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Exponential parse time with nested and out-of-order attributes #105165
Description
Found with a modified fuzz-rustc
Code
#![a = { #[y] #![x]
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#![a = { #[y] #![x]Time complexity
Each additional line roughly doubles the time taken to reject the input.
Where it's slow
From -Z time-passes:
- the slow pass is
parse_crate
From sample-head.txt:
annotate_following_item_if_applicableis on the stack repeatedly
Regression
Regression in nightly-2021-09-06, likely from #88257 (@estebank)
Version
rustc 1.67.0-nightly (1eb62b123 2022-11-27)
binary: rustc
commit-hash: 1eb62b1235fd77200e6bd967d70e83c0f2497233
commit-date: 2022-11-27
host: x86_64-apple-darwin
release: 1.67.0-nightly
LLVM version: 15.0.4
@rustbot label +I-compiletime
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