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Check variances in the non-hir wfchecker

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This commit is contained in:
Oli Scherer 2025-06-04 11:16:11 +00:00
parent d27c05709c
commit ee8fa4eb16
12 changed files with 105 additions and 78 deletions
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7
compiler/rustc_hir_analysis/src/check/check.rs
View file

@ -36,6 +36,7 @@ use {rustc_attr_data_structures as attrs, rustc_hir as hir};
use super::compare_impl_item::check_type_bounds;
use super::*;
use crate::check::wfcheck::check_variances_for_type_defn;
fn add_abi_diag_help<T: EmissionGuarantee>(abi: ExternAbi, diag: &mut Diag<'_, T>) {
if let ExternAbi::Cdecl { unwind } = abi {
@ -762,6 +763,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
DefKind::Const => {}
DefKind::Enum => {
check_enum(tcx, def_id);
check_variances_for_type_defn(tcx, def_id);
}
DefKind::Fn => {
if let Some(i) = tcx.intrinsic(def_id) {
@ -802,9 +804,11 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
}
DefKind::Struct => {
check_struct(tcx, def_id);
check_variances_for_type_defn(tcx, def_id);
}
DefKind::Union => {
check_union(tcx, def_id);
check_variances_for_type_defn(tcx, def_id);
}
DefKind::OpaqueTy => {
check_opaque_precise_captures(tcx, def_id);
@ -832,6 +836,9 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(),
}
DefKind::TyAlias => {
check_type_alias_type_params_are_used(tcx, def_id);
if tcx.type_alias_is_lazy(def_id) {
check_variances_for_type_defn(tcx, def_id);
}
}
DefKind::ForeignMod => {
let it = tcx.hir_expect_item(def_id);

26
compiler/rustc_hir_analysis/src/check/wfcheck.rs
View file

@ -292,25 +292,13 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
}
hir::ItemKind::Fn { ident, sig, .. } => check_item_fn(tcx, def_id, ident, sig.decl),
hir::ItemKind::Const(_, _, ty, _) => check_const_item(tcx, def_id, ty.span, item.span),
hir::ItemKind::Struct(..) => {
let res = check_type_defn(tcx, item, false);
check_variances_for_type_defn(tcx, def_id);
res
}
hir::ItemKind::Union(..) => {
let res = check_type_defn(tcx, item, true);
check_variances_for_type_defn(tcx, def_id);
res
}
hir::ItemKind::Enum(..) => {
let res = check_type_defn(tcx, item, true);
check_variances_for_type_defn(tcx, def_id);
res
}
hir::ItemKind::Struct(..) => check_type_defn(tcx, item, false),
hir::ItemKind::Union(..) => check_type_defn(tcx, item, true),
hir::ItemKind::Enum(..) => check_type_defn(tcx, item, true),
hir::ItemKind::Trait(..) => check_trait(tcx, item),
hir::ItemKind::TraitAlias(..) => check_trait(tcx, item),
hir::ItemKind::TyAlias(.., hir_ty) if tcx.type_alias_is_lazy(item.owner_id) => {
let res = enter_wf_checking_ctxt(tcx, def_id, |wfcx| {
enter_wf_checking_ctxt(tcx, def_id, |wfcx| {
let ty = tcx.type_of(def_id).instantiate_identity();
let item_ty =
wfcx.deeply_normalize(hir_ty.span, Some(WellFormedLoc::Ty(def_id)), ty);
@ -321,9 +309,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
);
check_where_clauses(wfcx, item.span, def_id);
Ok(())
});
check_variances_for_type_defn(tcx, def_id);
res
})
}
_ => Ok(()),
}
@ -1977,7 +1963,7 @@ fn legacy_receiver_is_implemented<'tcx>(
}
}
fn check_variances_for_type_defn<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) {
pub(super) fn check_variances_for_type_defn<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) {
match tcx.def_kind(def_id) {
DefKind::Enum | DefKind::Struct | DefKind::Union => {
// Ok

16
tests/ui/generic-associated-types/static-lifetime-tip-with-default-type.stderr
View file

@ -82,6 +82,14 @@ help: consider adding an explicit lifetime bound
LL | struct Far<T: 'static
| +++++++++
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/static-lifetime-tip-with-default-type.rs:22:10
|
LL | struct S<'a, K: 'a = i32>(&'static K);
| ^^ unused lifetime parameter
|
= help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`
error[E0310]: the parameter type `K` may not live long enough
--> $DIR/static-lifetime-tip-with-default-type.rs:22:27
|
@ -96,14 +104,6 @@ help: consider adding an explicit lifetime bound
LL | struct S<'a, K: 'a + 'static = i32>(&'static K);
| +++++++++
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/static-lifetime-tip-with-default-type.rs:22:10
|
LL | struct S<'a, K: 'a = i32>(&'static K);
| ^^ unused lifetime parameter
|
= help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`
error: aborting due to 8 previous errors
Some errors have detailed explanations: E0310, E0392.

