diff options
| -rw-r--r-- | compiler/rustc_resolve/src/late/diagnostics.rs | 57 | ||||
| -rw-r--r-- | tests/ui/privacy/suggest-box-new.stderr | 4 |
2 files changed, 60 insertions, 1 deletions
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs index ce4e0eecf39..71732261efc 100644 --- a/compiler/rustc_resolve/src/late/diagnostics.rs +++ b/compiler/rustc_resolve/src/late/diagnostics.rs @@ -1,6 +1,7 @@ use crate::diagnostics::{ImportSuggestion, LabelSuggestion, TypoSuggestion}; use crate::late::{AliasPossibility, LateResolutionVisitor, RibKind}; use crate::late::{LifetimeBinderKind, LifetimeRes, LifetimeRibKind, LifetimeUseSet}; +use crate::ty::fast_reject::SimplifiedType; use crate::{errors, path_names_to_string}; use crate::{Module, ModuleKind, ModuleOrUniformRoot}; use crate::{PathResult, PathSource, Segment}; @@ -1595,7 +1596,11 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> { Some(Vec::from(pattern_spans)) } // e.g. `let _ = Enum::TupleVariant(field1, field2);` - PathSource::Expr(Some(Expr { kind: ExprKind::Call(_, ref args), .. })) => { + PathSource::Expr(Some(Expr { + kind: ExprKind::Call(path, ref args), + span: call_span, + .. + })) => { err.set_primary_message( "cannot initialize a tuple struct which contains private fields", ); @@ -1675,6 +1680,56 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> { ); } } + // We'd ideally use `type_implements_trait` but don't have access to + // the trait solver here. We can't use `get_diagnostic_item` or + // `all_traits` in resolve either. So instead we abuse the import + // suggestion machinery to get `std::default::Default` and perform some + // checks to confirm that we got *only* that trait. We then see if the + // Adt we have has a direct implementation of `Default`. If so, we + // provide a structured suggestion. + let default_trait = self + .r + .lookup_import_candidates( + Ident::with_dummy_span(sym::Default), + Namespace::TypeNS, + &self.parent_scope, + &|res: Res| matches!(res, Res::Def(DefKind::Trait, _)), + ) + .iter() + .filter_map(|candidate| candidate.did) + .filter(|did| { + self.r + .tcx + .get_attrs(*did, sym::rustc_diagnostic_item) + .any(|attr| attr.value_str() == Some(sym::Default)) + }) + .next(); + if let Some(default_trait) = default_trait + && self.r.extern_crate_map.iter().flat_map(|(_, crate_)| { + self + .r + .tcx + .implementations_of_trait((*crate_, default_trait)) + }) + .filter_map(|(_, simplified_self_ty)| *simplified_self_ty) + .filter_map(|simplified_self_ty| match simplified_self_ty { + SimplifiedType::Adt(did) => Some(did), + _ => None + }) + .any(|did| did == def_id) + { + err.multipart_suggestion( + "consider using the `Default` trait", + vec![ + (path.span.shrink_to_lo(), "<".to_string()), + ( + path.span.shrink_to_hi().with_hi(call_span.hi()), + " as std::default::Default>::default()".to_string(), + ), + ], + Applicability::MaybeIncorrect, + ); + } } // Use spans of the tuple struct definition. self.r.field_def_ids(def_id).map(|field_ids| { diff --git a/tests/ui/privacy/suggest-box-new.stderr b/tests/ui/privacy/suggest-box-new.stderr index dbed66d0ae4..46fb860eb70 100644 --- a/tests/ui/privacy/suggest-box-new.stderr +++ b/tests/ui/privacy/suggest-box-new.stderr @@ -21,6 +21,10 @@ LL | wtf: Some(Box::new_zeroed_in(U { LL | wtf: Some(Box::new_uninit_slice(U { | ++++++++++++++++++ and 10 other candidates +help: consider using the `Default` trait + | +LL | wtf: Some(<Box as std::default::Default>::default()), + | + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: aborting due to previous error |