bjoernager/rust
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Report the selection error when possible

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This commit is contained in:
Deadbeef 2022-01-28 21:57:29 +11:00
parent cccf4b2fc3
commit 12397ab48b
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GPG key ID: 6D017A96D8E6C2F9
13 changed files with 107 additions and 37 deletions
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51
compiler/rustc_const_eval/src/transform/check_consts/check.rs
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@ -14,6 +14,7 @@ use rustc_middle::ty::{self, adjustment::PointerCast, Instance, InstanceDef, Ty,
use rustc_middle::ty::{Binder, TraitPredicate, TraitRef};
use rustc_mir_dataflow::{self, Analysis};
use rustc_span::{sym, Span, Symbol};
use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
use rustc_trait_selection::traits::SelectionContext;
use std::mem;
@ -808,15 +809,13 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
}
let trait_ref = TraitRef::from_method(tcx, trait_id, substs);
let obligation = Obligation::new(
ObligationCause::dummy(),
param_env,
Binder::dummy(TraitPredicate {
trait_ref,
constness: ty::BoundConstness::NotConst,
polarity: ty::ImplPolarity::Positive,
}),
);
let poly_trait_pred = Binder::dummy(TraitPredicate {
trait_ref,
constness: ty::BoundConstness::ConstIfConst,
polarity: ty::ImplPolarity::Positive,
});
let obligation =
Obligation::new(ObligationCause::dummy(), param_env, poly_trait_pred);
let implsrc = tcx.infer_ctxt().enter(|infcx| {
let mut selcx = SelectionContext::new(&infcx);
@ -860,15 +859,37 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
// #[default_method_body_is_const], and the callee is in the same
// trait.
let callee_trait = tcx.trait_of_item(callee);
if callee_trait.is_some() {
if tcx.has_attr(caller, sym::default_method_body_is_const) {
if tcx.trait_of_item(caller) == callee_trait {
nonconst_call_permission = true;
}
}
if callee_trait.is_some()
&& tcx.has_attr(caller, sym::default_method_body_is_const)
&& callee_trait == tcx.trait_of_item(caller)
// Can only call methods when it's `<Self as TheTrait>::f`.
&& tcx.types.self_param == substs.type_at(0)
{
nonconst_call_permission = true;
}
if !nonconst_call_permission {
let obligation = Obligation::new(
ObligationCause::dummy_with_span(*fn_span),
param_env,
tcx.mk_predicate(
poly_trait_pred.map_bound(ty::PredicateKind::Trait),
),
);
// improve diagnostics by showing what failed. Our requirements are stricter this time
// as we are going to error again anyways.
tcx.infer_ctxt().enter(|infcx| {
if let Err(e) = implsrc {
infcx.report_selection_error(
obligation.clone(),
&obligation,
&e,
false,
);
}
});
self.check_op(ops::FnCallNonConst {
caller,
callee,