Auto merge of #115289 - compiler-errors:adjust-comments, r=estebank

Add some needed comments in `adjust_fulfillment_errors.rs`

r? `@estebank`
This commit is contained in:
bors 2023-09-19 03:52:48 +00:00
commit af78bae565
2 changed files with 34 additions and 32 deletions

View File

@ -33,27 +33,17 @@ pub fn adjust_fulfillment_error_for_expr_obligation(
};
let generics = self.tcx.generics_of(def_id);
let predicate_args = match unsubstituted_pred.kind().skip_binder() {
ty::ClauseKind::Trait(pred) => pred.trait_ref.args.to_vec(),
ty::ClauseKind::Projection(pred) => pred.projection_ty.args.to_vec(),
ty::ClauseKind::ConstArgHasType(arg, ty) => {
vec![ty.into(), arg.into()]
let (predicate_args, predicate_self_type_to_point_at) =
match unsubstituted_pred.kind().skip_binder() {
ty::ClauseKind::Trait(pred) => {
(pred.trait_ref.args.to_vec(), Some(pred.self_ty().into()))
}
ty::ClauseKind::ConstEvaluatable(e) => vec![e.into()],
ty::ClauseKind::Projection(pred) => (pred.projection_ty.args.to_vec(), None),
ty::ClauseKind::ConstArgHasType(arg, ty) => (vec![ty.into(), arg.into()], None),
ty::ClauseKind::ConstEvaluatable(e) => (vec![e.into()], None),
_ => return false,
};
let direct_param = if let ty::ClauseKind::Trait(pred) = unsubstituted_pred.kind().skip_binder()
&& let ty = pred.trait_ref.self_ty()
&& let ty::Param(_param) = ty.kind()
&& let Some(arg) = predicate_args.get(0)
&& let ty::GenericArgKind::Type(arg_ty) = arg.unpack()
&& arg_ty == ty
{
Some(*arg)
} else {
None
};
let find_param_matching = |matches: &dyn Fn(ty::ParamTerm) -> bool| {
predicate_args.iter().find_map(|arg| {
arg.walk().find_map(|arg| {
@ -112,18 +102,21 @@ pub fn adjust_fulfillment_error_for_expr_obligation(
let qpath =
if let hir::ExprKind::Path(qpath) = expr.kind { Some(qpath) } else { None };
(Some(*expr), qpath)
(Some(&expr.kind), qpath)
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::Path(qpath), .. }) => (None, Some(*qpath)),
_ => return false,
};
if let Some(qpath) = qpath {
if let Some(param) = direct_param {
if self.point_at_path_if_possible(error, def_id, param, &qpath) {
// Prefer pointing at the turbofished arg that corresponds to the
// self type of the failing predicate over anything else.
if let Some(param) = predicate_self_type_to_point_at
&& self.point_at_path_if_possible(error, def_id, param, &qpath)
{
return true;
}
}
if let hir::Node::Expr(hir::Expr {
kind: hir::ExprKind::Call(callee, args),
hir_id: call_hir_id,
@ -166,11 +159,16 @@ pub fn adjust_fulfillment_error_for_expr_obligation(
}
}
match expr.map(|e| e.kind) {
match expr {
Some(hir::ExprKind::MethodCall(segment, receiver, args, ..)) => {
if let Some(param) = direct_param
if let Some(param) = predicate_self_type_to_point_at
&& self.point_at_generic_if_possible(error, def_id, param, segment)
{
// HACK: This is not correct, since `predicate_self_type_to_point_at` might
// not actually correspond to the receiver of the method call. But we
// re-adjust the cause code here in order to prefer pointing at one of
// the method's turbofish segments but still use `FunctionArgumentObligation`
// elsewhere. Hopefully this doesn't break something.
error.obligation.cause.map_code(|parent_code| {
ObligationCauseCode::FunctionArgumentObligation {
arg_hir_id: receiver.hir_id,
@ -180,6 +178,7 @@ pub fn adjust_fulfillment_error_for_expr_obligation(
});
return true;
}
for param in [param_to_point_at, fallback_param_to_point_at, self_param_to_point_at]
.into_iter()
.flatten()
@ -237,7 +236,7 @@ pub fn adjust_fulfillment_error_for_expr_obligation(
}
for param in [
direct_param,
predicate_self_type_to_point_at,
param_to_point_at,
fallback_param_to_point_at,
self_param_to_point_at,

View File

@ -325,13 +325,16 @@ fn set_tainted_by_errors(&self, e: ErrorGuaranteed) {
fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span) {
// FIXME: normalization and escaping regions
let ty = if !ty.has_escaping_bound_vars() {
if let ty::Alias(
ty::AliasKind::Projection | ty::AliasKind::Weak,
ty::AliasTy { args, def_id, .. },
) = ty.kind()
// NOTE: These obligations are 100% redundant and are implied by
// WF obligations that are registered elsewhere, but they have a
// better cause code assigned to them in `add_required_obligations_for_hir`.
// This means that they should shadow obligations with worse spans.
if let ty::Alias(ty::Projection | ty::Weak, ty::AliasTy { args, def_id, .. }) =
ty.kind()
{
self.add_required_obligations_for_hir(span, *def_id, args, hir_id);
}
self.normalize(span, ty)
} else {
ty