| use crate::FnCtxt; |
| use rustc_ast::util::parser::PREC_POSTFIX; |
| use rustc_data_structures::fx::FxHashMap; |
| use rustc_errors::MultiSpan; |
| use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed}; |
| use rustc_hir as hir; |
| use rustc_hir::def::CtorKind; |
| use rustc_hir::intravisit::Visitor; |
| use rustc_hir::lang_items::LangItem; |
| use rustc_hir::{is_range_literal, Node}; |
| use rustc_infer::infer::InferOk; |
| use rustc_middle::lint::in_external_macro; |
| use rustc_middle::middle::stability::EvalResult; |
| use rustc_middle::ty::adjustment::AllowTwoPhase; |
| use rustc_middle::ty::error::{ExpectedFound, TypeError}; |
| use rustc_middle::ty::fold::{BottomUpFolder, TypeFolder}; |
| use rustc_middle::ty::print::{with_forced_trimmed_paths, with_no_trimmed_paths}; |
| use rustc_middle::ty::relate::TypeRelation; |
| use rustc_middle::ty::{self, Article, AssocItem, Ty, TypeAndMut, TypeVisitableExt}; |
| use rustc_span::symbol::{sym, Symbol}; |
| use rustc_span::{BytePos, Span}; |
| use rustc_trait_selection::infer::InferCtxtExt as _; |
| use rustc_trait_selection::traits::error_reporting::method_chain::CollectAllMismatches; |
| use rustc_trait_selection::traits::ObligationCause; |
| |
| use super::method::probe; |
| |
| use std::cmp::min; |
| use std::iter; |
| |
| impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
| pub fn emit_type_mismatch_suggestions( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'tcx>, |
| expr_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| error: Option<TypeError<'tcx>>, |
| ) { |
| if expr_ty == expected { |
| return; |
| } |
| |
| self.annotate_alternative_method_deref(err, expr, error); |
| |
| // Use `||` to give these suggestions a precedence |
| let suggested = self.suggest_missing_parentheses(err, expr) |
| || self.suggest_remove_last_method_call(err, expr, expected) |
| || self.suggest_associated_const(err, expr, expected) |
| || self.suggest_deref_ref_or_into(err, expr, expected, expr_ty, expected_ty_expr) |
| || self.suggest_option_to_bool(err, expr, expr_ty, expected) |
| || self.suggest_compatible_variants(err, expr, expected, expr_ty) |
| || self.suggest_non_zero_new_unwrap(err, expr, expected, expr_ty) |
| || self.suggest_calling_boxed_future_when_appropriate(err, expr, expected, expr_ty) |
| || self.suggest_no_capture_closure(err, expected, expr_ty) |
| || self.suggest_boxing_when_appropriate(err, expr, expected, expr_ty) |
| || self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected) |
| || self.suggest_copied_or_cloned(err, expr, expr_ty, expected) |
| || self.suggest_clone_for_ref(err, expr, expr_ty, expected) |
| || self.suggest_into(err, expr, expr_ty, expected) |
| || self.suggest_floating_point_literal(err, expr, expected) |
| || self.suggest_null_ptr_for_literal_zero_given_to_ptr_arg(err, expr, expected) |
| || self.note_result_coercion(err, expr, expected, expr_ty); |
| if !suggested { |
| self.point_at_expr_source_of_inferred_type(err, expr, expr_ty, expected, expr.span); |
| } |
| } |
| |
| pub fn emit_coerce_suggestions( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'tcx>, |
| expr_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| error: Option<TypeError<'tcx>>, |
| ) { |
| if expr_ty == expected { |
| return; |
| } |
| |
| self.annotate_expected_due_to_let_ty(err, expr, error); |
| self.emit_type_mismatch_suggestions(err, expr, expr_ty, expected, expected_ty_expr, error); |
| self.note_type_is_not_clone(err, expected, expr_ty, expr); |
| self.note_internal_mutation_in_method(err, expr, expected, expr_ty); |
| self.check_for_range_as_method_call(err, expr, expr_ty, expected); |
| self.check_for_binding_assigned_block_without_tail_expression(err, expr, expr_ty, expected); |
| self.check_wrong_return_type_due_to_generic_arg(err, expr, expr_ty); |
| } |
| |
| /// Requires that the two types unify, and prints an error message if |
| /// they don't. |
| pub fn demand_suptype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) { |
| if let Some(mut e) = self.demand_suptype_diag(sp, expected, actual) { |
| e.emit(); |
| } |
| } |
| |
| pub fn demand_suptype_diag( |
| &self, |
| sp: Span, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>, |
| ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
| self.demand_suptype_with_origin(&self.misc(sp), expected, actual) |
| } |
| |
| #[instrument(skip(self), level = "debug")] |
