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Compilation Exhausts Memory Instead of Detecting Potential Syntax Error #117080
Description
I tried this code():
trait Mul<T> {
type Output;
}
trait Matrix: Mul<<Self as Matrix>::Row, Output = ()> {
type Row;
type Transpose: Matrix<Row = Self::Row>;
}
fn is_mul<S, T: Mul<S, Output = ()>>() {}
fn f<T: Matrix>() {
is_mul::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<f::<>();
}I expected to see this happen: the compiler to recognize a potential syntax error and provide an error report.
Instead, this happened: the compiler consumes all available memory and exits.
This code contains obvious syntax errors, so it doesn't seem reasonable for it to be compiled for a long time.
Meta
rustc --version --verbose:
commit-hash: 1c05d50c8403c56d9a8b6fb871f15aaa26fb5d07
commit-date: 2023-10-21
host: x86_64-unknown-linux-gnu
release: 1.75.0-nightly
LLVM version: 17.0.3
The same problem is reproduced on the stable version(1.73 cc66ad4 2023-10-03)
Backtrace
<backtrace>
Activity
estebank commentedon Oct 24, 2023
The problem is introduced by
parse_angle_args_with_leading_angle_bracket_recovery. We need to take a look to add a further check to avoid falling into this pathological case.Avoid unbounded O(n^2) when parsing nested type args
Auto merge of rust-lang#117143 - estebank:issue-117080, r=<try>
Avoid unbounded O(n^2) when parsing nested type args
Avoid unbounded O(n^2) when parsing nested type args
Rollup merge of rust-lang#117143 - estebank:issue-117080, r=wesleywiser
Unrolled build for rust-lang#117143