Fix #4184: Add regression test

compiler/test-resources/repl/i4184

@@ -0,0 +1,10 @@
+scala> object foo { class Foo }
+// defined object foo
+scala> object bar { class Foo }
+// defined object bar
+scala> implicit def eqFoo: Eq[foo.Foo, foo.Foo] = Eq
+def eqFoo: Eq[foo.Foo, foo.Foo]
+scala> object Bar { new foo.Foo == new bar.Foo }
+1 | object Bar { new foo.Foo == new bar.Foo }
+  |              ^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |      Values of types foo.Foo and bar.Foo cannot be compared with == or !=

tests/pos/i4184.scala

@@ -0,0 +1,3 @@
+object Bar {
+  true == (true: java.lang.Boolean)
+}