Expected operator, found EOI

[lambdaknight]

Describe the bug
Pratt parser fails to parse a set of Pairs if EOI is included in them.

To Reproduce
Steps to reproduce the behavior:

1. Modify the derive/examples/calc.rs example to not do the calls on lines 93-98.

Expected behavior
It should work?

Additional context
Seems like EOI should be ignored or handled in some other way than requiring you to manually handle the parse tree for one level.

[lambdaknight]

Also of note is that it seems like going one level deep into the parse tree isn't enough. A call to pairs.next().unwrap().into_inner() returns the expr just below program, but it still has the EOI token in the Pairs

[tomtau]

@segeljakt

[tenstad]

.op(Op::postfix(Rule::EOI))

and

.map_postfix(|lhs, op| match op.as_rule() {
    Rule::EOI => lhs,

seems to work 😄