Fuzzer bug test_syntax "after formatting, the source code no longer parsed"

[lukewilliamboswell]

Run on @joshuawarner32's branch for #7353

$ cargo run --bin minimize expr todo
    Finished dev [unoptimized + debuginfo] target(s) in 0.12s
     Running `target/debug/minimize expr todo`
Error found: Reparse failed: Expr(Record(End(@0), @0), @0)
Proceeding with minimization
Successfully minimized, new length: 72
Successfully minimized, new length: 71
Successfully minimized, new length: 64
Successfully minimized, new length: 58
Successfully minimized, new length: 53
Successfully minimized, new length: 48
Successfully minimized, new length: 43
Successfully minimized, new length: 39
Successfully minimized, new length: 36
Successfully minimized, new length: 33
Successfully minimized, new length: 31
Successfully minimized, new length: 29
Successfully minimized, new length: 28
Successfully minimized, new length: 27
Successfully minimized, new length: 26
No more minimizations found
Final result:
M{s?s{J&
}}{s?s{J&
}}:p
y

thread '<unnamed>' panicked at /Users/luke/Documents/GitHub/roc/crates/compiler/test_syntax/src/test_helpers.rs:333:13:
After formatting, the source code no longer parsed!

Parse error was: Expr(Record(End(@119), @100), @0)

The original code was:

Mxpsat{pdes?s{J&ta,rvm
?r}}Mxpsat{pdes?s{J&ta,rvm
?r}}Aqelntp:op

OAqelntp:op

O=
Fs
Aqyqy


The code that failed to parse:

Mxpsat { pdes ? s
        { J &
            ta,
            rvm
            ? r,
        } } Mxpsat { pdes ? s
        { J &
            ta,
            rvm
            ? r,
        } } Aqelntp : op

OAqelntp : op

O =
    Fs
Aqyqy

The original ast was:

Expr(
    @0-90 SpaceAfter(
        Defs(
            Defs {
                tags: [
                    EitherIndex(0),
                    EitherIndex(1),
                    EitherIndex(2147483648),
                ],
                regions: [
                    @0-64,
                    @66-77,
                    @79-84,
                ],
                space_before: [
                    Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
                    Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 2 },
                    Slice<roc_parse::ast::CommentOrNewline> { start: 2, length: 2 },
                ],
                space_after: [
                    Slice<roc_parse::ast::CommentOrNewline> { start: 0, length: 0 },
                    Slice<roc_parse::ast::CommentOrNewline> { start: 2, length: 0 },
                    Slice<roc_parse::ast::CommentOrNewline> { start: 4, length: 0 },
                ],
                spaces: [
                    Newline,
                    Newline,
                    Newline,
                    Newline,
                ],
                type_defs: [
                    Alias {
                        header: TypeHeader {
                            name: @0-6 "Mxpsat",
                            vars: [
                                @6-27 RecordDestructure(
                                    [
                                        @7-26 OptionalField(
                                            "pdes",
                                            @12-26 Apply(
                                                @12-13 Var {
                                                    module_name: "",
                                                    ident: "s",
                                                },
                                                [
                                                    @13-26 RecordUpdate {
                                                        update: @14-15 Tag(
                                                            "J",
                                                        ),
                                                        fields: [
                                                            @16-18 LabelOnly(
                                                                @16-18 "ta",
                                                            ),
                                                            @19-25 OptionalValue(
                                                                @19-22 "rvm",
                                                                [
                                                                    Newline,
                                                                ],
                                                                @24-25 Var {
                                                                    module_name: "",
                                                                    ident: "r",
                                                                },
                                                            ),
                                                        ],
                                                    },
                                                ],
                                                Space,
                                            ),
                                        ),
                                    ],
                                ),
                                @27-33 Tag(
                                    "Mxpsat",
                                ),
                                @33-54 RecordDestructure(
                                    [
                                        @34-53 OptionalField(
                                            "pdes",
                                            @39-53 Apply(
                                                @39-40 Var {
                                                    module_name: "",
                                                    ident: "s",
                                                },
                                                [
                                                    @40-53 RecordUpdate {
                                                        update: @41-42 Tag(
                                                            "J",
                                                        ),
                                                        fields: [
                                                            @43-45 LabelOnly(
                                                                @43-45 "ta",
                                                            ),
                                                            @46-52 OptionalValue(
                                                                @46-49 "rvm",
                                                                [
                                                                    Newline,
                                                                ],
                                                                @51-52 Var {
                                                                    module_name: "",
                                                                    ident: "r",
                                                                },
                                                            ),
                                                        ],
                                                    },
                                                ],
                                                Space,
                                            ),
                                        ),
                                    ],
                                ),
                                @54-61 Tag(
                                    "Aqelntp",
                                ),
                            ],
                        },
                        ann: @62-64 BoundVariable(
                            "op",
                        ),
                    },
                    Alias {
                        header: TypeHeader {
                            name: @66-74 "OAqelntp",
                            vars: [],
                        },
                        ann: @75-77 BoundVariable(
                            "op",
                        ),
                    },
                ],
                value_defs: [
                    Body(
                        @79-80 Tag(
                            "O",
                        ),
                        @82-84 SpaceBefore(
                            Tag(
                                "Fs",
                            ),
                            [
                                Newline,
                            ],
                        ),
                    ),
                ],
            },
            @85-90 SpaceBefore(
                Tag(
                    "Aqyqy",
                ),
                [
                    Newline,
                ],
            ),
        ),
        [
            Newline,
        ],
    ),
)


