diff --git a/core/src/main/scala/cats/data/EitherT.scala b/core/src/main/scala/cats/data/EitherT.scala
index 13724cc88b..e473ff9ae0 100644
--- a/core/src/main/scala/cats/data/EitherT.scala
+++ b/core/src/main/scala/cats/data/EitherT.scala
@@ -1186,13 +1186,13 @@ private[data] trait EitherTSemigroupK[F[_], L] extends SemigroupK[EitherT[F, L,
   def combineK[A](x: EitherT[F, L, A], y: EitherT[F, L, A]): EitherT[F, L, A] =
     EitherT(F.flatMap(x.value) {
       case r @ Right(_) => F.pure(r)
-      case _            => y.value
+      case Left(_)      => y.value
     })
 
   override def combineKEval[A](x: EitherT[F, L, A], y: Eval[EitherT[F, L, A]]): Eval[EitherT[F, L, A]] =
     Eval.now(EitherT(F.flatMap(x.value) {
       case r @ Right(_) => F.pure(r: Either[L, A])
-      case _            => y.value.value
+      case Left(_)      => y.value.value
     }))
 }
 
diff --git a/core/src/main/scala/cats/data/Ior.scala b/core/src/main/scala/cats/data/Ior.scala
index ce6c0410fd..68379989a8 100644
--- a/core/src/main/scala/cats/data/Ior.scala
+++ b/core/src/main/scala/cats/data/Ior.scala
@@ -941,7 +941,7 @@ sealed abstract private[data] class IorInstances extends IorInstances0 {
               ff match {
                 case Ior.Left(e2)    => Ior.Left(E.combine(e2, e1))
                 case Ior.Both(e2, _) => Ior.Left(E.combine(e2, e1))
-                case _               => Ior.Left(e1)
+                case Ior.Right(_)    => Ior.Left(e1)
               }
           }
       }
diff --git a/core/src/main/scala/cats/data/Validated.scala b/core/src/main/scala/cats/data/Validated.scala
index 48a12f8356..f67ea8d799 100644
--- a/core/src/main/scala/cats/data/Validated.scala
+++ b/core/src/main/scala/cats/data/Validated.scala
@@ -908,8 +908,8 @@ sealed abstract private[data] class ValidatedInstances extends ValidatedInstance
             }
           case Valid(a) =>
             fb match {
-              case Valid(b) => Valid(f(Ior.both(a, b)))
-              case _        => Valid(f(Ior.left(a)))
+              case Valid(b)   => Valid(f(Ior.both(a, b)))
+              case Invalid(_) => Valid(f(Ior.left(a)))
             }
         }
     }
diff --git a/core/src/main/scala/cats/instances/either.scala b/core/src/main/scala/cats/instances/either.scala
index 6ad19ebb50..586abc48c8 100644
--- a/core/src/main/scala/cats/instances/either.scala
+++ b/core/src/main/scala/cats/instances/either.scala
@@ -201,12 +201,12 @@ trait EitherInstances extends cats.kernel.instances.EitherInstances {
           case Right(b) =>
             fc match {
               case Right(c) => Right(f(Ior.both(b, c)))
-              case _        => Right(f(Ior.left(b)))
+              case Left(_)  => Right(f(Ior.left(b)))
             }
           case left @ Left(_) =>
             fc match {
               case Right(c) => Right(f(Ior.right(c)))
-              case _        => left.rightCast[D]
+              case Left(_)  => left.rightCast[D]
             }
         }