error[E0423]: expected value, found trait `SomeTrait`
  --> $DIR/E0033-teach.rs:8:37
   |
LL |     let trait_obj: &dyn SomeTrait = SomeTrait;
   |                                     ^^^^^^^^^ not a value

error[E0038]: the trait `SomeTrait` cannot be made into an object
  --> $DIR/E0033-teach.rs:8:20
   |
LL |     let trait_obj: &dyn SomeTrait = SomeTrait;
   |                    ^^^^^^^^^^^^^^ `SomeTrait` cannot be made into an object
   |
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
  --> $DIR/E0033-teach.rs:4:8
   |
LL | trait SomeTrait {
   |       --------- this trait cannot be made into an object...
LL |     fn foo();
   |        ^^^ ...because associated function `foo` has no `self` parameter
help: consider turning `foo` into a method by giving it a `&self` argument
   |
LL |     fn foo(&self);
   |            +++++
help: alternatively, consider constraining `foo` so it does not apply to trait objects
   |
LL |     fn foo() where Self: Sized;
   |              +++++++++++++++++

error[E0033]: type `&dyn SomeTrait` cannot be dereferenced
  --> $DIR/E0033-teach.rs:12:9
   |
LL |     let &invalid = trait_obj;
   |         ^^^^^^^^ type `&dyn SomeTrait` cannot be dereferenced
   |
   = note: This error indicates that a pointer to a trait type cannot be implicitly dereferenced by a pattern. Every trait defines a type, but because the size of trait implementors isn't fixed, this type has no compile-time size. Therefore, all accesses to trait types must be through pointers. If you encounter this error you should try to avoid dereferencing the pointer.
           
           You can read more about trait objects in the Trait Objects section of the Reference: https://doc.rust-lang.org/reference/types.html#trait-objects

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0033, E0038, E0423.
For more information about an error, try `rustc --explain E0033`.