--- /dev/null
+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<i32>: Copy`
+ * - because `Option<Vec<i32>>: Copy` needs `Vec<i32>: Copy` because `impl <T: Copy> Copy for Option<T>`
+ * - because `(Option<Vec<i32>, bool)` needs `Option<Vec<i32>>: Copy` because `impl <A: Copy, B: Copy> 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: Filling,
+ /// }
+ /// impl <Filling: Delicious> Delicious for Burrito<Filling> {}
+ /// fn eat_delicious_food<Food: Delicious>(_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<ty::TraitRef<'tcx>> =
+ 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<Vec<T>, 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<T> {
+ // 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<Box<String>>`, 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<String>` 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<T> {
+ // 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<Box<String>>`, 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<String>` 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<T>(mut iterator: impl Iterator<Item = T>) -> Option<T> {
+ match (iterator.next(), iterator.next()) {
+ (_, Some(_)) => None,
+ (first, _) => first,
+ }
+ }
+}
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
.into_iter()
.flatten()
{
- if self.point_at_arg_if_possible(
+ if self.blame_specific_arg_if_possible(
error,
def_id,
param,
.into_iter()
.flatten()
{
- if self.point_at_arg_if_possible(
+ if self.blame_specific_arg_if_possible(
error,
def_id,
param,
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;
+ }
+ }
}
}
}
}
}
- 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,
.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,
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);
.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();
// 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(
}
}
}
-
-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
-}
mod _impl;
+mod adjust_fulfillment_errors;
mod arg_matrix;
mod checks;
mod suggestions;
traits::ImplDerivedObligationCause {
derived,
impl_def_id,
+ impl_def_predicate_index: None,
span,
},
))
// 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 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 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(),
+ 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.
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<usize>,
pub span: Span,
}
ImplDerivedObligation(Box::new(ImplDerivedObligationCause {
derived,
impl_def_id,
+ impl_def_predicate_index: None,
span: obligation.cause.span,
}))
});
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,
}))
});
-Subproject commit 2cd1b5593d26dc6a03c20f8619187ad4b2485552
+Subproject commit 2bd5d42c9956369132228da6409f0e68da56c51a
-Subproject commit 960d610e7f33889a2577f5f17c26f0d5c82b30df
+Subproject commit 8ca261268068d80c0969260fff15199bad87b587
-Subproject commit 2cb0ed9ba56360949f492f9866afe8c293f9f9da
+Subproject commit 3ae62681ff236d5528ef7c8c28ba7c6b2ecc6731
-Subproject commit a9fb7d13eadfcc5f457962731f105b97f9a7474a
+Subproject commit 8888f9428fe9a48f31de6bd2cef9b9bf80791edc
-Subproject commit 985d561f0bb9b76ec043a2b12511790ec7a2b954
+Subproject commit 8c460b2237a6359a7e3335890db8da049bdd62fc
error[E0277]: the trait bound `B<C>: 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<C>`
+ | ------- ^ the trait `Copy` is not implemented for `B<C>`
| |
| required by a bound introduced by this call
|
= 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<C>: 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<C>`
+ | -------- ^ the trait `Clone` is not implemented for `B<C>`
| |
| required by a bound introduced by this call
|
= 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<D>: 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<D>`
+ | ------- ^ the trait `Copy` is not implemented for `B<D>`
| |
| required by a bound introduced by this call
|
= 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
--- /dev/null
+trait T1 {}
+trait T2 {}
+trait T3 {}
+trait T4 {}
+
+impl<B: T2> T1 for Wrapper<B> {}
+
+impl T2 for i32 {}
+impl T3 for i32 {}
+
+impl<A: T3> T2 for Burrito<A> {}
+
+struct Wrapper<W> {
+ value: W,
+}
+
+struct Burrito<F> {
+ filling: F,
+}
+
+fn want<V: T1>(_x: V) {}
+
+fn example<Q>(q: Q) {
+ want(Wrapper { value: Burrito { filling: q } });
+ //~^ ERROR the trait bound `Q: T3` is not satisfied [E0277]
+}
+
+fn main() {}
--- /dev/null
+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<Q>` to implement `T2`
+ --> $DIR/blame-trait-error.rs:11:13
+ |
+LL | impl<A: T3> T2 for Burrito<A> {}
+ | -- ^^ ^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<Burrito<Q>>` to implement `T1`
+ --> $DIR/blame-trait-error.rs:6:13
+ |
+LL | impl<B: T2> T1 for Wrapper<B> {}
+ | -- ^^ ^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required by a bound in `want`
+ --> $DIR/blame-trait-error.rs:21:12
+ |
+LL | fn want<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(q: Q) {
+ | ++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
--- /dev/null
+// This test examines the error spans reported when a generic `impl` fails.