note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
==2254== ERROR: libFuzzer: deadly signal
NOTE: libFuzzer has rudimentary signal handlers.
      Combine libFuzzer with AddressSanitizer or similar for better crash reports.
SUMMARY: libFuzzer: deadly signal
MS: 1 CopyPart-; base unit: 03c90bd5fa52f03b184d0dbd5bd88f21a43ba352
0x4d,0x78,0x70,0x73,0x61,0x74,0x7b,0x70,0x64,0x65,0x73,0x3f,0x73,0x7b,0x4a,0x26,0x74,0x61,0x2c,0x72,0x76,0x6d,0xa,0x3f,0x72,0x7d,0x7d,0x4d,0x78,0x70,0x73,0x61,0x74,0x7b,0x70,0x64,0x65,0x73,0x3f,0x73,0x7b,0x4a,0x26,0x74,0x61,0x2c,0x72,0x76,0x6d,0xa,0x3f,0x72,0x7d,0x7d,0x41,0x71,0x65,0x6c,0x6e,0x74,0x70,0x3a,0x6f,0x70,0xa,0xa,0x4f,0x41,0x71,0x65,0x6c,0x6e,0x74,0x70,0x3a,0x6f,0x70,0xa,0xa,0x4f,0x3d,0xa,0x46,0x73,0xa,0x41,0x71,0x79,0x71,0x79,0xa,
Mxpsat{pdes?s{J&ta,rvm\012?r}}Mxpsat{pdes?s{J&ta,rvm\012?r}}Aqelntp:op\012\012OAqelntp:op\012\012O=\012Fs\012Aqyqy\012
artifact_prefix='/Users/luke/Documents/GitHub/roc/crates/compiler/test_syntax/fuzz/artifacts/fuzz_expr/'; Test unit written to /Users/luke/Documents/GitHub/roc/crates/compiler/test_syntax/fuzz/artifacts/fuzz_expr/crash-babf96565ee4a16d60f3f6378048c453c673b1f4
Base64: TXhwc2F0e3BkZXM/c3tKJnRhLHJ2bQo/cn19TXhwc2F0e3BkZXM/c3tKJnRhLHJ2bQo/cn19QXFlbG50cDpvcAoKT0FxZWxudHA6b3AKCk89CkZzCkFxeXF5Cg==
stat::number_of_executed_units: 627430
stat::average_exec_per_sec:     20914
stat::new_units_added:          11069
stat::slowest_unit_time_sec:    0
stat::peak_rss_mb:              432
INFO: exiting: 19712 time: 255s