Don't transform patterns during superaccessors:...

Don't transform patterns during superaccessors: the matcher can't deal
with funny trees. Closes #4062, review by dragos.

3 files changed, 22 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index c1a44dba93..5d19d469b5 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -144,6 +144,10 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
         else tree
 
       try tree match {
+        // Don't transform patterns or strange trees will reach the matcher (ticket #4062)
+        case CaseDef(pat, guard, body) =>
+          treeCopy.CaseDef(tree, pat, transform(guard), transform(body))
+
         case ClassDef(_, _, _, _) =>
           checkCompanionNameClashes(sym)
           val decls = sym.info.decls
diff --git a/test/files/run/bug4062.check b/test/files/run/bug4062.check
new file mode 100644
index 0000000000..1d474d5255
--- /dev/null
+++ b/test/files/run/bug4062.check
@@ -0,0 +1,2 @@
+false
+true
diff --git a/test/files/run/bug4062.scala b/test/files/run/bug4062.scala
new file mode 100644
index 0000000000..f5478e7593
--- /dev/null
+++ b/test/files/run/bug4062.scala
@@ -0,0 +1,16 @@
+class A(val f : String)
+
+class B(f: String) extends A(f) {
+  def foo(x: String) = x match {
+    case `f`  => true
+    case _    => false
+  }
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val b = new B("abc")
+    println(b foo "bippy")
+    println(b foo "abc")
+  }
+}