+// For example, if a function wants an `Option<T>` 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<W> {
+ value: W,
+}
+impl<B: T2> T1 for Wrapper<B> {}
+
+struct Burrito<F> {
+ spicy: bool,
+ filling: F,
+}
+impl<A: T3> T2 for Burrito<A> {}
+
+struct BurritoTuple<F>(F);
+impl<C: T3> T2 for BurritoTuple<C> {}
+
+enum BurritoKinds<G> {
+ SmallBurrito { spicy: bool, small_filling: G },
+ LargeBurrito { spicy: bool, large_filling: G },
+ MultiBurrito { first_filling: G, second_filling: G },
+}
+impl<D: T3> T2 for BurritoKinds<D> {}
+
+struct Taco<H>(bool, H);
+impl<E: T3> T2 for Taco<E> {}
+
+enum TacoKinds<H> {
+ OneTaco(bool, H),
+ TwoTacos(bool, H, H),
+}
+impl<F: T3> T2 for TacoKinds<F> {}
+
+struct GenericBurrito<Spiciness, Filling> {
+ spiciness: Spiciness,
+ filling: Filling,
+}
+impl<X, Y: T3> T2 for GenericBurrito<X, Y> {}
+struct NotSpicy;
+
+impl<A: T3, B: T3> T2 for (A, B) {}
+impl<A: T2, B: T2> T1 for (A, B) {}
+
+fn want<V: T1>(_x: V) {}
+
+// Some more-complex examples:
+type AliasBurrito<T> = GenericBurrito<T, T>;
+
+// The following example is fairly confusing. The idea is that we want to "misdirect" the location
+// of the error.
+
+struct Two<A, B> {
+ a: A,
+ b: B,
+}
+
+impl<X, Y: T1, Z> T1 for Two<Two<X, Y>, Z> {}
+
+struct DoubleWrapper<T> {
+ item: Wrapper<T>,
+}
+
+impl<T: T1> T1 for DoubleWrapper<T> {}
+
+fn example<Q>(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() {}
--- /dev/null
+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<Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:22:13
+ |
+LL | impl<A: T3> T2 for Burrito<A> {}
+ | -- ^^ ^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<Burrito<Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:32:13
+ |
+LL | impl<D: T3> T2 for BurritoKinds<D> {}
+ | -- ^^ ^^^^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<BurritoKinds<Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:35:13
+ |
+LL | impl<E: T3> T2 for Taco<E> {}
+ | -- ^^ ^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<Taco<Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:41:13
+ |
+LL | impl<F: T3> T2 for TacoKinds<F> {}
+ | -- ^^ ^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<TacoKinds<Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<NotSpicy, Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:47:16
+ |
+LL | impl<X, Y: T3> T2 for GenericBurrito<X, Y> {}
+ | -- ^^ ^^^^^^^^^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<GenericBurrito<NotSpicy, Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<A: T2, B: T2> 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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T2>(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<A: T3, B: T3> 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<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<A: T3, B: T3> 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<A: T2, B: T2> 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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<Q>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:72:13
+ |
+LL | impl<T: T1> T1 for DoubleWrapper<T> {}
+ | -- ^^ ^^^^^^^^^^^^^^^^
+ | |
+ | 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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T1>(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<Q>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:72:13
+ |
+LL | impl<T: T1> T1 for DoubleWrapper<T> {}
+ | -- ^^ ^^^^^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+ = note: 1 redundant requirement hidden
+ = note: required for `DoubleWrapper<DoubleWrapper<Q>>` to implement `T1`
+note: required by a bound in `want`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12
+ |
+LL | fn want<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T1>(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<Q, Q>` to implement `T2`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:47:16
+ |
+LL | impl<X, Y: T3> T2 for GenericBurrito<X, Y> {}
