From 5bd8ea0edffe7b725e5fa665a82a5795d5dafe8f Mon Sep 17 00:00:00 2001 From: Brian McKenna Date: Sun, 7 Sep 2014 12:33:52 -0600 Subject: SI-6806 Add an @implicitAmbiguous annotation Example usage: trait =!=[C, D] implicit def neq[E, F] : E =!= F = null @annotation.implicitAmbiguous("Could not prove ${J} =!= ${J}") implicit def neqAmbig1[G, H, J] : J =!= J = null implicit def neqAmbig2[I] : I =!= I = null implicitly[Int =!= Int] Which gives the following error: implicit-ambiguous.scala:9: error: Could not prove Int =!= Int implicitly[Int =!= Int] ^ Better than what was previously given: implicit-ambiguous.scala:9: error: ambiguous implicit values: both method neqAmbig1 in object Test of type [G, H, J]=> Main.$anon.Test.=!=[J,J] and method neqAmbig2 in object Test of type [I]=> Main.$anon.Test.=!=[I,I] match expected type Main.$anon.Test.=!=[Int,Int] implicitly[Int =!= Int] ^ --- test/files/neg/implicit-ambiguous-invalid.scala | 6 ++++++ 1 file changed, 6 insertions(+) create mode 100644 test/files/neg/implicit-ambiguous-invalid.scala (limited to 'test/files/neg/implicit-ambiguous-invalid.scala') diff --git a/test/files/neg/implicit-ambiguous-invalid.scala b/test/files/neg/implicit-ambiguous-invalid.scala new file mode 100644 index 0000000000..f8f9da655f --- /dev/null +++ b/test/files/neg/implicit-ambiguous-invalid.scala @@ -0,0 +1,6 @@ +object Test { + trait =!=[C, D] + + @annotation.implicitAmbiguous("Could not prove ${A} =!= ${B}") + implicit def neqAmbig1[A] : A =!= A = null +} -- cgit v1.2.3