Error E0308 (type mismatch) is sometimes confusing

[jdahlstrom]

Consider the following short snippet (playground):

fn bar<T>(_: T, _: T) {}

fn foo<T, U>(t: T, u: U) {
    bar(t, u);
}

It has a type error, of course, but the error message is not the most helpful. At least to me it seems to imply that the compiler found a literal type parameter (ie. in this case T or U) but expects another type parameter, when in actuality it's about values of those types. The note helps a bit though.

error[E0308]: mismatched types
 --> src/main.rs:4:12
  |
4 |     bar(t, u);
  |            ^ expected type parameter, found a different type parameter
  |
  = note: expected type `T`
             found type `U`

[jdahlstrom]

Oops, this is a near duplicate of #47319. Closing.