From 352796402f8a4b66536693219b65b56bcc14d3ee Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Esteban=20K=C3=BCber?= Date: Wed, 18 Nov 2020 08:33:27 -0800 Subject: [PATCH] Account for indirect cyclic requirements --- .../src/traits/error_reporting/mod.rs | 2 + .../src/traits/error_reporting/suggestions.rs | 12 +++- src/test/ui/issues/issue-20413.rs | 28 +++++++++ src/test/ui/issues/issue-20413.stderr | 62 ++++++++++++++++++- 4 files changed, 102 insertions(+), 2 deletions(-) diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs index d429d889fcc..fe4127fd4d8 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -200,6 +200,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &obligation.predicate, &obligation.cause.code, &mut vec![], + &mut Default::default(), ); err.emit(); @@ -1700,6 +1701,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> { &obligation.predicate, &obligation.cause.code, &mut vec![], + &mut Default::default(), ); self.suggest_unsized_bound_if_applicable(err, obligation); } diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index 29926ccf4e1..51c3ff61dd3 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -7,6 +7,7 @@ use crate::autoderef::Autoderef; use crate::infer::InferCtxt; use crate::traits::normalize_projection_type; +use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::stack::ensure_sufficient_stack; use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder, Style}; use rustc_hir as hir; @@ -158,6 +159,7 @@ pub trait InferCtxtExt<'tcx> { predicate: &T, cause_code: &ObligationCauseCode<'tcx>, obligated_types: &mut Vec<&ty::TyS<'tcx>>, + seen_requirements: &mut FxHashSet, ) where T: fmt::Display; @@ -1787,6 +1789,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &obligation.predicate, next_code.unwrap(), &mut Vec::new(), + &mut Default::default(), ); } @@ -1796,6 +1799,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { predicate: &T, cause_code: &ObligationCauseCode<'tcx>, obligated_types: &mut Vec<&ty::TyS<'tcx>>, + seen_requirements: &mut FxHashSet, ) where T: fmt::Display, { @@ -2050,12 +2054,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &parent_predicate, &data.parent_code, obligated_types, + seen_requirements, ) }); } } ObligationCauseCode::ImplDerivedObligation(ref data) => { let mut parent_trait_ref = self.resolve_vars_if_possible(data.parent_trait_ref); + let parent_def_id = parent_trait_ref.def_id(); err.note(&format!( "required because of the requirements on the impl of `{}` for `{}`", parent_trait_ref.print_only_trait_path(), @@ -2066,10 +2072,12 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { let mut data = data; let mut redundant = false; let mut count = 0; + seen_requirements.insert(parent_def_id); while let ObligationCauseCode::ImplDerivedObligation(child) = &*data.parent_code { // Skip redundant recursive obligation notes. See `ui/issue-20413.rs`. let child_trait_ref = self.resolve_vars_if_possible(child.parent_trait_ref); - if parent_trait_ref.def_id() != child_trait_ref.def_id() { + let child_def_id = child_trait_ref.def_id(); + if seen_requirements.insert(child_def_id) { break; } count += 1; @@ -2093,6 +2101,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &parent_predicate, &data.parent_code, obligated_types, + seen_requirements, ) }); } @@ -2106,6 +2115,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> { &parent_predicate, &data.parent_code, obligated_types, + seen_requirements, ) }); } diff --git a/src/test/ui/issues/issue-20413.rs b/src/test/ui/issues/issue-20413.rs index 19ef52af657..a4345ccdfbe 100644 --- a/src/test/ui/issues/issue-20413.rs +++ b/src/test/ui/issues/issue-20413.rs @@ -13,4 +13,32 @@ impl Foo for T where NoData: Foo { } } +trait Bar { + fn answer(self); +} + +trait Baz { + fn answer(self); +} + +struct AlmostNoData(Option); + +struct EvenLessData(Option); + +impl Bar for T where EvenLessData: Baz { +//~^ ERROR: overflow evaluating the requirement +//~| ERROR: overflow evaluating the requirement + fn answer(self) { + let val: EvenLessData = EvenLessData(None); + } +} + +impl Baz for T where AlmostNoData: Bar { +//~^ ERROR: overflow evaluating the requirement +//~| ERROR: overflow evaluating the requirement + fn answer(self) { + let val: NoData = AlmostNoData(None); + } +} + fn main() {} diff --git a/src/test/ui/issues/issue-20413.stderr b/src/test/ui/issues/issue-20413.stderr index 47ea29621ee..b167bb77b51 100644 --- a/src/test/ui/issues/issue-20413.stderr +++ b/src/test/ui/issues/issue-20413.stderr @@ -20,6 +20,36 @@ LL | impl Foo for T where NoData: Foo { = note: 127 redundant requirements hidden = note: required because of the requirements on the impl of `Foo` for `NoData` +error[E0275]: overflow evaluating the requirement `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Baz` + --> $DIR/issue-20413.rs:28:42 + | +LL | trait Baz { + | --------- required by this bound in `Baz` +... +LL | impl Bar for T where EvenLessData: Baz { + | ^^^ + | + = help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`issue_20413`) + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: required because of the requirements on the impl of `Baz` for `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: 126 redundant requirements hidden + = note: required because of the requirements on the impl of `Baz` for `EvenLessData` + +error[E0275]: overflow evaluating the requirement `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Bar` + --> $DIR/issue-20413.rs:36:42 + | +LL | trait Bar { + | --------- required by this bound in `Bar` +... +LL | impl Baz for T where AlmostNoData: Bar { + | ^^^ + | + = help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`issue_20413`) + = note: required because of the requirements on the impl of `Baz` for `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: 126 redundant requirements hidden + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData` + error[E0275]: overflow evaluating the requirement `NoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Foo` --> $DIR/issue-20413.rs:8:36 | @@ -34,7 +64,37 @@ LL | impl Foo for T where NoData: Foo { = note: 127 redundant requirements hidden = note: required because of the requirements on the impl of `Foo` for `NoData` -error: aborting due to 3 previous errors +error[E0275]: overflow evaluating the requirement `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Baz` + --> $DIR/issue-20413.rs:28:42 + | +LL | trait Baz { + | --------- required by this bound in `Baz` +... +LL | impl Bar for T where EvenLessData: Baz { + | ^^^ + | + = help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`issue_20413`) + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: required because of the requirements on the impl of `Baz` for `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: 126 redundant requirements hidden + = note: required because of the requirements on the impl of `Baz` for `EvenLessData` + +error[E0275]: overflow evaluating the requirement `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Bar` + --> $DIR/issue-20413.rs:36:42 + | +LL | trait Bar { + | --------- required by this bound in `Bar` +... +LL | impl Baz for T where AlmostNoData: Bar { + | ^^^ + | + = help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`issue_20413`) + = note: required because of the requirements on the impl of `Baz` for `EvenLessData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` + = note: 126 redundant requirements hidden + = note: required because of the requirements on the impl of `Bar` for `AlmostNoData` + +error: aborting due to 7 previous errors Some errors have detailed explanations: E0275, E0392. For more information about an error, try `rustc --explain E0275`.