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Adding helper to report_unused_parameter #108252

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cc811d7
Adding helper to report_unused_parameter
Feb 20, 2023
c76da7f
fixing tests
Feb 20, 2023
446e330
Merge branch 'master' into 107295
Feb 22, 2023
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11 changes: 10 additions & 1 deletion compiler/rustc_hir_analysis/src/impl_wf_check.rs
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Expand Up @@ -12,7 +12,7 @@ use crate::constrained_generic_params as cgp;
use min_specialization::check_min_specialization;

use rustc_data_structures::fx::FxHashSet;
use rustc_errors::struct_span_err;
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir::def::DefKind;
use rustc_hir::def_id::LocalDefId;
use rustc_middle::ty::query::Providers;
Expand Down Expand Up @@ -181,6 +181,15 @@ fn report_unused_parameter(tcx: TyCtxt<'_>, span: Span, kind: &str, name: Symbol
name
);
err.span_label(span, format!("unconstrained {} parameter", kind));
err.span_suggestion(
span,
format!(
"Either remove the type parameter '{}' or make use of it, for example ` for S<{}>`.",
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"Make use of it" is a little misleading, the user might already use it in a where clause. I'm not sure what the best wording for this would be.

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maybe just removing the "make" and leave it Either remove the type parameter or use it?
I am not sure on the words as well... =(

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yea that sounds better

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nit: our messages start lowercase

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we should not just suggest S<T>. Either load the trait or type name and append the generics to that or write prosa explaining what's going on without naming the trait or type.

name, name
),
"",
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I don't think it's a good idea to give a suggestion to remove it. Simply removing the parameter is usually not the solution to this error in my experience.

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I based myself on the "desired output" on #107295
What would be a good explanation? :)

Applicability::MaybeIncorrect,
);
if kind == "const" {
err.note(
"expressions using a const parameter must map each value to a distinct output value",
Expand Down
5 changes: 5 additions & 0 deletions tests/ui/async-await/issues/issue-78654.full.stderr
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Expand Up @@ -12,6 +12,11 @@ LL | impl<const H: feature> Foo {
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'H' or make use of it, for example ` for S<H>`.
|
LL - impl<const H: feature> Foo {
LL + impl<> Foo {
|

error: aborting due to 2 previous errors

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5 changes: 5 additions & 0 deletions tests/ui/async-await/issues/issue-78654.min.stderr
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Expand Up @@ -12,6 +12,11 @@ LL | impl<const H: feature> Foo {
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'H' or make use of it, for example ` for S<H>`.
|
LL - impl<const H: feature> Foo {
LL + impl<> Foo {
|

error: aborting due to 2 previous errors

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10 changes: 10 additions & 0 deletions tests/ui/const-generics/issues/issue-68366.full.stderr
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Expand Up @@ -6,6 +6,11 @@ LL | impl <const N: usize> Collatz<{Some(N)}> {}
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'N' or make use of it, for example ` for S<N>`.
|
LL - impl <const N: usize> Collatz<{Some(N)}> {}
LL + impl <> Collatz<{Some(N)}> {}
|
Comment on lines +9 to +13
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in this case the suggestion is wrong, removing it is never the right thing if it is used, but in a way that isn't legal.

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since we know it in this case (we are emitting the two notes above after all), you can re-use the condition for that and not emit the suggestion in that case


error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
--> $DIR/issue-68366.rs:17:6
Expand All @@ -15,6 +20,11 @@ LL | impl<const N: usize> Foo {}
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'N' or make use of it, for example ` for S<N>`.
|
LL - impl<const N: usize> Foo {}
LL + impl<> Foo {}
|

error: aborting due to 2 previous errors

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10 changes: 10 additions & 0 deletions tests/ui/const-generics/issues/issue-68366.min.stderr
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Expand Up @@ -15,6 +15,11 @@ LL | impl <const N: usize> Collatz<{Some(N)}> {}
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'N' or make use of it, for example ` for S<N>`.
|
LL - impl <const N: usize> Collatz<{Some(N)}> {}
LL + impl <> Collatz<{Some(N)}> {}
|

