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Existential_type compiler stack overflow #52977

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DutchGhost opened this issue Aug 2, 2018 · 5 comments · Fixed by #59459
Closed

Existential_type compiler stack overflow #52977

DutchGhost opened this issue Aug 2, 2018 · 5 comments · Fixed by #59459
Labels
E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added.

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@DutchGhost
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DutchGhost commented Aug 2, 2018 •
edited
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Playing with the nighly's existential types, I stumbled upon a compiler stack overflow:

#![feature(existential_type)]

existential type Foo: Fn() -> Foo;

fn crash(x: Foo) -> Foo {
    x
}

fn main() {
    
}

Error message:

Compiling playground v0.0.1 (file:///playground)

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
error: Could not compile `playground`.

To learn more, run the command again with --verbose.
@DutchGhost
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A better example might be this:

#![feature(existential_type)]

pub trait Bar<T> {
    type Item;
}

existential type Foo: Bar<Foo, Item = Foo>;

fn crash(x: Foo) -> Foo {
    x
}

fn main() {
    
}

removing the Item = Foo from the existential type decleration just compiles fine

@DutchGhost DutchGhost changed the title Compiler stack overflow existential_type Compiler stack overflow Aug 2, 2018
@DutchGhost DutchGhost changed the title existential_type Compiler stack overflow Existential_type compiler stack overflow Aug 2, 2018
@kennytm kennytm added A-impl-trait Area: `impl Trait`. Universally / existentially quantified anonymous types with static dispatch. C-bug Category: This is a bug. labels Aug 2, 2018
@oli-obk
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oli-obk commented Aug 3, 2018

Can you try running the compiler inside gdb and produce a backtrace?

@DutchGhost
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Backtrace: 
Starting program: /home/DutchGh0st/.cargo/bin/rustc main.rs
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
process 136 is executing new program: /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff75f0700 (LWP 140)]

Thread 2 "rustc" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff75f0700 (LWP 140)]
0x00007ffffece4401 in mallocx (size=96, flags=0) at /checkout/src/liballoc_jemalloc/../jemalloc/src/jemalloc.c:2278
2278    /checkout/src/liballoc_jemalloc/../jemalloc/src/jemalloc.c: No such file or directory.
#0  0x00007ffffece4401 in mallocx (size=96, flags=0) at /checkout/src/liballoc_jemalloc/../jemalloc/src/jemalloc.c:2278
#1  0x00007ffffac7028b in _$LT$alloc..vec..Vec$LT$T$GT$$u20$as$u20$core..clone..Clone$GT$::clone::h6df995c7d982ea03 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc-6b3bfd814e7184c8.so
#2  0x00007ffffb060b3d in rustc::ty::query::plumbing::_$LT$impl$u20$rustc..ty..context..TyCtxt$LT$$u27$a$C$$u20$$u27$gcx$C$$u20$$u27$tcx$GT$$GT$::get_query::h4615380c5ee9a0a7 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc-6b3bfd814e7184c8.so
#3  0x00007ffffb124693 in rustc::ty::query::_$LT$impl$u20$rustc..ty..context..TyCtxt$LT$$u27$a$C$$u20$$u27$tcx$C$$u20$$u27$lcx$GT$$GT$::predicates_of::hcbf22c835c6bc1a1 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc-6b3bfd814e7184c8.so
#4  0x00007ffffd824311 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#5  0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#6  0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#7  0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#8  0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#9  0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#10 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#11 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#12 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#13 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#14 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#15 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#16 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#17 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#18 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#19 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#20 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#21 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#22 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#23 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#24 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#25 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#26 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#27 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#28 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#29 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#30 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#31 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#32 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#33 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#34 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#35 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#36 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#37 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#38 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#39 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#40 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#41 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#42 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#43 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#44 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so
#45 0x00007ffffd824374 in _$LT$rustc_privacy..TypePrivacyVisitor$LT$$u27$a$C$$u20$$u27$tcx$GT$$u20$as$u20$rustc..ty..fold..TypeVisitor$LT$$u27$tcx$GT$$GT$::visit_ty::hf59619e6ff1f1998 () from /home/DutchGh0st/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/../lib/../lib/librustc_privacy-24b96028bea24937.so

@oli-obk
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oli-obk commented Aug 6, 2018

It's recursing in

rust/src/librustc_privacy/lib.rs

Lines 742 to 754 in 215bf3a

if self.in_body {
// Types in bodies.
if self.tables.node_id_to_type(hir_ty.hir_id).visit_with(self) {
return;
}
} else {
// Types in signatures.
// FIXME: This is very ineffective. Ideally each HIR type should be converted
// into a semantic type only once and the result should be cached somehow.
if rustc_typeck::hir_ty_to_ty(self.tcx, hir_ty).visit_with(self) {
return;
}
}

Ideally this should cause cycle errors. But I'm assuming

This is very ineffective. Ideally each HIR type should be converted into a semantic type only once and the result should be cached somehow.

Manually computes this without a query. Maybe we should just make hir_ty_to_ty a query? This would solve both the FIXME and this issue.

@oli-obk
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oli-obk commented Jan 25, 2019

Both examples now produce a cycle error. So we just need to add the two examples to src/test/ui/existential_types (if there aren't already tests for these situations)

@oli-obk oli-obk added E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added. and removed A-impl-trait Area: `impl Trait`. Universally / existentially quantified anonymous types with static dispatch. C-bug Category: This is a bug. labels Jan 25, 2019
@JohnTitor JohnTitor mentioned this issue Mar 27, 2019
Merged
Centril added a commit to Centril/rust that referenced this issue Mar 27, 2019
@Centril
Rollup merge of rust-lang#59459 - JohnTitor:add-tests, r=Centril
1d5a6b6 
Add some tests

close rust-lang#52977

It seems that there are no tests for this issue, so I opened this PR.
off-topic: I noticed [this test](https://github.com/rust-lang/rust/blob/master/src/test/ui/existential_types/nested_existential_types.rs)'s indents are bad, could I include commit to fix this, or should I separate?

r? @oli-obk
Centril added a commit to Centril/rust that referenced this issue Mar 27, 2019
@Centril
Rollup merge of rust-lang#59459 - JohnTitor:add-tests, r=Centril
d2757d0 
Add some tests

close rust-lang#52977

It seems that there are no tests for this issue, so I opened this PR.
off-topic: I noticed [this test](https://github.com/rust-lang/rust/blob/master/src/test/ui/existential_types/nested_existential_types.rs)'s indents are bad, could I include commit to fix this, or should I separate?

r? @oli-obk
cuviper added a commit to cuviper/rust that referenced this issue Mar 28, 2019
@cuviper
Rollup merge of rust-lang#59459 - JohnTitor:add-tests, r=Centril
4a322f5 
Add some tests

close rust-lang#52977

It seems that there are no tests for this issue, so I opened this PR.
off-topic: I noticed [this test](https://github.com/rust-lang/rust/blob/master/src/test/ui/existential_types/nested_existential_types.rs)'s indents are bad, could I include commit to fix this, or should I separate?

r? @oli-obk
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E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added.
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Add some tests JohnTitor/rust
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@kennytm @oli-obk @DutchGhost