SI-8900 Don't assert !isDelambdafyFunction, it may not be accurate

The implementations of isAnonymousClass, isAnonymousFunction,
isDelambdafyFunction and isDefaultGetter check if a specific substring
(eg "$lambda") exists in the symbol's name.

SI-8900 shows an example where a class ends up with "$lambda" in its
name even though it's not a delambdafy lambda class. In this case the
conflict seems to be introduced by a macro. It is possible that the
compiler itself never introduces such names, but in any case, the
above methods should be implemented more robustly.

This commit is band-aid, it fixes one specific known issue, but there
are many calls to the mentioned methods across the compiler which
are potentially wrong.

Thanks to Jason for the test case!

1 files changed, 11 insertions, 0 deletions

diff --git a/test/files/pos/t8900.scala b/test/files/pos/t8900.scala
new file mode 100644
index 0000000000..376bd786f2
--- /dev/null
+++ b/test/files/pos/t8900.scala
@@ -0,0 +1,11 @@
+package foo
+package lambdaking
+
+class Test {
+  def byname(b: => Any) = ???
+  def foo: Any = {
+    def bar: Any = {
+      byname(bar)
+    }
+  }
+}