Fix type resolution of associated const equality bounds #118360

fmease · 2023-11-27T09:54:10Z

Properly resolve the type of assoc consts in equality bounds by walking supertrait bounds and by instantiating the generic params of the trait and the assoc const (re. the latter: see feature generic_const_items)
Reject assoc consts referencing “escaping” generic params instead of ICE'ing (generic const generics are unsupported atm).
Resolve all assoc item bindings (type, const, fn (feature return_type_notation)) by namespace instead of trying to resolve a type first (in the non-RTN case) and falling back to consts afterwards. This is consistent with RTN. E.g., for Tr<K = {…}> we now always try to look up assoc consts (this extends to supertrait bounds). This gets rid of assoc tys shadowing assoc consts in assoc item bindings which is undesirable & inconsistent (types and consts live in different namespaces after all)
Fix assoc consts being labeled as assoc types in several diagnostics
Make a bunch of diagnostics translatable

Fixes #108271 (ICE → error), cc @BoxyUwU.
Fixes #112560 (error → pass).
Fixes #118040 (ICE → pass).

Best reviewed commit by commit.
r? types

…nst eq bounds

fmease · 2023-12-01T09:49:41Z

Fixed the diagnostic regression.

If a const is expected, resolve a const. If a type is expected, resolve a type. Don't try to resolve a type first falling back to consts.

fmease · 2023-12-01T19:37:14Z

Btw, I can try to split the last commit into more digestible chunks if you'd like me to.

bors · 2023-12-06T13:55:00Z

☔ The latest upstream changes (presumably #117661) made this pull request unmergeable. Please resolve the merge conflicts.

fmease · 2023-12-06T16:32:43Z

Closing in favor of different approach, one suggested by errs: type_of(assoc_item_binding).

…y-namespace, r=compiler-errors Resolve associated item bindings by namespace This is the 3rd commit split off from rust-lang#118360 with tests reblessed (they no longer contain duplicated diags which were caused by 4c0addc) & slightly adapted (removed supertraits from a UI test, cc rust-lang#118040). > * Resolve all assoc item bindings (type, const, fn (feature `return_type_notation`)) by namespace instead of trying to resolve a type first (in the non-RTN case) and falling back to consts afterwards. This is consistent with RTN. E.g., for `Tr<K = {…}>` we now always try to look up assoc consts (this extends to supertrait bounds). This gets rid of assoc tys shadowing assoc consts in assoc item bindings which is undesirable & inconsistent (types and consts live in different namespaces after all) > * Consolidate the resolution of assoc {ty, const} bindings and RTN (dedup, better diags for RTN) > * Fix assoc consts being labeled as assoc *types* in several diagnostics > * Make a bunch of diagnostics translatable Fixes rust-lang#112560 (error → pass). As discussed r? `@compiler-errors` --- **Addendum**: What I call “associated item bindings” are commonly referred to as “type bindings” for historical reasons. Nowadays, “type bindings” include assoc type bindings, assoc const bindings and RTN (return type notation) which is why I prefer not to use this outdated term.

…li-obk,cjgillot Fix type resolution of associated const equality bounds (take 2) Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding. --- Together with rust-lang#118668 (merged) and rust-lang#121258, this supersedes rust-lang#118360. Fixes rust-lang#118040. r? `@ghost`

…li-obk,cjgillot Fix type resolution of associated const equality bounds (take 2) Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding. --- Together with rust-lang#118668 (merged) and rust-lang#121258, this supersedes rust-lang#118360. Fixes rust-lang#118040. r? ``@ghost``

Rollup merge of rust-lang#119385 - fmease:assoc-const-eq-fixes-2, r=oli-obk,cjgillot Fix type resolution of associated const equality bounds (take 2) Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding. --- Together with rust-lang#118668 (merged) and rust-lang#121258, this supersedes rust-lang#118360. Fixes rust-lang#118040. r? ``@ghost``