| pub fn demand_suptype_with_origin( |
| &self, |
| cause: &ObligationCause<'tcx>, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>, |
| ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
| match self.at(cause, self.param_env).define_opaque_types(true).sup(expected, actual) { |
| Ok(InferOk { obligations, value: () }) => { |
| self.register_predicates(obligations); |
| None |
| } |
| Err(e) => Some(self.err_ctxt().report_mismatched_types(&cause, expected, actual, e)), |
| } |
| } |
| |
| pub fn demand_eqtype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) { |
| if let Some(mut err) = self.demand_eqtype_diag(sp, expected, actual) { |
| err.emit(); |
| } |
| } |
| |
| pub fn demand_eqtype_diag( |
| &self, |
| sp: Span, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>, |
| ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
| self.demand_eqtype_with_origin(&self.misc(sp), expected, actual) |
| } |
| |
| pub fn demand_eqtype_with_origin( |
| &self, |
| cause: &ObligationCause<'tcx>, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>, |
| ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
| match self.at(cause, self.param_env).define_opaque_types(true).eq(expected, actual) { |
| Ok(InferOk { obligations, value: () }) => { |
| self.register_predicates(obligations); |
| None |
| } |
| Err(e) => Some(self.err_ctxt().report_mismatched_types(cause, expected, actual, e)), |
| } |
| } |
| |
| pub fn demand_coerce( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| allow_two_phase: AllowTwoPhase, |
| ) -> Ty<'tcx> { |
| let (ty, err) = |
| self.demand_coerce_diag(expr, checked_ty, expected, expected_ty_expr, allow_two_phase); |
| if let Some(mut err) = err { |
| err.emit(); |
| } |
| ty |
| } |
| |
| /// Checks that the type of `expr` can be coerced to `expected`. |
| /// |
| /// N.B., this code relies on `self.diverges` to be accurate. In particular, assignments to `!` |
| /// will be permitted if the diverges flag is currently "always". |
| #[instrument(level = "debug", skip(self, expr, expected_ty_expr, allow_two_phase))] |
| pub fn demand_coerce_diag( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| allow_two_phase: AllowTwoPhase, |
| ) -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>) { |
| let expected = self.resolve_vars_with_obligations(expected); |
| |
| let e = match self.try_coerce(expr, checked_ty, expected, allow_two_phase, None) { |
| Ok(ty) => return (ty, None), |
| Err(e) => e, |
| }; |
| |
| self.set_tainted_by_errors(self.tcx.sess.delay_span_bug( |
| expr.span, |
| "`TypeError` when attempting coercion but no error emitted", |
| )); |
| let expr = expr.peel_drop_temps(); |
| let cause = self.misc(expr.span); |
| let expr_ty = self.resolve_vars_with_obligations(checked_ty); |
| let mut err = self.err_ctxt().report_mismatched_types(&cause, expected, expr_ty, e); |
| |
| let is_insufficiently_polymorphic = |
| matches!(e, TypeError::RegionsInsufficientlyPolymorphic(..)); |
| |
| // FIXME(#73154): For now, we do leak check when coercing function |
| // pointers in typeck, instead of only during borrowck. This can lead |
| // to these `RegionsInsufficientlyPolymorphic` errors that aren't helpful. |
| if !is_insufficiently_polymorphic { |
| self.emit_coerce_suggestions( |
| &mut err, |
| expr, |
| expr_ty, |
| expected, |
| expected_ty_expr, |
| Some(e), |
| ); |
| } |
| |
| (expected, Some(err)) |
| } |
| |
| pub fn point_at_expr_source_of_inferred_type( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| found: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| mismatch_span: Span, |
| ) -> bool { |
| let map = self.tcx.hir(); |
| |
| let hir::ExprKind::Path(hir::QPath::Resolved(None, p)) = expr.kind else { return false; }; |
| let [hir::PathSegment { ident, args: None, .. }] = p.segments else { return false; }; |
| let hir::def::Res::Local(hir_id) = p.res else { return false; }; |
| let Some(hir::Node::Pat(pat)) = map.find(hir_id) else { return false; }; |
| let Some(hir::Node::Local(hir::Local { |
| ty: None, |
| init: Some(init), |
| .. |
| })) = map.find_parent(pat.hir_id) else { return false; }; |
| let Some(ty) = self.node_ty_opt(init.hir_id) else { return false; }; |
| if ty.is_closure() || init.span.overlaps(expr.span) || pat.span.from_expansion() { |
| return false; |
| } |
| |
| // Locate all the usages of the relevant binding. |
| struct FindExprs<'hir> { |
