Rollup of 6 pull requests

compiler/rustc_errors/src/lib.rs

@@ -470,6 +470,7 @@ pub enum StashKey {
     /// Maybe there was a typo where a comma was forgotten before
     /// FRU syntax
     MaybeFruTypo,
+    CallAssocMethod,
 }
 
 fn default_track_diagnostic(_: &Diagnostic) {}

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -347,7 +347,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 assert!(self_ty.is_some());
             }
         } else {
-            assert!(self_ty.is_none() && parent_substs.is_empty());
+            assert!(self_ty.is_none());
         }
 
         let arg_count = Self::check_generic_arg_count(
@@ -1821,7 +1821,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
         // Check if we have an enum variant.
         let mut variant_resolution = None;
-        if let ty::Adt(adt_def, _) = qself_ty.kind() {
+        if let ty::Adt(adt_def, adt_substs) = qself_ty.kind() {
             if adt_def.is_enum() {
                 let variant_def = adt_def
                     .variants()
@@ -1923,8 +1923,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 let Some(assoc_ty_did) = self.lookup_assoc_ty(assoc_ident, hir_ref_id, span, impl_) else {
                     continue;
                 };
-                // FIXME(inherent_associated_types): This does not substitute parameters.
-                let ty = tcx.type_of(assoc_ty_did);
+                let item_substs = self.create_substs_for_associated_item(
+                    span,
+                    assoc_ty_did,
+                    assoc_segment,
+                    adt_substs,
+                );
+                let ty = tcx.bound_type_of(assoc_ty_did).subst(tcx, item_substs);
                 return Ok((ty, DefKind::AssocTy, assoc_ty_did));
             }
         }

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1544,7 +1544,7 @@ fn check_fn_or_method<'tcx>(
     check_where_clauses(wfcx, span, def_id);
 
     check_return_position_impl_trait_in_trait_bounds(
-        tcx,
+        wfcx,
         def_id,
         sig.output(),
         hir_decl.output.span(),
@@ -1580,13 +1580,14 @@ fn check_fn_or_method<'tcx>(
 
 /// Basically `check_associated_type_bounds`, but separated for now and should be
 /// deduplicated when RPITITs get lowered into real associated items.
-#[tracing::instrument(level = "trace", skip(tcx))]
+#[tracing::instrument(level = "trace", skip(wfcx))]
 fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
-    tcx: TyCtxt<'tcx>,
+    wfcx: &WfCheckingCtxt<'_, 'tcx>,
     fn_def_id: LocalDefId,
     fn_output: Ty<'tcx>,
     span: Span,
 ) {
+    let tcx = wfcx.tcx();
     if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id())
         && assoc_item.container == ty::AssocItemContainer::TraitContainer
     {
@@ -1596,22 +1597,20 @@ fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
                 && tcx.def_kind(proj.item_def_id) == DefKind::ImplTraitPlaceholder
                 && tcx.impl_trait_in_trait_parent(proj.item_def_id) == fn_def_id.to_def_id()
             {
-                // Create a new context, since we want the opaque's ParamEnv and not the parent's.
                 let span = tcx.def_span(proj.item_def_id);
-                enter_wf_checking_ctxt(tcx, span, proj.item_def_id.expect_local(), |wfcx| {
-                    let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id);
-                    let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
-                        let normalized_bound = wfcx.normalize(span, None, bound);
-                        traits::wf::predicate_obligations(
-                            wfcx.infcx,
-                            wfcx.param_env,
-                            wfcx.body_id,
-                            normalized_bound,
-                            bound_span,
-                        )
-                    });
-                    wfcx.register_obligations(wf_obligations);
+                let bounds = wfcx.tcx().explicit_item_bounds(proj.item_def_id);
+                let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| {
+                    let bound = ty::EarlyBinder(bound).subst(tcx, proj.substs);
+                    let normalized_bound = wfcx.normalize(span, None, bound);
+                    traits::wf::predicate_obligations(
+                        wfcx.infcx,
+                        wfcx.param_env,
+                        wfcx.body_id,
+                        normalized_bound,
+                        bound_span,
+                    )
                 });
+                wfcx.register_obligations(wf_obligations);
             }
         }
     }

compiler/rustc_hir_typeck/src/expr.rs

@@ -528,6 +528,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.resolve_ty_and_res_fully_qualified_call(qpath, expr.hir_id, expr.span);
         let ty = match res {
             Res::Err => {
+                self.suggest_assoc_method_call(segs);
                 let e =
                     self.tcx.sess.delay_span_bug(qpath.span(), "`Res::Err` but no error emitted");
                 self.set_tainted_by_errors(e);

