Making a puzzle involving moving a crate around, in order to jump over an obstruction of cast iron or steel, is also okay. Cast iron and steel are solid. We can see that with our own two eyes. Not a stretch. C'mon, it's something we might do in *real life*.
Combining the two isn't okay. The garbage can is an Obstruction, and as such, we can't get past it. It's a solid wall in a gamer's mind - the sheer fact that it's not a steel wall means that we can't treat it like one. It doesn't follow the same rules. You can see how a steel wall will behave because it already behaves like that in real life, but a garbage can? If you can't move it, it also means you can't bypass it. End of story.
You can't have your abstractions and your realism in the same package.