nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2024-11-23 07:14:28 +00:00
Code Issues Packages Projects Releases Wiki Activity
2b874f0242
rust/compiler
History
Matthias Krüger 2b874f0242
Rollup merge of #89829 - voidc:assoc-const-variance, r=lcnr 
Consider types appearing in const expressions to be invariant

This is an approach to fix #80977.
Currently, a type parameter which is only used in a constant expression is considered bivariant and will trigger error E0392 *"parameter T is never used"*.
Here is a short example:

```rust
pub trait Foo {
    const N: usize;
}

struct Bar<T: Foo>([u8; T::N])
where [(); T::N]:;
```
([playgound](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2015&gist=b51a272853f75925e72efc1597478aa5))

While it is possible to silence this error by adding a `PhantomData<T>` field, I think the better solution would be to make `T` invariant.
This would be analogous to the invariance constraints added for associated types.
However, I'm quite new to the compiler and unsure whether this is the right approach.

r? ``@varkor`` (since you authored #60058)
2021-10-23 14:58:41 +02:00
..
rustc Migrate to 2021 2021-09-20 22:21:42 -04:00
rustc_apfloat Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_arena Migrate to 2021 2021-09-20 22:21:42 -04:00
rustc_ast Rollup merge of #89991 - petrochenkov:visitok2, r=jackh726 2021-10-22 19:42:48 +09:00
rustc_ast_lowering Rollup merge of #89895 - camsteffen:for-loop-head-span, r=davidtwco 2021-10-22 19:42:45 +09:00
rustc_ast_passes Some "parenthesis" and "parentheses" fixes 2021-10-17 12:04:01 +02:00
rustc_ast_pretty Some "parenthesis" and "parentheses" fixes 2021-10-17 12:04:01 +02:00
rustc_attr Correct typo 2021-10-16 13:36:05 -07:00
rustc_borrowck Rollup merge of #89895 - camsteffen:for-loop-head-span, r=davidtwco 2021-10-22 19:42:45 +09:00
rustc_builtin_macros rustc_span: Ident::invalid -> Ident::empty 2021-10-17 23:20:30 +03:00
rustc_codegen_cranelift Make hash_result an Option. 2021-10-20 18:29:18 +02:00
rustc_codegen_gcc Make hash_result an Option. 2021-10-20 18:29:18 +02:00
rustc_codegen_llvm Make hash_result an Option. 2021-10-20 18:29:18 +02:00
rustc_codegen_ssa Auto merge of #90050 - michaelwoerister:fix-vtable-debug-name-crash-90019, r=wesleywiser 2021-10-20 14:37:48 +00:00
rustc_const_eval Rollup merge of #89920 - hudson-ayers:location-detail-control, r=davidtwco 2021-10-23 05:28:23 +02:00
rustc_data_structures Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_driver Auto merge of #89124 - cjgillot:owner-info, r=michaelwoerister 2021-10-18 19:53:05 +00:00
rustc_error_codes Rollup merge of #89922 - JohnTitor:update-e0637, r=jackh726 2021-10-22 19:42:46 +09:00
rustc_errors Rollup merge of #89468 - FabianWolff:issue-89358, r=jackh726 2021-10-23 05:28:22 +02:00
rustc_expand Rollup merge of #89991 - petrochenkov:visitok2, r=jackh726 2021-10-22 19:42:48 +09:00
rustc_feature Rollup merge of #89730 - crlf0710:type_changing_feature, r=jackh726 2021-10-23 05:28:22 +02:00
rustc_fs_util Migrate to 2021 2021-09-20 22:21:42 -04:00
rustc_graphviz Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_hir Rollup merge of #90071 - cjgillot:no-blocks, r=oli-obk 2021-10-21 14:11:08 +09:00
rustc_hir_pretty Auto merge of #89124 - cjgillot:owner-info, r=michaelwoerister 2021-10-18 19:53:05 +00:00