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -5,6 +5,7 @@ use crate::errors;
 use crate::FnCtxt;
 use rustc_ast::ast::Mutability;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_errors::StashKey;
 use rustc_errors::{
     pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
     MultiSpan,
@@ -13,6 +14,8 @@ use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::lang_items::LangItem;
+use rustc_hir::PatKind::Binding;
+use rustc_hir::PathSegment;
 use rustc_hir::{ExprKind, Node, QPath};
 use rustc_infer::infer::{
     type_variable::{TypeVariableOrigin, TypeVariableOriginKind},
@@ -35,11 +38,11 @@ use rustc_trait_selection::traits::{
     FulfillmentError, Obligation, ObligationCause, ObligationCauseCode,
 };
 
-use std::cmp::Ordering;
-use std::iter;
-
 use super::probe::{AutorefOrPtrAdjustment, IsSuggestion, Mode, ProbeScope};
 use super::{CandidateSource, MethodError, NoMatchData};
+use rustc_hir::intravisit::Visitor;
+use std::cmp::Ordering;
+use std::iter;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn is_fn_ty(&self, ty: Ty<'tcx>, span: Span) -> bool {
@@ -1462,6 +1465,61 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         false
     }
 
+    /// For code `rect::area(...)`,
+    /// if `rect` is a local variable and `area` is a valid assoc method for it,
+    /// we try to suggest `rect.area()`
+    pub(crate) fn suggest_assoc_method_call(&self, segs: &[PathSegment<'_>]) {
+        debug!("suggest_assoc_method_call segs: {:?}", segs);
+        let [seg1, seg2] = segs else { return; };
+        let Some(mut diag) =
+                self.tcx.sess.diagnostic().steal_diagnostic(seg1.ident.span, StashKey::CallAssocMethod)
+                else { return };
+
+        let map = self.infcx.tcx.hir();
+        let body = map.body(rustc_hir::BodyId { hir_id: self.body_id });
+        struct LetVisitor<'a> {
+            result: Option<&'a hir::Expr<'a>>,
+            ident_name: Symbol,
+        }
+
+        impl<'v> Visitor<'v> for LetVisitor<'v> {
+            fn visit_stmt(&mut self, ex: &'v hir::Stmt<'v>) {
+                if let hir::StmtKind::Local(hir::Local { pat, init, .. }) = &ex.kind {
+                    if let Binding(_, _, ident, ..) = pat.kind &&
+                        ident.name == self.ident_name {
+                        self.result = *init;
+                    }
+                }
+                hir::intravisit::walk_stmt(self, ex);
+            }
+        }
+
+        let mut visitor = LetVisitor { result: None, ident_name: seg1.ident.name };
+        visitor.visit_body(&body);
+
+        let parent = self.tcx.hir().get_parent_node(seg1.hir_id);
+        if let Some(Node::Expr(call_expr)) = self.tcx.hir().find(parent) &&
+            let Some(expr) = visitor.result {
+            let self_ty = self.node_ty(expr.hir_id);
+            let probe = self.lookup_probe(
+                seg2.ident,
+                self_ty,
+                call_expr,
+                ProbeScope::TraitsInScope,
+            );
+            if probe.is_ok() {
+                let sm = self.infcx.tcx.sess.source_map();
+                diag.span_suggestion_verbose(
+                    sm.span_extend_while(seg1.ident.span.shrink_to_hi(), |c| c == ':').unwrap(),
+                    "you may have meant to call an instance method",
+                    ".".to_string(),
+                    Applicability::MaybeIncorrect
+                );
+            }
+        }
+        diag.emit();
+    }
+
     /// Suggest calling a method on a field i.e. `a.field.bar()` instead of `a.bar()`
     fn suggest_calling_method_on_field(
         &self,

compiler/rustc_parse/src/parser/stmt.rs

@@ -72,14 +72,22 @@ impl<'a> Parser<'a> {
 
         Ok(Some(if self.token.is_keyword(kw::Let) {
             self.parse_local_mk(lo, attrs, capture_semi, force_collect)?
-        } else if self.is_kw_followed_by_ident(kw::Mut) {
-            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::MissingLet)?
-        } else if self.is_kw_followed_by_ident(kw::Auto) {
+        } else if self.is_kw_followed_by_ident(kw::Mut) && self.may_recover() {
+            self.recover_stmt_local_after_let(lo, attrs, InvalidVariableDeclarationSub::MissingLet)?
+        } else if self.is_kw_followed_by_ident(kw::Auto) && self.may_recover() {
             self.bump(); // `auto`
-            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotAuto)?
-        } else if self.is_kw_followed_by_ident(sym::var) {
+            self.recover_stmt_local_after_let(
+                lo,
+                attrs,
+                InvalidVariableDeclarationSub::UseLetNotAuto,
+            )?
+        } else if self.is_kw_followed_by_ident(sym::var) && self.may_recover() {
             self.bump(); // `var`
-            self.recover_stmt_local(lo, attrs, InvalidVariableDeclarationSub::UseLetNotVar)?
+            self.recover_stmt_local_after_let(
+                lo,
+                attrs,
+                InvalidVariableDeclarationSub::UseLetNotVar,
+            )?
         } else if self.check_path() && !self.token.is_qpath_start() && !self.is_path_start_item() {
             // We have avoided contextual keywords like `union`, items with `crate` visibility,
             // or `auto trait` items. We aim to parse an arbitrary path `a::b` but not something
@@ -213,13 +221,21 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn recover_stmt_local(
+    fn recover_stmt_local_after_let(
         &mut self,
         lo: Span,
         attrs: AttrWrapper,
         subdiagnostic: fn(Span) -> InvalidVariableDeclarationSub,
     ) -> PResult<'a, Stmt> {
-        let stmt = self.recover_local_after_let(lo, attrs)?;
+        let stmt =
+            self.collect_tokens_trailing_token(attrs, ForceCollect::Yes, |this, attrs| {
+                let local = this.parse_local(attrs)?;
+                // FIXME - maybe capture semicolon in recovery?
+                Ok((
+                    this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)),
+                    TrailingToken::None,
+                ))
+            })?;
         self.sess.emit_err(InvalidVariableDeclaration { span: lo, sub: subdiagnostic(lo) });
         Ok(stmt)
     }
@@ -243,17 +259,6 @@ impl<'a> Parser<'a> {
         })
     }
 
