diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs index 462fc27009de9..9bb64d4023bca 100644 --- a/compiler/rustc_middle/src/ty/diagnostics.rs +++ b/compiler/rustc_middle/src/ty/diagnostics.rs @@ -272,7 +272,10 @@ pub fn suggest_constraining_type_params<'a>( continue; } - let constraint = constraints.iter().map(|&(c, _)| c).collect::>().join(" + "); + let mut constraint = constraints.iter().map(|&(c, _)| c).collect::>(); + constraint.sort(); + constraint.dedup(); + let constraint = constraint.join(" + "); let mut suggest_restrict = |span, bound_list_non_empty| { suggestions.push(( span, diff --git a/compiler/rustc_typeck/src/coherence/builtin.rs b/compiler/rustc_typeck/src/coherence/builtin.rs index d08d9938708c9..c809b8bdd73db 100644 --- a/compiler/rustc_typeck/src/coherence/builtin.rs +++ b/compiler/rustc_typeck/src/coherence/builtin.rs @@ -2,7 +2,7 @@ //! up data structures required by type-checking/codegen. use crate::errors::{CopyImplOnNonAdt, CopyImplOnTypeWithDtor, DropImplOnWrongItem}; -use rustc_errors::struct_span_err; +use rustc_errors::{struct_span_err, MultiSpan}; use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::lang_items::LangItem; @@ -11,12 +11,12 @@ use rustc_infer::infer; use rustc_infer::infer::outlives::env::OutlivesEnvironment; use rustc_infer::infer::{RegionckMode, TyCtxtInferExt}; use rustc_middle::ty::adjustment::CoerceUnsizedInfo; -use rustc_middle::ty::TypeFoldable; -use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeFoldable}; use rustc_trait_selection::traits::error_reporting::InferCtxtExt; use rustc_trait_selection::traits::misc::{can_type_implement_copy, CopyImplementationError}; use rustc_trait_selection::traits::predicate_for_trait_def; use rustc_trait_selection::traits::{self, ObligationCause, TraitEngine, TraitEngineExt}; +use std::collections::BTreeMap; pub fn check_trait(tcx: TyCtxt<'_>, trait_def_id: DefId) { let lang_items = tcx.lang_items(); @@ -91,6 +91,20 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { E0204, "the trait `Copy` may not be implemented for this type" ); + + // We'll try to suggest constraining type parameters to fulfill the requirements of + // their `Copy` implementation. + let mut generics = None; + if let ty::Adt(def, _substs) = self_type.kind() { + let self_def_id = def.did(); + if let Some(local) = self_def_id.as_local() { + let self_item = tcx.hir().expect_item(local); + generics = self_item.kind.generics(); + } + } + let mut errors: BTreeMap<_, Vec<_>> = Default::default(); + let mut bounds = vec![]; + for (field, ty) in fields { let field_span = tcx.def_span(field.did); err.span_label(field_span, "this field does not implement `Copy`"); @@ -115,17 +129,46 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) { // FIXME: This error could be more descriptive, especially if the error_predicate // contains a foreign type or if it's a deeply nested type... if error_predicate != error.root_obligation.predicate { - err.span_note( - error.obligation.cause.span, - &format!( - "the `Copy` impl for `{}` requires that `{}`", - ty, error_predicate - ), - ); + errors + .entry((ty.to_string(), error_predicate.to_string())) + .or_default() + .push(error.obligation.cause.span); + } + if let ty::PredicateKind::Trait(ty::TraitPredicate { + trait_ref, + polarity: ty::ImplPolarity::Positive, + .. + }) = error_predicate.kind().skip_binder() + { + let ty = trait_ref.self_ty(); + if let ty::Param(_) = ty.kind() { + bounds.push(( + format!("{ty}"), + trait_ref.print_only_trait_path().to_string(), + Some(trait_ref.def_id), + )); + } } } }); } + for ((ty, error_predicate), spans) in errors { + let span: MultiSpan = spans.into(); + err.span_note( + span, + &format!