Merge pull request #660 from retronym/ticket/5167-3

SI-5167 An impl class method should refer to its own parameter symbols.

5 files changed, 40 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
index e5fc98f23c..8c5d25e6c4 100644
--- a/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
+++ b/src/compiler/scala/tools/nsc/transform/AddInterfaces.scala
@@ -257,11 +257,21 @@ abstract class AddInterfaces extends InfoTransform { self: Erasure =>
   /** Transforms the member tree containing the implementation
    *  into a member of the impl class.
    */
-  private def implMethodDef(tree: Tree): Tree = (
-    implMethodMap get tree.symbol
-            map (impl => new ChangeOwnerAndReturnTraverser(tree.symbol, impl)(tree setSymbol impl))
-      getOrElse abort("implMethod missing for " + tree.symbol)
-  )
+  private def implMethodDef(tree: Tree): Tree = {
+    val impl = implMethodMap.getOrElse(tree.symbol, abort("implMethod missing for " + tree.symbol))
+
+    val newTree = if (impl.isErroneous) tree else { // e.g. res/t687
+      // SI-5167: Ensure that the tree that we are grafting refers the parameter symbols from the
+      // new method symbol `impl`, rather than the symbols of the original method signature in
+      // the trait. `tree setSymbol impl` does *not* suffice!
+      val DefDef(_, _, _, vparamss, _, _) = tree
+      val oldSyms = vparamss.flatten.map(_.symbol)
+      val newSyms = impl.info.paramss.flatten
+      assert(oldSyms.length == newSyms.length, (oldSyms, impl, impl.info))
+      tree.substTreeSyms(oldSyms, newSyms)
+    }
+    new ChangeOwnerAndReturnTraverser(newTree.symbol, impl)(newTree setSymbol impl)
+  }
 
   /** Add mixin constructor definition
    *    def $init$(): Unit = ()
diff --git a/test/files/res/t5167.check b/test/files/res/t5167.check
new file mode 100644
index 0000000000..6cf64f734b
--- /dev/null
+++ b/test/files/res/t5167.check
@@ -0,0 +1,4 @@
+
+nsc> 
+nsc> 
+nsc> 
diff --git a/test/files/res/t5167.res b/test/files/res/t5167.res
new file mode 100644
index 0000000000..a485cbee41
--- /dev/null
+++ b/test/files/res/t5167.res
@@ -0,0 +1,2 @@
+t5167/t5167_1.scala
+t5167/t5167_2.scala
\ No newline at end of file
diff --git a/test/files/res/t5167/t5167_1.scala b/test/files/res/t5167/t5167_1.scala
new file mode 100644
index 0000000000..ed28243507
--- /dev/null
+++ b/test/files/res/t5167/t5167_1.scala
@@ -0,0 +1,12 @@
+package compilerbug
+
+trait SadTrait {
+  def buggyMethod[T](argWithDefault1: Int = 0)(argWithDefault2: String = "default") {
+    for (i <- 0 to 1) {
+      val x = argWithDefault1
+      val y = argWithDefault2
+    }
+  }
+}
+
+object SadObject extends SadTrait
diff --git a/test/files/res/t5167/t5167_2.scala b/test/files/res/t5167/t5167_2.scala
new file mode 100644
index 0000000000..5aa56efe75
--- /dev/null
+++ b/test/files/res/t5167/t5167_2.scala
@@ -0,0 +1,7 @@
+package compilerbug
+
+class TestClass {
+  def repro() {
+    SadObject.buggyMethod[Int]()()
+  }
+}