From cae569b3133456636e63f8e8a7cdda8ef88bd055 Mon Sep 17 00:00:00 2001
From: Guillaume Martres <smarter@ubuntu.com>
Date: Sun, 27 Mar 2016 21:34:59 +0200
Subject: [PATCH 1/2] Include used types in the set of used names

This is a backport of https://github.com/sbt/zinc/pull/87

When `B2.scala` replaces `B.scala` in the new test
`types-in-used-names-a`, the name hash of `listb` does not change because
the signature of `C.listb` is still `List[B]`, however users of
`C.listb` have to be recompiled since the subtyping relationships of its
type have changed.

This commit does this by extending the definition of "used names" to
also include the names of the types of trees, even if these types
do not appear in the source like `List[B]` in `D.scala` (since `B` has
been invalidated, this will force the recompilation of `D.scala`).

This commit does not fix every issue with used types as illustrated by
the pending test `types-in-used-names-b`, `B.scala` is not recompiled
because it uses the type `T` whose hash has not changed, but `T` is
bounded by `S` and `S` has changed, so it should be recompiled.
This should be fixable by including the type bounds underlying a
`TypeRef` in `symbolsInType`.

The test `as-seen-from-a` that did not work before shows that we may not
have to worry about tracking prefixes in `ExtractAPI` anymore, see the
discussion in sbt/zinc#87 for more information.
---
 .../src/main/scala/xsbt/Compat.scala          | 16 +++++++
 .../src/main/scala/xsbt/Dependency.scala      | 40 +++++------------
 .../main/scala/xsbt/ExtractUsedNames.scala    | 18 +++++---
 .../src/main/scala/xsbt/GlobalHelpers.scala   | 18 ++++++++
 .../xsbt/ExtractUsedNamesSpecification.scala  | 45 +++++++++++++++++--
 .../as-seen-from-a/A.scala                    |  6 +++
 .../as-seen-from-a/B.scala                    |  3 ++
 .../as-seen-from-a/C.scala                    |  1 +
 .../as-seen-from-a/D.scala                    |  3 ++
 .../as-seen-from-a/changes/B2.scala           |  3 ++
 .../source-dependencies/as-seen-from-a/test   |  3 ++
 .../as-seen-from-b/A.scala                    |  7 +++
 .../as-seen-from-b/B.scala                    |  3 ++
 .../as-seen-from-b/C.scala                    |  1 +
 .../as-seen-from-b/D.scala                    |  3 ++
 .../as-seen-from-b/changes/B2.scala           |  3 ++
 .../as-seen-from-b/pending                    |  3 ++
 .../types-in-used-names-a/A.scala             |  1 +
 .../types-in-used-names-a/B.scala             |  1 +
 .../types-in-used-names-a/C.scala             |  3 ++
 .../types-in-used-names-a/D.scala             |  3 ++
 .../types-in-used-names-a/changes/B2.scala    |  1 +
 .../types-in-used-names-a/test                |  4 ++
 .../types-in-used-names-b/A.scala             |  5 +++
 .../types-in-used-names-b/B.scala             |  3 ++
 .../types-in-used-names-b/changes/A2.scala    |  5 +++
 .../types-in-used-names-b/pending             |  5 +++
 27 files changed, 168 insertions(+), 39 deletions(-)
 create mode 100644 compile/interface/src/main/scala/xsbt/GlobalHelpers.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/A.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/B.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/C.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/D.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/changes/B2.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-a/test
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B2.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/A.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/B.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/C.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/D.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/changes/B2.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-a/test
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-b/A.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-b/B.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-b/changes/A2.scala
 create mode 100644 sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending

diff --git a/compile/interface/src/main/scala/xsbt/Compat.scala b/compile/interface/src/main/scala/xsbt/Compat.scala
index a4859275d..bbf5b9a41 100644
--- a/compile/interface/src/main/scala/xsbt/Compat.scala
+++ b/compile/interface/src/main/scala/xsbt/Compat.scala
@@ -51,6 +51,22 @@ abstract class Compat {
     def transformedType(tpe: Type): Type = tpe
   }
 
