Fix ICE when Self is used in enum discriminant of a generic enum
Fixesrust-lang/rust#153756
Let discriminant AnonConst inherit parent generics via Node::Variant in generics_of, and emit a proper error instead of span_bug! for the TooGeneric case in wfcheck.
* Fix ICE when Self is used in enum discriminant of a generic enum
Move the validation into the existing `check_param_uses_if_mcg` machinery
in HIR ty lowering instead of adding a new check in wfcheck. After the
`AnonConstKind` refactoring, `ForbidMCGParamUsesFolder` was only gated on
`AnonConstKind::MCG`, causing discriminant anon consts (`NonTypeSystem`) to
bypass it entirely.
Add `anon_const_forbids_generic_params()` which returns the appropriate
`ForbidParamContext` for both MCG and enum discriminant contexts. Wire it
into `check_param_uses_if_mcg` so that `Self` aliasing a generic type is
caught before reaching `const_eval_poly`. Convert the `TooGeneric` span_bug
into a proper diagnostic as a fallback for anything slipping through
type-dependent path resolution.
* Address review comments
- Rename `ForbidMCGParamUsesFolder` to `ForbidParamUsesFolder`
- Rename `MinConstGenerics` variant to `ConstArgument` with updated doc
- Simplify doc comment on `anon_const_forbids_generic_params`
- Make match on `AnonConstKind` exhaustive
- Move `anon_const_def_id` inside the `if let` in `check_param_uses_if_mcg`
- Remove now-unreachable `TooGeneric` span_err in wfcheck
* Revert TooGeneric arm back to span_bug! as requested by reviewer
* Use generics_of to determine if NonTypeSystem anon consts allow generic params
* Also check InlineConst and Closure defs nested in enum discriminants
* Simplify logic for determining anonymous constant parent in generic contexts
* add test
- On `const` and `static` point at the type (like we do for let bindings)
- On fn calls, point at const parameter in fn definition
- On type, point at const parameter in type definition
- On array type lengths, explain that array length is always `usize`
- On enum variant discriminant, mention `repr`
Currently, `Representability::from_cycle_error` prints an "infinite
size" error and then returns `Representability::Infinite`, which lets
analysis continue. This commit changes it so it just aborts after
printing the error. This has two benefits.
First, the error messages are better. The error messages we get after
continuing are mostly bad -- we usually get another cycle error, e.g.
about drop checking or layout, which is not much use to the user, and
then abort after that. The only exception is `issue-105231.rs` where a
"conflicting implementations" error is now omitted, but there are three
other errors before that one so it's no great loss.
Second, it allows some simplifications: see the next commit.
All usages of `memory_index` start by calling `invert_bijective_mapping`, so
storing the inverted mapping directly saves some work and simplifies the code.
Rehome 32 `tests/ui/issues/` tests to other subdirectories under `tests/ui/`
rust-lang/rust#143902 divided into smaller, easier to review chunks.
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
We lost the following comment during refactorings:
The current code for niche-filling relies on variant indices instead of actual discriminants, so enums with explicit discriminants (RFC 2363) would misbehave.
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
- `check-pass` test for a MRE of #135020
- fail test for #135138
- switch to `TooGeneric` for checking CMSE fn signatures
- switch to `TooGeneric` for compute `SizeSkeleton` (for transmute)
- fix broken tests
When constant evaluation fails because its MIR is tainted by errors,
suppress note indicating that erroneous constant was used, since those
errors have to be fixed regardless of the constant being used or not.
Moulins