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

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#71973
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[ICE] with const generics in subst.rs#71922
#71973
Labels
A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)A-const-genericsArea: const generics (parameters and arguments)C-bugCategory: This is a bug.E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.F-const_generics`#![feature(const_generics)]`I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.fixed-by-const-genericsEnabling feature `const_generics` fixes the issue.glacierICE tracked in rust-lang/glacier.

Description

@leonardo-m
leonardo-m
opened on May 5, 2020

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

Activity

  1. leonardo-m
    added
    C-bugCategory: This is a bug.
    I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️
    T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
    on May 5, 2020
  2. jonas-schievink
    added
    A-const-genericsArea: const generics (parameters and arguments)
    F-const_generics`#![feature(const_generics)]`
    A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)
    on May 5, 2020

  3. lcnr commented on May 5, 2020

    @lcnr
    lcnr
    on May 5, 2020
    Contributor

    blocked on lazy normalization #67890.

    Probably a duplicate of #69913

  4. rust-lang-glacier-bot
    added
    glacierICE tracked in rust-lang/glacier.
    on May 10, 2020
  5. Dylan-DPC-zz
    added 2 commits that reference this issue on May 18, 2020

    Rollup merge of rust-lang#71973 - lcnr:lazy-norm, r=nikomatsakis

    9f59db5

    Rollup merge of rust-lang#71973 - lcnr:lazy-norm, r=nikomatsakis

    c6030c9
  6. bors
    closed this as completedin c6030c9on May 19, 2020

  7. lcnr commented on Jun 30, 2020

    @lcnr
    lcnr
    on Jun 30, 2020
    Contributor

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

  8. lcnr
    reopened this on Jun 30, 2020
  9. Dylan-DPC-zz
    added a commit that references this issue on Jul 1, 2020

    Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink

    32e74ae
  10. Manishearth
    added 4 commits that reference this issue on Jul 1, 2020

    Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink

    555397d

    Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink

    59c2762

    Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink

    e2f84f3

    Rollup merge of rust-lang#73898 - lcnr:issue61383, r=jonas-schievink

    37e812e
  11. varkor
    added
    fixed-by-const-genericsEnabling feature `const_generics` fixes the issue.
    on Sep 13, 2020
  12. Dylan-DPC-zz
    added a commit that references this issue on Oct 5, 2020

    Rollup merge of rust-lang#77439 - varkor:min_const_generics-tests, r=…

    e032bb7

  13. JohnTitor commented on Dec 30, 2020

    @JohnTitor
    JohnTitor
    on Dec 30, 2020
    Member

    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

  14. JohnTitor
    added
    E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.
    on Dec 30, 2020

  15. lcnr commented on Dec 30, 2020

    @lcnr
    lcnr
    on Dec 30, 2020
    Contributor

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

  16. lcnr
    closed this as completedon Dec 30, 2020
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    A-const-evalArea: Constant evaluation, covers all const contexts (static, const fn, ...)A-const-genericsArea: const generics (parameters and arguments)C-bugCategory: This is a bug.E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.F-const_generics`#![feature(const_generics)]`I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.fixed-by-const-genericsEnabling feature `const_generics` fixes the issue.glacierICE tracked in rust-lang/glacier.

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