+  /**
+   * Traverses given type and collects result of applying a partial function `pf`.
+   *
+   * NOTE: This class exists in Scala 2.10 as CollectTypeCollector but does not in earlier
+   * versions (like 2.9) of Scala compiler that incremental cmpiler supports so we had to
+   * reimplement that class here.
+   */
+  class CollectTypeTraverser[T](pf: PartialFunction[Type, T]) extends TypeTraverser {
+    var collected: List[T] = Nil
+    def traverse(tpe: Type): Unit = {
+      if (pf.isDefinedAt(tpe))
+        collected = pf(tpe) :: collected
+      mapOver(tpe)
+    }
+  }
+
   private[this] final class MiscCompat {
     // in 2.9, nme.LOCALCHILD was renamed to tpnme.LOCAL_CHILD
     def tpnme = nme
diff --git a/compile/interface/src/main/scala/xsbt/Dependency.scala b/compile/interface/src/main/scala/xsbt/Dependency.scala
index b10975ec8..34c237bb3 100644
--- a/compile/interface/src/main/scala/xsbt/Dependency.scala
+++ b/compile/interface/src/main/scala/xsbt/Dependency.scala
@@ -29,7 +29,7 @@ object Dependency {
  * where it originates from. The Symbol->Classfile mapping is implemented by
  * LocateClassFile that we inherit from.
  */
-final class Dependency(val global: CallbackGlobal) extends LocateClassFile {
+final class Dependency(val global: CallbackGlobal) extends LocateClassFile with GlobalHelpers {
   import global._
 
   def newPhase(prev: Phase): Phase = new DependencyPhase(prev)
@@ -79,6 +79,12 @@ final class Dependency(val global: CallbackGlobal) extends LocateClassFile {
   private class ExtractDependenciesTraverser extends Traverser {
     private val _dependencies = collection.mutable.HashSet.empty[Symbol]
     protected def addDependency(dep: Symbol): Unit = if (dep ne NoSymbol) _dependencies += dep
+    protected def addTreeDependency(tree: Tree): Unit = {
+      addDependency(tree.symbol)
+      if (tree.tpe != null)
+        symbolsInType(tree.tpe).foreach(addDependency)
+      ()
+    }
     def dependencies: Iterator[Symbol] = _dependencies.iterator
     def topLevelDependencies: Iterator[Symbol] = _dependencies.map(enclosingTopLevelClass).iterator
 
@@ -118,11 +124,11 @@ final class Dependency(val global: CallbackGlobal) extends LocateClassFile {
        *    this looks fishy, see this thread:
        *    https://groups.google.com/d/topic/scala-internals/Ms9WUAtokLo/discussion
        */
-      case id: Ident => addDependency(id.symbol)
+      case id: Ident => addTreeDependency(id)
       case sel @ Select(qual, _) =>
-        traverse(qual); addDependency(sel.symbol)
+        traverse(qual); addTreeDependency(sel)
       case sel @ SelectFromTypeTree(qual, _) =>
-        traverse(qual); addDependency(sel.symbol)
+        traverse(qual); addTreeDependency(sel)
 
       case Template(parents, self, body) =>
         // use typeSymbol to dealias type aliases -- we want to track the dependency on the real class in the alias's RHS
@@ -151,32 +157,6 @@ final class Dependency(val global: CallbackGlobal) extends LocateClassFile {
         super.traverse(m)
       case other => super.traverse(other)
     }
-
-    private def symbolsInType(tp: Type): Set[Symbol] = {
-      val typeSymbolCollector =
-        new CollectTypeTraverser({
-          case tpe if (tpe != null) && !tpe.typeSymbolDirect.isPackage => tpe.typeSymbolDirect
-        })
-
-      typeSymbolCollector.traverse(tp)
-      typeSymbolCollector.collected.toSet
-    }
-  }
-
-  /**
-   * Traverses given type and collects result of applying a partial function `pf`.
-   *
-   * NOTE: This class exists in Scala 2.10 as CollectTypeCollector but does not in earlier
-   * versions (like 2.9) of Scala compiler that incremental cmpiler supports so we had to
-   * reimplement that class here.
-   */
-  private final class CollectTypeTraverser[T](pf: PartialFunction[Type, T]) extends TypeTraverser {
-    var collected: List[T] = Nil
-    def traverse(tpe: Type): Unit = {
-      if (pf.isDefinedAt(tpe))
-        collected = pf(tpe) :: collected
-      mapOver(tpe)
-    }
   }
 
   /** Copied straight from Scala 2.10 as it does not exist in Scala 2.9 compiler */
diff --git a/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala b/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala
index 281131736..56e55cc20 100644
--- a/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala
+++ b/compile/interface/src/main/scala/xsbt/ExtractUsedNames.scala
@@ -7,6 +7,8 @@ import scala.tools.nsc._
  *
  * Extracts simple (unqualified) names mentioned in given in non-definition position by collecting
  * all symbols associated with non-definition trees and extracting names from all collected symbols.
+ * Also extract the names of the types of non-definition trees (see source-dependencies/types-in-used-names
+ * for an example where this is required).
  *
  * If given symbol is mentioned both in definition and in non-definition position (e.g. in member
  * selection) then that symbol is collected. It means that names of symbols defined and used in the
@@ -38,7 +40,7 @@ import scala.tools.nsc._
  * The tree walking algorithm walks into TypeTree.original explicitly.
  *
  */
-class ExtractUsedNames[GlobalType <: CallbackGlobal](val global: GlobalType) extends Compat {
+class ExtractUsedNames[GlobalType <: CallbackGlobal](val global: GlobalType) extends Compat with GlobalHelpers {
   import global._
 