| hir_id: hir::HirId, |
| uses: Vec<&'hir hir::Expr<'hir>>, |
| } |
| impl<'v> Visitor<'v> for FindExprs<'v> { |
| fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) { |
| if let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = ex.kind |
| && let hir::def::Res::Local(hir_id) = path.res |
| && hir_id == self.hir_id |
| { |
| self.uses.push(ex); |
| } |
| hir::intravisit::walk_expr(self, ex); |
| } |
| } |
| |
| let mut expr_finder = FindExprs { hir_id, uses: vec![] }; |
| let id = map.get_parent_item(hir_id); |
| let hir_id: hir::HirId = id.into(); |
| |
| let Some(node) = map.find(hir_id) else { return false; }; |
| let Some(body_id) = node.body_id() else { return false; }; |
| let body = map.body(body_id); |
| expr_finder.visit_expr(body.value); |
| // Hack to make equality checks on types with inference variables and regions useful. |
| let mut eraser = BottomUpFolder { |
| tcx: self.tcx, |
| lt_op: |_| self.tcx.lifetimes.re_erased, |
| ct_op: |c| c, |
| ty_op: |t| match *t.kind() { |
| ty::Infer(ty::TyVar(_)) => self.tcx.mk_ty_var(ty::TyVid::from_u32(0)), |
| ty::Infer(ty::IntVar(_)) => self.tcx.mk_int_var(ty::IntVid { index: 0 }), |
| ty::Infer(ty::FloatVar(_)) => self.tcx.mk_float_var(ty::FloatVid { index: 0 }), |
| _ => t, |
| }, |
| }; |
| let mut prev = eraser.fold_ty(ty); |
| let mut prev_span: Option<Span> = None; |
| |
| for binding in expr_finder.uses { |
| // In every expression where the binding is referenced, we will look at that |
| // expression's type and see if it is where the incorrect found type was fully |
| // "materialized" and point at it. We will also try to provide a suggestion there. |
| if let Some(hir::Node::Expr(expr) |
| | hir::Node::Stmt(hir::Stmt { |
| kind: hir::StmtKind::Expr(expr) | hir::StmtKind::Semi(expr), |
| .. |
| })) = &map.find_parent(binding.hir_id) |
| && let hir::ExprKind::MethodCall(segment, rcvr, args, _span) = expr.kind |
| && rcvr.hir_id == binding.hir_id |
| && let Some(def_id) = self.typeck_results.borrow().type_dependent_def_id(expr.hir_id) |
| { |
| // We special case methods, because they can influence inference through the |
| // call's arguments and we can provide a more explicit span. |
| let sig = self.tcx.fn_sig(def_id).subst_identity(); |
| let def_self_ty = sig.input(0).skip_binder(); |
| let param_tys = sig.inputs().skip_binder().iter().skip(1); |
| // If there's an arity mismatch, pointing out the call as the source of an inference |
| // can be misleading, so we skip it. |
| if param_tys.len() != args.len() { |
| continue; |
| } |
| let rcvr_ty = self.node_ty(rcvr.hir_id); |
| // Get the evaluated type *after* calling the method call, so that the influence |
| // of the arguments can be reflected in the receiver type. The receiver |
| // expression has the type *before* theis analysis is done. |
| let ty = match self.lookup_probe_for_diagnostic( |
| segment.ident, |
| rcvr_ty, |
| expr, |
| probe::ProbeScope::TraitsInScope, |
| None, |
| ) { |
| Ok(pick) => eraser.fold_ty(pick.self_ty), |
| Err(_) => rcvr_ty, |
| }; |
| // Remove one layer of references to account for `&mut self` and |
| // `&self`, so that we can compare it against the binding. |
| let (ty, def_self_ty) = match (ty.kind(), def_self_ty.kind()) { |
| (ty::Ref(_, ty, a), ty::Ref(_, self_ty, b)) if a == b => (*ty, *self_ty), |
| _ => (ty, def_self_ty), |
| }; |
| let mut param_args = FxHashMap::default(); |
| let mut param_expected = FxHashMap::default(); |
| let mut param_found = FxHashMap::default(); |
| if self.can_eq(self.param_env, ty, found) { |
| // We only point at the first place where the found type was inferred. |
| for (param_ty, arg) in param_tys.zip(args) { |
| if def_self_ty.contains(*param_ty) && let ty::Param(_) = param_ty.kind() { |
| // We found an argument that references a type parameter in `Self`, |
| // so we assume that this is the argument that caused the found |
| // type, which we know already because of `can_eq` above was first |
| // inferred in this method call. |
| let arg_ty = self.node_ty(arg.hir_id); |
| if !arg.span.overlaps(mismatch_span) { |
| err.span_label( |
| arg.span, |
| &format!( |
| "this is of type `{arg_ty}`, which causes `{ident}` to be \ |
| inferred as `{ty}`", |
| ), |
| ); |
| } |
| param_args.insert(param_ty, (arg, arg_ty)); |
| } |
| } |
| } |
| |
| // Here we find, for a type param `T`, the type that `T` is in the current |
