Fixes #SI-5578.

ResetAttrs shouldn't be side-effecting on the original tree,
since it can lead to NPEs in erroneous trees (or maybe even for valid ones?).
Review by @odersky

(Patch by plocinic, applied without his complicity by extempore)

1 files changed, 39 insertions, 0 deletions

diff --git a/test/files/neg/t5578.scala b/test/files/neg/t5578.scala
new file mode 100644
index 0000000000..ce72f32d53
--- /dev/null
+++ b/test/files/neg/t5578.scala
@@ -0,0 +1,39 @@
+trait Base {
+  type Rep[T]
+}
+
+trait Expressions {
+  // constants/symbols (atomic)
+  abstract class Exp[T]
+  // ...
+  case class Sym[T](n: Int) extends Exp[T]
+
+  // operations (composite, defined in subtraits)
+  abstract class Def[T]
+
+  // additional members for managing encountered definitions
+  def findOrCreateDefinition[T](rhs: Def[T]): Sym[T]
+  implicit def toExp[T:Manifest](d: Def[T]): Exp[T] = findOrCreateDefinition(d)
+}
+
+trait BaseExp extends Base with Expressions {
+  type Rep[T] = Exp[T]
+
+  def findOrCreateDefinition[T](rhs: Def[T]): Sym[T] = null // stub
+}
+
+trait NumericOps extends Base {
+  def plus[T](x: Rep[T], y: Rep[T]): Rep[T]
+}
+
+trait NumericOpsExp extends BaseExp {
+  case class Plus[T:Numeric](x: Rep[T], y: Rep[T])
+    extends Def[T]
+
+  def plus[T: Numeric](x: Rep[T], y: Rep[T]): Rep[T] = Plus[T](x,y)
+
+  // Possible solutions:
+// def plus[T: Numeric: Manifest](x: Rep[T], y: Rep[T]): Rep[T] = Plus[T](x, y)
+// def plus[T](x: Rep[T], y: Rep[T])(implicit num: Numeric[T], man: Manifest[T]): Rep[T] = Plus(x,y)
+
+}