PRINT-BANG INPUT (DISPLAY): 0 + 1 + 2 + 3
PRINT-BANG INPUT (DEBUG): TokenStream [
    Group {
        delimiter: None,
        stream: TokenStream [
            Group {
                delimiter: None,
                stream: TokenStream [
                    Group {
                        delimiter: None,
                        stream: TokenStream [
                            Literal {
                                kind: Integer,
                                symbol: "0",
                                suffix: None,
                                span: $DIR/nested-nonterminal-tokens.rs:25:26: 25:27 (#0),
                            },
                        ],
                        span: $DIR/nested-nonterminal-tokens.rs:17:41: 17:43 (#4),
                    },
                    Punct {
                        ch: '+',
                        spacing: Alone,
                        span: $DIR/nested-nonterminal-tokens.rs:17:44: 17:45 (#4),
                    },
                    Literal {
                        kind: Integer,
                        symbol: "1",
                        suffix: None,
                        span: $DIR/nested-nonterminal-tokens.rs:17:46: 17:47 (#4),
                    },
                ],
                span: $DIR/nested-nonterminal-tokens.rs:18:41: 18:43 (#5),
            },
            Punct {
                ch: '+',
                spacing: Alone,
                span: $DIR/nested-nonterminal-tokens.rs:18:44: 18:45 (#5),
            },
            Literal {
                kind: Integer,
                symbol: "2",
                suffix: None,
                span: $DIR/nested-nonterminal-tokens.rs:18:46: 18:47 (#5),
            },
        ],
        span: $DIR/nested-nonterminal-tokens.rs:20:21: 20:23 (#6),
    },
    Punct {
        ch: '+',
        spacing: Alone,
        span: $DIR/nested-nonterminal-tokens.rs:20:24: 20:25 (#6),
    },
    Literal {
        kind: Integer,
        symbol: "3",
        suffix: None,
        span: $DIR/nested-nonterminal-tokens.rs:20:26: 20:27 (#6),
    },
]