diff options
Diffstat (limited to 'compiler/rustc_trait_selection/src')
| -rw-r--r-- | compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs | 70 |
1 files changed, 49 insertions, 21 deletions
diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs index 72a4d4c1205..9ab47057859 100644 --- a/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs +++ b/compiler/rustc_trait_selection/src/error_reporting/traits/ambiguity.rs @@ -388,39 +388,67 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> { trait_impls.non_blanket_impls().values().flatten().count(); // If there is only one implementation of the trait, suggest using it. // Otherwise, use a placeholder comment for the implementation. - let (message, self_type) = if non_blanket_impl_count == 1 { + let (message, self_types) = if non_blanket_impl_count == 1 { ( "use the fully-qualified path to the only available \ implementation", - format!( + vec![format!( "{}", self.tcx.type_of(impl_def_id).instantiate_identity() - ), + )], + ) + } else if non_blanket_impl_count < 20 { + ( + "use a fully-qualified path to one of the available \ + implementations", + trait_impls + .non_blanket_impls() + .values() + .flatten() + .map(|id| { + format!( + "{}", + self.tcx.type_of(id).instantiate_identity() + ) + }) + .collect::<Vec<String>>(), ) } else { ( "use a fully-qualified path to a specific available \ implementation", - "/* self type */".to_string(), + vec!["/* self type */".to_string()], ) }; - let mut suggestions = - vec![(path.span.shrink_to_lo(), format!("<{self_type} as "))]; - if let Some(generic_arg) = trait_path_segment.args { - let between_span = - trait_path_segment.ident.span.between(generic_arg.span_ext); - // get rid of :: between Trait and <type> - // must be '::' between them, otherwise the parser won't accept the code - suggestions.push((between_span, "".to_string())); - suggestions - .push((generic_arg.span_ext.shrink_to_hi(), ">".to_string())); - } else { - suggestions.push(( - trait_path_segment.ident.span.shrink_to_hi(), - ">".to_string(), - )); - } - err.multipart_suggestion( + let suggestions: Vec<_> = self_types + .into_iter() + .map(|self_type| { + let mut suggestions = vec![( + path.span.shrink_to_lo(), + format!("<{self_type} as "), + )]; + if let Some(generic_arg) = trait_path_segment.args { + let between_span = trait_path_segment + .ident + .span + .between(generic_arg.span_ext); + // get rid of :: between Trait and <type> + // must be '::' between them, otherwise the parser won't accept the code + suggestions.push((between_span, "".to_string())); + suggestions.push(( + generic_arg.span_ext.shrink_to_hi(), + ">".to_string(), + )); + } else { + suggestions.push(( + trait_path_segment.ident.span.shrink_to_hi(), + ">".to_string(), + )); + } + suggestions + }) + .collect(); + err.multipart_suggestions( message, suggestions, Applicability::MaybeIncorrect, |