+ | -- ^^ ^^^^^^^^^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+note: required for `Wrapper<GenericBurrito<Q, Q>>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:16:13
+ |
+LL | impl<B: T2> T1 for Wrapper<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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T3>(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<Two<(), Q>, ()>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:66:19
+ |
+LL | impl<X, Y: T1, Z> T1 for Two<Two<X, Y>, 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<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T1>(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<Two<(), Q>, ()>` to implement `T1`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:66:19
+ |
+LL | impl<X, Y: T1, Z> T1 for Two<Two<X, Y>, Z> {}
+ | -- ^^ ^^^^^^^^^^^^^^^^^
+ | |
+ | unsatisfied trait bound introduced here
+ = note: 1 redundant requirement hidden
+ = note: required for `Two<Two<(), Two<Two<(), Q>, ()>>, ()>` to implement `T1`
+note: required by a bound in `want`
+ --> $DIR/blame-trait-error-spans-on-exprs.rs:53:12
+ |
+LL | fn want<V: T1>(_x: V) {}
+ | ^^ required by this bound in `want`
+help: consider restricting type parameter `Q`
+ |
+LL | fn example<Q: T1>(q: Q) {
+ | ++++
+
+error: aborting due to 13 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
}
fn main() {
- let v = Unit2.m(
- L {
- //~^ ERROR to be a closure that returns `Unit3`, but it returns `Unit4`
- //~| ERROR type mismatch
- f: |x| {
- drop(x);
- Unit4
- },
+ let v = Unit2.m(L {
+ //~^ ERROR type mismatch
+ //~| ERROR to be a closure that returns `Unit3`, but it returns `Unit4`
+ f: |x| {
+ drop(x);
+ Unit4
},
- );
+ });
}
impl<'a> Ty<'a> for Unit2 {
-error[E0271]: type mismatch resolving `for<'r> <L<[closure@issue-62203-hrtb-ice.rs:42:16]> as T0<'r, (&'r u8,)>>::O == <_ as Ty<'r>>::V`
- --> $DIR/issue-62203-hrtb-ice.rs:39:9
+error[E0271]: type mismatch resolving `for<'r> <L<[closure@issue-62203-hrtb-ice.rs:41:12]> as T0<'r, (&'r u8,)>>::O == <_ as Ty<'r>>::V`
+ --> $DIR/issue-62203-hrtb-ice.rs:38:21
|
-LL | let v = Unit2.m(
- | - required by a bound introduced by this call
-LL | / L {
+LL | let v = Unit2.m(L {
+ | ___________________-_^
+ | | |
+ | | required by a bound introduced by this call
LL | |
LL | |
-LL | | f: |x| {
+LL | | f: |x| {
... |
-LL | | },
LL | | },
- | |_________^ type mismatch resolving `for<'r> <L<[closure@issue-62203-hrtb-ice.rs:42:16]> as T0<'r, (&'r u8,)>>::O == <_ as Ty<'r>>::V`
+LL | | });
+ | |_____^ type mismatch resolving `for<'r> <L<[closure@issue-62203-hrtb-ice.rs:41:12]> as T0<'r, (&'r u8,)>>::O == <_ as Ty<'r>>::V`
|
note: expected this to be `<_ as Ty<'_>>::V`
--> $DIR/issue-62203-hrtb-ice.rs:21:14
LL | F: for<'r> T0<'r, (<Self as Ty<'r>>::V,), O = <B as Ty<'r>>::V>,
| ^^^^^^^^^^^^^^^^^^^^ required by this bound in `T1::m`
-error[E0271]: expected `[closure@issue-62203-hrtb-ice.rs:42:16]` to be a closure that returns `Unit3`, but it returns `Unit4`
- --> $DIR/issue-62203-hrtb-ice.rs:39:9
+error[E0271]: expected `[closure@issue-62203-hrtb-ice.rs:41:12]` to be a closure that returns `Unit3`, but it returns `Unit4`
+ --> $DIR/issue-62203-hrtb-ice.rs:38:21
|
-LL | let v = Unit2.m(
- | - required by a bound introduced by this call
-LL | / L {
+LL | let v = Unit2.m(L {
+ | ___________________-_^
+ | | |
+ | | required by a bound introduced by this call
LL | |
LL | |
-LL | | f: |x| {
+LL | | f: |x| {
... |
-LL | | },
LL | | },
- | |_________^ expected struct `Unit3`, found struct `Unit4`
+LL | | });
+ | |_____^ expected struct `Unit3`, found struct `Unit4`
|
-note: required for `L<[closure@$DIR/issue-62203-hrtb-ice.rs:42:16: 42:19]>` to implement `for<'r> T0<'r, (&'r u8,)>`
+note: required for `L<[closure@$DIR/issue-62203-hrtb-ice.rs:41:12: 41:15]>` to implement `for<'r> T0<'r, (&'r u8,)>`
--> $DIR/issue-62203-hrtb-ice.rs:17:16
|
LL | impl<'a, A, T> T0<'a, A> for L<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
|
projects / rust.git / commitdiff