SI-6440 Address regressions around MissingRequirementError

 Go back to using globalError to report when a stub's info is referenced,
 and only throw the MissingRequirementError when compilation really
 must abort due to having a StubTermSymbol in a place where a
 StubClassSymbol would have been a better choice.

 This situation arises when an entire package is missing from the
 classpath, as was the case in the reported bug.

 Adds `StoreReporterDirectTest`, which buffers messages issued
 during compilation for more structured interrogation. Use this
 in two test for manifests -- these tests were using a crude means
 of grepping compiler console output to focus on the relevant output,
 but this approach was insufficient with the new multi-line error
 message emitted as part of this change.

 Also used that base test class to add two new tests: one for
 the reported error (package missing), and another for a simpler
 error (class missing). The latter test shows how stub symbols
 allow code to compile if it doesn't the subset of signatures
 in some type that refer to a missing class.

 Gave the INFO/WARNING/ERROR members of Reporter sensible
 toString implementations; they inherit from Enumeration#Value
 in an unusual manner (why?) that means the built in toString of
 Enumeration printed `Severity@0`.

9 files changed, 139 insertions, 27 deletions

diff --git a/test/files/neg/t5148.check b/test/files/neg/t5148.check
index 6edfdf2b1e..25107c4dbe 100644
--- a/test/files/neg/t5148.check
+++ b/test/files/neg/t5148.check
@@ -1,3 +1,9 @@
-error: bad symbolic reference to value global in class IMain - referenced from t5148.scala (a classfile may be missing)
-error: bad symbolic reference to value memberHandlers in class IMain - referenced from t5148.scala (a classfile may be missing)
+error: bad symbolic reference. A signature in Imports.class refers to term global
+in class scala.tools.nsc.interpreter.IMain which is not available.
+It may be completely missing from the current classpath, or the version on
+the classpath might be incompatible with the version used when compiling Imports.class.
+error: bad symbolic reference. A signature in Imports.class refers to term memberHandlers
+in class scala.tools.nsc.interpreter.IMain which is not available.
+It may be completely missing from the current classpath, or the version on
+the classpath might be incompatible with the version used when compiling Imports.class.
 two errors found
diff --git a/test/files/run/t6440.check b/test/files/run/t6440.check
index b5684daee4..69c253eab4 100644
--- a/test/files/run/t6440.check
+++ b/test/files/run/t6440.check
@@ -1 +1,4 @@
-Stream((), ?)
+pos: source-newSource1,line-9,offset=109 bad symbolic reference. A signature in U.class refers to term pack1
+in package <root> which is not available.
+It may be completely missing from the current classpath, or the version on
+the classpath might be incompatible with the version used when compiling U.class. ERROR
diff --git a/test/files/run/t6440.scala b/test/files/run/t6440.scala
index 2b690f31e1..5a3a4150d9 100644
--- a/test/files/run/t6440.scala
+++ b/test/files/run/t6440.scala
@@ -1,7 +1,48 @@
-object Test {
+import scala.tools.partest._
+import java.io.File
 
-  def main(args: Array[String]): Unit = {
-    println(Stream.continually(()).filterNot(_ => false).take(2))
+object Test extends StoreReporterDirectTest {
+  def code = ???
+
+  def compileCode(code: String) = {
+    val classpath = List(sys.props("partest.lib"), testOutput.path) mkString sys.props("path.separator")
+    compileString(newCompiler("-cp", classpath, "-d", testOutput.path))(code)
   }
 
