diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs new file mode 100644 index 00000000000..2eab68050d4 --- /dev/null +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/adjust_fulfillment_errors.rs @@ -0,0 +1,457 @@ +use crate::FnCtxt; +use rustc_hir as hir; +use rustc_hir::def::Res; +use rustc_middle::ty::{self, DefIdTree, Ty}; +use rustc_trait_selection::traits; + +impl<'a, 'tcx> FnCtxt<'a, 'tcx> { + /** + * Recursively searches for the most-specific blamable expression. + * For example, if you have a chain of constraints like: + * - want `Vec: Copy` + * - because `Option>: Copy` needs `Vec: Copy` because `impl Copy for Option` + * - because `(Option, bool)` needs `Option>: Copy` because `impl Copy for (A, B)` + * then if you pass in `(Some(vec![1, 2, 3]), false)`, this helper `point_at_specific_expr_if_possible` + * will find the expression `vec![1, 2, 3]` as the "most blameable" reason for this missing constraint. + * + * This function only updates the error span. + */ + pub fn blame_specific_expr_if_possible( + &self, + error: &mut traits::FulfillmentError<'tcx>, + expr: &'tcx hir::Expr<'tcx>, + ) { + // Whether it succeeded or failed, it likely made some amount of progress. + // In the very worst case, it's just the same `expr` we originally passed in. + let expr = match self.blame_specific_expr_if_possible_for_obligation_cause_code( + &error.obligation.cause.code(), + expr, + ) { + Ok(expr) => expr, + Err(expr) => expr, + }; + + // Either way, use this expression to update the error span. + // If it doesn't overlap the existing span at all, use the original span. + // FIXME: It would possibly be better to do this more continuously, at each level... + error.obligation.cause.span = expr + .span + .find_ancestor_in_same_ctxt(error.obligation.cause.span) + .unwrap_or(error.obligation.cause.span); + } + + fn blame_specific_expr_if_possible_for_obligation_cause_code( + &self, + obligation_cause_code: &traits::ObligationCauseCode<'tcx>, + expr: &'tcx hir::Expr<'tcx>, + ) -> Result<&'tcx hir::Expr<'tcx>, &'tcx hir::Expr<'tcx>> { + match obligation_cause_code { + traits::ObligationCauseCode::ExprBindingObligation(_, _, _, _) => { + // This is the "root"; we assume that the `expr` is already pointing here. + // Therefore, we return `Ok` so that this `expr` can be refined further. + Ok(expr) + } + traits::ObligationCauseCode::ImplDerivedObligation(impl_derived) => self + .blame_specific_expr_if_possible_for_derived_predicate_obligation( + impl_derived, + expr, + ), + _ => { + // We don't recognize this kind of constraint, so we cannot refine the expression + // any further. + Err(expr) + } + } + } + + /// We want to achieve the error span in the following example: + /// + /// ```ignore (just for demonstration) + /// struct Burrito { + /// filling: Filling, + /// } + /// impl Delicious for Burrito {} + /// fn eat_delicious_food(_food: Food) {} + /// + /// fn will_type_error() { + /// eat_delicious_food(Burrito { filling: Kale }); + /// } // ^--- The trait bound `Kale: Delicious` + /// // is not satisfied + /// ``` + /// + /// Without calling this function, the error span will cover the entire argument expression. + /// + /// Before we do any of this logic, we recursively call `point_at_specific_expr_if_possible` on the parent + /// obligation. Hence we refine the `expr` "outwards-in" and bail at the first kind of expression/impl we don't recognize. + /// + /// This function returns a `Result<&Expr, &Expr>` - either way, it returns the `Expr` whose span should be + /// reported as an error. If it is `Ok`, then it means it refined successfull. If it is `Err`, then it may be + /// only a partial success - but it cannot be refined even further. + fn blame_specific_expr_if_possible_for_derived_predicate_obligation( + &self, + obligation: &traits::ImplDerivedObligationCause<'tcx>, + expr: &'tcx hir::Expr<'tcx>, + ) -> Result<&'tcx hir::Expr<'tcx>, &'tcx hir::Expr<'tcx>> { + // First, we attempt to refine the `expr` for our span using the parent obligation. + // If this cannot be done, then we are already stuck, so we stop early (hence the use + // of the `?` try operator here). + let expr = self.blame_specific_expr_if_possible_for_obligation_cause_code( + &*obligation.derived.parent_code, + expr, + )?; + + // This is the "trait" (meaning, the predicate "proved" by this `impl`) which provides the `Self` type we care about. + // For the purposes of this function, we hope that it is a `struct` type, and that our current `expr` is a literal of + // that struct type. + let impl_trait_self_ref: Option> = + self.tcx.impl_trait_ref(obligation.impl_def_id).map(|impl_def| impl_def.skip_binder()); + + let Some(impl_trait_self_ref) = impl_trait_self_ref else { + // It is possible that this is absent. In this case, we make no progress. + return Err(expr); + }; + + // We only really care about the `Self` type itself, which we extract from the ref. + let impl_self_ty: