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Detect cycle errors hidden by opaques during monomorphization

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This commit is contained in:
Michael Goulet 2023-09-13 17:33:40 +00:00
parent e5fedceabf
commit 8fbd78ccea
7 changed files with 147 additions and 1 deletions
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26
compiler/rustc_traits/src/normalize_projection_ty.rs
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@ -3,10 +3,13 @@ use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::query::Providers;
use rustc_middle::ty::{ParamEnvAnd, TyCtxt};
use rustc_trait_selection::infer::InferCtxtBuilderExt;
use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
use rustc_trait_selection::traits::query::{
normalize::NormalizationResult, CanonicalProjectionGoal, NoSolution,
};
use rustc_trait_selection::traits::{self, ObligationCause, SelectionContext};
use rustc_trait_selection::traits::{
self, FulfillmentErrorCode, ObligationCause, SelectionContext,
};
use std::sync::atomic::Ordering;
pub(crate) fn provide(p: &mut Providers) {
@ -40,6 +43,27 @@ fn normalize_projection_ty<'tcx>(
&mut obligations,
);
ocx.register_obligations(obligations);
// #112047: With projections and opaques, we are able to create opaques that
// are recursive (given some substitution of the opaque's type variables).
// In that case, we may only realize a cycle error when calling
// `normalize_erasing_regions` in mono.
if !ocx.infcx.next_trait_solver() {
let errors = ocx.select_where_possible();
if !errors.is_empty() {
// Rustdoc may attempt to normalize type alias types which are not
// well-formed. Rustdoc also normalizes types that are just not
// well-formed, since we don't do as much HIR analysis (checking
// that impl vars are constrained by the signature, for example).
if !tcx.sess.opts.actually_rustdoc {
for error in &errors {
if let FulfillmentErrorCode::CodeCycle(cycle) = &error.code {
ocx.infcx.err_ctxt().report_overflow_obligation_cycle(cycle);
}
}
}
return Err(NoSolution);
}
}
// FIXME(associated_const_equality): All users of normalize_projection_ty expected
// a type, but there is the possibility it could've been a const now. Maybe change
// it to a Term later?