   @inline def debug(msg: => String) = if (settings.verbose.value) inform(msg)
@@ -61,10 +63,12 @@ class ExtractUsedNames[GlobalType <: CallbackGlobal](val global: GlobalType) ext
      */
     val inspectedOriginalTrees = collection.mutable.Set.empty[Tree]
 
-    def addSymbol(symbol: Symbol): Unit = {
-      val symbolNameAsString = symbol.name.decode.trim
-      namesBuffer += symbolNameAsString
-    }
+    def addSymbol(symbol: Symbol): Unit =
+      if (eligibleAsUsedName(symbol)) {
+        val symbolNameAsString = symbol.name.decode.trim
+        namesBuffer += symbolNameAsString
+        ()
+      }
 
     def handleTreeNode(node: Tree): Unit = {
       def handleMacroExpansion(original: Tree): Unit = {
@@ -91,8 +95,10 @@ class ExtractUsedNames[GlobalType <: CallbackGlobal](val global: GlobalType) ext
         // not what we need
         case t: TypeTree if t.original != null =>
           t.original.foreach(handleTreeNode)
-        case t if t.hasSymbol && eligibleAsUsedName(t.symbol) =>
+        case t if t.hasSymbol =>
           addSymbol(t.symbol)
+          if (t.tpe != null)
+            symbolsInType(t.tpe).foreach(addSymbol)
         case _ => ()
       }
 
diff --git a/compile/interface/src/main/scala/xsbt/GlobalHelpers.scala b/compile/interface/src/main/scala/xsbt/GlobalHelpers.scala
new file mode 100644
index 000000000..46f0ec5eb
--- /dev/null
+++ b/compile/interface/src/main/scala/xsbt/GlobalHelpers.scala
@@ -0,0 +1,18 @@
+package xsbt
+
+import scala.tools.nsc.Global
+
+trait GlobalHelpers extends Compat {
+  val global: CallbackGlobal
+  import global.{ Tree, Type, Symbol, TypeTraverser }
+
+  def symbolsInType(tp: Type): Set[Symbol] = {
+    val typeSymbolCollector =
+      new CollectTypeTraverser({
+        case tpe if (tpe != null) && !tpe.typeSymbolDirect.isPackage => tpe.typeSymbolDirect
+      })
+
+    typeSymbolCollector.traverse(tp)
+    typeSymbolCollector.collected.toSet
+  }
+}
diff --git a/compile/interface/src/test/scala/xsbt/ExtractUsedNamesSpecification.scala b/compile/interface/src/test/scala/xsbt/ExtractUsedNamesSpecification.scala
index e9dcbf49e..00efc1b6f 100644
--- a/compile/interface/src/test/scala/xsbt/ExtractUsedNamesSpecification.scala
+++ b/compile/interface/src/test/scala/xsbt/ExtractUsedNamesSpecification.scala
@@ -17,8 +17,9 @@ class ExtractUsedNamesSpecification extends Specification {
    * definition.
    */
   private val standardNames = Set(
-    // AnyRef is added as default parent of a class
-    "scala", "AnyRef",
+    "scala",
+    // The default parent of a class is "AnyRef" which is an alias for "Object"
+    "AnyRef", "Object",
     // class receives a default constructor which is internally called "<init>"
     "<init>")
 
