Unlink type when entering clashing package

Here we unlink the existing type that clashes with the package to be
entered into the symbol table, issue an error and the proceed to enter
the rest of the symbols.

My concern with this approach is what happens during typechecking
if other things reference the unlinked type.

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/neg/i1708.scala b/tests/neg/i1708.scala
new file mode 100644
index 000000000..47bc456f3
--- /dev/null
+++ b/tests/neg/i1708.scala
@@ -0,0 +1,2 @@
+package foo { trait identifier }
+package foo { class identifier } // error