Created TypeDiagnostics trait and have begun op...

Created TypeDiagnostics trait and have begun opportunistically moving
code into it. Along the way, some improvements to error messages.
The situation described in ticket #2206 has always had an applicable
error message, but it wasn't making it out to the user. More kinds of
ambiguity are disambiguated, see the test cases. And overload errors are
printed with some formatting so one has some hope of parsing. Review by
odersky.

6 files changed, 42 insertions, 2 deletions

diff --git a/test/files/neg/bug2206.check b/test/files/neg/bug2206.check
new file mode 100644
index 0000000000..3deb4d99ef
--- /dev/null
+++ b/test/files/neg/bug2206.check
@@ -0,0 +1,5 @@
+bug2206.scala:10: error: value f is not a member of o.A
+ Note: implicit method ax is not applicable here because it comes after the application point and it lacks an explicit result type
+  a.f()
+    ^
+one error found
diff --git a/test/files/neg/bug2206.scala b/test/files/neg/bug2206.scala
new file mode 100644
index 0000000000..cd2ec225e9
--- /dev/null
+++ b/test/files/neg/bug2206.scala
@@ -0,0 +1,15 @@
+object o {
+  class A
+
+  class AX {
+      def f() { }
+  }
+
+  import Implicits._
+  val a = new A
+  a.f()
+
+  object Implicits {
+      implicit def ax(a: A) = new AX
+  }
+}
\ No newline at end of file
diff --git a/test/files/neg/bug278.check b/test/files/neg/bug278.check
index a3d44f6508..ad0a97371e 100644
--- a/test/files/neg/bug278.check
+++ b/test/files/neg/bug278.check
@@ -1,4 +1,7 @@
-bug278.scala:5: error: overloaded method value a with alternatives => (C.this.A) => Unit <and> => () => Unit does not take type parameters
+bug278.scala:5: error: overloaded method value a with alternatives:
+  => (C.this.A) => Unit <and>
+  => () => Unit
+ does not take type parameters
   a[A]
   ^
 bug278.scala:4: error: method a is defined twice
diff --git a/test/files/neg/overload-msg.check b/test/files/neg/overload-msg.check
new file mode 100644
index 0000000000..780830bff9
--- /dev/null
+++ b/test/files/neg/overload-msg.check
@@ -0,0 +1,13 @@
+overload-msg.scala:3: error: overloaded method value + with alternatives:
+  (Double)Double <and>
+  (Float)Float <and>
+  (Long)Long <and>
+  (scala.Int)scala.Int <and>
+  (Char)scala.Int <and>
+  (Short)scala.Int <and>
+  (Byte)scala.Int <and>
+  (java.lang.String)java.lang.String
+ cannot be applied to (Int(in method f))
+  def f[Int](y: Int) = x + y
+                       ^
+one error found
diff --git a/test/files/neg/overload-msg.scala b/test/files/neg/overload-msg.scala
new file mode 100644
index 0000000000..8715c156a2
--- /dev/null
+++ b/test/files/neg/overload-msg.scala
@@ -0,0 +1,4 @@
+// type parameter shadows actual type, massive overload error confuses.
+class A(x: Int) {
+  def f[Int](y: Int) = x + y
+}
diff --git a/test/files/neg/typeerror.check b/test/files/neg/typeerror.check
index 3e21a79ad5..3ce11dad8a 100644
--- a/test/files/neg/typeerror.check
+++ b/test/files/neg/typeerror.check
@@ -1,6 +1,6 @@
 typeerror.scala:6: error: type mismatch;
  found   : Long(in method add)
- required: Long(in package scala)
+ required: scala.Long
     else add2(x.head, y.head) :: add(x.tail, y.tail)
                 ^
 one error found