783.check
@@ -0,0 +1,16 @@
+t7783.scala:1: error: type D in object O is deprecated: 
+object O { class C; @deprecated("", "") type D = C; def foo: Seq[D] = Nil }
+                                                             ^
+t7783.scala:11: error: type D in object O is deprecated: 
+  type T = O.D
+             ^
+t7783.scala:12: error: type D in object O is deprecated: 
+  locally(null: O.D)
+                  ^
+t7783.scala:13: error: type D in object O is deprecated: 
+  val x: O.D = null
+           ^
+t7783.scala:14: error: type D in object O is deprecated: 
+  locally(null.asInstanceOf[O.D])
+                              ^
+5 errors found
diff --git a/test/files/neg/t7783.flags b/test/files/neg/t7783.flags
new file mode 100644
index 0000000000..d1b831ea87
--- /dev/null
+++ b/test/files/neg/t7783.flags
@@ -0,0 +1 @@
+-deprecation -Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/neg/t7783.scala b/test/files/neg/t7783.scala
new file mode 100644
index 0000000000..995b644a09
--- /dev/null
+++ b/test/files/neg/t7783.scala
@@ -0,0 +1,15 @@
+object O { class C; @deprecated("", "") type D = C; def foo: Seq[D] = Nil }
+
+object NoWarn {
+  O.foo                        // nowarn
+  O.foo +: Nil                 // nowarn
+  def bar(a: Any, b: Any) = () // nowarn
+  bar(b = O.foo, a = ())       // nowarn
+}
+
+object Warn {
+  type T = O.D
+  locally(null: O.D)
+  val x: O.D = null
+  locally(null.asInstanceOf[O.D])
+}
diff --git a/test/files/run/t4542.check b/test/files/run/t4542.check
index cd7a2905e2..5c293a8d80 100644
--- a/test/files/run/t4542.check
+++ b/test/files/run/t4542.check
@@ -11,9 +11,6 @@ defined class Foo
 scala> val f = new Foo
 <console>:8: warning: class Foo is deprecated: foooo
        val f = new Foo
-           ^
-<console>:8: warning: class Foo is deprecated: foooo
-       val f = new Foo
                    ^
 f: Foo = Bippy