Auto merge of rust-lang#108324 - notriddle:notriddle/assoc-fn-method, r=compiler-errors,davidtwco,estebank,oli-obk

diagnostics: if AssocFn has self argument, describe as method

Discussed in https://rust-lang.zulipchat.com/#narrow/stream/147480-t-compiler.2Fwg-diagnostics/topic/.22associated.20function.22.20vs.20.22method.22/near/329265515

This commit also changes the tooltips on rustdoc intra-doc links targeting methods.

For anyone not sure why this is being done, see the Reference definitions of these terms in <https://doc.rust-lang.org/1.67.1/reference/items/associated-items.html#methods>

> Associated functions whose first parameter is named `self` are called methods and may be invoked using the [method call operator](https://doc.rust-lang.org/1.67.1/reference/expressions/method-call-expr.html), for example, `x.foo()`, as well as the usual function call notation.

In particular, while this means it's technically correct for rustc to refer to a method as an associated function (and there are a few cases where it'll still do so), rustc *must never* use the term "method" to refer to an associated function that does not have a `self` parameter.

Author: bors

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -2135,7 +2135,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
         let tcx = self.infcx.tcx;
 
-        let (_, escapes_from) = tcx.article_and_description(self.mir_def_id().to_def_id());
+        let escapes_from = tcx.def_descr(self.mir_def_id().to_def_id());
 
         let mut err =
             borrowck_errors::borrowed_data_escapes_closure(tcx, escape_span, escapes_from);

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -660,10 +660,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             errci.outlived_fr,
         );
 
-        let (_, escapes_from) = self
-            .infcx
-            .tcx
-            .article_and_description(self.regioncx.universal_regions().defining_ty.def_id());
+        let escapes_from =
+            self.infcx.tcx.def_descr(self.regioncx.universal_regions().defining_ty.def_id());
 
         // Revert to the normal error in these cases.
         // Assignments aren't "escapes" in function items.
@@ -757,8 +755,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
             ..
         } = errci;
 
-        let (_, mir_def_name) =
-            self.infcx.tcx.article_and_description(self.mir_def_id().to_def_id());
+        let mir_def_name = self.infcx.tcx.def_descr(self.mir_def_id().to_def_id());
 
         let err = LifetimeOutliveErr { span: *span };
         let mut diag = self.infcx.tcx.sess.create_err(err);

compiler/rustc_hir/src/def.rs

@@ -124,6 +124,11 @@ pub enum DefKind {
 }
 
 impl DefKind {
+    /// Get an English description for the item's kind.
+    ///
+    /// If you have access to `TyCtxt`, use `TyCtxt::def_descr` or
+    /// `TyCtxt::def_kind_descr` instead, because they give better
+    /// information for generators and associated functions.
     pub fn descr(self, def_id: DefId) -> &'static str {
         match self {
             DefKind::Fn => "function",
@@ -166,6 +171,10 @@ impl DefKind {
     }
 
     /// Gets an English article for the definition.
+    ///
+    /// If you have access to `TyCtxt`, use `TyCtxt::def_descr_article` or
+    /// `TyCtxt::def_kind_descr_article` instead, because they give better
+    /// information for generators and associated functions.
     pub fn article(&self) -> &'static str {
         match *self {
             DefKind::AssocTy

compiler/rustc_hir_analysis/src/astconv/errors.rs

@@ -304,10 +304,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             if let Some(did) = adt_did {
                 err.span_label(
                     tcx.def_span(did),
-                    format!(
-                        "associated item `{name}` not found for this {}",
-                        tcx.def_kind(did).descr(did)
-                    ),
+                    format!("associated item `{name}` not found for this {}", tcx.def_descr(did)),
                 );
             }
         };