Ty<'tcx> = impl_trait_self_ref.self_ty(); + + let impl_predicates: ty::GenericPredicates<'tcx> = + self.tcx.predicates_of(obligation.impl_def_id); + let Some(impl_predicate_index) = obligation.impl_def_predicate_index else { + // We don't have the index, so we can only guess. + return Err(expr); + }; + + if impl_predicate_index >= impl_predicates.predicates.len() { + // This shouldn't happen, but since this is only a diagnostic improvement, avoid breaking things. + return Err(expr); + } + let relevant_broken_predicate: ty::PredicateKind<'tcx> = + impl_predicates.predicates[impl_predicate_index].0.kind().skip_binder(); + + match relevant_broken_predicate { + ty::PredicateKind::Clause(ty::Clause::Trait(broken_trait)) => { + // ... + self.blame_specific_part_of_expr_corresponding_to_generic_param( + broken_trait.trait_ref.self_ty().into(), + expr, + impl_self_ty.into(), + ) + } + _ => Err(expr), + } + } + + /// Drills into `expr` to arrive at the equivalent location of `find_generic_param` in `in_ty`. + /// For example, given + /// - expr: `(Some(vec![1, 2, 3]), false)` + /// - param: `T` + /// - in_ty: `(Option, bool)` + /// we would drill until we arrive at `vec![1, 2, 3]`. + /// + /// If successful, we return `Ok(refined_expr)`. If unsuccesful, we return `Err(partially_refined_expr`), + /// which will go as far as possible. For example, given `(foo(), false)` instead, we would drill to + /// `foo()` and then return `Err("foo()")`. + /// + /// This means that you can (and should) use the `?` try operator to chain multiple calls to this + /// function with different types, since you can only continue drilling the second time if you + /// succeeded the first time. + fn blame_specific_part_of_expr_corresponding_to_generic_param( + &self, + param: ty::GenericArg<'tcx>, + expr: &'tcx hir::Expr<'tcx>, + in_ty: ty::GenericArg<'tcx>, + ) -> Result<&'tcx hir::Expr<'tcx>, &'tcx hir::Expr<'tcx>> { + if param == in_ty { + // The types match exactly, so we have drilled as far as we can. + return Ok(expr); + } + + let ty::GenericArgKind::Type(in_ty) = in_ty.unpack() else { + return Err(expr); + }; + + if let (hir::ExprKind::Tup(expr_elements), ty::Tuple(in_ty_elements)) = + (&expr.kind, in_ty.kind()) + { + if in_ty_elements.len() != expr_elements.len() { + return Err(expr); + } + // Find out which of `in_ty_elements` refer to `param`. + // FIXME: It may be better to take the first if there are multiple, + // just so that the error points to a smaller expression. + let Some((drill_expr, drill_ty)) = Self::is_iterator_singleton(expr_elements.iter().zip( in_ty_elements.iter()).filter(|(_expr_elem, in_ty_elem)| { + Self::find_param_in_ty((*in_ty_elem).into(), param) + })) else { + // The param is not mentioned, or it is mentioned in multiple indexes. + return Err(expr); + }; + + return self.blame_specific_part_of_expr_corresponding_to_generic_param( + param, + drill_expr, + drill_ty.into(), + ); + } + + if let ( + hir::ExprKind::Struct(expr_struct_path, expr_struct_fields, _expr_struct_rest), + ty::Adt(in_ty_adt, in_ty_adt_generic_args), + ) = (&expr.kind, in_ty.kind()) + { + // First, confirm that this struct is the same one as in the types, and if so, + // find the right variant. + let Res::Def(expr_struct_def_kind, expr_struct_def_id) = self.typeck_results.borrow().qpath_res(expr_struct_path, expr.hir_id) else { + return Err(expr); + }; + + let variant_def_id = match expr_struct_def_kind { + hir::def::DefKind::Struct => { + if in_ty_adt.did() != expr_struct_def_id { + // FIXME: Deal with type aliases? + return Err(expr); + } + expr_struct_def_id + } + hir::def::DefKind::Variant => { + // If this is a variant, its parent is the type definition. + if in_ty_adt.did() != self.tcx.parent(expr_struct_def_id) { + // FIXME: Deal with type aliases? + return Err(expr); + } + expr_struct_def_id + } + _ => { + return Err(expr); + } + }; + + // We need to know which of the generic parameters mentions our target param. + // We expect that at least one of them does, since it is expected to be mentioned. + let Some((drill_generic_index, generic_argument_type)) = + Self::is_iterator_singleton( + in_ty_adt_generic_args.iter().enumerate().filter( + |(_index, in_ty_generic)| { + Self::find_param_in_ty(*in_ty_generic, param) + }, + ), + ) else { + return Err(expr); + }; + + let struct_generic_parameters: &ty::Generics = self.tcx.generics_of(in_ty_adt.did()); + if drill_generic_index >= struct_generic_parameters.params.len() { + return Err(expr); + } + + let param_to_point_at_in_struct = self.tcx.mk_param_from_def( + struct_generic_parameters.param_at(drill_generic_index, self.tcx), + ); + + // We make 3 steps: + // Suppose we have a type like + // ```ignore (just for demonstration) + // struct ExampleStruct { + // enabled: bool, + // item: Option<(usize, T, bool)>, + // } + // + // f(ExampleStruct { + // enabled: false, + // item: Some((0, Box::new(String::new()), 1) }, true)), + // }); + // ``` + // Here, `f` is passed a `ExampleStruct>`, but it wants + // for `String: Copy`, which isn't true here. + // + // (1) First, we drill into `.item` and highlight that expression + // (2) Then we use the template type `Option<(usize, T, bool)>` to + // drill into the `T`, arriving at a `Box` expression. + // (3) Then we keep going, drilling into this expression using our + // outer contextual information. + + // (1) Find the (unique) field which mentions the type in our constraint: + let (field_expr, field_type) = self + .point_at_field_if_possible( + in_ty_adt.did(), + param_to_point_at_in_struct, + variant_def_id, + expr_struct_fields, + ) + .ok_or(expr)?; + + // (2) Continue drilling into the struct, ignoring the struct's + // generic argument types. + let expr = self.blame_specific_part_of_expr_corresponding_to_generic_param( + param_to_point_at_in_struct, + field_expr, + field_type.into(), + )?; + + // (3) Continue drilling into the expression, having "passed + // through" the struct entirely. + return self.blame_specific_part_of_expr_corresponding_to_generic_param( + param, + expr, + generic_argument_type, + ); + } + + if let ( + hir::ExprKind::Call(expr_callee, expr_args), + ty::Adt(in_ty_adt, in_ty_adt_generic_args), + ) = (&expr.kind, in_ty.kind()) + { + let hir::ExprKind::Path(expr_callee_path) = &expr_callee.kind else { + // FIXME: This case overlaps with another one worth handling, + // which should happen above since it applies to non-ADTs: + // we can drill down into regular generic functions. + return Err(expr); + }; + // This is (possibly) a constructor call, like `Some(...)` or `MyStruct(a, b, c)`. + + let Res::Def(expr_struct_def_kind, expr_ctor_def_id) = self.typeck_results.borrow().qpath_res(expr_callee_path, expr_callee.hir_id) else { + return Err(expr); + }; + + let variant_def_id = match expr_struct_def_kind { + hir::def::DefKind::Ctor(hir::def::CtorOf::Struct, hir::def::CtorKind::Fn) => { + if in_ty_adt.did() != self.tcx.parent(expr_ctor_def_id) { + // FIXME: Deal with type aliases? + return Err(expr); + } + self.tcx.parent(expr_ctor_def_id) + } + hir::def::DefKind::Ctor(hir::def::CtorOf::Variant, hir::def::CtorKind::Fn) => { + // If this is a variant, its parent is the type definition. + if in_ty_adt.did() != self.tcx.parent(expr_ctor_def_id) { + // FIXME: Deal with type aliases? + return Err(expr); + } + expr_ctor_def_id + } + _ => { + return Err(expr); + } + }; + + // We need to know which of the generic parameters mentions our target param. + // We expect that at least one of them does, since it is expected to be mentioned. + let Some((drill_generic_index, generic_argument_type)) = + Self::is_iterator_singleton( + in_ty_adt_generic_args.iter().enumerate().filter( + |(_index, in_ty_generic)| { + Self::find_param_in_ty(*in_ty_generic, param) + }, + ), + ) else { + return Err(expr); + }; + + let struct_generic_parameters: &ty::Generics = self.tcx.generics_of(in_ty_adt.did()); + if drill_generic_index >= struct_generic_parameters.params.len() { + return Err(expr); + } + + let param_to_point_at_in_struct = self.tcx.mk_param_from_def( + struct_generic_parameters.param_at(drill_generic_index, self.tcx), + ); + + // We make 3 steps: + // Suppose we have a type like + // ```ignore (just for demonstration) + // struct ExampleStruct { + // enabled: bool, + // item: Option<(usize, T, bool)>, + // } + // + // f(ExampleStruct { + // enabled: false, + // item: Some((0, Box::new(String::new()), 1) }, true)), + // }); + // ``` + // Here, `f` is passed a `ExampleStruct>`, but it wants + // for `String: Copy`, which isn't true here. + // + // (1) First, we drill into `.item` and highlight that expression + // (2) Then we use the template type `Option<(usize, T, bool)>` to + // drill into the `T`, arriving at a `Box` expression. + // (3) Then we keep going, drilling into this expression using our + // outer contextual information. + + // (1) Find the (unique) field index which mentions the type in our constraint: + let Some((field_index, field_type)) = Self::is_iterator_singleton( + in_ty_adt + .variant_with_id(variant_def_id) + .fields + .iter() + .map(|field| field.ty(self.tcx, *in_ty_adt_generic_args)) + .enumerate() + .filter(|(_index, field_type)| Self::find_param_in_ty((*field_type).into(), param)) + ) else { + return Err(expr); + }; + + if field_index >= expr_args.len() { + return Err(expr); + } + + // (2) Continue drilling into the struct, ignoring the struct's + // generic argument types. + let expr = self.blame_specific_part_of_expr_corresponding_to_generic_param( + param_to_point_at_in_struct, + &expr_args[field_index], + field_type.into(), + )?; + + // (3) Continue drilling into the expression, having "passed + // through" the struct entirely. + return self.blame_specific_part_of_expr_corresponding_to_generic_param( + param, + expr, + generic_argument_type, + ); + } + + // At this point, none of the basic patterns matched. + // One major possibility which remains is that we