24
tests/ui/lazy-type-alias/inherent-impls-overflow.current.stderr
View file

@ -14,6 +14,17 @@ LL | impl Loop {}
|
= note: in case this is a recursive type alias, consider using a struct, enum, or union instead
error: type parameter `T` is only used recursively
--> $DIR/inherent-impls-overflow.rs:17:24
|
LL | type Poly0<T> = Poly1<(T,)>;
| - ^
| |
| type parameter must be used non-recursively in the definition
|
= help: consider removing `T` or referring to it in the body of the type alias
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0275]: overflow normalizing the type alias `Poly0<(((((((...,),),),),),),)>`
--> $DIR/inherent-impls-overflow.rs:17:17
|
@ -22,6 +33,17 @@ LL | type Poly0<T> = Poly1<(T,)>;
|
= note: in case this is a recursive type alias, consider using a struct, enum, or union instead
error: type parameter `T` is only used recursively
--> $DIR/inherent-impls-overflow.rs:21:24
|
LL | type Poly1<T> = Poly0<(T,)>;
| - ^
| |
| type parameter must be used non-recursively in the definition
|
= help: consider removing `T` or referring to it in the body of the type alias
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0275]: overflow normalizing the type alias `Poly1<(((((((...,),),),),),),)>`
--> $DIR/inherent-impls-overflow.rs:21:17
|
@ -38,6 +60,6 @@ LL | impl Poly0<()> {}
|
= note: in case this is a recursive type alias, consider using a struct, enum, or union instead
error: aborting due to 5 previous errors
error: aborting due to 7 previous errors
For more information about this error, try `rustc --explain E0275`.

22
tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr
View file

@ -16,14 +16,6 @@ error[E0271]: type mismatch resolving `Loop normalizes-to _`
LL | impl Loop {}
| ^^^^ types differ
error[E0275]: overflow evaluating the requirement `Poly1<(T,)> == _`
--> $DIR/inherent-impls-overflow.rs:17:17
|
LL | type Poly0<T> = Poly1<(T,)>;
| ^^^^^^^^^^^
|
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_impls_overflow`)
error: type parameter `T` is only used recursively
--> $DIR/inherent-impls-overflow.rs:17:24
|
@ -35,10 +27,10 @@ LL | type Poly0<T> = Poly1<(T,)>;
= help: consider removing `T` or referring to it in the body of the type alias
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0275]: overflow evaluating the requirement `Poly0<(T,)> == _`
--> $DIR/inherent-impls-overflow.rs:21:17
error[E0275]: overflow evaluating the requirement `Poly1<(T,)> == _`
--> $DIR/inherent-impls-overflow.rs:17:17
|
LL | type Poly1<T> = Poly0<(T,)>;
LL | type Poly0<T> = Poly1<(T,)>;
| ^^^^^^^^^^^
|
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_impls_overflow`)
@ -54,6 +46,14 @@ LL | type Poly1<T> = Poly0<(T,)>;
= help: consider removing `T` or referring to it in the body of the type alias
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0275]: overflow evaluating the requirement `Poly0<(T,)> == _`
--> $DIR/inherent-impls-overflow.rs:21:17
|
LL | type Poly1<T> = Poly0<(T,)>;
| ^^^^^^^^^^^
|
= help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_impls_overflow`)
error[E0275]: overflow evaluating the requirement `Poly0<()> == _`
--> $DIR/inherent-impls-overflow.rs:26:1
|

8
tests/ui/lazy-type-alias/inherent-impls-overflow.rs
View file

@ -16,12 +16,12 @@ impl Loop {}
type Poly0<T> = Poly1<(T,)>;
//[current]~^ ERROR overflow normalizing the type alias `Poly0<(((((((...,),),),),),),)>`
//[next]~^^ ERROR type parameter `T` is only used recursively
//[next]~| ERROR overflow evaluating the requirement
//~^^ ERROR type parameter `T` is only used recursively
//[next]~^^^ ERROR overflow evaluating the requirement
type Poly1<T> = Poly0<(T,)>;
//[current]~^ ERROR overflow normalizing the type alias `Poly1<(((((((...,),),),),),),)>`
//[next]~^^ ERROR type parameter `T` is only used recursively
//[next]~| ERROR overflow evaluating the requirement
//~^^ ERROR type parameter `T` is only used recursively
//[next]~^^^ ERROR overflow evaluating the requirement
impl Poly0<()> {}
//[current]~^ ERROR overflow normalizing the type alias `Poly1<(((((((...,),),),),),),)>`

1
tests/ui/lazy-type-alias/unconstrained-params-in-impl-due-to-overflow.rs
View file

@ -4,5 +4,6 @@
impl<T> Loop<T> {} //~ ERROR the type parameter `T` is not constrained
type Loop<T> = Loop<T>; //~ ERROR overflow
//~^ ERROR: `T` is only used recursively
fn main() {}

13
tests/ui/lazy-type-alias/unconstrained-params-in-impl-due-to-overflow.stderr
View file

