error[E0282]: type annotations needed for `Foo<N>`
  --> $DIR/doesnt_infer.rs:11:9
   |
LL |     let foo = Foo::foo();
   |         ^^^
   |
help: consider giving `foo` an explicit type, where the value of const parameter `N` is specified
   |
LL |     let foo: Foo<N> = Foo::foo();
   |            ++++++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0282`.