have a function call. + // In this case, it's often possible to dive deeper into the call to find something to blame, + // but this is not always possible. + + Err(expr) + } + + // FIXME: This can be made into a private, non-impl function later. + /// Traverses the given ty (either a `ty::Ty` or a `ty::GenericArg`) and searches for references + /// to the given `param_to_point_at`. Returns `true` if it finds any use of the param. + pub fn find_param_in_ty( + ty: ty::GenericArg<'tcx>, + param_to_point_at: ty::GenericArg<'tcx>, + ) -> bool { + let mut walk = ty.walk(); + while let Some(arg) = walk.next() { + if arg == param_to_point_at { + return true; + } else if let ty::GenericArgKind::Type(ty) = arg.unpack() + && let ty::Alias(ty::Projection, ..) = ty.kind() + { + // This logic may seem a bit strange, but typically when + // we have a projection type in a function signature, the + // argument that's being passed into that signature is + // not actually constraining that projection's substs in + // a meaningful way. So we skip it, and see improvements + // in some UI tests. + walk.skip_current_subtree(); + } + } + false + } + + // FIXME: This can be made into a private, non-impl function later. + /// Returns `Some(iterator.next())` if it has exactly one item, and `None` otherwise. + pub fn is_iterator_singleton(mut iterator: impl Iterator) -> Option { + match (iterator.next(), iterator.next()) { + (_, Some(_)) => None, + (first, _) => first, + } + } +} diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs index 47ef106e750..1055ee953ea 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs @@ -34,9 +34,10 @@ use rustc_trait_selection::traits::{self, ObligationCauseCode, SelectionContext} use std::iter; use std::mem; -use std::ops::ControlFlow; use std::slice; +use std::ops::ControlFlow; + impl<'a, 'tcx> FnCtxt<'a, 'tcx> { pub(in super::super) fn check_casts(&mut self) { // don't hold the borrow to deferred_cast_checks while checking to avoid borrow checker errors @@ -1843,7 +1844,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .into_iter() .flatten() { - if self.point_at_arg_if_possible( + if self.blame_specific_arg_if_possible( error, def_id, param, @@ -1873,7 +1874,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .into_iter() .flatten() { - if self.point_at_arg_if_possible( + if self.blame_specific_arg_if_possible( error, def_id, param, @@ -1898,16 +1899,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { for param in [param_to_point_at, fallback_param_to_point_at, self_param_to_point_at] { - if let Some(param) = param - && self.point_at_field_if_possible( - error, + if let Some(param) = param { + let refined_expr = self.point_at_field_if_possible( def_id, param, variant_def_id, fields, - ) - { - return true; + ); + + match refined_expr { + None => {} + Some((refined_expr, _)) => { + error.obligation.cause.span = refined_expr + .span + .find_ancestor_in_same_ctxt(error.obligation.cause.span) + .unwrap_or(refined_expr.span); + return true; + } + } } } } @@ -1940,7 +1949,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } } - fn point_at_arg_if_possible( + /// - `blame_specific_*` means that the function will recursively traverse the expression, + /// looking for the most-specific-possible span to blame. + /// + /// - `point_at_*` means that the function will only go "one level", pointing at the specific + /// expression mentioned. + /// + /// `blame_specific_arg_if_possible` will find the most-specific expression anywhere inside + /// the provided function call expression, and mark it as responsible for the fullfillment + /// error. + fn blame_specific_arg_if_possible( &self, error: &mut traits::FulfillmentError<'tcx>, def_id: DefId, @@ -1959,13 +1977,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .inputs() .iter() .enumerate() - .filter(|(_, ty)| find_param_in_ty(**ty, param_to_point_at)) + .filter(|(_, ty)| Self::find_param_in_ty((**ty).into(), param_to_point_at)) .collect(); // If there's one field that references the given generic, great! if let [(idx, _)] = args_referencing_param.as_slice() && let Some(arg) = receiver .map_or(args.get(*idx), |rcvr| if *idx == 0 { Some(rcvr) } else { args.get(*idx - 1) }) { + error.obligation.cause.span = arg.span.find_ancestor_in_same_ctxt(error.obligation.cause.span).unwrap_or(arg.span); + + if let hir::Node::Expr(arg_expr) = self.tcx.hir().get(arg.hir_id) { + // This is more specific than pointing at the entire argument. + self.blame_specific_expr_if_possible(error, arg_expr) + } + error.obligation.cause.map_code(|parent_code| { ObligationCauseCode::FunctionArgumentObligation { arg_hir_id: arg.hir_id, @@ -1983,14 +2008,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { false } - fn point_at_field_if_possible( + // FIXME: Make this private and move to mod adjust_fulfillment_errors + pub fn point_at_field_if_possible( &self, - error: &mut traits::FulfillmentError<'tcx>, def_id: DefId, param_to_point_at: ty::GenericArg<'tcx>, variant_def_id: DefId, expr_fields: &[hir::ExprField<'tcx>], - ) -> bool { + ) -> Option<(&'tcx hir::Expr<'tcx>, Ty<'tcx>)> { let def = self.tcx.adt_def(def_id); let identity_substs = ty::InternalSubsts::identity_for_item(self.tcx, def_id); @@ -2000,7 +2025,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { .iter() .filter(|field| { let field_ty = field.ty(self.tcx, identity_substs); - find_param_in_ty(field_ty, param_to_point_at) + Self::find_param_in_ty(field_ty.into(), param_to_point_at) }) .collect(); @@ -2010,17 +2035,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { // same rules that check_expr_struct uses for macro hygiene. if self.tcx.adjust_ident(expr_field.ident, variant_def_id) == field.ident(self.tcx) { - error.obligation.cause.span = expr_field - .expr - .span - .find_ancestor_in_same_ctxt(error.obligation.cause.span) - .unwrap_or(expr_field.span); - return true; + return Some((expr_field.expr, self.tcx.type_of(field.did))); } } } - false + None } fn point_at_path_if_possible( @@ -2240,23 +2260,3 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } } } - -fn find_param_in_ty<'tcx>(ty: Ty<'tcx>, param_to_point_at: ty::GenericArg<'tcx>) -> bool { - let mut walk = ty.walk(); - while let Some(arg) = walk.next() { - if arg == param_to_point_at { - return true; - } else if let ty::GenericArgKind::Type(ty) = arg.unpack() - && let ty::Alias(ty::Projection, ..) = ty.kind() - { - // This logic may seem a bit strange, but typically when - // we have a projection type in a function signature, the - // argument that's being passed into that signature is - // not actually constraining that projection's substs in - // a meaningful way. So we skip it, and see improvements - // in some UI tests. - walk.skip_current_subtree(); - } - } - false -} diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs index 4940015ddd5..1e14eddd4c8 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs @@ -1,4 +1,5 @@ mod _impl; +mod adjust_fulfillment_errors; mod arg_matrix; mod checks; mod suggestions; diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs index 0b30bf957a3..9ab29a6778f 100644 --- a/compiler/rustc_hir_typeck/src/method/probe.rs +++ b/compiler/rustc_hir_typeck/src/method/probe.rs @@ -1563,6 +1563,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> { traits::ImplDerivedObligationCause { derived, impl_def_id, + impl_def_predicate_index: None, span, }, )) diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs index cd5bde2a791..18a966449aa 100644 --- a/compiler/rustc_infer/src/traits/util.rs +++ b/compiler/rustc_infer/src/traits/util.rs @@ -145,30 +145,32 @@ impl<'tcx> Elaborator<'tcx> { // Get predicates declared on the trait. let predicates = tcx.super_predicates_of(data.def_id()); - let obligations = predicates.predicates.iter().map(|&(mut pred, span)| { - // when parent predicate is non-const, elaborate it to non-const predicates. - if data.constness == ty::BoundConstness::NotConst { - pred = pred.without_const(tcx); - } + let obligations = + predicates.predicates.iter().enumerate().map(|(index, &(mut pred, span))| { + // when parent predicate is non-const, elaborate it to non-const predicates. + if data.constness == ty::BoundConstness::NotConst { + pred = pred.without_const(tcx); + } - let cause = obligation.cause.clone().derived_cause( - bound_predicate.rebind(data), - |derived| { - traits::ImplDerivedObligation(Box::new( - traits::ImplDerivedObligationCause { - derived, - impl_def_id: data.def_id(), - span, - }, - )) - }, - ); - predicate_obligation( - pred.subst_supertrait(tcx, &bound_predicate.rebind(data.trait_ref)), - obligation.param_env, - cause, - ) - }); + let cause = obligation.cause.clone().derived_cause( + bound_predicate.rebind(data), + |derived| { + traits::ImplDerivedObligation(Box::new( + traits::ImplDerivedObligationCause { + derived, + impl_def_id: data.def_id(), + impl_def_predicate_index: Some(index), + span, + }, + )) + }, + ); + predicate_obligation( + pred.subst_supertrait(tcx, &bound_predicate.rebind(data.trait_ref)), + obligation.param_env, + cause, + ) + }); debug!(?data, ?obligations, "super_predicates"); // Only keep those bounds that we haven't already seen. diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs index 75525059e90..c528929e756 100644 --- a/compiler/rustc_middle/src/traits/mod.rs +++ b/compiler/rustc_middle/src/traits/mod.rs @@ -475,6 +475,8 @@ pub enum WellFormedLoc { pub struct ImplDerivedObligationCause<'tcx> { pub derived: DerivedObligationCause<'tcx>, pub impl_def_id: DefId, + /// The index of the derived predicate in the parent impl's predicates. + pub impl_def_predicate_index: Option, pub span: Span, } diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index 0a4136dc1cf..94d9eb8f587 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -1190,6 +1190,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ImplDerivedObligation(Box::new(ImplDerivedObligationCause { derived, impl_def_id, + impl_def_predicate_index: None, span: obligation.cause.span, })) }); diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index ad7d479896f..0c6b2406bbd 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -2608,11 +2608,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { assert_eq!