+  def library1 = """
+    package pack1
+    trait T
+  """
+
+  def library2 = """
+    package pack2
+    trait U extends pack1.T
+  """
+
+  def app = """
+    package pack3
+    object X {
+      trait U
+    }
+    import X._
+    import pack2._
+
+    trait V extends U
+  """
+
+  def show(): Unit = {
+    Seq(library1, library2) foreach compileCode
+    assert(filteredInfos.isEmpty, filteredInfos)
+
+    // blow away the entire package
+    val pack1 = new File(testOutput.path, "pack1")
+    val tClass = new File(pack1, "T.class")
+    assert(tClass.exists)
+    assert(tClass.delete())
+    assert(pack1.delete())
+
+    // bad symbolic reference error expected (but no stack trace!)
+    compileCode(app)
+    println(filteredInfos.mkString("\n"))
+  }
 }
diff --git a/test/files/run/t6440b.check b/test/files/run/t6440b.check
new file mode 100644
index 0000000000..9771ce5efb
--- /dev/null
+++ b/test/files/run/t6440b.check
@@ -0,0 +1,4 @@
+pos: NoPosition bad symbolic reference. A signature in U.class refers to type T
+in package pack1 which is not available.
+It may be completely missing from the current classpath, or the version on
+the classpath might be incompatible with the version used when compiling U.class. ERROR
diff --git a/test/files/run/t6440b.scala b/test/files/run/t6440b.scala
new file mode 100644
index 0000000000..974aca2844
--- /dev/null
+++ b/test/files/run/t6440b.scala
@@ -0,0 +1,61 @@
+import scala.tools.partest._
+import java.io.File
+
+object Test extends StoreReporterDirectTest {
+  def code = ???
+
+  def compileCode(code: String) = {
+    val classpath = List(sys.props("partest.lib"), testOutput.path) mkString sys.props("path.separator")
+    compileString(newCompiler("-cp", classpath, "-d", testOutput.path))(code)
+  }
+
+  def library1 = """
+    package pack1
+    trait T
+    class U {
+      def t = new T {}
+      def one = 1
+    }
+  """
+
+  def library2 = """
+    package pack2
+    object V {
+      def u = new pack1.U
+    }
+    """
+
+  def app1 = """
+    package pack3
+    object Test {
+      pack2.V.u.one // okay
+    }
+  """
+
+  def app2 = """
+    package pack3
+    object Test {
+      pack2.V.u.t // we have to fail if T.class is misisng
+    }
+  """
+
+  def show(): Unit = {
+    compileCode(library1)
+    val pack1 = new File(testOutput.path, "pack1")
+    val tClass = new File(pack1, "T.class")
+    assert(tClass.exists)
+    assert(tClass.delete())
+
+    // allowed to compile, no direct reference to `T`
+    compileCode(library2)
+    assert(filteredInfos.isEmpty, filteredInfos)
+
+    // allowed to compile, no direct reference to `T`
+    compileCode(app1)
+    assert(filteredInfos.isEmpty, filteredInfos)
+
+    // bad symbolic reference error expected (but no stack trace!)
+    compileCode(app2)
+    println(filteredInfos.mkString("\n"))
+  }
+}
diff --git a/test/files/run/typetags_without_scala_reflect_typetag_lookup.check b/test/files/run/typetags_without_scala_reflect_typetag_lookup.check
index 53df68cfc2..8c558ced60 100644
--- a/test/files/run/typetags_without_scala_reflect_typetag_lookup.check
+++ b/test/files/run/typetags_without_scala_reflect_typetag_lookup.check
@@ -1,3 +1,2 @@
-newSource1:9: error: could not find implicit value for evidence parameter of type reflect.runtime.package.universe.TypeTag[Int]
-      Library.foo[Int]
-                 ^
+
+pos: source-newSource1,line-9,offset=466 could not find implicit value for evidence parameter of type reflect.runtime.package.universe.TypeTag[Int] ERROR
diff --git a/test/files/run/typetags_without_scala_reflect_typetag_lookup.scala b/test/files/run/typetags_without_scala_reflect_typetag_lookup.scala
index e51ecdb180..1fbdc62a1e 100644
--- a/test/files/run/typetags_without_scala_reflect_typetag_lookup.scala
+++ b/test/files/run/typetags_without_scala_reflect_typetag_lookup.scala
@@ -1,6 +1,6 @@
 import scala.tools.partest._
 
-object Test extends DirectTest {
+object Test extends StoreReporterDirectTest {
   def code = ???
 
   def library = """
@@ -32,14 +32,12 @@ object Test extends DirectTest {
   }
 
   def show(): Unit = {
-    val prevErr = System.err
-    val baos = new java.io.ByteArrayOutputStream();
-    System.setErr(new java.io.PrintStream(baos));
     compileLibrary();
+    println(filteredInfos.mkString("\n"))
+    storeReporter.infos.clear()
     compileApp();
-    // we should get bad symbolic reference errors, because we're trying to call a method that can't be unpickled
+    // we should get bad symbolic reference errors, because we're trying to use an implicit that can't be unpickled
     // but we don't know the number of these errors and their order, so I just ignore them all
-    baos.toString.split("\n") filter (!_.startsWith("error: bad symbolic reference")) foreach println
-    System.setErr(prevErr)
+    println(filteredInfos.filterNot(_.msg.contains("bad symbolic reference")).mkString("\n"))
   }
-}
\ No newline at end of file
+}
diff --git a/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.check b/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.check
index 729c0715df..acfecce628 100644
--- a/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.check
+++ b/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.check
@@ -1,3 +1,2 @@
-newSource1:9: error: No Manifest available for App.this.T.
-      manifest[T]
-              ^
+
+pos: source-newSource1,line-9,offset=479 No Manifest available for App.this.T. ERROR
diff --git a/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.scala b/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.scala
index e984127583..6804baa0c3 100644
--- a/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.scala
+++ b/test/files/run/typetags_without_scala_reflect_typetag_manifest_interop.scala
@@ -1,6 +1,7 @@
 import scala.tools.partest._
+import scala.tools.nsc.Settings
 
-object Test extends DirectTest {
+object Test extends StoreReporterDirectTest {
   def code = ???
 
   def library = """
@@ -29,18 +30,18 @@ object Test extends DirectTest {
   """
   def compileApp() = {
     val classpath = List(sys.props("partest.lib"), testOutput.path) mkString sys.props("path.separator")
+    val global = newCompiler("-cp", classpath, "-d", testOutput.path)
     compileString(newCompiler("-cp", classpath, "-d", testOutput.path))(app)
+    //global.reporter.ERROR.foreach(println)
   }
 
   def show(): Unit = {
-    val prevErr = System.err
-    val baos = new java.io.ByteArrayOutputStream();
-    System.setErr(new java.io.PrintStream(baos));
     compileLibrary();
+    println(filteredInfos.mkString("\n"))
+    storeReporter.infos.clear()
     compileApp();
     // we should get bad symbolic reference errors, because we're trying to use an implicit that can't be unpickled
     // but we don't know the number of these errors and their order, so I just ignore them all
-    baos.toString.split("\n") filter (!_.startsWith("error: bad symbolic reference")) foreach println
-    System.setErr(prevErr)
+    println(filteredInfos.filterNot (_.msg.contains("bad symbolic reference")).mkString("\n"))
   }
-}
\ No newline at end of file
+}