X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_trait_selection%2Fsrc%2Ftraits%2Ferror_reporting%2Fmod.rs;h=c68da3e24a19002fd02bd4549dbe2b44516fcb23;hb=6d3a93c82342ee7bbf0b6f90570207bd48653229;hp=19a1f2481770067250878c92e734e436c2d0f4d4;hpb=8ed0384ca4651e914793dd8a05c9cdec9b2089b4;p=rust.git 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 19a1f248177..c68da3e24a1 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs @@ -42,7 +42,7 @@ }; use rustc_session::Limit; use rustc_span::def_id::LOCAL_CRATE; -use rustc_span::symbol::{kw, sym}; +use rustc_span::symbol::sym; use rustc_span::{ExpnKind, Span, DUMMY_SP}; use std::fmt; use std::iter; @@ -980,6 +980,7 @@ fn report_selection_error( trait_ref, obligation.cause.body_id, &mut err, + true, ) { // This is *almost* equivalent to // `obligation.cause.code().peel_derives()`, but it gives us the @@ -1015,6 +1016,7 @@ fn report_selection_error( trait_ref, obligation.cause.body_id, &mut err, + true, ); } } @@ -1434,6 +1436,7 @@ fn report_similar_impl_candidates( trait_ref: ty::PolyTraitRef<'tcx>, body_id: hir::HirId, err: &mut Diagnostic, + other: bool, ) -> bool; /// Gets the parent trait chain start @@ -1888,7 +1891,9 @@ fn report_similar_impl_candidates( trait_ref: ty::PolyTraitRef<'tcx>, body_id: hir::HirId, err: &mut Diagnostic, + other: bool, ) -> bool { + let other = if other { "other " } else { "" }; let report = |mut candidates: Vec>, err: &mut Diagnostic| { candidates.sort(); candidates.dedup(); @@ -1939,7 +1944,7 @@ fn report_similar_impl_candidates( candidates.dedup(); let end = if candidates.len() <= 9 { candidates.len() } else { 8 }; err.help(&format!( - "the following other types implement trait `{}`:{}{}", + "the following {other}types implement trait `{}`:{}{}", trait_ref.print_only_trait_path(), candidates[..end].join(""), if len > 9 { format!("\nand {} others", len - 8) } else { String::new() } @@ -2180,7 +2185,7 @@ fn maybe_report_ambiguity( trait_ref.skip_binder().substs.types().any(|t| !t.is_ty_infer()); // It doesn't make sense to talk about applicable impls if there are more // than a handful of them. - if impls.len() > 1 && impls.len() < 5 && has_non_region_infer { + if impls.len() > 1 && impls.len() < 10 && has_non_region_infer { self.annotate_source_of_ambiguity(&mut err, &impls, predicate); } else { if self.tainted_by_errors().is_some() { @@ -2188,6 +2193,18 @@ fn maybe_report_ambiguity( return; } err.note(&format!("cannot satisfy `{}`", predicate)); + let impl_candidates = self.find_similar_impl_candidates( + predicate.to_opt_poly_trait_pred().unwrap(), + ); + if impl_candidates.len() < 10 { + self.report_similar_impl_candidates( + impl_candidates, + trait_ref, + body_id.map(|id| id.hir_id).unwrap_or(obligation.cause.body_id), + &mut err, + false, + ); + } } } _ => { @@ -2199,60 +2216,10 @@ fn maybe_report_ambiguity( } } - if let ObligationCauseCode::ItemObligation(def_id) | ObligationCauseCode::ExprItemObligation(def_id, ..) = *obligation.cause.code() { - self.suggest_fully_qualified_path(&mut err, def_id, span, trait_ref.def_id()); - } else if let Ok(snippet) = &self.tcx.sess.source_map().span_to_snippet(span) - && let ObligationCauseCode::BindingObligation(def_id, _) | ObligationCauseCode::ExprBindingObligation(def_id, ..) - = *obligation.cause.code() + if let ObligationCauseCode::ItemObligation(def_id) + | ObligationCauseCode::ExprItemObligation(def_id, ..) = *obligation.cause.code() { - let generics = self.tcx.generics_of(def_id); - if generics.params.iter().any(|p| p.name != kw::SelfUpper) - && !snippet.ends_with('>') - && !generics.has_impl_trait() - && !self.tcx.is_fn_trait(def_id) - { - // FIXME: To avoid spurious suggestions in functions where type arguments - // where already supplied, we check the snippet to make sure it doesn't - // end with a turbofish. Ideally we would have access to a `PathSegment` - // instead. Otherwise we would produce the following output: - // - // error[E0283]: type annotations needed - // --> $DIR/issue-54954.rs:3:24 - // | - // LL | const ARR_LEN: usize = Tt::const_val::<[i8; 123]>(); - // | ^^^^^^^^^^^^^^^^^^^^^^^^^^ - // | | - // | cannot infer type - // | help: consider specifying the type argument - // | in the function call: - // | `Tt::const_val::<[i8; 123]>::` - // ... - // LL | const fn const_val() -> usize { - // | - required by this bound in `Tt::const_val` - // | - // = note: cannot satisfy `_: Tt` - - // Clear any more general suggestions in favor of our specific one - err.clear_suggestions(); - - err.span_suggestion_verbose( - span.shrink_to_hi(), - &format!( - "consider specifying the type argument{} in the function call", - pluralize!(generics.params.len()), - ), - format!( - "::<{}>", - generics - .params - .iter() - .map(|p| p.name.to_string()) - .collect::>() - .join(", ") - ), - Applicability::HasPlaceholders, - ); - } + self.suggest_fully_qualified_path(&mut err, def_id, span, trait_ref.def_id()); } if let (Some(body_id), Some(ty::subst::GenericArgKind::Type(_))) =