(predicates.parent, None); let predicates = predicates.instantiate_own(tcx, substs); let mut obligations = Vec::with_capacity(predicates.len()); - for (predicate, span) in predicates { + for (index, (predicate, span)) in predicates.into_iter().enumerate() { let cause = cause.clone().derived_cause(parent_trait_pred, |derived| { ImplDerivedObligation(Box::new(ImplDerivedObligationCause { derived, impl_def_id: def_id, + impl_def_predicate_index: Some(index), span, })) }); diff --git a/tests/ui/derives/deriving-copyclone.stderr b/tests/ui/derives/deriving-copyclone.stderr index 9c4ca01ff37..c0c2215c04a 100644 --- a/tests/ui/derives/deriving-copyclone.stderr +++ b/tests/ui/derives/deriving-copyclone.stderr @@ -1,8 +1,8 @@ error[E0277]: the trait bound `B: Copy` is not satisfied - --> $DIR/deriving-copyclone.rs:31:13 + --> $DIR/deriving-copyclone.rs:31:26 | LL | is_copy(B { a: 1, b: C }); - | ------- ^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `B` + | ------- ^ the trait `Copy` is not implemented for `B` | | | required by a bound introduced by this call | @@ -19,14 +19,14 @@ LL | fn is_copy(_: T) {} = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider borrowing here | -LL | is_copy(&B { a: 1, b: C }); - | + +LL | is_copy(B { a: 1, b: &C }); + | + error[E0277]: the trait bound `B: Clone` is not satisfied - --> $DIR/deriving-copyclone.rs:32:14 + --> $DIR/deriving-copyclone.rs:32:27 | LL | is_clone(B { a: 1, b: C }); - | -------- ^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `B` + | -------- ^ the trait `Clone` is not implemented for `B` | | | required by a bound introduced by this call | @@ -43,14 +43,14 @@ LL | fn is_clone(_: T) {} = note: this error originates in the derive macro `Clone` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider borrowing here | -LL | is_clone(&B { a: 1, b: C }); - | + +LL | is_clone(B { a: 1, b: &C }); + | + error[E0277]: the trait bound `B: Copy` is not satisfied - --> $DIR/deriving-copyclone.rs:35:13 + --> $DIR/deriving-copyclone.rs:35:26 | LL | is_copy(B { a: 1, b: D }); - | ------- ^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `B` + | ------- ^ the trait `Copy` is not implemented for `B` | | | required by a bound introduced by this call | @@ -67,8 +67,8 @@ LL | fn is_copy(_: T) {} = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info) help: consider borrowing here | -LL | is_copy(&B { a: 1, b: D }); - | + +LL | is_copy(B { a: 1, b: &D }); + | + error: aborting due to 3 previous errors diff --git a/tests/ui/errors/trait-bound-error-spans/blame-trait-error.rs b/tests/ui/errors/trait-bound-error-spans/blame-trait-error.rs new file mode 100644 index 00000000000..5134c672f5f --- /dev/null +++ b/tests/ui/errors/trait-bound-error-spans/blame-trait-error.rs @@ -0,0 +1,28 @@ +trait T1 {} +trait T2 {} +trait T3 {} +trait T4 {} + +impl T1 for Wrapper {} + +impl T2 for i32 {} +impl T3 for i32 {} + +impl T2 for Burrito {} + +struct Wrapper { + value: W, +} + +struct Burrito { + filling: F, +} + +fn want(_x: V) {} + +fn example(q: Q) { + want(Wrapper { value: Burrito { filling: q } }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] +} + +fn main() {} diff --git a/tests/ui/errors/trait-bound-error-spans/blame-trait-error.stderr b/tests/ui/errors/trait-bound-error-spans/blame-trait-error.stderr new file mode 100644 index 00000000000..27b002db130 --- /dev/null +++ b/tests/ui/errors/trait-bound-error-spans/blame-trait-error.stderr @@ -0,0 +1,35 @@ +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error.rs:24:46 + | +LL | want(Wrapper { value: Burrito { filling: q } }); + | ---- ^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `Burrito` to implement `T2` + --> $DIR/blame-trait-error.rs:11:13 + | +LL | impl T2 for Burrito {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error.rs:6:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error.rs:21:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.rs b/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.rs new file mode 100644 index 00000000000..2b75f432412 --- /dev/null +++ b/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.rs @@ -0,0 +1,131 @@ +// This test examines the error spans reported when a generic `impl` fails. +// For example, if a function wants an `Option` where `T: Copy` but you pass `Some(vec![1, 2])`, +// then we want to point at the `vec![1, 2]` and not the `Some( ... )` expression. + +trait T1 {} +trait T2 {} +trait T3 {} +trait T4 {} + +impl T2 for i32 {} +impl T3 for i32 {} + +struct Wrapper { + value: W, +} +impl T1 for Wrapper {} + +struct Burrito { + spicy: bool, + filling: F, +} +impl T2 for Burrito {} + +struct BurritoTuple(F); +impl