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[ICE] with const generics in subst.rs #71922

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leonardo-m opened this issue May 5, 2020 · 4 comments · Fixed by #71973
Closed

[ICE] with const generics in subst.rs #71922

leonardo-m opened this issue May 5, 2020 · 4 comments · Fixed by #71973
Labels
A-const-eval Area: Constant evaluation (MIR interpretation) A-const-generics Area: const generics (parameters and arguments) C-bug Category: This is a bug. const-generics-fixed-by-const_generics A bug that has been fixed once `const_generics` is enabled. E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added. F-const_generics `#![feature(const_generics)]` glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@leonardo-m
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This is wrong code because it lacks the const_generics feature request, and because currently calling a const function in this context isn't allowed:

const fn foo(n: usize) -> usize { n * 2 }
fn bar<const N: usize>() -> [u32; foo(N)] {
    [0; foo(N)]
}
fn main() {}

Gives:

error[E0658]: const generics are unstable
 --> ...\test.rs:2:14
  |
2 | fn bar<const N: usize>() -> [u32; foo(N)] {
  |              ^
  |
  = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
  = help: add `#![feature(const_generics)]` to the crate attributes to enable

error: internal compiler error: src\librustc_middle\ty\subst.rs:581: const parameter `N/#0` (Const { ty: usize, val: Param(N/#0) }/0) out of range when substituting substs=[]

thread 'rustc' panicked at 'Box<Any>', /rustc/2454a68cfbb63aa7b8e09fe05114d5f98b2f9740\src\libstd\macros.rs:13:23
stack backtrace:
  ...

note: rustc 1.45.0-nightly (2454a68cf 2020-05-04) running on x86_64-pc-windows-gnu

query stack during panic:
#0 [const_eval_raw] const-evaluating `bar::{{constant}}#0`
#1 [const_eval_validated] const-evaluating + checking `bar::{{constant}}#0`
#2 [const_eval_validated] const-evaluating + checking `bar::{{constant}}#0`
#3 [check_item_well_formed] processing `bar`
#4 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors
@leonardo-m leonardo-m added C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 5, 2020
@jonas-schievink jonas-schievink added A-const-generics Area: const generics (parameters and arguments) F-const_generics `#![feature(const_generics)]` A-const-eval Area: Constant evaluation (MIR interpretation) labels May 5, 2020
@lcnr
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lcnr commented May 5, 2020

blocked on lazy normalization #67890.

Probably a duplicate of #69913

@lcnr lcnr mentioned this issue May 7, 2020
Merged
@rust-lang-glacier-bot rust-lang-glacier-bot added the glacier ICE tracked in rust-lang/glacier. label May 10, 2020
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this issue May 18, 2020
@Dylan-DPC
Rollup merge of rust-lang#71973 - lcnr:lazy-norm, r=nikomatsakis
9f59db5 
Lazy normalization of constants (Reprise)

Continuation of rust-lang#67890 by @Skinny121.

Initial implementation of rust-lang#60471 for constants.

Perform normalization/evaluation of constants lazily, which is known as lazy normalization. Lazy normalization is only enabled when using `#![feature(lazy_normalization_consts)]`, by default constants are still evaluated eagerly as there are currently.

Lazy normalization of constants is achieved with a new ConstEquate predicate which type inferences uses to delay checking whether constants are equal to each other until later, avoiding cycle errors.

Note this doesn't allow the use of generics within repeat count expressions as that is still evaluated during conversion to mir. There are also quite a few other known problems with lazy normalization which will be fixed in future PRs.

r? @nikomatsakis

fixes rust-lang#71922, fixes rust-lang#71986
@bors bors closed this as completed in c6030c9 May 19, 2020
@lcnr
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lcnr commented Jun 30, 2020

This issue still isn't fixed 🤔 It seems like I made a mistake in #71973

@lcnr lcnr reopened this Jun 30, 2020
@lcnr lcnr mentioned this issue Jun 30, 2020
Merged
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this issue Jul 1, 2020
@Dylan-DPC
Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink
32e74ae 
remove duplicate test for rust-lang#61935

Apparently I somehow messed up the issue number in rust-lang#67890
which caused us to add this test twice, both as https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/issues/issue-61935.rs and https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/lazy-normalization/issue-71922.rs

rust-lang#61935 is the actually fixed issue while rust-lang#71922 is still not working, as it depends on lazy norm of repeat expressions
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 1, 2020
@Manishearth
Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink
555397d 
remove duplicate test for rust-lang#61935