error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
--> $DIR/issue-68366.rs:17:6
Expand All @@ -24,6 +29,11 @@ LL | impl<const N: usize> Foo {}
|
= note: expressions using a const parameter must map each value to a distinct output value
= note: proving the result of expressions other than the parameter are unique is not supported
help: Either remove the type parameter 'N' or make use of it, for example ` for S<N>`.
|
LL - impl<const N: usize> Foo {}
LL + impl<> Foo {}
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should remove the generic parameters entirely instead of leaving empty ones around

|

error: aborting due to 3 previous errors

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6 changes: 6 additions & 0 deletions tests/ui/duplicate/duplicate-type-parameter.stderr
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Expand Up @@ -59,6 +59,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T,T> Qux<T,T> for Option<T> {}
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T,T> Qux<T,T> for Option<T> {}
LL + impl<T,> Qux<T,T> for Option<T> {}
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stray comma in the suggestion

|

error: aborting due to 8 previous errors

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6 changes: 6 additions & 0 deletions tests/ui/error-codes/E0207.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T: Default> Foo {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T: Default> Foo {
LL + impl<: Default> Foo {
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Need to remove the bounds, too

|

error: aborting due to previous error

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6 changes: 6 additions & 0 deletions tests/ui/generic-associated-types/bugs/issue-87735.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `U` is not constrained by the impl trait, self
|
LL | impl<'b, T, U> AsRef2 for Foo<T>
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<'b, T, U> AsRef2 for Foo<T>
LL + impl<'b, T, > AsRef2 for Foo<T>
|

error: aborting due to previous error

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6 changes: 6 additions & 0 deletions tests/ui/generic-associated-types/bugs/issue-88526.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `I` is not constrained by the impl trait, self
|
LL | impl<'q, Q, I, F> A for TestB<Q, F>
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'I' or make use of it, for example ` for S<I>`.
|
LL - impl<'q, Q, I, F> A for TestB<Q, F>
LL + impl<'q, Q, , F> A for TestB<Q, F>
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stray comma

|

error: aborting due to previous error

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6 changes: 6 additions & 0 deletions tests/ui/generic-associated-types/gat-trait-path-generic-type-arg.stderr
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Expand Up @@ -18,6 +18,12 @@ error[E0207]: the type parameter `T1` is not constrained by the impl trait, self
|
LL | impl <T, T1> Foo for T {
| ^^ unconstrained type parameter
|
help: Either remove the type parameter 'T1' or make use of it, for example ` for S<T1>`.
|
LL - impl <T, T1> Foo for T {
LL + impl <T, > Foo for T {
|

error: aborting due to 3 previous errors

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/impl-trait/issues/issue-87340.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T> X for () {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T> X for () {
LL + impl<> X for () {
|

error: aborting due to previous error

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6 changes: 6 additions & 0 deletions tests/ui/impl-unused-rps-in-assoc-type.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait,
|
LL | impl<'a> Fun for Holder {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a> Fun for Holder {
LL + impl<> Fun for Holder {
|

error: aborting due to previous error

Expand Down
12 changes: 12 additions & 0 deletions tests/ui/impl-unused-tps-inherent.stderr
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Expand Up @@ -3,12 +3,24 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T> MyType {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T> MyType {
LL + impl<> MyType {
|

error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
--> $DIR/impl-unused-tps-inherent.rs:17:8
|
LL | impl<T,U> MyType1<T> {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<T,U> MyType1<T> {
LL + impl<T,> MyType1<T> {
|

error: aborting due to 2 previous errors

Expand Down
30 changes: 30 additions & 0 deletions tests/ui/impl-unused-tps.stderr
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Expand Up @@ -3,30 +3,60 @@ error[E0207]: the type parameter `U` is not constrained by the impl trait, self
|
LL | impl<T,U> Foo<T> for [isize;1] {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<T,U> Foo<T> for [isize;1] {
LL + impl<T,> Foo<T> for [isize;1] {
|