T2 for BurritoTuple {} + +enum BurritoKinds { + SmallBurrito { spicy: bool, small_filling: G }, + LargeBurrito { spicy: bool, large_filling: G }, + MultiBurrito { first_filling: G, second_filling: G }, +} +impl T2 for BurritoKinds {} + +struct Taco(bool, H); +impl T2 for Taco {} + +enum TacoKinds { + OneTaco(bool, H), + TwoTacos(bool, H, H), +} +impl T2 for TacoKinds {} + +struct GenericBurrito { + spiciness: Spiciness, + filling: Filling, +} +impl T2 for GenericBurrito {} +struct NotSpicy; + +impl T2 for (A, B) {} +impl T1 for (A, B) {} + +fn want(_x: V) {} + +// Some more-complex examples: +type AliasBurrito = GenericBurrito; + +// The following example is fairly confusing. The idea is that we want to "misdirect" the location +// of the error. + +struct Two { + a: A, + b: B, +} + +impl T1 for Two, Z> {} + +struct DoubleWrapper { + item: Wrapper, +} + +impl T1 for DoubleWrapper {} + +fn example(q: Q) { + // In each of the following examples, we expect the error span to point at the 'q' variable, + // since the missing constraint is `Q: T3`. + + // Verifies for struct: + want(Wrapper { value: Burrito { spicy: false, filling: q } }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for enum with named fields in variant: + want(Wrapper { value: BurritoKinds::SmallBurrito { spicy: true, small_filling: q } }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for tuple struct: + want(Wrapper { value: Taco(false, q) }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for tuple enum variant: + want(Wrapper { value: TacoKinds::OneTaco(false, q) }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for generic type with multiple parameters: + want(Wrapper { value: GenericBurrito { spiciness: NotSpicy, filling: q } }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for tuple: + want((3, q)); + //~^ ERROR the trait bound `Q: T2` is not satisfied [E0277] + + // Verifies for nested tuple: + want(Wrapper { value: (3, q) }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + // Verifies for nested tuple: + want(((3, q), 5)); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + want(DoubleWrapper { item: Wrapper { value: q } }); + //~^ ERROR the trait bound `Q: T1` is not satisfied [E0277] + + want(DoubleWrapper { item: Wrapper { value: DoubleWrapper { item: Wrapper { value: q } } } }); + //~^ ERROR the trait bound `Q: T1` is not satisfied [E0277] + + // Verifies for type alias to struct: + want(Wrapper { value: AliasBurrito { spiciness: q, filling: q } }); + //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277] + + want(Two { a: Two { a: (), b: q }, b: () }); + //~^ ERROR the trait bound `Q: T1` is not satisfied [E0277] + + // We *should* blame the 'q'. + // FIXME: Right now, the wrong field is blamed. + want( + Two { a: Two { a: (), b: Two { a: Two { a: (), b: q }, b: () } }, b: () }, + //~^ ERROR the trait bound `Q: T1` is not satisfied [E0277] + ); +} + +fn main() {} diff --git a/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.stderr b/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.stderr new file mode 100644 index 00000000000..5f87c670d8a --- /dev/null +++ b/tests/ui/errors/traits/blame-trait-error-spans-on-exprs.stderr @@ -0,0 +1,380 @@ +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:79:60 + | +LL | want(Wrapper { value: Burrito { spicy: false, filling: q } }); + | ---- required by a bound introduced by this call ^ the trait `T3` is not implemented for `Q` + | +note: required for `Burrito` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:22:13 + | +LL | impl T2 for Burrito {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:83:84 + | +LL | want(Wrapper { value: BurritoKinds::SmallBurrito { spicy: true, small_filling: q } }); + | ---- required by a bound introduced by this call ^ the trait `T3` is not implemented for `Q` + | +note: required for `BurritoKinds` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:32:13 + | +LL | impl T2 for BurritoKinds {} + | -- ^^ ^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:87:39 + | +LL | want(Wrapper { value: Taco(false, q) }); + | ---- ^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `Taco` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:35:13 + | +LL | impl T2 for Taco {} + | -- ^^ ^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:91:27 + | +LL | want(Wrapper { value: TacoKinds::OneTaco(false, q) }); + | ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `TacoKinds` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:41:13 + | +LL | impl T2 for TacoKinds {} + | -- ^^ ^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:95:74 + | +LL | want(Wrapper { value: GenericBurrito { spiciness: NotSpicy, filling: q } }); + | ---- required by a bound introduced by this call ^ the trait `T3` is not implemented for `Q` + | +note: required for `GenericBurrito` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:47:16 + | +LL | impl T2 for GenericBurrito {} + | -- ^^ ^^^^^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T2` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:99:14 + | +LL | want((3, q)); + | ---- ^ the trait `T2` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `(i32, Q)` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:51:20 + | +LL | impl T1 for (A, B) {} + | -- ^^ ^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:103:31 + | +LL | want(Wrapper { value: (3, q) }); + | ---- ^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `(i32, Q)` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:50:20 + | +LL | impl T2 for (A, B) {} + | -- ^^ ^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper<(i32, Q)>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:107:15 + | +LL | want(((3, q), 5)); + | ---- ^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `(i32, Q)` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:50:20 + | +LL | impl T2 for (A, B) {} + | -- ^^ ^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `((i32, Q), i32)` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:51:20 + | +LL | impl T1 for (A, B) {} + | -- ^^ ^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T1` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:110:49 + | +LL | want(DoubleWrapper { item: Wrapper { value: q } }); + | ---- ^ the trait `T1` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `DoubleWrapper` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:72:13 + | +LL | impl T1 for DoubleWrapper {} + | -- ^^ ^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T1` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:113:88 + | +LL | want(DoubleWrapper { item: Wrapper { value: DoubleWrapper { item: Wrapper { value: q } } } }); + | ---- required by a bound introduced by this call ^ the trait `T1` is not implemented for `Q` + | +note: required for `DoubleWrapper` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:72:13 + | +LL | impl T1 for DoubleWrapper {} + | -- ^^ ^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here + = note: 1 redundant requirement hidden + = note: required for `DoubleWrapper>` to implement `T1` +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T3` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:117:27 + | +LL | want(Wrapper { value: AliasBurrito { spiciness: q, filling: q } }); + | ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `T3` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `GenericBurrito` to implement `T2` + --> $DIR/blame-trait-error-spans-on-exprs.rs:47:16 + | +LL | impl T2 for GenericBurrito {} + | -- ^^ ^^^^^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required for `Wrapper>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13 + | +LL | impl T1 for Wrapper {} + | -- ^^ ^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T1` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:120:35 + | +LL | want(Two { a: Two { a: (), b: q }, b: () }); + | ---- ^ the trait `T1` is not implemented for `Q` + | | + | required by a bound introduced by this call + | +note: required for `Two, ()>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:66:19 + | +LL | impl T1 for Two, Z> {} + | -- ^^ ^^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error[E0277]: the trait bound `Q: T1` is not satisfied + --> $DIR/blame-trait-error-spans-on-exprs.rs:126:59 + | +LL | want( + | ---- required by a bound introduced by this call +LL | Two { a: Two { a: (), b: Two { a: Two { a: (), b: q }, b: () } }, b: () }, + | ^ the trait `T1` is not implemented for `Q` + | +note: required for `Two, ()>` to implement `T1` + --> $DIR/blame-trait-error-spans-on-exprs.rs:66:19 + | +LL | impl T1 for Two, Z> {} + | -- ^^ ^^^^^^^^^^^^^^^^^ + | | + | unsatisfied trait bound introduced here + = note: 1 redundant requirement hidden + = note: required for `Two, ()>>, ()>` to implement `T1` +note: required by a bound in `want` + --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12 + | +LL | fn want(_x: V) {} + | ^^ required by this bound in `want` +help: consider restricting type parameter `Q` + | +LL | fn example(q: Q) { + | ++++ + +error: aborting due to 13 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/traits/negative-impls/negated-auto-traits-error.stderr b/tests/ui/traits/negative-impls/negated-auto-traits-error.stderr index ce690b749f5..b680ce7f990 100644 --- a/tests/ui/traits/negative-impls/negated-auto-traits-error.stderr +++ b/tests/ui/traits/negative-impls/negated-auto-traits-error.stderr @@ -101,10 +101,10 @@ LL | fn is_send(_: T) {} | ^^^^ required by this bound in `is_send` error[E0277]: `main::TestType` cannot be sent between threads safely - --> $DIR/negated-auto-traits-error.rs:66:13 + --> $DIR/negated-auto-traits-error.rs:66:20 | LL | is_sync(Outer2(TestType)); - | ------- ^^^^^^^^^^^^^^^^ `main::TestType` cannot be sent between threads safely + | ------- ^^^^^^^^ `main::TestType` cannot be sent between threads safely | | | required by a bound introduced by this call |