@ -4,6 +4,17 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
LL | impl<T> Loop<T> {}
| ^ unconstrained type parameter
error: type parameter `T` is only used recursively
--> $DIR/unconstrained-params-in-impl-due-to-overflow.rs:6:21
|
LL | type Loop<T> = Loop<T>;
| - ^
| |
| type parameter must be used non-recursively in the definition
|
= help: consider removing `T` or referring to it in the body of the type alias
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0275]: overflow normalizing the type alias `Loop<T>`
--> $DIR/unconstrained-params-in-impl-due-to-overflow.rs:6:16
|
@ -12,7 +23,7 @@ LL | type Loop<T> = Loop<T>;
|
= note: in case this is a recursive type alias, consider using a struct, enum, or union instead
error: aborting due to 2 previous errors
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0207, E0275.
For more information about an error, try `rustc --explain E0207`.

12
tests/ui/lifetimes/issue-64173-unused-lifetimes.stderr
View file

@ -7,12 +7,6 @@ LL | beta: [(); foo::<&'a ()>()],
= note: lifetime parameters may not be used in const expressions
= help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
error: generic `Self` types are currently not permitted in anonymous constants
--> $DIR/issue-64173-unused-lifetimes.rs:4:28
|
LL | array: [(); size_of::<&Self>()],
| ^^^^
error[E0392]: lifetime parameter `'s` is never used
--> $DIR/issue-64173-unused-lifetimes.rs:3:12
|
@ -21,6 +15,12 @@ LL | struct Foo<'s> {
|
= help: consider removing `'s`, referring to it in a field, or using a marker such as `PhantomData`
error: generic `Self` types are currently not permitted in anonymous constants
--> $DIR/issue-64173-unused-lifetimes.rs:4:28
|
LL | array: [(); size_of::<&Self>()],
| ^^^^
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/issue-64173-unused-lifetimes.rs:15:12
|

16
tests/ui/regions/region-bounds-on-objects-and-type-parameters.stderr
View file

@ -4,6 +4,14 @@ error[E0226]: only a single explicit lifetime bound is permitted
LL | z: Box<dyn Is<'a>+'b+'c>,
| ^^
error[E0392]: lifetime parameter `'c` is never used
--> $DIR/region-bounds-on-objects-and-type-parameters.rs:11:18
|
LL | struct Foo<'a,'b,'c> {
| ^^ unused lifetime parameter
|
= help: consider removing `'c`, referring to it in a field, or using a marker such as `PhantomData`
error[E0478]: lifetime bound not satisfied
--> $DIR/region-bounds-on-objects-and-type-parameters.rs:21:8
|
@ -21,14 +29,6 @@ note: but lifetime parameter must outlive the lifetime `'a` as defined here
LL | struct Foo<'a,'b,'c> {
| ^^
error[E0392]: lifetime parameter `'c` is never used
--> $DIR/region-bounds-on-objects-and-type-parameters.rs:11:18
|
LL | struct Foo<'a,'b,'c> {
| ^^ unused lifetime parameter
|
= help: consider removing `'c`, referring to it in a field, or using a marker such as `PhantomData`
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0226, E0392, E0478.

22
tests/ui/traits/issue-105231.stderr
View file

@ -1,3 +1,14 @@
error: type parameter `T` is only used recursively
--> $DIR/issue-105231.rs:1:15
|
LL | struct A<T>(B<T>);
| - ^
| |
| type parameter must be used non-recursively in the definition
|
= help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error[E0072]: recursive types `A` and `B` have infinite size
--> $DIR/issue-105231.rs:1:1
|
@ -15,17 +26,6 @@ LL |
LL ~ struct B<T>(Box<A<A<T>>>);
|
error: type parameter `T` is only used recursively
--> $DIR/issue-105231.rs:1:15
|
LL | struct A<T>(B<T>);
| - ^
| |
| type parameter must be used non-recursively in the definition
|
= help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
= note: all type parameters must be used in a non-recursive way in order to constrain their variance
error: type parameter `T` is only used recursively
--> $DIR/issue-105231.rs:4:17
|

16
tests/ui/variance/variance-regions-unused-indirect.stderr
View file

@ -1,3 +1,11 @@
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/variance-regions-unused-indirect.rs:3:10
|
LL | enum Foo<'a> {
| ^^ unused lifetime parameter
|
= help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`
error[E0072]: recursive types `Foo` and `Bar` have infinite size
--> $DIR/variance-regions-unused-indirect.rs:3:1
|
@ -21,14 +29,6 @@ LL | enum Bar<'a> {
LL ~ Bar1(Box<Foo<'a>>)
|
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/variance-regions-unused-indirect.rs:3:10
|
LL | enum Foo<'a> {
| ^^ unused lifetime parameter
|
= help: consider removing `'a`, referring to it in a field, or using a marker such as `PhantomData`
error[E0392]: lifetime parameter `'a` is never used
--> $DIR/variance-regions-unused-indirect.rs:8:10
|