| // method call *and* in the original expected type. That way, we can see if we |
| // can give any structured suggestion for the function argument. |
| let mut c = CollectAllMismatches { |
| infcx: &self.infcx, |
| param_env: self.param_env, |
| errors: vec![], |
| }; |
| let _ = c.relate(def_self_ty, ty); |
| for error in c.errors { |
| if let TypeError::Sorts(error) = error { |
| param_found.insert(error.expected, error.found); |
| } |
| } |
| c.errors = vec![]; |
| let _ = c.relate(def_self_ty, expected); |
| for error in c.errors { |
| if let TypeError::Sorts(error) = error { |
| param_expected.insert(error.expected, error.found); |
| } |
| } |
| for (param, (arg, arg_ty)) in param_args.iter() { |
| let Some(expected) = param_expected.get(param) else { continue; }; |
| let Some(found) = param_found.get(param) else { continue; }; |
| if !self.can_eq(self.param_env, *arg_ty, *found) { continue; } |
| self.emit_coerce_suggestions(err, arg, *found, *expected, None, None); |
| } |
| |
| let ty = eraser.fold_ty(ty); |
| if ty.references_error() { |
| break; |
| } |
| if ty != prev |
| && param_args.is_empty() |
| && self.can_eq(self.param_env, ty, found) |
| { |
| // We only point at the first place where the found type was inferred. |
| if !segment.ident.span.overlaps(mismatch_span) { |
| err.span_label( |
| segment.ident.span, |
| with_forced_trimmed_paths!(format!( |
| "here the type of `{ident}` is inferred to be `{ty}`", |
| )), |
| );} |
| break; |
| } else if !param_args.is_empty() { |
| break; |
| } |
| prev = ty; |
| } else { |
| let ty = eraser.fold_ty(self.node_ty(binding.hir_id)); |
| if ty.references_error() { |
| break; |
| } |
| if ty != prev |
| && let Some(span) = prev_span |
| && self.can_eq(self.param_env, ty, found) |
| { |
| // We only point at the first place where the found type was inferred. |
| // We use the *previous* span because if the type is known *here* it means |
| // it was *evaluated earlier*. We don't do this for method calls because we |
| // evaluate the method's self type eagerly, but not in any other case. |
| if !span.overlaps(mismatch_span) { |
| err.span_label( |
| span, |
| with_forced_trimmed_paths!(format!( |
| "here the type of `{ident}` is inferred to be `{ty}`", |
| )), |
| ); |
| } |
| break; |
| } |
| prev = ty; |
| } |
| if binding.hir_id == expr.hir_id { |
| // Do not look at expressions that come after the expression we were originally |
| // evaluating and had a type error. |
| break; |
| } |
| prev_span = Some(binding.span); |
| } |
| true |
| } |
| |
| fn annotate_expected_due_to_let_ty( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| error: Option<TypeError<'tcx>>, |
| ) { |
| let parent = self.tcx.hir().parent_id(expr.hir_id); |
| match (self.tcx.hir().find(parent), error) { |
| (Some(hir::Node::Local(hir::Local { ty: Some(ty), init: Some(init), .. })), _) |
| if init.hir_id == expr.hir_id => |
| { |
| // Point at `let` assignment type. |
| err.span_label(ty.span, "expected due to this"); |
| } |
| ( |
| Some(hir::Node::Expr(hir::Expr { |
| kind: hir::ExprKind::Assign(lhs, rhs, _), .. |
| })), |
| Some(TypeError::Sorts(ExpectedFound { expected, .. })), |
| ) if rhs.hir_id == expr.hir_id && !expected.is_closure() => { |
| // We ignore closures explicitly because we already point at them elsewhere. |
| // Point at the assigned-to binding. |
| let mut primary_span = lhs.span; |
| let mut secondary_span = lhs.span; |
| let mut post_message = ""; |
| match lhs.kind { |
| hir::ExprKind::Path(hir::QPath::Resolved( |
| None, |
| hir::Path { |
| res: |
| hir::def::Res::Def( |
| hir::def::DefKind::Static(_) | hir::def::DefKind::Const, |
| def_id, |
| ), |
| .. |
| }, |
| )) => { |
| if let Some(hir::Node::Item(hir::Item { |
| ident, |
| kind: hir::ItemKind::Static(ty, ..) | hir::ItemKind::Const(ty, ..), |
| .. |
| })) = self.tcx.hir().get_if_local(*def_id) |
| { |
| primary_span = ty.span; |
| secondary_span = ident.span; |
| post_message = " type"; |
| } |
| } |
| hir::ExprKind::Path(hir::QPath::Resolved( |
| None, |
| hir::Path { res: hir::def::Res::Local(hir_id), .. }, |
| )) => { |
| if let Some(hir::Node::Pat(pat)) = self.tcx.hir().find(*hir_id) { |
| primary_span = pat.span; |
| secondary_span = pat.span; |
| match self.tcx.hir().find_parent(pat.hir_id) { |
| Some(hir::Node::Local(hir::Local { ty: Some(ty), .. })) => { |
| primary_span = ty.span; |
| post_message = " type"; |
| } |