…y-generic-tys, r=compiler-errors Reject overly generic assoc const binding types Split off from rust-lang#119385 to make rust-lang#119385 easier to review. --- In the *instantiated* type of assoc const bindings 1. reject **early-bound generic params** * Provide a rich error message instead of ICE'ing ([rust-lang#108271](rust-lang#108271)). * This is a temporary and semi-artificial restriction until the arrival of *generic const generics*. * It's quite possible that rustc could already perfectly support this subset of generic const generics if we just removed some checks (some `.no_bound_vars().expect(…)`) but even if that was the case, I'd rather gate it behind a new feature flag. Reporting an error instead of ICE'ing is a good first step towards an eventual feature gate error. 2. reject **escaping late-bound generic params** * They lead to ICEs before & I'm pretty sure that they remain incorrect even in a world with *generic const generics* --- Together with rust-lang#118668 & rust-lang#119385, this supersedes rust-lang#118360. Fixes rust-lang#108271.

Rollup merge of rust-lang#121258 - fmease:assoc-const-eq-reject-overly-generic-tys, r=compiler-errors Reject overly generic assoc const binding types Split off from rust-lang#119385 to make rust-lang#119385 easier to review. --- In the *instantiated* type of assoc const bindings 1. reject **early-bound generic params** * Provide a rich error message instead of ICE'ing ([rust-lang#108271](rust-lang#108271)). * This is a temporary and semi-artificial restriction until the arrival of *generic const generics*. * It's quite possible that rustc could already perfectly support this subset of generic const generics if we just removed some checks (some `.no_bound_vars().expect(…)`) but even if that was the case, I'd rather gate it behind a new feature flag. Reporting an error instead of ICE'ing is a good first step towards an eventual feature gate error. 2. reject **escaping late-bound generic params** * They lead to ICEs before & I'm pretty sure that they remain incorrect even in a world with *generic const generics* --- Together with rust-lang#118668 & rust-lang#119385, this supersedes rust-lang#118360. Fixes rust-lang#108271.

rustbot assigned spastorino Nov 27, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Nov 27, 2023

fmease added F-associated_const_equality `#![feature(associated_const_equality)]` T-types Relevant to the types team, which will review and decide on the PR/issue. labels Nov 27, 2023

Check supertraits and gen args when resolving anon consts in assoc co…

4c0addc

…nst eq bounds

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fmease force-pushed the assoc-const-eq-fixes branch from 0d4af5e to 37965ed Compare November 27, 2023 10:52

Reject 'escaping' gen params in the ty of assoc consts in eq bounds

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fmease force-pushed the assoc-const-eq-fixes branch from 37965ed to 5004096 Compare November 27, 2023 11:00

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fmease force-pushed the assoc-const-eq-fixes branch from 5004096 to 3d6b6fc Compare November 27, 2023 12:54

compiler-errors self-assigned this Nov 27, 2023

fmease force-pushed the assoc-const-eq-fixes branch from 3d6b6fc to 73284b8 Compare December 1, 2023 09:32

fmease force-pushed the assoc-const-eq-fixes branch from 73284b8 to 361bcd3 Compare December 1, 2023 10:13

Resolve assoc item bindings by namespace

b8d3e71

If a const is expected, resolve a const. If a type is expected, resolve a type. Don't try to resolve a type first falling back to consts.

fmease force-pushed the assoc-const-eq-fixes branch from 361bcd3 to b8d3e71 Compare December 1, 2023 10:13

fmease mentioned this pull request Dec 6, 2023

Resolve associated item bindings by namespace #118668

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fmease closed this Dec 6, 2023

fmease deleted the assoc-const-eq-fixes branch December 6, 2023 16:32

fmease mentioned this pull request Dec 28, 2023

Fix type resolution of associated const equality bounds (take 2) #119385

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fmease mentioned this pull request Feb 18, 2024

Reject overly generic assoc const binding types #121258

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Fix type resolution of associated const equality bounds #118360

Fix type resolution of associated const equality bounds #118360

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Fix type resolution of associated const equality bounds #118360

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