panicked at 'attempt to add with overflow', src/scanners.rs:586:49
A real edge case this, impressive work by the fuzzer...
I imagine that the testcase can be shrunk, but I haven't tried:
[]([]([]([](\x1b]([](|AN\x0b|||[](&&�\x01\x00\x00\x00[]([]([]([](|||||||[](&&�\x1000000000[]([]([](|||||||[](&&�([](|||||||[](&&�\x01\x00\x00\x00[]([]\x112\x00372\x008\x005156194&#&#&#&
10: core::panicking::panic
at src/libcore/panicking.rs:49
11: pulldown_cmark::scanners::parse_decimal::{{closure}}
at src/scanners.rs:586
12: <core::iter::adapters::TakeWhile<I,P> as core::iter::traits::iterator::Iterator>::try_fold::{{closure}}
at /rustc/627486af15d222bcba336b12ea92a05237cc9ab1/src/libcore/iter/adapters/mod.rs:1375
13: <core::slice::Iter<T> as core::iter::traits::iterator::Iterator>::try_fold
at /rustc/627486af15d222bcba336b12ea92a05237cc9ab1/src/libcore/slice/mod.rs:3140
14: <core::iter::adapters::TakeWhile<I,P> as core::iter::traits::iterator::Iterator>::try_fold
at /rustc/627486af15d222bcba336b12ea92a05237cc9ab1/src/libcore/iter/adapters/mod.rs:1373
15: pulldown_cmark::scanners::parse_decimal
at src/scanners.rs:582
16: pulldown_cmark::scanners::scan_entity
at src/scanners.rs:640
17: pulldown_cmark::parse::FirstPass::parse_line::{{closure}}
at src/parse.rs:742
18: pulldown_cmark::parse::scalar_iterate_special_bytes
at src/parse.rs:2273
19: pulldown_cmark::parse::iterate_special_bytes
at src/parse.rs:2266
20: pulldown_cmark::parse::FirstPass::parse_line
at src/parse.rs:580
21: pulldown_cmark::parse::FirstPass::parse_paragraph
at src/parse.rs:523
22: pulldown_cmark::parse::FirstPass::parse_block
at src/parse.rs:399
23: pulldown_cmark::parse::FirstPass::run
at src/parse.rs:252
24: pulldown_cmark::parse::Parser::new_with_broken_link_callback
at src/parse.rs:1798
25: pulldown_cmark::parse::Parser::new_ext
at src/parse.rs:1784
26: pulldown_cmark::parse::Parser::new
at src/parse.rs:1780