| Some(hir::Node::Local(hir::Local { init: Some(init), .. })) => { |
| primary_span = init.span; |
| post_message = " value"; |
| } |
| Some(hir::Node::Param(hir::Param { ty_span, .. })) => { |
| primary_span = *ty_span; |
| post_message = " parameter type"; |
| } |
| _ => {} |
| } |
| } |
| } |
| _ => {} |
| } |
| |
| if primary_span != secondary_span |
| && self |
| .tcx |
| .sess |
| .source_map() |
| .is_multiline(secondary_span.shrink_to_hi().until(primary_span)) |
| { |
| // We are pointing at the binding's type or initializer value, but it's pattern |
| // is in a different line, so we point at both. |
| err.span_label(secondary_span, "expected due to the type of this binding"); |
| err.span_label(primary_span, &format!("expected due to this{post_message}")); |
| } else if post_message == "" { |
| // We are pointing at either the assignment lhs or the binding def pattern. |
| err.span_label(primary_span, "expected due to the type of this binding"); |
| } else { |
| // We are pointing at the binding's type or initializer value. |
| err.span_label(primary_span, &format!("expected due to this{post_message}")); |
| } |
| |
| if !lhs.is_syntactic_place_expr() { |
| // We already emitted E0070 "invalid left-hand side of assignment", so we |
| // silence this. |
| err.downgrade_to_delayed_bug(); |
| } |
| } |
| ( |
| Some(hir::Node::Expr(hir::Expr { |
| kind: hir::ExprKind::Binary(_, lhs, rhs), .. |
| })), |
| Some(TypeError::Sorts(ExpectedFound { expected, .. })), |
| ) if rhs.hir_id == expr.hir_id |
| && self.typeck_results.borrow().expr_ty_adjusted_opt(lhs) == Some(expected) => |
| { |
| err.span_label(lhs.span, &format!("expected because this is `{expected}`")); |
| } |
| _ => {} |
| } |
| } |
| |
| fn annotate_alternative_method_deref( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| error: Option<TypeError<'tcx>>, |
| ) { |
| let parent = self.tcx.hir().parent_id(expr.hir_id); |
| let Some(TypeError::Sorts(ExpectedFound { expected, .. })) = error else {return;}; |
| let Some(hir::Node::Expr(hir::Expr { |
| kind: hir::ExprKind::Assign(lhs, rhs, _), .. |
| })) = self.tcx.hir().find(parent) else {return; }; |
| if rhs.hir_id != expr.hir_id || expected.is_closure() { |
| return; |
| } |
| let hir::ExprKind::Unary(hir::UnOp::Deref, deref) = lhs.kind else { return; }; |
| let hir::ExprKind::MethodCall(path, base, args, _) = deref.kind else { return; }; |
| let Some(self_ty) = self.typeck_results.borrow().expr_ty_adjusted_opt(base) else { return; }; |
| |
| let Ok(pick) = self |
| .lookup_probe_for_diagnostic( |
| path.ident, |
| self_ty, |
| deref, |
| probe::ProbeScope::TraitsInScope, |
| None, |
| ) else { |
| return; |
| }; |
| let in_scope_methods = self.probe_for_name_many( |
| probe::Mode::MethodCall, |
| path.ident, |
| Some(expected), |
| probe::IsSuggestion(true), |
| self_ty, |
| deref.hir_id, |
| probe::ProbeScope::TraitsInScope, |
| ); |
| let other_methods_in_scope: Vec<_> = |
| in_scope_methods.iter().filter(|c| c.item.def_id != pick.item.def_id).collect(); |
| |
| let all_methods = self.probe_for_name_many( |
| probe::Mode::MethodCall, |
| path.ident, |
| Some(expected), |
| probe::IsSuggestion(true), |
| self_ty, |
| deref.hir_id, |
| probe::ProbeScope::AllTraits, |
| ); |
| let suggestions: Vec<_> = all_methods |
| .into_iter() |
| .filter(|c| c.item.def_id != pick.item.def_id) |
| .map(|c| { |
| let m = c.item; |
| let substs = ty::InternalSubsts::for_item(self.tcx, m.def_id, |param, _| { |
| self.var_for_def(deref.span, param) |
| }); |
| let mutability = |
| match self.tcx.fn_sig(m.def_id).skip_binder().input(0).skip_binder().kind() { |
| ty::Ref(_, _, hir::Mutability::Mut) => "&mut ", |
| ty::Ref(_, _, _) => "&", |
| _ => "", |
| }; |
| vec![ |
| ( |
| deref.span.until(base.span), |
| format!( |
| "{}({}", |
| with_no_trimmed_paths!( |
| self.tcx.def_path_str_with_substs(m.def_id, substs,) |
| ), |
| mutability, |
| ), |
| ), |
| match &args[..] { |
| [] => (base.span.shrink_to_hi().with_hi(deref.span.hi()), ")".to_string()), |
| [first, ..] => (base.span.between(first.span), ", ".to_string()), |
| }, |
| ] |
| }) |
| .collect(); |
| if suggestions.is_empty() { |
| return; |
| } |
| let mut path_span: MultiSpan = path.ident.span.into(); |
| path_span.push_span_label( |
| path.ident.span, |
| with_no_trimmed_paths!(format!( |
| "refers to `{}`", |
| self.tcx.def_path_str(pick.item.def_id), |
| )), |