@@ -69,7 +70,45 @@ class ExtractUsedNamesSpecification extends Specification {
 			|}""".stripMargin
     val compilerForTesting = new ScalaCompilerForUnitTesting(nameHashing = true)
     val usedNames = compilerForTesting.extractUsedNamesFromSrc(srcA, srcB)
-    val expectedNames = standardNames ++ Set("A", "a", "B", "=")
+    val expectedNames = standardNames ++ Set("A", "a", "B", "=", "Int")
+    usedNames === expectedNames
+  }
+
+  "extract names in the types of trees" in {
+    val src1 = """|class X0
+                  |class X1 extends X0
+                  |class Y
+                  |class A {
+                  |  type T >: X1 <: X0
+                  |}
+                  |class M
+                  |class N
+                  |class P0
+                  |class P1 extends P0
+                  |object B {
+                  |  type S = Y
+                  |  val lista: List[A] = ???
+                  |  val at: A#T = ???
+                  |  val as: S = ???
+                  |  def foo(m: M): N = ???
+                  |  def bar[Param >: P1 <: P0](p: Param): Param = ???
+                  |}""".stripMargin
+    val src2 = """|object Test {
+                  |  val x = B.lista
+                  |  val y = B.at
+                  |  val z = B.as
+                  |  B.foo(???)
+                  |  B.bar(???)
+                  |}""".stripMargin
+    val compilerForTesting = new ScalaCompilerForUnitTesting(nameHashing = true)
+    val usedNames = compilerForTesting.extractUsedNamesFromSrc(src1, src2)
+    val expectedNames = standardNames ++ Set("Test", "B", "x", "y", "z",
+      "Predef", "???", "Nothing",
+      "lista", "package", "List", "A",
+      "at", "T",
+      "as", "S",
+      "foo", "M", "N",
+      "bar", "Param", "P1", "P0")
     usedNames === expectedNames
   }
 
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/A.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/A.scala
new file mode 100644
index 000000000..fe6a784a4
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/A.scala
@@ -0,0 +1,6 @@
+abstract class A {
+  type T
+  object X {
+    def foo(x: T): T = x
+  }
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/B.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/B.scala
new file mode 100644
index 000000000..60059966f
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/B.scala
@@ -0,0 +1,3 @@
+class B extends A {
+  type T = Int
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/C.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/C.scala
new file mode 100644
index 000000000..3753dbeec
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/C.scala
@@ -0,0 +1 @@
+object C extends B
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/D.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/D.scala
new file mode 100644
index 000000000..ace241491
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/D.scala
@@ -0,0 +1,3 @@
+object D {
+  C.X.foo(12)
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/changes/B2.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/changes/B2.scala
new file mode 100644
index 000000000..18f3eefdd
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/changes/B2.scala
@@ -0,0 +1,3 @@
+class B extends A {
+  type T = String
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-a/test b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/test
new file mode 100644
index 000000000..176a86399
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-a/test
@@ -0,0 +1,3 @@
+> compile
+$ copy-file changes/B2.scala B.scala
+-> compile
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala
new file mode 100644
index 000000000..f4ae0b78d
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala
@@ -0,0 +1,7 @@
+abstract class A {
+  type T <: S
+  type S
+  object X {
+    def foo: T = null.asInstanceOf[T]
+  }
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala
new file mode 100644
index 000000000..f97007480
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala
@@ -0,0 +1,3 @@
+class B extends A {
+  type S <: Int
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala
new file mode 100644
index 000000000..3753dbeec
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala
@@ -0,0 +1 @@
+object C extends B
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala
new file mode 100644
index 000000000..ec333ca60
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala
@@ -0,0 +1,3 @@
+object D {
+  val x: Int = C.X.foo
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B2.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B2.scala
new file mode 100644
index 000000000..f8fa3ad03
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B2.scala
@@ -0,0 +1,3 @@
+class B extends A {
+  type S <: String
+}
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
new file mode 100644
index 000000000..176a86399
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
@@ -0,0 +1,3 @@
+> compile
+$ copy-file changes/B2.scala B.scala
+-> compile
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/A.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/A.scala
new file mode 100644
index 000000000..83d15dc73
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/A.scala
@@ -0,0 +1 @@
+class A
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/B.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/B.scala
new file mode 100644
index 000000000..a18aec3db
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/B.scala
@@ -0,0 +1 @@
+class B extends A
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/C.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/C.scala
new file mode 100644
index 000000000..d8c306253
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/C.scala
@@ -0,0 +1,3 @@
+object C {
+  val listb: List[B] = List(new B)
+}
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/D.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/D.scala
new file mode 100644
index 000000000..fa8f13a1b
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/D.scala
@@ -0,0 +1,3 @@
+object D {
+  val lista: List[A] = C.listb
+}
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/changes/B2.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/changes/B2.scala
new file mode 100644
index 000000000..179f0d275
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/changes/B2.scala
@@ -0,0 +1 @@
+class B
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/test b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/test
new file mode 100644
index 000000000..134321021
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-a/test
@@ -0,0 +1,4 @@
+> compile
+$ copy-file changes/B2.scala B.scala
+# Compilation of D.scala should fail because B is no longer a subtype of A
+-> compile
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/A.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/A.scala
new file mode 100644
index 000000000..301b546cb
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/A.scala
@@ -0,0 +1,5 @@
+class A {
+  type T <: S
+  type S <: Int
+  def foo: T = null.asInstanceOf[T]
+}
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/B.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/B.scala
new file mode 100644
index 000000000..edfe2e6a8
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/B.scala
@@ -0,0 +1,3 @@
+object B {
+  val x: Int = (new A).foo
+}
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/changes/A2.scala b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/changes/A2.scala
new file mode 100644
index 000000000..bbe60f206
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/changes/A2.scala
@@ -0,0 +1,5 @@
+class A {
+  type T <: S
+  type S <: String
+  def foo: T = null.asInstanceOf[T]
+}
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending
new file mode 100644
index 000000000..b6cce2d46
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending
@@ -0,0 +1,5 @@
+> compile
+$ copy-file changes/A2.scala A.scala
+# Same workaround as #2565
+# Compilation of B.scala should fail because A#S is no longer a subtype of Int
+-> compile

