SI-7602 Avoid crash in LUBs with erroneous code

If a class contains a double defintion of a method that overrides
an interface method, LUBs could run into a spot where filtering
overloaded alternatives to those that match the interface method
fails to resolve to a single overload, which crashes the compiler.

This commit uses `filter` rather than `suchThat` to avoid the crash.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/files/neg/t7602.scala b/test/files/neg/t7602.scala
new file mode 100644
index 0000000000..5a9444a1ab
--- /dev/null
+++ b/test/files/neg/t7602.scala
@@ -0,0 +1,26 @@
+trait Table[T]{
+  def foo : T
+}
+trait Computer
+trait Device
+ 
+object schema{
+  def lub[T]( a:T, b:T ) = ???
+  lub(null:Computers,null:Devices)
+}
+trait Computers extends Table[Computer]{
+  def foo : Computer
+}
+trait Devices extends Table[Device]{
+  def foo : Device
+  def foo : Device
+}
+/* Was:
+Exception in thread "main" java.lang.AssertionError: assertion failed: List(method foo, method foo)
+        at scala.Predef$.assert(Predef.scala:165)
+        at scala.reflect.internal.Symbols$Symbol.suchThat(Symbols.scala:1916)
+        at scala.reflect.internal.tpe.GlbLubs$$anonfun$23.apply(GlbLubs.scala:350)
+        at scala.reflect.internal.tpe.GlbLubs$$anonfun$23.apply(GlbLubs.scala:349)
+        at scala.collection.immutable.List.map(List.scala:272)
+        at scala.reflect.internal.tpe.GlbLubs$class.lubsym$1(GlbLubs.scala:349)
+*/
\ No newline at end of file