diff --git a/compiler/rustc_hir_analysis/src/astconv/errors.rs b/compiler/rustc_hir_analysis/src/astconv/errors.rs index 407517b15ef5e..869e218400639 100644 --- a/compiler/rustc_hir_analysis/src/astconv/errors.rs +++ b/compiler/rustc_hir_analysis/src/astconv/errors.rs @@ -14,6 +14,7 @@ use rustc_errors::{ use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_infer::traits::FulfillmentError; +use rustc_middle::query::Key; use rustc_middle::ty::{self, suggest_constraining_type_param, Ty, TyCtxt, TypeVisitableExt}; use rustc_session::parse::feature_err; use rustc_span::edit_distance::find_best_match_for_name; @@ -859,6 +860,56 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { self.set_tainted_by_errors(err.emit()); } + + /// On ambiguous associated type, look for an associated function whose name matches the + /// extended path and, if found, emit an E0223 error with a structured suggestion. + /// e.g. for `String::from::utf8`, suggest `String::from_utf8` (#109195) + pub(crate) fn maybe_report_similar_assoc_fn( + &self, + span: Span, + qself_ty: Ty<'tcx>, + qself: &hir::Ty<'_>, + ) -> Result<(), ErrorGuaranteed> { + let tcx = self.tcx(); + if let Some((_, node)) = tcx.hir().parent_iter(qself.hir_id).skip(1).next() + && let hir::Node::Expr(hir::Expr { + kind: + hir::ExprKind::Path(hir::QPath::TypeRelative( + hir::Ty { + kind: + hir::TyKind::Path(hir::QPath::TypeRelative( + _, + hir::PathSegment { ident: ident2, .. }, + )), + .. + }, + hir::PathSegment { ident: ident3, .. }, + )), + .. + }) = node + && let Some(ty_def_id) = qself_ty.ty_def_id() + && let Ok([inherent_impl]) = tcx.inherent_impls(ty_def_id) + && let name = format!("{ident2}_{ident3}") + && let Some(ty::AssocItem { kind: ty::AssocKind::Fn, .. }) = tcx + .associated_items(inherent_impl) + .filter_by_name_unhygienic(Symbol::intern(&name)) + .next() + { + let reported = + struct_span_code_err!(tcx.dcx(), span, E0223, "ambiguous associated type") + .with_span_suggestion_verbose( + ident2.span.to(ident3.span), + format!("there is an associated function with a similar name: `{name}`"), + name, + Applicability::MaybeIncorrect, + ) + .emit(); + self.set_tainted_by_errors(reported); + Err(reported) + } else { + Ok(()) + } + } } /// Emits an error regarding forbidden type binding associations diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs index 89f39897ea874..cfd38fb48f472 100644 --- a/compiler/rustc_hir_analysis/src/astconv/mod.rs +++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs @@ -1373,6 +1373,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { ) .emit() // Already reported in an earlier stage. } else { + self.maybe_report_similar_assoc_fn(span, qself_ty, qself)?; + let traits: Vec<_> = self.probe_traits_that_match_assoc_ty(qself_ty, assoc_ident); diff --git a/tests/ui/suggestions/issue-109195.rs b/tests/ui/suggestions/issue-109195.rs new file mode 100644 index 0000000000000..cc499b0d77618 --- /dev/null +++ b/tests/ui/suggestions/issue-109195.rs @@ -0,0 +1,20 @@ +fn main() { + String::from::utf8; + //~^ ERROR ambiguous associated type [E0223] + //~| HELP there is an associated function with a similar name: `from_utf8` + String::from::utf8(); + //~^ ERROR ambiguous associated type [E0223] + //~| HELP there is an associated function with a similar name: `from_utf8` + String::from::utf16(); + //~^ ERROR ambiguous associated type [E0223] + //~| HELP there is an associated function with a similar name: `from_utf16` + String::from::method_that_doesnt_exist(); + //~^ ERROR ambiguous associated type [E0223] + //~| HELP if there were a trait named `Example` with associated type `from` + str::from::utf8(); + //~^ ERROR ambiguous associated type [E0223] + //~| HELP if there were a trait named `Example` with associated type `from` + str::from::utf8_mut(); + //~^ ERROR ambiguous associated type [E0223] + //~| HELP if there were a trait named `Example` with associated type `from` +} diff --git a/tests/ui/suggestions/issue-109195.stderr b/tests/ui/suggestions/issue-109195.stderr new file mode 100644 index 0000000000000..10cf9cfd28ca7 --- /dev/null +++ b/tests/ui/suggestions/issue-109195.stderr @@ -0,0 +1,69 @@ +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:2:5 + | +LL | String::from::utf8; + | ^^^^^^^^^^^^ + | +help: there is an associated function with a similar name: `from_utf8` + | +LL | String::from_utf8; + | ~~~~~~~~~ + +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:5:5 + | +LL | String::from::utf8(); + | ^^^^^^^^^^^^ + | +help: there is an associated function with a similar name: `from_utf8` + | +LL | String::from_utf8(); + | ~~~~~~~~~ + +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:8:5 + | +LL | String::from::utf16(); + | ^^^^^^^^^^^^ + | +help: there is an associated function with a similar name: `from_utf16` + | +LL | String::from_utf16(); + | ~~~~~~~~~~ + +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:11:5 + | +LL | String::from::method_that_doesnt_exist(); + | ^^^^^^^^^^^^ + | +help: if there were a trait named `Example` with associated type `from` implemented for `String`, you could use the fully-qualified path + | +LL | ::from::method_that_doesnt_exist(); + | ~~~~~~~~~~~~~~~~~~~~~~~~~ + +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:14:5 + | +LL | str::from::utf8(); + | ^^^^^^^^^ + | +help: if there were a trait named `Example` with associated type `from` implemented for `str`, you could use the fully-qualified path + | +LL | ::from::utf8(); + | ~~~~~~~~~~~~~~~~~~~~~~ + +error[E0223]: ambiguous associated type + --> $DIR/issue-109195.rs:17:5 + | +LL | str::from::utf8_mut(); + | ^^^^^^^^^ + | +help: if there were a trait named `Example` with associated type `from` implemented for `str`, you could use the fully-qualified path + | +LL | ::from::utf8_mut(); + | ~~~~~~~~~~~~~~~~~~~~~~ + +error: aborting due to 6 previous errors + +For more information about this error, try `rustc --explain E0223`.