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Rollup merge of #99651 - compiler-errors:fn-and-raw-ptr-in-const-generics, r=oli-obk

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Deeply deny fn and raw ptrs in const generics

I think this is right -- just because we wrap a fn ptr in a wrapper type does not mean we should allow it in a const parameter.

We now reject both of these in the same way:

```
#![feature(adt_const_params)]

#[derive(Eq, PartialEq)]
struct Wrapper();

fn foo<const W: Wrapper>() {}

fn foo2<const F: fn()>() {}
```

This does regress one test (`src/test/ui/consts/refs_check_const_eq-issue-88384.stderr`), but I'm not sure it should've passed in the first place.

cc: ``@b-naber`` who introduced that test^
fixes #99641
This commit is contained in:
Guillaume Gomez 2022-07-27 17:55:04 +02:00 • committed by GitHub
commit 9e7b7d5e1c
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18 changed files with 193 additions and 139 deletions
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60
compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
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@ -120,37 +120,35 @@ impl<'a, 'tcx> ConstToPat<'a, 'tcx> {
}
fn search_for_structural_match_violation(&self, ty: Ty<'tcx>) -> Option<String> {
traits::search_for_structural_match_violation(self.span, self.tcx(), ty, true).map(
|non_sm_ty| {
with_no_trimmed_paths!(match non_sm_ty.kind {
traits::NonStructuralMatchTyKind::Adt(adt) => self.adt_derive_msg(adt),
traits::NonStructuralMatchTyKind::Dynamic => {
"trait objects cannot be used in patterns".to_string()
}
traits::NonStructuralMatchTyKind::Opaque => {
"opaque types cannot be used in patterns".to_string()
}
traits::NonStructuralMatchTyKind::Closure => {
"closures cannot be used in patterns".to_string()
}
traits::NonStructuralMatchTyKind::Generator => {
"generators cannot be used in patterns".to_string()
}
traits::NonStructuralMatchTyKind::Float => {
"floating-point numbers cannot be used in patterns".to_string()
}
traits::NonStructuralMatchTyKind::Param => {
bug!("use of a constant whose type is a parameter inside a pattern")
}
traits::NonStructuralMatchTyKind::Projection => {
bug!("use of a constant whose type is a projection inside a pattern")
}
traits::NonStructuralMatchTyKind::Foreign => {
bug!("use of a value of a foreign type inside a pattern")
}
})
},
)
traits::search_for_structural_match_violation(self.span, self.tcx(), ty).map(|non_sm_ty| {
with_no_trimmed_paths!(match non_sm_ty.kind() {
ty::Adt(adt, _) => self.adt_derive_msg(*adt),
ty::Dynamic(..) => {
"trait objects cannot be used in patterns".to_string()
}
ty::Opaque(..) => {
"opaque types cannot be used in patterns".to_string()
}
ty::Closure(..) => {
"closures cannot be used in patterns".to_string()
}
ty::Generator(..) | ty::GeneratorWitness(..) => {
"generators cannot be used in patterns".to_string()
}
ty::Float(..) => {
"floating-point numbers cannot be used in patterns".to_string()
}
ty::FnPtr(..) => {
"function pointers cannot be used in patterns".to_string()
}
ty::RawPtr(..) => {
"raw pointers cannot be used in patterns".to_string()
}
_ => {
bug!("use of a value of `{non_sm_ty}` inside a pattern")
}
})
})
}
fn type_marked_structural(&self, ty: Ty<'tcx>) -> bool {