-    fn recover_local_after_let(&mut self, lo: Span, attrs: AttrWrapper) -> PResult<'a, Stmt> {
-        self.collect_tokens_trailing_token(attrs, ForceCollect::No, |this, attrs| {
-            let local = this.parse_local(attrs)?;
-            // FIXME - maybe capture semicolon in recovery?
-            Ok((
-                this.mk_stmt(lo.to(this.prev_token.span), StmtKind::Local(local)),
-                TrailingToken::None,
-            ))
-        })
-    }
-
     /// Parses a local variable declaration.
     fn parse_local(&mut self, attrs: AttrVec) -> PResult<'a, P<Local>> {
         let lo = self.prev_token.span;

compiler/rustc_resolve/src/diagnostics.rs

@@ -1840,13 +1840,16 @@ impl<'a> Resolver<'a> {
 
             (format!("use of undeclared type `{}`", ident), suggestion)
         } else {
-            let suggestion = if ident.name == sym::alloc {
-                Some((
+            let mut suggestion = None;
+            if ident.name == sym::alloc {
+                suggestion = Some((
                     vec![],
                     String::from("add `extern crate alloc` to use the `alloc` crate"),
                     Applicability::MaybeIncorrect,
                 ))
-            } else {
+            }
+
+            suggestion = suggestion.or_else(|| {
                 self.find_similarly_named_module_or_crate(ident.name, &parent_scope.module).map(
                     |sugg| {
                         (
@@ -1856,7 +1859,7 @@ impl<'a> Resolver<'a> {
                         )
                     },
                 )
-            };
+            });
             (format!("use of undeclared crate or module `{}`", ident), suggestion)
         }
     }

compiler/rustc_resolve/src/late.rs

@@ -3365,13 +3365,13 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             // Before we start looking for candidates, we have to get our hands
             // on the type user is trying to perform invocation on; basically:
             // we're transforming `HashMap::new` into just `HashMap`.
-            let path = match path.split_last() {
+            let prefix_path = match path.split_last() {
                 Some((_, path)) if !path.is_empty() => path,
                 _ => return Some(parent_err),
             };
 
             let (mut err, candidates) =
-                this.smart_resolve_report_errors(path, path_span, PathSource::Type, None);
+                this.smart_resolve_report_errors(prefix_path, path_span, PathSource::Type, None);
 
             // There are two different error messages user might receive at
             // this point:
@@ -3415,11 +3415,23 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
 
             if this.should_report_errs() {
                 if candidates.is_empty() {
-                    // When there is no suggested imports, we can just emit the error
-                    // and suggestions immediately. Note that we bypass the usually error
-                    // reporting routine (ie via `self.r.report_error`) because we need
-                    // to post-process the `ResolutionError` above.
-                    err.emit();
+                    if path.len() == 2 && prefix_path.len() == 1 {
+                        // Delay to check whether methond name is an associated function or not
+                        // ```
+                        // let foo = Foo {};
+                        // foo::bar(); // possibly suggest to foo.bar();
+                        //```
+                        err.stash(
+                            prefix_path[0].ident.span,
+                            rustc_errors::StashKey::CallAssocMethod,
+                        );
+                    } else {
+                        // When there is no suggested imports, we can just emit the error
+                        // and suggestions immediately. Note that we bypass the usually error
+                        // reporting routine (ie via `self.r.report_error`) because we need
+                        // to post-process the `ResolutionError` above.
+                        err.emit();
+                    }
                 } else {
                     // If there are suggested imports, the error reporting is delayed
                     this.r.use_injections.push(UseError {
@@ -3428,7 +3440,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                         def_id,
                         instead: false,
                         suggestion: None,
-                        path: path.into(),
+                        path: prefix_path.into(),
                         is_call: source.is_call(),
                     });
                 }