diff options
| -rw-r--r-- | compiler/rustc_hir_analysis/messages.ftl | 5 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/wfcheck.rs | 83 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/errors.rs | 15 | ||||
| -rw-r--r-- | tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr | 23 | ||||
| -rw-r--r-- | tests/ui/lazy-type-alias/inherent-impls-overflow.rs | 4 | ||||
| -rw-r--r-- | tests/ui/traits/issue-105231.rs | 4 | ||||
| -rw-r--r-- | tests/ui/traits/issue-105231.stderr | 22 | ||||
| -rw-r--r-- | tests/ui/variance/variance-unused-type-param.rs | 2 | ||||
| -rw-r--r-- | tests/ui/variance/variance-unused-type-param.stderr | 10 |
9 files changed, 119 insertions, 49 deletions
diff --git a/compiler/rustc_hir_analysis/messages.ftl b/compiler/rustc_hir_analysis/messages.ftl index 24c5377a3b1..b37c19ed8a8 100644 --- a/compiler/rustc_hir_analysis/messages.ftl +++ b/compiler/rustc_hir_analysis/messages.ftl @@ -382,6 +382,10 @@ hir_analysis_placeholder_not_allowed_item_signatures = the placeholder `_` is no hir_analysis_precise_capture_self_alias = `Self` can't be captured in `use<...>` precise captures list, since it is an alias .label = `Self` is not a generic argument, but an alias to the type of the {$what} +hir_analysis_recursive_generic_parameter = {$param_def_kind} `{$param_name}` is only used recursively + .label = {$param_def_kind} must be used non-recursively in the definition + .note = all type parameters must be used in a non-recursive way in order to constrain its variance + hir_analysis_redundant_lifetime_args = unnecessary lifetime parameter `{$victim}` .note = you can use the `{$candidate}` lifetime directly, in place of `{$victim}` @@ -549,6 +553,7 @@ hir_analysis_unused_generic_parameter = {$param_def_kind} `{$param_name}` is never used .label = unused {$param_def_kind} .const_param_help = if you intended `{$param_name}` to be a const parameter, use `const {$param_name}: /* Type */` instead + hir_analysis_unused_generic_parameter_adt_help = consider removing `{$param_name}`, referring to it in a field, or using a marker such as `{$phantom_data}` hir_analysis_unused_generic_parameter_adt_no_phantom_data_help = diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index b2ef07d65c5..a4bff9272af 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -4,12 +4,12 @@ use crate::constrained_generic_params::{identify_constrained_generic_params, Par use crate::errors; use crate::fluent_generated as fluent; -use hir::intravisit::Visitor; +use hir::intravisit::{self, Visitor}; use rustc_ast as ast; use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; use rustc_errors::{codes::*, pluralize, struct_span_code_err, Applicability, ErrorGuaranteed}; use rustc_hir as hir; -use rustc_hir::def::DefKind; +use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId}; use rustc_hir::lang_items::LangItem; use rustc_hir::ItemKind; @@ -1799,7 +1799,7 @@ fn receiver_is_implemented<'tcx>( fn check_variances_for_type_defn<'tcx>( tcx: TyCtxt<'tcx>, - item: &hir::Item<'tcx>, + item: &'tcx hir::Item<'tcx>, hir_generics: &hir::Generics<'tcx>, ) { let identity_args = ty::GenericArgs::identity_for_item(tcx, item.owner_id); @@ -1886,21 +1886,21 @@ fn check_variances_for_type_defn<'tcx>( hir::ParamName::Error => {} _ => { let has_explicit_bounds = explicitly_bounded_params.contains(¶meter); - report_bivariance(tcx, hir_param, has_explicit_bounds, item.kind); + report_bivariance(tcx, hir_param, has_explicit_bounds, item); } } } } -fn report_bivariance( - tcx: TyCtxt<'_>, - param: &rustc_hir::GenericParam<'_>, +fn report_bivariance<'tcx>( + tcx: TyCtxt<'tcx>, + param: &'tcx hir::GenericParam<'tcx>, has_explicit_bounds: bool, - item_kind: ItemKind<'_>, + item: &'tcx hir::Item<'tcx>, ) -> ErrorGuaranteed { let param_name = param.name.ident(); - let help = match item_kind { + let help = match item.kind { ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) => { if let Some(def_id) = tcx.lang_items().phantom_data() { errors::UnusedGenericParameterHelp::Adt { @@ -1915,19 +1915,60 @@ fn report_bivariance( item_kind => bug!("report_bivariance: unexpected item kind: {item_kind:?}"), }; - let const_param_help = - matches!