From 4aaf65894497c5d7f67f19fb3872c5e7361f8f14 Mon Sep 17 00:00:00 2001
From: Eugene Yokota <eed3si9n@gmail.com>
Date: Mon, 2 May 2016 07:16:31 -0400
Subject: [PATCH 2/2] Disable #2523 testing for now

---
 .../as-seen-from-b/build.sbt                  |  4 ++++
 .../{A.scala => changes/A1.scala}             |  0
 .../{B.scala => changes/B1.scala}             |  0
 .../{C.scala => changes/C1.scala}             |  0
 .../{D.scala => changes/D1.scala}             |  0
 .../as-seen-from-b/disabled                   | 22 +++++++++++++++++++
 .../as-seen-from-b/pending                    |  3 ---
 .../{pending => disabled}                     |  0
 8 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/build.sbt
 rename sbt/src/sbt-test/source-dependencies/as-seen-from-b/{A.scala => changes/A1.scala} (100%)
 rename sbt/src/sbt-test/source-dependencies/as-seen-from-b/{B.scala => changes/B1.scala} (100%)
 rename sbt/src/sbt-test/source-dependencies/as-seen-from-b/{C.scala => changes/C1.scala} (100%)
 rename sbt/src/sbt-test/source-dependencies/as-seen-from-b/{D.scala => changes/D1.scala} (100%)
 create mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/disabled
 delete mode 100644 sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
 rename sbt/src/sbt-test/source-dependencies/types-in-used-names-b/{pending => disabled} (100%)

diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/build.sbt b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/build.sbt
new file mode 100644
index 000000000..7333e8428
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/build.sbt
@@ -0,0 +1,4 @@
+lazy val root = (project in file(".")).
+  settings(
+    scalaVersion := "2.11.8"
+  )
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/A1.scala
similarity index 100%
rename from sbt/src/sbt-test/source-dependencies/as-seen-from-b/A.scala
rename to sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/A1.scala
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B1.scala
similarity index 100%
rename from sbt/src/sbt-test/source-dependencies/as-seen-from-b/B.scala
rename to sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/B1.scala
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/C1.scala
similarity index 100%
rename from sbt/src/sbt-test/source-dependencies/as-seen-from-b/C.scala
rename to sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/C1.scala
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/D1.scala
similarity index 100%
rename from sbt/src/sbt-test/source-dependencies/as-seen-from-b/D.scala
rename to sbt/src/sbt-test/source-dependencies/as-seen-from-b/changes/D1.scala
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/disabled b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/disabled
new file mode 100644
index 000000000..0b07aad6a
--- /dev/null
+++ b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/disabled
@@ -0,0 +1,22 @@
+$ copy-file changes/A1.scala A.scala
+
+> compile
+
+$ copy-file changes/B1.scala B.scala
+
+> compile
+
+
+$ copy-file changes/C1.scala C.scala
+
+> compile
+
+
+$ copy-file changes/D1.scala D.scala
+
+> compile
+
+$ copy-file changes/B2.scala B.scala
+$ sleep 1000
+
+-> compile
diff --git a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending b/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
deleted file mode 100644
index 176a86399..000000000
--- a/sbt/src/sbt-test/source-dependencies/as-seen-from-b/pending
+++ /dev/null
@@ -1,3 +0,0 @@
-> compile
-$ copy-file changes/B2.scala B.scala
--> compile
diff --git a/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending b/sbt/src/sbt-test/source-dependencies/types-in-used-names-b/disabled
similarity index 100%
rename from sbt/src/sbt-test/source-dependencies/types-in-used-names-b/pending
rename to sbt/src/sbt-test/source-dependencies/types-in-used-names-b/disabled