error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
--> $DIR/impl-unused-tps.rs:30:8
|
LL | impl<T,U> Bar for T {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<T,U> Bar for T {
LL + impl<T,> Bar for T {
|

error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
--> $DIR/impl-unused-tps.rs:38:8
|
LL | impl<T,U> Bar for T
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<T,U> Bar for T
LL + impl<T,> Bar for T
|

error[E0207]: the type parameter `U` is not constrained by the impl trait, self type, or predicates
--> $DIR/impl-unused-tps.rs:46:8
|
LL | impl<T,U,V> Foo<T> for T
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'U' or make use of it, for example ` for S<U>`.
|
LL - impl<T,U,V> Foo<T> for T
LL + impl<T,,V> Foo<T> for T
|

error[E0207]: the type parameter `V` is not constrained by the impl trait, self type, or predicates
--> $DIR/impl-unused-tps.rs:46:10
|
LL | impl<T,U,V> Foo<T> for T
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'V' or make use of it, for example ` for S<V>`.
|
LL - impl<T,U,V> Foo<T> for T
LL + impl<T,U,> Foo<T> for T
|

error: aborting due to 5 previous errors

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/issues/issue-16562.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T, M: MatrixShape> Collection for Col<M, usize> {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T, M: MatrixShape> Collection for Col<M, usize> {
LL + impl<, M: MatrixShape> Collection for Col<M, usize> {
|

error: aborting due to previous error

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/issues/issue-22886.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait,
|
LL | impl<'a> Iterator for Newtype {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a> Iterator for Newtype {
LL + impl<> Iterator for Newtype {
|

error: aborting due to previous error

Expand Down
12 changes: 12 additions & 0 deletions tests/ui/issues/issue-26262.stderr
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Expand Up @@ -3,12 +3,24 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T: Tr> S<T::Assoc> {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T: Tr> S<T::Assoc> {
LL + impl<: Tr> S<T::Assoc> {
|

error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
--> $DIR/issue-26262.rs:17:6
|
LL | impl<'a,T: Trait2<'a>> Trait1<<T as Trait2<'a>>::Foo> for T {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a,T: Trait2<'a>> Trait1<<T as Trait2<'a>>::Foo> for T {
LL + impl<,T: Trait2<'a>> Trait1<<T as Trait2<'a>>::Foo> for T {
|

error: aborting due to 2 previous errors

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/issues/issue-29861.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait,
|
LL | impl<'a, T: 'a> MakeRef2 for T {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a, T: 'a> MakeRef2 for T {
LL + impl<, T: 'a> MakeRef2 for T {
|

error: aborting due to previous error

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/issues/issue-35139.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait,
|
LL | impl<'a> MethodType for MTFn {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a> MethodType for MTFn {
LL + impl<> MethodType for MTFn {
|

error: aborting due to previous error

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/type-alias-impl-trait/assoc-type-lifetime-unconstrained.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait,
|
LL | impl<'a, I> UnwrapItemsExt for I {
| ^^ unconstrained lifetime parameter
|
help: Either remove the type parameter ''a' or make use of it, for example ` for S<'a>`.
|
LL - impl<'a, I> UnwrapItemsExt for I {
LL + impl<, I> UnwrapItemsExt for I {
|

error: aborting due to previous error

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/type-alias-impl-trait/impl-with-unconstrained-param.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T> X for () {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T> X for () {
LL + impl<> X for () {
|

error: aborting due to previous error

Expand Down
6 changes: 6 additions & 0 deletions tests/ui/type-alias-impl-trait/issue-74244.stderr
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Expand Up @@ -3,6 +3,12 @@ error[E0207]: the type parameter `T` is not constrained by the impl trait, self
|
LL | impl<T> Allocator for DefaultAllocator {
| ^ unconstrained type parameter
|
help: Either remove the type parameter 'T' or make use of it, for example ` for S<T>`.
|
LL - impl<T> Allocator for DefaultAllocator {
LL + impl<> Allocator for DefaultAllocator {
|

error: aborting due to previous error

Expand Down
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