| ); |
| let container_id = pick.item.container_id(self.tcx); |
| let container = with_no_trimmed_paths!(self.tcx.def_path_str(container_id)); |
| for def_id in pick.import_ids { |
| let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id); |
| path_span.push_span_label( |
| self.tcx.hir().span(hir_id), |
| format!("`{container}` imported here"), |
| ); |
| } |
| let tail = with_no_trimmed_paths!(match &other_methods_in_scope[..] { |
| [] => return, |
| [candidate] => format!( |
| "the method of the same name on {} `{}`", |
| match candidate.kind { |
| probe::CandidateKind::InherentImplCandidate(..) => "the inherent impl for", |
| _ => "trait", |
| }, |
| self.tcx.def_path_str(candidate.item.container_id(self.tcx)) |
| ), |
| [.., last] if other_methods_in_scope.len() < 5 => { |
| format!( |
| "the methods of the same name on {} and `{}`", |
| other_methods_in_scope[..other_methods_in_scope.len() - 1] |
| .iter() |
| .map(|c| format!( |
| "`{}`", |
| self.tcx.def_path_str(c.item.container_id(self.tcx)) |
| )) |
| .collect::<Vec<String>>() |
| .join(", "), |
| self.tcx.def_path_str(last.item.container_id(self.tcx)) |
| ) |
| } |
| _ => format!( |
| "the methods of the same name on {} other traits", |
| other_methods_in_scope.len() |
| ), |
| }); |
| err.span_note( |
| path_span, |
| &format!( |
| "the `{}` call is resolved to the method in `{container}`, shadowing {tail}", |
| path.ident, |
| ), |
| ); |
| if suggestions.len() > other_methods_in_scope.len() { |
| err.note(&format!( |
| "additionally, there are {} other available methods that aren't in scope", |
| suggestions.len() - other_methods_in_scope.len() |
| )); |
| } |
| err.multipart_suggestions( |
| &format!( |
| "you might have meant to call {}; you can use the fully-qualified path to call {} \ |
| explicitly", |
| if suggestions.len() == 1 { |
| "the other method" |
| } else { |
| "one of the other methods" |
| }, |
| if suggestions.len() == 1 { "it" } else { "one of them" }, |
| ), |
| suggestions, |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| |
| pub(crate) fn note_result_coercion( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'tcx>, |
| expected: Ty<'tcx>, |
| found: Ty<'tcx>, |
| ) -> bool { |
| let ty::Adt(e, substs_e) = expected.kind() else { return false; }; |
| let ty::Adt(f, substs_f) = found.kind() else { return false; }; |
| if e.did() != f.did() { |
| return false; |
| } |
| if Some(e.did()) != self.tcx.get_diagnostic_item(sym::Result) { |
| return false; |
| } |
| let map = self.tcx.hir(); |
| if let Some(hir::Node::Expr(expr)) = map.find_parent(expr.hir_id) |
| && let hir::ExprKind::Ret(_) = expr.kind |
| { |
| // `return foo;` |
| } else if map.get_return_block(expr.hir_id).is_some() { |
| // Function's tail expression. |
| } else { |
| return false; |
| } |
| let e = substs_e.type_at(1); |
| let f = substs_f.type_at(1); |
| if self |
| .infcx |
| .type_implements_trait( |
| self.tcx.get_diagnostic_item(sym::Into).unwrap(), |
| [f, e], |
| self.param_env, |
| ) |
| .must_apply_modulo_regions() |
| { |
| err.multipart_suggestion( |
| "use `?` to coerce and return an appropriate `Err`, and wrap the resulting value \ |
| in `Ok` so the expression remains of type `Result`", |
| vec![ |
| (expr.span.shrink_to_lo(), "Ok(".to_string()), |
| (expr.span.shrink_to_hi(), "?)".to_string()), |
| ], |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| false |
| } |
| |
| /// If the expected type is an enum (Issue #55250) with any variants whose |
| /// sole field is of the found type, suggest such variants. (Issue #42764) |
| fn suggest_compatible_variants( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| expected: Ty<'tcx>, |
| expr_ty: Ty<'tcx>, |
| ) -> bool { |
| if let ty::Adt(expected_adt, substs) = expected.kind() { |
| if let hir::ExprKind::Field(base, ident) = expr.kind { |
| let base_ty = self.typeck_results.borrow().expr_ty(base); |
| if self.can_eq(self.param_env, base_ty, expected) |
| && let Some(base_span) = base.span.find_ancestor_inside(expr.span) |
| { |
| err.span_suggestion_verbose( |
| expr.span.with_lo(base_span.hi()), |
| format!("consider removing the tuple struct field `{ident}`"), |
| "", |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| } |
| |
| // If the expression is of type () and it's the return expression of a block, |
| // we suggest adding a separate return expression instead. |
