compiler hangs trying to print an overflow error #83150
Labels
A-diagnostics
Area: Messages for errors, warnings, and lints
A-trait-system
Area: Trait system
C-bug
Category: This is a bug.
I-hang
Issue: The compiler never terminates, due to infinite loops, deadlock, livelock, etc.
P-high
High priority
regression-from-stable-to-stable
Performance or correctness regression from one stable version to another.
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
Comments
jonas-schievink
added
I-hang
|
Slightly smaller: fn main() {
func(0..1)
}
fn func<T: Iterator<Item=u8>>(iter: T) {
func(iter.map(|x| x+1))
} |
Actually, I am very curious that, why rustc do not reach the recursion limit. |
Oh sorry, you're right, it does hit the recursion limit if I let it run long enough (about 10 seconds). |
|
Here's a proper minimization: fn main() {
let mut iter = 0u8..1;
func(&mut iter)
}
fn func<T: Iterator<Item = u8>>(iter: &mut T) {
func(&mut iter.map(|x| x + 1))
} |
|
Partial backtrace of the hang: |
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So it actually hangs while trying to print the overflow error 😆 |
jyn514
changed the title
JohnTitor
added
the
T-compiler
|
Bisected: |
|
#72412 looks suspicious. |
#![type_length_limit="393"]
fn main() {
func(&mut(0u8..1))
}
fn func<T: Iterator<Item = u8>>(iter: &mut T) {
func(&mut iter.map(|x| x + 1))
}hang but #![type_length_limit="392"]
fn main() {
func(&mut(0u8..1))
}
fn func<T: Iterator<Item = u8>>(iter: &mut T) {
func(&mut iter.map(|x| x + 1))
}generate a failed massage: |
jyn514
added
the
regression-from-stable-to-stable
|
Assigning |
JohnTitor
added
P-high
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I tried this code:
I expected to see this happen:
program either compiled successful or compiler generate an error
Instead, this happened:
rustc eats 100% CPU for several minutes, but nothing generated.
I compile this code using both
rustc testxx.rs -C opt-level=3 -C target-cpu=native -C codegen-units=1 -C lto -o testxxandrustc testxx.rs -C opt-level=0 -o testxxbefore I began to write this issue, but compiler do not compile even after this issue is submitted.Meta
rustc --version --verbose:Backtrace
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