Improved structural type error messages, and ot...

Improved structural type error messages, and other error message related
boosts. Closes SI-4877, review by odersky.

3 files changed, 45 insertions, 0 deletions

diff --git a/test/files/neg/bug4877.check b/test/files/neg/bug4877.check
new file mode 100644
index 0000000000..6970271c40
--- /dev/null
+++ b/test/files/neg/bug4877.check
@@ -0,0 +1,22 @@
+bug4877.scala:4: error: type mismatch;
+ found   : java.lang.Object{def bar: Int}
+ required: AnyRef{def bar: String}
+  def foo: AnyRef { def bar: String } = new AnyRef { def bar = 42 }
+                                        ^
+bug4877.scala:6: error: type mismatch;
+ found   : java.lang.Object{def bar(x: Int): java.lang.String}
+ required: AnyRef{def bar(x: Int): Int}
+  def foo3: AnyRef { def bar(x: Int): Int } = new AnyRef { def bar(x: Int) = "abc" }
+                                              ^
+bug4877.scala:7: error: type mismatch;
+ found   : java.lang.Object with C{def bar(x: Int): Int}
+ required: C{def bar(x: Int): Int; def quux(x: Int): Int}
+  def foo4: C { def bar(x: Int): Int ; def quux(x: Int): Int } = new C { def bar(x: Int) = 5 }
+                                                                 ^
+bug4877.scala:17: error: type mismatch;
+ found   : java.lang.Object{type Mom = String; def bar(x: Int): Int; def bippy(): List[Int]}
+ required: B.this.Bippy    (which expands to)
+             AnyRef{type Mom; def bar(x: Int): this.Mom; def bippy(): List[this.Mom]}
+  val x: Bippy = new AnyRef {
+                 ^
+four errors found
diff --git a/test/files/neg/bug4877.flags b/test/files/neg/bug4877.flags
new file mode 100644
index 0000000000..7ccd56103a
--- /dev/null
+++ b/test/files/neg/bug4877.flags
@@ -0,0 +1 @@
+-Xlint
\ No newline at end of file
diff --git a/test/files/neg/bug4877.scala b/test/files/neg/bug4877.scala
new file mode 100644
index 0000000000..5d97877518
--- /dev/null
+++ b/test/files/neg/bug4877.scala
@@ -0,0 +1,22 @@
+trait C { }
+
+class A {
+  def foo: AnyRef { def bar: String } = new AnyRef { def bar = 42 }
+  def foo2: AnyRef { def bar: String } = new AnyRef { def bar = "abc" }
+  def foo3: AnyRef { def bar(x: Int): Int } = new AnyRef { def bar(x: Int) = "abc" }
+  def foo4: C { def bar(x: Int): Int ; def quux(x: Int): Int } = new C { def bar(x: Int) = 5 }
+}
+
+class B {
+  type Bippy = {
+    type Mom
+    def bar(x: Int): Mom
+    def bippy(): List[Mom]
+  }
+
+  val x: Bippy = new AnyRef {
+    type Mom = String
+    def bar(x: Int) = 55
+    def bippy() = List(bar(55))
+  }
+}
\ No newline at end of file