(param.kind, hir::GenericParamKind::Type { .. } if !has_explicit_bounds) - .then_some(()); + let mut usage_spans = vec![]; + intravisit::walk_item( + &mut CollectUsageSpans { spans: &mut usage_spans, param_def_id: param.def_id.to_def_id() }, + item, + ); - let mut diag = tcx.dcx().create_err(errors::UnusedGenericParameter { - span: param.span, - param_name, - param_def_kind: tcx.def_descr(param.def_id.to_def_id()), - help, - const_param_help, - }); - diag.code(E0392); - diag.emit() + if usage_spans.is_empty() { + let const_param_help = + matches!(param.kind, hir::GenericParamKind::Type { .. } if !has_explicit_bounds) + .then_some(()); + + let mut diag = tcx.dcx().create_err(errors::UnusedGenericParameter { + span: param.span, + param_name, + param_def_kind: tcx.def_descr(param.def_id.to_def_id()), + help, + const_param_help, + }); + diag.code(E0392); + diag.emit() + } else { + let diag = tcx.dcx().create_err(errors::RecursiveGenericParameter { + spans: usage_spans, + param_span: param.span, + param_name, + param_def_kind: tcx.def_descr(param.def_id.to_def_id()), + help, + note: (), + }); + diag.emit() + } +} + +struct CollectUsageSpans<'a> { + spans: &'a mut Vec<Span>, + param_def_id: DefId, +} + +impl<'tcx> Visitor<'tcx> for CollectUsageSpans<'_> { + type Result = (); + + fn visit_generics(&mut self, _g: &'tcx rustc_hir::Generics<'tcx>) -> Self::Result { + // Skip the generics. We only care about fields, not where clause/param bounds. + } + + fn visit_ty(&mut self, t: &'tcx hir::Ty<'tcx>) -> Self::Result { + if let hir::TyKind::Path(hir::QPath::Resolved(None, qpath)) = t.kind + && let Res::Def(DefKind::TyParam, def_id) = qpath.res + && def_id == self.param_def_id + { + self.spans.push(t.span); + } + intravisit::walk_ty(self, t); + } } impl<'tcx> WfCheckingCtxt<'_, 'tcx> { diff --git a/compiler/rustc_hir_analysis/src/errors.rs b/compiler/rustc_hir_analysis/src/errors.rs index 0ee87a13e9e..2edd8f54adb 100644 --- a/compiler/rustc_hir_analysis/src/errors.rs +++ b/compiler/rustc_hir_analysis/src/errors.rs @@ -1603,6 +1603,21 @@ pub(crate) struct UnusedGenericParameter { pub const_param_help: Option<()>, } +#[derive(Diagnostic)] +#[diag(hir_analysis_recursive_generic_parameter)] +pub(crate) struct RecursiveGenericParameter { + #[primary_span] + pub spans: Vec<Span>, + #[label] + pub param_span: Span, + pub param_name: Ident, + pub param_def_kind: &'static str, + #[subdiagnostic] + pub help: UnusedGenericParameterHelp, + #[note] + pub note: (), +} + #[derive(Subdiagnostic)] pub(crate) enum UnusedGenericParameterHelp { #[help(hir_analysis_unused_generic_parameter_adt_help)] diff --git a/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr b/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr index 944fe8aa8e5..b60fdea004e 100644 --- a/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr +++ b/tests/ui/lazy-type-alias/inherent-impls-overflow.next.stderr @@ -4,23 +4,27 @@ error[E0275]: overflow evaluating the requirement `Loop == _` LL | impl Loop {} | ^^^^ -error[E0392]: type parameter `T` is never used - --> $DIR/inherent-impls-overflow.rs:14:12 +error: type parameter `T` is only used recursively + --> $DIR/inherent-impls-overflow.rs:14:24 | LL | type Poly0<T> = Poly1<(T,)>; - | ^ unused type parameter + | - ^ + | | + | 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 - = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead + = note: all type parameters must be used in a non-recursive way in order to constrain its variance -error[E0392]: type parameter `T` is never used - --> $DIR/inherent-impls-overflow.rs:17:12 +error: type parameter `T` is only used recursively + --> $DIR/inherent-impls-overflow.rs:17:24 | LL | type Poly1<T> = Poly0<(T,)>; - | ^ unused type parameter + | - ^ + | | + | 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 - = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead + = note: all type parameters must be used in a non-recursive way in order to constrain its variance error[E0275]: overflow evaluating the requirement `Poly0<()> == _` --> $DIR/inherent-impls-overflow.rs:21:6 @@ -32,5 +36,4 @@ LL | impl Poly0<()> {} error: aborting due to 4 previous errors -Some errors have detailed explanations: E0275, E0392. -For more information about an error, try `rustc --explain E0275`. +For more information about this error, try `rustc --explain E0275`. diff --git a/tests/ui/lazy-type-alias/inherent-impls-overflow.rs b/tests/ui/lazy-type-alias/inherent-impls-overflow.rs index 98f0d811a47..1397695a3fe 100644 --- a/tests/ui/lazy-type-alias/inherent-impls-overflow.rs +++ b/tests/ui/lazy-type-alias/inherent-impls-overflow.rs @@ -13,10 +13,10 @@ impl Loop {} type Poly0<T> = Poly1<(T,)>; //[current]~^ ERROR overflow normalizing the type alias `Poly0<(((((((...,),),),),),),)>` -//[next]~^^ ERROR type parameter `T` is never used +//[next]~^^ ERROR type parameter `T` is only used recursively type Poly1<T> = Poly0<(T,)>; //[current]~^ ERROR overflow normalizing the type alias `Poly1<(((((((...,),),),),),),)>` -//[next]~^^ ERROR type parameter `T` is never used +//[next]~^^ ERROR type parameter `T` is only used recursively impl Poly0<()> {} //[current]~^ ERROR overflow normalizing the type alias `Poly1<(((((((...,),),),),),),)>` diff --git a/tests/ui/traits/issue-105231.rs b/tests/ui/traits/issue-105231.rs index 89b2da4452a..7338642beef 100644 --- a/tests/ui/traits/issue-105231.rs +++ b/tests/ui/traits/issue-105231.rs @@ -1,9 +1,9 @@ //~ ERROR overflow evaluating the requirement `A<A<A<A<A<A<A<...>>>>>>>: Send` struct A<T>(B<T>); //~^ ERROR recursive types `A` and `B` have infinite size -//~| ERROR `T` is never used +//~| ERROR `T` is only used recursively struct B<T>(A<A<T>>); -//~^ ERROR `T` is never used +//~^ ERROR `T` is only used recursively trait Foo {} impl<T> Foo for T where T: Send {} impl Foo for B<u8> {} diff --git a/tests/ui/traits/issue-105231.stderr b/tests/ui/traits/issue-105231.stderr index 6467a438375..6fd73b29f21 100644 --- a/tests/ui/traits/issue-105231.stderr +++ b/tests/ui/traits/issue-105231.stderr @@ -15,23 +15,27 @@ LL | LL ~ struct B<T>(Box<A<A<T>>>); | -error[E0392]: type parameter `T` is never used - --> $DIR/issue-105231.rs:2:10 +error: type parameter `T` is only used recursively + --> $DIR/issue-105231.rs:2:15 | LL | struct A<T>(B<T>); - | ^ unused type parameter + | - ^ + | | + | 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` - = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead + = note: all type parameters must be used in a non-recursive way in order to constrain its variance -error[E0392]: type parameter `T` is never used - --> $DIR/issue-105231.rs:5:10 +error: type parameter `T` is only used recursively + --> $DIR/issue-105231.rs:5:17 | LL | struct B<T>(A<A<T>>); - | ^ unused type parameter + | - ^ + | | + | 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` - = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead + = note: all type parameters must be used in a non-recursive way in order to constrain its variance error[E0275]: overflow evaluating the requirement `A<A<A<A<A<A<A<...>>>>>>>: Send` | @@ -44,5 +48,5 @@ LL | struct B<T>(A<A<T>>); error: aborting due to 4 previous errors -Some errors have detailed explanations: E0072, E0275, E0392. +Some errors have detailed explanations: E0072, E0275. For more information about an error, try `rustc --explain E0072`. diff --git a/tests/ui/variance/variance-unused-type-param.rs b/tests/ui/variance/variance-unused-type-param.rs index d1114064364..7e35f59fd84 100644 --- a/tests/ui/variance/variance-unused-type-param.rs +++ b/tests/ui/variance/variance-unused-type-param.rs @@ -11,8 +11,8 @@ enum SomeEnum<A> { Nothing } // Here T might *appear* used, but in fact it isn't. enum ListCell<T> { -//~^ ERROR parameter `T` is never used Cons(Box<ListCell<T>>), + //~^ ERROR parameter `T` is only used recursively Nil } diff --git a/tests/ui/variance/variance-unused-type-param.stderr b/tests/ui/variance/variance-unused-type-param.stderr index 3011b7bd18f..212db564ac4 100644 --- a/tests/ui/variance/variance-unused-type-param.stderr +++ b/tests/ui/variance/variance-unused-type-param.stderr @@ -16,14 +16,16 @@ LL | enum SomeEnum<A> { Nothing } = help: consider removing `A`, referring to it in a field, or using a marker such as `PhantomData` = help: if you intended `A` to be a const parameter, use `const A: /* Type */` instead -error[E0392]: type parameter `T` is never used - --> $DIR/variance-unused-type-param.rs:13:15 +error: type parameter `T` is only used recursively + --> $DIR/variance-unused-type-param.rs:14:23 | LL | enum ListCell<T> { - | ^ unused type parameter + | - type parameter must be used non-recursively in the definition +LL | Cons(Box<ListCell<T>>), + | ^ | = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData` - = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead + = note: all type parameters must be used in a non-recursive way in order to constrain its variance error[E0392]: type parameter `T` is never used --> $DIR/variance-unused-type-param.rs:19:19 |