Improving error message.

Hacked filename into message to alleviate meaningless
"_$1 defined twice" error condition.  References SI-4893.

8 files changed, 49 insertions, 14 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
index ea5223e32f..140df53816 100644
--- a/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala
@@ -624,11 +624,21 @@ trait ContextErrors {
         setError(tree)
       }
 
-    // checkNoDoubleDefs...
-      def DefDefinedTwiceError(sym0: Symbol, sym1: Symbol) =
-        issueSymbolTypeError(sym0, sym1+" is defined twice"+
-                                   {if(!settings.debug.value) "" else " in "+context0.unit}+
-                                   {if (sym0.isMacro && sym1.isMacro) " \n(note that macros cannot be overloaded)" else ""})
+      // checkNoDoubleDefs...
+      // @PP: I hacked the filename in (context0.unit) to work around SI-4893.  It would be
+      // much better if every symbol could offer some idea of where it came from, else
+      // the obviously untrue claim that something has been defined twice can only frustrate.
+      // There's no direct test because partest doesn't work, but to reproduce, separately
+      // compile the next two lines:
+      //    package object foo { val x: Class[_] = null }
+      //    package foo
+      def DefDefinedTwiceError(sym0: Symbol, sym1: Symbol) = {
+        val isBug = sym0.isAbstractType && sym1.isAbstractType && (sym0.name startsWith "_$")
+        issueSymbolTypeError(sym0, sym1+" is defined twice in " + context0.unit
+          + ( if (sym0.isMacro && sym1.isMacro) "\n(note that macros cannot be overloaded)" else "" )
+          + ( if (isBug) "\n(this error is likely due to a bug in the scala compiler involving wildcards in package objects)" else "" )
+        )
+      }
 
       // cyclic errors
      def CyclicAliasingOrSubtypingError(errPos: Position, sym0: Symbol) =
diff --git a/test/files/neg/t200.check b/test/files/neg/t200.check
index 78701f8533..3ef6665fe5 100644
--- a/test/files/neg/t200.check
+++ b/test/files/neg/t200.check
@@ -1,4 +1,4 @@
-t200.scala:7: error: method foo is defined twice
+t200.scala:7: error: method foo is defined twice in t200.scala
   def foo: Int;
       ^
 one error found
diff --git a/test/files/neg/t2779.check b/test/files/neg/t2779.check
index 4f94a780a1..d642541e3e 100644
--- a/test/files/neg/t2779.check
+++ b/test/files/neg/t2779.check
@@ -1,4 +1,4 @@
-t2779.scala:16: error: method f is defined twice
+t2779.scala:16: error: method f is defined twice in t2779.scala
     override def f = List(M1)
                  ^
 one error found
diff --git a/test/files/neg/t278.check b/test/files/neg/t278.check
index 675ef910ee..0c2dfeb67a 100644
--- a/test/files/neg/t278.check
+++ b/test/files/neg/t278.check
@@ -4,7 +4,7 @@ t278.scala:5: error: overloaded method value a with alternatives:
  does not take type parameters
   println(a[A])
           ^
-t278.scala:4: error: method a is defined twice
+t278.scala:4: error: method a is defined twice in t278.scala
   def a = (p:A) => ()
       ^
 two errors found
diff --git a/test/files/neg/t591.check b/test/files/neg/t591.check
index 434c2dd002..5cdeebf079 100644
--- a/test/files/neg/t591.check
+++ b/test/files/neg/t591.check
@@ -1,4 +1,4 @@
-t591.scala:38: error: method input_= is defined twice
+t591.scala:38: error: method input_= is defined twice in t591.scala
     def input_=(in : Input) = {}
         ^
 one error found
diff --git a/test/files/neg/t800.check b/test/files/neg/t800.check
index 4bfba5420b..44c316a95b 100644
--- a/test/files/neg/t800.check
+++ b/test/files/neg/t800.check
@@ -1,13 +1,13 @@
 t800.scala:4: error: qualification is already defined as value qualification
   val qualification = false;
       ^
-t800.scala:8: error: method qualification is defined twice
+t800.scala:8: error: method qualification is defined twice in t800.scala
   val qualification = false;
       ^
-t800.scala:12: error: value qualification is defined twice
+t800.scala:12: error: value qualification is defined twice in t800.scala
   var qualification = false;
       ^
-t800.scala:16: error: method qualification is defined twice
+t800.scala:16: error: method qualification is defined twice in t800.scala
   var qualification = false;
       ^
 four errors found
diff --git a/test/files/neg/t960.check b/test/files/neg/t960.check
index 4cc76d3602..603b1cb032 100644
--- a/test/files/neg/t960.check
+++ b/test/files/neg/t960.check
@@ -7,7 +7,7 @@ match argument types (List[a])
 t960.scala:22: error: cannot resolve overloaded unapply
     case List(x, xs) => 7
          ^
-t960.scala:12: error: method unapply is defined twice
+t960.scala:12: error: method unapply is defined twice in t960.scala
   def unapply[a](xs: List[a]): Option[Null] = xs match {
       ^
-three errors found
\ No newline at end of file
+three errors found
diff --git a/test/pending/run/t4511b.scala b/test/pending/run/t4511b.scala
new file mode 100644
index 0000000000..3337fb3203
--- /dev/null
+++ b/test/pending/run/t4511b.scala
@@ -0,0 +1,25 @@
+import scala.{specialized => spec}
+
+class Interval[@spec(Int) T](high:T)
+
+class X1[@spec(Int) T](interval:Interval[T]) { val x = interval }
+class Y1[@spec(Int) T](interval:Interval[T]) { val y = Some(interval) }
+
+class X2[T](val interval:Interval[T]) { val x = interval }
+class Y2[T](val interval:Interval[T]) { val y = Some(interval) }
+
+class X3[@spec(Int) T](val interval:Interval[T]) { val x = interval }
+class Y3[@spec(Int) T](val interval:Interval[T]) { val y = Some(interval) }
+
+object Test {
+ def tryit(o: => Any) = println(try { "ok: " + o.getClass.getName } catch { case e => "FAIL: " + e + "\n" + e.getStackTrace.mkString("\n  ") })
+
+ def main(args: Array[String]) {
+   tryit(new X1(new Interval(3)))
+   tryit(new X2(new Interval(3)))
+   tryit(new X3(new Interval(3)))
+   tryit(new Y1(new Interval(3)))
+   tryit(new Y2(new Interval(3)))
+   tryit(new Y3(new Interval(3)))
+ }
+}