| // (To avoid things like suggesting `Ok(while .. { .. })`.) |
| if expr_ty.is_unit() { |
| let mut id = expr.hir_id; |
| let mut parent; |
| |
| // Unroll desugaring, to make sure this works for `for` loops etc. |
| loop { |
| parent = self.tcx.hir().parent_id(id); |
| if let Some(parent_span) = self.tcx.hir().opt_span(parent) { |
| if parent_span.find_ancestor_inside(expr.span).is_some() { |
| // The parent node is part of the same span, so is the result of the |
| // same expansion/desugaring and not the 'real' parent node. |
| id = parent; |
| continue; |
| } |
| } |
| break; |
| } |
| |
| if let Some(hir::Node::Block(&hir::Block { |
| span: block_span, expr: Some(e), .. |
| })) = self.tcx.hir().find(parent) |
| { |
| if e.hir_id == id { |
| if let Some(span) = expr.span.find_ancestor_inside(block_span) { |
| let return_suggestions = if self |
| .tcx |
| .is_diagnostic_item(sym::Result, expected_adt.did()) |
| { |
| vec!["Ok(())"] |
| } else if self.tcx.is_diagnostic_item(sym::Option, expected_adt.did()) { |
| vec!["None", "Some(())"] |
| } else { |
| return false; |
| }; |
| if let Some(indent) = |
| self.tcx.sess.source_map().indentation_before(span.shrink_to_lo()) |
| { |
| // Add a semicolon, except after `}`. |
| let semicolon = |
| match self.tcx.sess.source_map().span_to_snippet(span) { |
| Ok(s) if s.ends_with('}') => "", |
| _ => ";", |
| }; |
| err.span_suggestions( |
| span.shrink_to_hi(), |
| "try adding an expression at the end of the block", |
| return_suggestions |
| .into_iter() |
| .map(|r| format!("{semicolon}\n{indent}{r}")), |
| Applicability::MaybeIncorrect, |
| ); |
| } |
| return true; |
| } |
| } |
| } |
| } |
| |
| let compatible_variants: Vec<(String, _, _, Option<String>)> = expected_adt |
| .variants() |
| .iter() |
| .filter(|variant| { |
| variant.fields.len() == 1 |
| }) |
| .filter_map(|variant| { |
| let sole_field = &variant.fields[0]; |
| |
| let field_is_local = sole_field.did.is_local(); |
| let field_is_accessible = |
| sole_field.vis.is_accessible_from(expr.hir_id.owner.def_id, self.tcx) |
| // Skip suggestions for unstable public fields (for example `Pin::pointer`) |
| && matches!(self.tcx.eval_stability(sole_field.did, None, expr.span, None), EvalResult::Allow | EvalResult::Unmarked); |
| |
| if !field_is_local && !field_is_accessible { |
| return None; |
| } |
| |
| let note_about_variant_field_privacy = (field_is_local && !field_is_accessible) |
| .then(|| " (its field is private, but it's local to this crate and its privacy can be changed)".to_string()); |
| |
| let sole_field_ty = sole_field.ty(self.tcx, substs); |
| if self.can_coerce(expr_ty, sole_field_ty) { |
| let variant_path = |
| with_no_trimmed_paths!(self.tcx.def_path_str(variant.def_id)); |
| // FIXME #56861: DRYer prelude filtering |
| if let Some(path) = variant_path.strip_prefix("std::prelude::") |
| && let Some((_, path)) = path.split_once("::") |
| { |
| return Some((path.to_string(), variant.ctor_kind(), sole_field.name, note_about_variant_field_privacy)); |
| } |
| Some((variant_path, variant.ctor_kind(), sole_field.name, note_about_variant_field_privacy)) |
| } else { |
| None |
| } |
| }) |
| .collect(); |
| |
| let suggestions_for = |variant: &_, ctor_kind, field_name| { |
| let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { |
| Some(ident) => format!("{ident}: "), |
| None => String::new(), |
| }; |
| |
| let (open, close) = match ctor_kind { |
| Some(CtorKind::Fn) => ("(".to_owned(), ")"), |
| None => (format!(" {{ {field_name}: "), " }"), |
| |
| // unit variants don't have fields |
| Some(CtorKind::Const) => unreachable!(), |
| }; |
| |
| // Suggest constructor as deep into the block tree as possible. |
| // This fixes https://github.com/rust-lang/rust/issues/101065, |
| // and also just helps make the most minimal suggestions. |
| let mut expr = expr; |
| while let hir::ExprKind::Block(block, _) = &expr.kind |
| && let Some(expr_) = &block.expr |
| { |
| expr = expr_ |
| } |
| |
| vec![ |
| (expr.span.shrink_to_lo(), format!("{prefix}{variant}{open}")), |
| (expr.span.shrink_to_hi(), close.to_owned()), |
| ] |
| }; |
| |
| match &compatible_variants[..] { |
| [] => { /* No variants to format */ } |
| [(variant, ctor_kind, field_name, note)] => { |
| // Just a single matching variant. |
| err.multipart_suggestion_verbose( |
| &format!( |
| "try wrapping the expression in `{variant}`{note}", |