rustc_incremental Merge two query callbacks arrays. 2021-10-20 18:29:27 +02:00
rustc_index Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_infer nice_region_error: Include lifetime placeholders in error output 2021-10-22 15:26:20 -07:00
rustc_interface Rollup merge of #89920 - hudson-ayers:location-detail-control, r=davidtwco 2021-10-23 05:28:23 +02:00
rustc_lexer Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_lint Rollup merge of #89895 - camsteffen:for-loop-head-span, r=davidtwco 2021-10-22 19:42:45 +09:00
rustc_lint_defs Make all proc-macro back-compat lints deny-by-default 2021-10-18 13:17:05 -05:00
rustc_llvm RustWrapper: adapt for an LLVM API change 2021-10-18 09:48:47 +02:00
rustc_macros Do not depend on the stored value when trying to cache on disk. 2021-10-21 20:00:45 +02:00
rustc_metadata Don't emit a warning for empty rmeta files. 2021-10-19 16:56:47 -07:00
rustc_middle Auto merge of #90065 - cjgillot:novalcache, r=Mark-Simulacrum 2021-10-23 09:21:45 +00:00
rustc_mir_build Rollup merge of #90028 - tmiasko:structural-match-closure, r=spastorino 2021-10-22 19:42:48 +09:00
rustc_mir_dataflow Adopt let_else across the compiler 2021-10-16 07:18:05 +02:00
rustc_mir_transform Auto merge of #89893 - camsteffen:redundant-dump-enabled, r=matthewjasper 2021-10-22 17:32:20 +00:00
rustc_monomorphize Auto merge of #89933 - est31:let_else, r=michaelwoerister 2021-10-19 14:41:39 +00:00
rustc_parse Rollup merge of #89257 - aDotInTheVoid:macro-error-2, r=estebank 2021-10-22 19:42:43 +09:00
rustc_parse_format Migrate to 2021 2021-09-20 22:21:42 -04:00
rustc_passes Use Ancestory to check default fn in const impl instead of comparing idents 2021-10-11 18:19:54 +01:00
rustc_plugin_impl Move rustc_middle::middle::cstore to rustc_session. 2021-10-03 16:08:51 +02:00
rustc_privacy Rollup merge of #88644 - eopb:abstractconst_leaf_subst, r=lcnr 2021-10-21 14:11:03 +09:00
rustc_query_impl Do not depend on the stored value when trying to cache on disk. 2021-10-21 20:00:45 +02:00
rustc_query_system Do not depend on the stored value when trying to cache on disk. 2021-10-21 20:00:45 +02:00
rustc_resolve Revert "Auto merge of #89100 - petrochenkov:localbind, r=cjgillot" 2021-10-21 09:09:24 -04:00
rustc_save_analysis Auto merge of #89266 - cjgillot:session-ich, r=michaelwoerister 2021-10-05 09:45:11 +00:00
rustc_serialize Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions_2, r=petrochenkov" 2021-10-15 11:28:23 +02:00
rustc_session Rollup merge of #89920 - hudson-ayers:location-detail-control, r=davidtwco 2021-10-23 05:28:23 +02:00
rustc_span Rollup merge of #89730 - crlf0710:type_changing_feature, r=jackh726 2021-10-23 05:28:22 +02:00
rustc_symbol_mangling Remove re-export. 2021-10-03 16:08:54 +02:00
rustc_target Auto merge of #90040 - nbdd0121:issue-90038, r=oli-obk 2021-10-19 08:13:35 +00:00
rustc_trait_selection Rollup merge of #90028 - tmiasko:structural-match-closure, r=spastorino 2021-10-22 19:42:48 +09:00
rustc_traits Move some outlives bounds things from rustc_trait_selection to rustc_typeck 2021-10-15 12:14:19 -04:00
rustc_ty_utils Replace FnLikeNode by FnKind. 2021-10-19 23:31:51 +02:00
rustc_type_ir Add two inline annotations for hot functions 2021-10-03 12:43:43 -04:00
rustc_typeck Rollup merge of #89829 - voidc:assoc-const-variance, r=lcnr 2021-10-23 14:58:41 +02:00