Expect a specific instance for mock in Scalamock - scala

Question

Why can I not tell a mock that it should expect an instance of a class without explicitly giving the type? Here is what I mean:
val myClass = new MyClass(...)
val traitMock = mock[MyTrait]
(traitMock.mymethod _).expects(myClass).returning(12.3)
does not work, while
val myClass: MyClass = new MyClass(...)
val traitMock = mock[MyTrait]
(traitMock.mymethod _).expects(myClass).returning(12.3)
does work. How come the type can not be inferred?
My testing part in build.sbt is
libraryDependencies ++= Seq(
"org.scalatest" %% "scalatest" % "3.0.0" % "test"
exclude("org.scala-lang", "scala-reflect")
exclude("org.scala-lang.modules", "scala-xml")
)
libraryDependencies += "org.scalamock" %% "scalamock-scalatest-support" % "3.3.0" % "test"
Since I was asked for MyClass (it is SpacePoint here):
trait SpacePoint {
val location: SpaceLocation
}
val sp = new SpacePoint {
override val location: SpaceLocation = new SpaceLocation(DenseVector(1.0, 1.0))
}

Answer 1

So actually it works for me. Let me mention that type inference in the code:
val myClass = new MyClass(...)
has nothing to do with ScalaMock but is guaranteed by scala itself. Below I will specify working sample with library versions and sources of the classes.
Testing libraries:
"org.scalatest" %% "scalatest" % "2.2.4" % "test",
"org.scalamock" %% "scalamock-scalatest-support" % "3.2.2" % "test"
Source code of classes:
class MyClass(val something: String)
trait MyTrait {
def mymethod(smth: MyClass): Double
}
Source code of test:
import org.scalamock.scalatest.MockFactory
import org.scalatest.{Matchers, WordSpec}
class ScalamockTest extends WordSpec with MockFactory with Matchers {
"ScalaMock" should {
"infers type" in {
val myClass = new MyClass("Hello")
val traitMock = mock[MyTrait]
(traitMock.mymethod _).expects(myClass).returning(12.3)
traitMock.mymethod(myClass) shouldBe 12.3
}
}
}
Hope it helps. Will be ready to update answer once you provide more details.