("the `Copy` impl for `{}` requires that `{}`", ty, error_predicate), + ); + } + if let Some(generics) = generics { + suggest_constraining_type_params( + tcx, + generics, + &mut err, + bounds.iter().map(|(param, constraint, def_id)| { + (param.as_str(), constraint.as_str(), *def_id) + }), + ); + } err.emit(); } Err(CopyImplementationError::NotAnAdt) => { diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed b/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed index ba1b745ba8422..45acf5beb1217 100644 --- a/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed +++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.fixed @@ -21,7 +21,7 @@ fn duplicate_tup2(t: (A, B)) -> ((A, B), (A, B)) { (t, t) //~ use of moved value: `t` } -fn duplicate_custom(t: S) -> (S, S) { +fn duplicate_custom(t: S) -> (S, S) { //~^ HELP consider restricting type parameter `T` (t, t) //~ use of moved value: `t` } @@ -39,14 +39,14 @@ trait A {} trait B {} // Test where bounds are added with different bound placements -fn duplicate_custom_1(t: S) -> (S, S) where { +fn duplicate_custom_1(t: S) -> (S, S) where { //~^ HELP consider restricting type parameter `T` (t, t) //~ use of moved value: `t` } fn duplicate_custom_2(t: S) -> (S, S) where - T: A + Trait + Copy, + T: A + Copy + Trait, //~^ HELP consider further restricting this bound { (t, t) //~ use of moved value: `t` @@ -54,14 +54,14 @@ where fn duplicate_custom_3(t: S) -> (S, S) where - T: A + Trait + Copy, + T: A + Copy + Trait, //~^ HELP consider further restricting this bound T: B, { (t, t) //~ use of moved value: `t` } -fn duplicate_custom_4(t: S) -> (S, S) +fn duplicate_custom_4(t: S) -> (S, S) //~^ HELP consider further restricting this bound where T: B, diff --git a/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr index 2353cd079a370..5a84e3b81a656 100644 --- a/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr +++ b/src/test/ui/moves/use_of_moved_value_copy_suggestions.stderr @@ -75,7 +75,7 @@ LL | (t, t) | help: consider restricting type parameter `T` | -LL | fn duplicate_custom(t: S) -> (S, S) { +LL | fn duplicate_custom(t: S) -> (S, S) { | ++++++++++++++ error[E0382]: use of moved value: `t` @@ -91,7 +91,7 @@ LL | (t, t) | help: consider restricting type parameter `T` | -LL | fn duplicate_custom_1(t: S) -> (S, S) where { +LL | fn duplicate_custom_1(t: S) -> (S, S) where { | ++++++++++++++ error[E0382]: use of moved value: `t` @@ -107,7 +107,7 @@ LL | (t, t) | help: consider further restricting this bound | -LL | T: A + Trait + Copy, +LL | T: A + Copy + Trait, | ++++++++++++++ error[E0382]: use of moved value: `t` @@ -123,7 +123,7 @@ LL | (t, t) | help: consider further restricting this bound | -LL | T: A + Trait + Copy, +LL | T: A + Copy + Trait, | ++++++++++++++ error[E0382]: use of moved value: `t` @@ -139,7 +139,7 @@ LL | (t, t) | help: consider further restricting this bound | -LL | fn duplicate_custom_4(t: S) -> (S, S) +LL | fn duplicate_custom_4(t: S) -> (S, S) | ++++++++++++++ error[E0382]: use of moved value: `t` diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed new file mode 100644 index 0000000000000..ac0b14fba83b6 --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.fixed @@ -0,0 +1,16 @@ +// run-rustfix +use std::fmt::Debug; + +#[derive(Debug, Copy, Clone)] +pub struct Vector2{ + pub x: T, + pub y: T +} + +#[derive(Debug, Copy, Clone)] +pub struct AABB{ + pub loc: Vector2, //~ ERROR the trait bound `K: Copy` is not satisfied + pub size: Vector2 +} + +fn main() {} diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.rs b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.rs new file mode 100644 index 0000000000000..31f8cd6fcf79e --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.rs @@ -0,0 +1,16 @@ +// run-rustfix +use std::fmt::Debug; + +#[derive(Debug, Copy, Clone)] +pub struct Vector2{ + pub x: T, + pub y: T +} + +#[derive(Debug, Copy, Clone)] +pub struct AABB{ + pub loc: Vector2, //~ ERROR the trait bound `K: Copy` is not satisfied + pub size: Vector2 +} + +fn main() {} diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.stderr b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.stderr new file mode 100644 index 0000000000000..03082be690fbf --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-2.stderr @@ -0,0 +1,19 @@ +error[E0277]: the trait bound `K: Copy` is not satisfied + --> $DIR/missing-bound-in-derive-copy-impl-2.rs:12:14 + | +LL | pub loc: Vector2, + | ^^^^^^^^^^ the trait `Copy` is not implemented for `K` + | +note: required by a bound in `Vector2` + --> $DIR/missing-bound-in-derive-copy-impl-2.rs:5:31 + | +LL | pub struct Vector2{ + | ^^^^ required by this bound in `Vector2` +help: consider further restricting this bound + | +LL | pub struct AABB{ + | +++++++++++++++++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0277`. diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed new file mode 100644 index 0000000000000..304360d48a261 --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.fixed @@ -0,0 +1,16 @@ +//run-rustfix +use std::fmt::Debug; + +#[derive(Debug, Copy, Clone)] +pub struct Vector2{ + pub x: T, + pub y: T +} + +#[derive(Debug, Copy, Clone)] //~ ERROR the trait `Copy` may not be implemented for this type +pub struct AABB{ + pub loc: Vector2, + pub size: Vector2 +} + +fn main() {} diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.rs b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.rs new file mode 100644 index 0000000000000..14e1fbb33112a --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.rs @@ -0,0 +1,16 @@ +//run-rustfix +use std::fmt::Debug; + +#[derive(Debug, Copy, Clone)] +pub struct Vector2{ + pub x: T, + pub y: T +} + +#[derive(Debug, Copy, Clone)] //~ ERROR the trait `Copy` may not be implemented for this type +pub struct AABB{ + pub loc: Vector2, + pub size: Vector2 +} + +fn main() {} diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.stderr b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.stderr new file mode 100644 index 0000000000000..4eb1e318d97c3 --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl-3.stderr @@ -0,0 +1,27 @@ +error[E0204]: the trait `Copy` may not be implemented for this type + --> $DIR/missing-bound-in-derive-copy-impl-3.rs:10:17 + | +LL | #[derive(Debug, Copy, Clone)] + | ^^^^ +LL | pub struct AABB{ +LL | pub loc: Vector2, + | ------------------- this field does not implement `Copy` +LL | pub size: Vector2 + | -------------------- this field does not implement `Copy` + | +note: the `Copy` impl for `Vector2` requires that `K: Debug` + --> $DIR/missing-bound-in-derive-copy-impl-3.rs:12:5 + | +LL | pub loc: Vector2, + | ^^^^^^^^^^^^^^^^^^^ +LL | pub size: Vector2 + | ^^^^^^^^^^^^^^^^^^^^ + = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info) +help: consider further restricting this bound + | +LL | pub struct AABB{ + | +++++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0204`. diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.rs b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.rs new file mode 100644 index 0000000000000..52163bddd4ff5 --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.rs @@ -0,0 +1,15 @@ +use std::fmt::Debug; + +#[derive(Debug, Copy, Clone)] +pub struct Vector2{ + pub x: T, + pub y: T +} + +#[derive(Debug, Copy, Clone)] //~ ERROR the trait `Copy` may not be implemented for this type +pub struct AABB{ + pub loc: Vector2, + pub size: Vector2 +} + +fn main() {} diff --git a/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.stderr b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.stderr new file mode 100644 index 0000000000000..1cf2ab95bc3a8 --- /dev/null +++ b/src/test/ui/suggestions/missing-bound-in-derive-copy-impl.stderr @@ -0,0 +1,27 @@ +error[E0204]: the trait `Copy` may not be implemented for this type + --> $DIR/missing-bound-in-derive-copy-impl.rs:9:17 + | +LL | #[derive(Debug, Copy, Clone)] + | ^^^^ +LL | pub struct AABB{ +LL | pub loc: Vector2, + | ------------------- this field does not implement `Copy` +LL | pub size: Vector2 + | -------------------- this field does not implement `Copy` + | +note: the `Copy` impl for `Vector2` requires that `K: Debug` + --> $DIR/missing-bound-in-derive-copy-impl.rs:11:5 + | +LL | pub loc: Vector2, + | ^^^^^^^^^^^^^^^^^^^ +LL | pub size: Vector2 + | ^^^^^^^^^^^^^^^^^^^^ + = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info) +help: consider restricting type parameter `K` + | +LL | pub struct AABB{ + | +++++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0204`.