Apparently I somehow messed up the issue number in rust-lang#67890
which caused us to add this test twice, both as https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/issues/issue-61935.rs and https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/lazy-normalization/issue-71922.rs

rust-lang#61935 is the actually fixed issue while rust-lang#71922 is still not working, as it depends on lazy norm of repeat expressions
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 2, 2020
@Manishearth
Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink
59c2762 
remove duplicate test for rust-lang#61935

Apparently I somehow messed up the issue number in rust-lang#67890
which caused us to add this test twice, both as https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/issues/issue-61935.rs and https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/lazy-normalization/issue-71922.rs

rust-lang#61935 is the actually fixed issue while rust-lang#71922 is still not working, as it depends on lazy norm of repeat expressions
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 2, 2020
@Manishearth
Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink
e2f84f3 
remove duplicate test for rust-lang#61935

Apparently I somehow messed up the issue number in rust-lang#67890
which caused us to add this test twice, both as https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/issues/issue-61935.rs and https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/lazy-normalization/issue-71922.rs

rust-lang#61935 is the actually fixed issue while rust-lang#71922 is still not working, as it depends on lazy norm of repeat expressions
Manishearth added a commit to Manishearth/rust that referenced this issue Jul 2, 2020
@Manishearth
Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink
37e812e 
remove duplicate test for rust-lang#61935

Apparently I somehow messed up the issue number in rust-lang#67890
which caused us to add this test twice, both as https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/issues/issue-61935.rs and https://github.com/rust-lang/rust/blob/master/src/test/ui/const-generics/lazy-normalization/issue-71922.rs

rust-lang#61935 is the actually fixed issue while rust-lang#71922 is still not working, as it depends on lazy norm of repeat expressions
@lcnr lcnr mentioned this issue Aug 5, 2020
Closed
@varkor varkor added the const-generics-fixed-by-const_generics A bug that has been fixed once `const_generics` is enabled. label Sep 13, 2020
@varkor varkor mentioned this issue Oct 2, 2020
Merged
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this issue Oct 5, 2020
@Dylan-DPC
Rollup merge of rust-lang#77439 - varkor:min_const_generics-tests, r=…
e032bb7 
…lcnr,estebank

Fix missing diagnostic span for `impl Trait` with const generics, and add various tests for `min_const_generics` and `const_generics`

Closes rust-lang#61410.

Adds `min_const_generics` tests for:
- rust-lang#73727
- rust-lang#72293
- rust-lang#67375
- rust-lang#75153
- rust-lang#71922
- rust-lang#69913
- rust-lang#67945
- rust-lang#69239

Adds `const_generics` tests for:
- rust-lang#67375
- rust-lang#75153
- rust-lang#71922
- rust-lang#69913
- rust-lang#67945
- rust-lang#69239

(I only added separate `min_const_generics` and `const_generics` tests if they were handled differently by the two features.)

We need to figure out how to deduplicate when `const_generics` is stabilised, but we can discuss that later. For now, we should be checking neither feature breaks, so require regression tests for both. I've given them identical names when I've added both, which should make it easier to spot them later.

r? @lcnr
@lcnr lcnr mentioned this issue Oct 12, 2020
Closed
@camelid camelid mentioned this issue Dec 20, 2020
Closed
@github-actions github-actions bot mentioned this issue Dec 28, 2020
Closed
@JohnTitor
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Triage: This is no longer ICE (even with const_generics) on the latest nightly: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=f0afc6e029354b7b4e933cb00c9b0cba

@JohnTitor JohnTitor added the E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added. label Dec 30, 2020
@lcnr
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lcnr commented Dec 30, 2020

we already have a bunch of similar tests, closing without adding an additional one

@lcnr lcnr closed this as completed Dec 30, 2020
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A-const-eval Area: Constant evaluation (MIR interpretation) A-const-generics Area: const generics (parameters and arguments) C-bug Category: This is a bug. const-generics-fixed-by-const_generics A bug that has been fixed once `const_generics` is enabled. E-needs-test Call for participation: An issue has been fixed and does not reproduce, but no test has been added. F-const_generics `#![feature(const_generics)]` glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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Lazy normalization of constants (Reprise) lcnr/rust
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@jonas-schievink @varkor @leonardo-m @JohnTitor @lcnr @rust-lang-glacier-bot