corrected several problems with error reporting...

corrected several problems with error reporting: positions checked
twice, warnings masking errors. Refined solution of forward implicits
without5 result type.

13 files changed, 91 insertions, 29 deletions

diff --git a/src/compiler/scala/tools/nsc/CompilationUnits.scala b/src/compiler/scala/tools/nsc/CompilationUnits.scala
index f536a16a62..bf02e114ab 100644
--- a/src/compiler/scala/tools/nsc/CompilationUnits.scala
+++ b/src/compiler/scala/tools/nsc/CompilationUnits.scala
@@ -44,19 +44,11 @@ trait CompilationUnits { self: Global =>
      */
     val icode: HashSet[icodes.IClass] = new HashSet
 
-    val errorPositions = new HashSet[Position]
-
     def error(pos: Position, msg: String) =
-      if (inIDE || !(errorPositions contains pos)) {
-        if (!inIDE) errorPositions += pos
-        reporter.error((pos), msg)
-      }
+      reporter.error(pos, msg)
 
     def warning(pos: Position, msg: String) =
-      if (inIDE || !(errorPositions contains pos)) {
-        if (!inIDE) errorPositions += pos
-        reporter.warning((pos), msg)
-      }
+      reporter.warning(pos, msg)
 
     def deprecationWarning(pos: Position, msg: String) =
       if (settings.deprecation.value) warning(pos, msg)
@@ -67,10 +59,7 @@ trait CompilationUnits { self: Global =>
       else currentRun.uncheckedWarnings = true
 
     def incompleteInputError(pos: Position, msg:String) =
-      if (inIDE || !(errorPositions contains pos)) {
-        if (!inIDE) errorPositions += pos
-        reporter.incompleteInputError((pos), msg)
-      }
+      reporter.incompleteInputError(pos, msg)
 
     /** Is this about a .java source file? */
     lazy val isJava = source.file.name.endsWith(".java")
@@ -81,7 +70,6 @@ trait CompilationUnits { self: Global =>
       fresh = null
       body = null
       depends.clear
-      errorPositions.clear
       defined.clear
     }
   }
diff --git a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
index 52c1cacb29..f38f0cde1e 100755
--- a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
+++ b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
@@ -32,7 +32,7 @@ trait JavaParsers extends JavaScanners {
   abstract class JavaParser {
 
     val in: JavaScanner
-    protected def posToReport: Int = in.p2g(in.currentPos)
+    protected def posToReport: Int = in.currentPos
     protected def freshName(pos : Position, prefix : String): Name
     protected implicit def i2p(offset : Int) : Position
     private implicit def p2i(pos : Position): Int = pos.offset.getOrElse(-1)
diff --git a/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala b/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
index 53cbbddcc7..a4f682a715 100644
--- a/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
+++ b/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
@@ -6,7 +6,7 @@
 
 package scala.tools.nsc.reporters
 
-import scala.collection.mutable.HashSet
+import scala.collection.mutable.HashMap
 import scala.tools.nsc.Settings
 import scala.tools.nsc.util.Position
 
@@ -14,7 +14,7 @@ import scala.tools.nsc.util.Position
  * This reporter implements filtering.
  */
 abstract class AbstractReporter extends Reporter {
-  private val positions = new HashSet[Position]()
+  private val positions = new HashMap[Position, Severity]
 
   override def reset = {
     super.reset
@@ -31,13 +31,13 @@ abstract class AbstractReporter extends Reporter {
       case INFO    =>
         if (force || settings.verbose.value) display(pos, msg, severity)
       case WARNING =>
-        val hidden = testAndLog(pos)
+        val hidden = testAndLog(pos, severity)
         if (!settings.nowarnings.value) {
 	  if (!hidden || settings.prompt.value) display(pos, msg, severity)
 	  if (settings.prompt.value) displayPrompt
         }
       case ERROR =>
-        val hidden = testAndLog(pos)
+        val hidden = testAndLog(pos, severity)
         if (!hidden || settings.prompt.value) display(pos, msg, severity)
         if (settings.prompt.value) displayPrompt
     }
@@ -48,11 +48,11 @@ abstract class AbstractReporter extends Reporter {
    *  @param pos ...
    *  @return    <code>true</code> if <code>pos</code> was already logged.
    */
-  private def testAndLog(pos: Position): Boolean = {
+  private def testAndLog(pos: Position, severity: Severity): Boolean = {
     if (pos eq null) return false
     if (pos.offset.isEmpty) return false
-    if (positions contains pos) return true
-    positions += pos
+    if ((positions contains pos) && positions(pos) >= severity) return true
+    positions += (pos -> severity)
     false
   }
 
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 51288bab2e..567ff3479e 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -197,6 +197,14 @@ trait Infer {
 
     /* -- Error Messages --------------------------------------------------- */
 
+    private var addendumPos: Position = NoPosition
+    private var addendum: () => String = _
+
+    def setAddendum(pos: Position, msg: () => String) = {
+      addendumPos = pos
+      addendum = msg
+    }
+
     def setError[T <: Tree](tree: T): T = {
       if (tree.hasSymbol)
         if (context.reportGeneralErrors) {
@@ -265,7 +273,10 @@ trait Infer {
 
