workaround for a possible scala bug

core/src/main/scala/cats/Show.scala

@@ -13,11 +13,12 @@ import cats.functor.Contravariant
 @typeclass trait Show[T] extends Show.ContravariantShow[T] {
   // duplicated so simulacrum knows it requires an instance of this trait
   def show(t: T): String
+  def _show(t: T): String = show(t)
 }
 
 object Show {
   trait ContravariantShow[-T] {
-    def show(t: T): String
+    def _show(t: T): String
   }
 
   /** creates an instance of [[Show]] using the provided function */
@@ -32,7 +33,7 @@ object Show {
 
   final case class Shown(override val toString: String) extends AnyVal
   object Shown {
-    implicit def mat[A](x: A)(implicit z: ContravariantShow[A]): Shown = Shown(z show x)
+    implicit def mat[A](x: A)(implicit z: ContravariantShow[A]): Shown = Shown(z _show x)
   }
 
   final case class ShowInterpolator(_sc: StringContext) extends AnyVal {

tests/src/test/scala/cats/tests/RegressionTests.scala

@@ -4,7 +4,7 @@ package tests
 import cats.data.{Const, NonEmptyList}
 
 import scala.collection.mutable
-
+import RegressionTests._
 class RegressionTests extends CatsSuite {
 
   // toy state class
@@ -123,4 +123,19 @@ class RegressionTests extends CatsSuite {
     NonEmptyList.of(6,7,8).traverse_(validate) should === (Either.left("6 is greater than 5"))
     checkAndResetCount(1)
   }
+
+  test("#1802 duplicated method name") {
+    Show[First[String]]
+  }
+}
+
+
+object RegressionTests {
+  final case class First[A](getFirst: A) extends AnyVal
+  object First {
+    implicit def showInstance[A](implicit ev: Show[A]): Show[First[A]] = new Show[First[A]] {
+      override def show(f: First[A]): String = s"First(${ev.show(f.getFirst)})"
+    }
+  }
+
 }