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1217,7 +1217,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     | (hir::def::DefKind::AssocConst, ty::TermKind::Const(_)) => (),
                     (_, _) => {
                         let got = if let Some(_) = term.ty() { "type" } else { "constant" };
-                        let expected = def_kind.descr(assoc_item_def_id);
+                        let expected = tcx.def_descr(assoc_item_def_id);
                         let mut err = tcx.sess.struct_span_err(
                             binding.span,
                             &format!("expected {expected} bound, found {got}"),
@@ -1552,7 +1552,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         i.bottom().1,
                         E0038,
                         "the {} `{}` cannot be made into an object",
-                        tcx.def_kind(def_id).descr(def_id),
+                        tcx.def_descr(def_id),
                         tcx.item_name(def_id),
                     );
                     err.note(
@@ -2174,7 +2174,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             "`{}` could{} refer to the {} defined here",
                             assoc_ident,
                             also,
-                            kind.descr(def_id)
+                            tcx.def_kind_descr(kind, def_id)
                         );
                         lint.span_note(tcx.def_span(def_id), &note_msg);
                     };
@@ -2350,7 +2350,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         let kind = DefKind::AssocTy;
 
         if !tcx.visibility(item).is_accessible_from(def_scope, tcx) {
-            let kind = kind.descr(item);
+            let kind = tcx.def_kind_descr(kind, item);
             let msg = format!("{kind} `{name}` is private");
             let def_span = tcx.def_span(item);
             tcx.sess

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1461,7 +1461,7 @@ fn opaque_type_cycle_error(
                                     span,
                                     format!(
                                         "{} captures itself here",
-                                        tcx.def_kind(closure_def_id).descr(closure_def_id)
+                                        tcx.def_descr(closure_def_id)
                                     ),
                                 );
                             }

compiler/rustc_hir_analysis/src/check/dropck.rs

@@ -71,7 +71,7 @@ fn ensure_drop_params_and_item_params_correspond<'tcx>(
 
     let drop_impl_span = tcx.def_span(drop_impl_did);
     let item_span = tcx.def_span(self_type_did);
-    let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
+    let self_descr = tcx.def_descr(self_type_did);
     let mut err =
         struct_span_err!(tcx.sess, drop_impl_span, E0366, "`Drop` impls cannot be specialized");
     match arg {
@@ -217,7 +217,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
 
         if !assumptions_in_impl_context.iter().copied().any(predicate_matches_closure) {
             let item_span = tcx.def_span(self_type_did);
-            let self_descr = tcx.def_kind(self_type_did).descr(self_type_did.to_def_id());
+            let self_descr = tcx.def_descr(self_type_did.to_def_id());
             let reported = struct_span_err!(
                 tcx.sess,
                 predicate_sp,

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -532,7 +532,7 @@ fn lint_auto_trait_impl<'tcx>(
         }),
         |lint| {
             let item_span = tcx.def_span(self_type_did);
-            let self_descr = tcx.def_kind(self_type_did).descr(self_type_did);
+            let self_descr = tcx.def_descr(self_type_did);
             match arg {
                 ty::util::NotUniqueParam::DuplicateParam(arg) => {
                     lint.note(&format!("`{}` is mentioned multiple times", arg));

compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs

@@ -439,7 +439,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
 
     fn create_error_message(&self) -> String {
         let def_path = self.tcx.def_path_str(self.def_id);
-        let def_kind = self.tcx.def_kind(self.def_id).descr(self.def_id);
+        let def_kind = self.tcx.def_descr(self.def_id);
         let (quantifier, bound) = self.get_quantifier_and_bound();
         let kind = self.kind();
         let provided_lt_args = self.num_provided_lifetime_args();
@@ -990,7 +990,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
         };
 
         let msg = {
-            let def_kind = self.tcx.def_kind(self.def_id).descr(self.def_id);
+            let def_kind = self.tcx.def_descr(self.def_id);
             let (quantifier, bound) = self.get_quantifier_and_bound();
 
             let params = if bound == 0 {

compiler/rustc_hir_typeck/src/callee.rs

@@ -671,7 +671,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 && !self.type_is_sized_modulo_regions(self.param_env, output_ty, callee_expr.span)
             {
                 let descr = match maybe_def {
-                    DefIdOrName::DefId(def_id) => self.tcx.def_kind(def_id).descr(def_id),
+                    DefIdOrName::DefId(def_id) => self.tcx.def_descr(def_id),
                     DefIdOrName::Name(name) => name,
                 };
                 err.span_label(