     def typeError(pos: Position, found: Type, req: Type) {
       if (!found.isErroneous && !req.isErroneous) {
-        error(pos, typeErrorMsg(found, req))
+        error(pos,
+              typeErrorMsg(found, req)+
+              (if (pos != NoPosition && pos == addendumPos) addendum()
+               else ""))
         if (settings.explaintypes.value) explainTypes(found, req)
       }
     }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 4d57d8bc33..138d2f469d 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3648,6 +3648,7 @@ trait Typers { self: Analyzer =>
         def comesBefore(sym: Symbol, owner: Symbol) =
           sym.pos.offset.getOrElse(0) < owner.pos.offset.getOrElse(Integer.MAX_VALUE) &&
           !(owner.ownerChain contains sym)
+
         /** Should implicit definition symbol `sym' be considered for applicability testing?
          *  This is the case if one of the following holds:
          *   - the symbol's type is initialized
@@ -3666,19 +3667,27 @@ trait Typers { self: Analyzer =>
           hasExplicitResultType(sym) ||
           comesBefore(sym, context.owner)
         }
+        val lateImpls = new ListBuffer[Symbol]
         def isApplicable(info: ImplicitInfo): Boolean =
-          (true /* for now */ || isValid(info.sym)) &&
           !containsError(info.tpe) &&
           !(isLocal && shadowed.contains(info.name)) &&
           (!isView || info.sym != Predef_identity) &&
           tc.typedImplicit(pos, info, pt0, pt, isLocal) != EmptyTree
-        def applicableInfos(is: List[ImplicitInfo]) = {
-          val result = is filter isApplicable
+        def applicableInfos(is: List[ImplicitInfo]): List[ImplicitInfo] = {
+          val applicable = new ListBuffer[ImplicitInfo]
+          for (i <- is)
+            if (!isValid(i.sym)) lateImpls += i.sym
+            else if (isApplicable(i)) applicable += i
           if (isLocal)
             for (i <- is) shadowed addEntry i.name
-          result
+          applicable.toList
+        }
+        val applicable = implicitInfoss flatMap applicableInfos
+        if (applicable.isEmpty && !lateImpls.isEmpty) {
+          infer.setAddendum(pos, () =>
+            "\n Note: implicit "+lateImpls.first+" is not applicable here"+
+            "\n because it comes after the application point and it lacks an explicit result type")
         }
-        val applicable = List.flatten(implicitInfoss map applicableInfos)
         val best = (NoImplicitInfo /: applicable) ((best, alt) => if (improves(alt, best)) alt else best)
         if (best == NoImplicitInfo) EmptyTree
         else {
diff --git a/test/files/neg/t1049.check b/test/files/neg/t1049.check
new file mode 100755
index 0000000000..4a63cb175d
--- /dev/null
+++ b/test/files/neg/t1049.check
@@ -0,0 +1,4 @@
+t1049.scala:6: error: not found: value a
+            case a : a.MapTo =>
+                     ^
+one error found
diff --git a/test/files/neg/t1049.scala b/test/files/neg/t1049.scala
new file mode 100755
index 0000000000..2f59ed3c09
--- /dev/null
+++ b/test/files/neg/t1049.scala
@@ -0,0 +1,9 @@
+class J {
+    type tttt[a, b] <: _root_.scala.collection.mutable.Map[a, b]
+
+    def r(aa : tttt[String, String]) = {
+        0 match {
+            case a : a.MapTo =>
+        }
+    }
+}
diff --git a/test/files/pos/t1001.scala b/test/files/pos/t1001.scala
new file mode 100755
index 0000000000..88321e6e8e
--- /dev/null
+++ b/test/files/pos/t1001.scala
@@ -0,0 +1,6 @@
+class Foo;
+
+object Overload{
+  val foo = classOf[Foo].getConstructors()(0)
+  foo.getDeclaringClass
+}
diff --git a/test/files/pos/t1049.scala b/test/files/pos/t1049.scala
new file mode 100755
index 0000000000..dad83579a6
--- /dev/null
+++ b/test/files/pos/t1049.scala
@@ -0,0 +1,9 @@
+class J {
+    type tttt[a, b] <: _root_.scala.collection.mutable.Map[a, b]
+
+    def r(a : tttt[String, String]) = {
+        0 match {
+            case a : a.MapTo =>
+        }
+    }
+}
diff --git a/test/pending/pos/t0816.scala b/test/pending/pos/t0816.scala
new file mode 100644
index 0000000000..44282ea872
--- /dev/null
+++ b/test/pending/pos/t0816.scala
@@ -0,0 +1,12 @@
+abstract class Atest(val data: String)
+
+case class Btest(override val data: String, val b: boolean) extends Atest(data)
+
+case class Ctest(override val data: String) extends Btest(data, true)
+
+class testCaseClass {
+  def test(x: Atest) = x match {
+    case Ctest(data) => Console.println("C")
+    case Btest(data, b) => Console.println("B")
+  }
+}
diff --git a/test/pending/pos/t1053.scala b/test/pending/pos/t1053.scala
new file mode 100755
index 0000000000..1d4dfb637e
--- /dev/null
+++ b/test/pending/pos/t1053.scala
@@ -0,0 +1,6 @@
+trait T[A] { trait U { type W = A; val x = 3 } }
+
+object Test {
+  val x : ({ type V = T[this.type] })#V = null
+  val y = new x.U { }
+}
diff --git a/test/pending/pos/t1131.scala b/test/pending/pos/t1131.scala
new file mode 100755
index 0000000000..5ef980348d
--- /dev/null
+++ b/test/pending/pos/t1131.scala
@@ -0,0 +1,4 @@
+trait A { self: Any { def p: Any } =>
+  def f(b: => Unit) {}
+  f { p }
+}
diff --git a/test/pending/run/t1044.scala b/test/pending/run/t1044.scala
new file mode 100644
index 0000000000..136cc51af2
--- /dev/null
+++ b/test/pending/run/t1044.scala
@@ -0,0 +1,4 @@
+object Main extends Application{
+ val ducks = Array[AnyRef]("Huey", "Dewey", "Louie")
+ ducks.elements/*.asInstanceOf[Iterator[String]]*/
+}