| note = note.as_deref().unwrap_or("") |
| ), |
| suggestions_for(&**variant, *ctor_kind, *field_name), |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| _ => { |
| // More than one matching variant. |
| err.multipart_suggestions( |
| &format!( |
| "try wrapping the expression in a variant of `{}`", |
| self.tcx.def_path_str(expected_adt.did()) |
| ), |
| compatible_variants.into_iter().map( |
| |(variant, ctor_kind, field_name, _)| { |
| suggestions_for(&variant, ctor_kind, field_name) |
| }, |
| ), |
| Applicability::MaybeIncorrect, |
| ); |
| return true; |
| } |
| } |
| } |
| |
| false |
| } |
| |
| fn suggest_non_zero_new_unwrap( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| expected: Ty<'tcx>, |
| expr_ty: Ty<'tcx>, |
| ) -> bool { |
| let tcx = self.tcx; |
| let (adt, unwrap) = match expected.kind() { |
| // In case Option<NonZero*> is wanted, but * is provided, suggest calling new |
| ty::Adt(adt, substs) if tcx.is_diagnostic_item(sym::Option, adt.did()) => { |
| // Unwrap option |
| let ty::Adt(adt, _) = substs.type_at(0).kind() else { return false; }; |
| |
| (adt, "") |
| } |
| // In case NonZero* is wanted, but * is provided also add `.unwrap()` to satisfy types |
| ty::Adt(adt, _) => (adt, ".unwrap()"), |
| _ => return false, |
| }; |
| |
| let map = [ |
| (sym::NonZeroU8, tcx.types.u8), |
| (sym::NonZeroU16, tcx.types.u16), |
| (sym::NonZeroU32, tcx.types.u32), |
| (sym::NonZeroU64, tcx.types.u64), |
| (sym::NonZeroU128, tcx.types.u128), |
| (sym::NonZeroI8, tcx.types.i8), |
| (sym::NonZeroI16, tcx.types.i16), |
| (sym::NonZeroI32, tcx.types.i32), |
| (sym::NonZeroI64, tcx.types.i64), |
| (sym::NonZeroI128, tcx.types.i128), |
| ]; |
| |
| let Some((s, _)) = map |
| .iter() |
| .find(|&&(s, t)| self.tcx.is_diagnostic_item(s, adt.did()) && self.can_coerce(expr_ty, t)) |
| else { return false; }; |
| |
| let path = self.tcx.def_path_str(adt.non_enum_variant().def_id); |
| |
| err.multipart_suggestion( |
| format!("consider calling `{s}::new`"), |
| vec![ |
| (expr.span.shrink_to_lo(), format!("{path}::new(")), |
| (expr.span.shrink_to_hi(), format!("){unwrap}")), |
| ], |
| Applicability::MaybeIncorrect, |
| ); |
| |
| true |
| } |
| |
| pub fn get_conversion_methods( |
| &self, |
| span: Span, |
| expected: Ty<'tcx>, |
| checked_ty: Ty<'tcx>, |
| hir_id: hir::HirId, |
| ) -> Vec<AssocItem> { |
| let methods = self.probe_for_return_type( |
| span, |
| probe::Mode::MethodCall, |
| expected, |
| checked_ty, |
| hir_id, |
| |m| { |
| self.has_only_self_parameter(m) |
| && self |
| .tcx |
| // This special internal attribute is used to permit |
| // "identity-like" conversion methods to be suggested here. |
| // |
| // FIXME (#46459 and #46460): ideally |
| // `std::convert::Into::into` and `std::borrow:ToOwned` would |
| // also be `#[rustc_conversion_suggestion]`, if not for |
| // method-probing false-positives and -negatives (respectively). |
| // |
| // FIXME? Other potential candidate methods: `as_ref` and |
| // `as_mut`? |
| .has_attr(m.def_id, sym::rustc_conversion_suggestion) |
| }, |
| ); |
| |
| methods |
| } |
| |
| /// This function checks whether the method is not static and does not accept other parameters than `self`. |
| fn has_only_self_parameter(&self, method: &AssocItem) -> bool { |
| match method.kind { |
| ty::AssocKind::Fn => { |
| method.fn_has_self_parameter |
| && self.tcx.fn_sig(method.def_id).skip_binder().inputs().skip_binder().len() |
| == 1 |
| } |
| _ => false, |
| } |
| } |
| |
| /// Identify some cases where `as_ref()` would be appropriate and suggest it. |
| /// |
| /// Given the following code: |
| /// ```compile_fail,E0308 |
| /// struct Foo; |
| /// fn takes_ref(_: &Foo) {} |
| /// let ref opt = Some(Foo); |
| /// |
| /// opt.map(|param| takes_ref(param)); |
| /// ``` |
| /// Suggest using `opt.as_ref().map(|param| takes_ref(param));` instead. |
| /// |
| /// It only checks for `Option` and `Result` and won't work with |
| /// ```ignore (illustrative) |
| /// opt.map(|param| { takes_ref(param) }); |
| /// ``` |
| fn can_use_as_ref(&self, expr: &hir::Expr<'_>) -> Option<(Span, &'static str, String)> { |
| let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind else { |
| return None; |
| }; |
| |
| let hir::def::Res::Local(local_id) = path.res else { |
| return None; |
| }; |
| |
| let local_parent = self.tcx.hir().parent_id(local_id); |
| let Some(Node::Param(hir::Param { hir_id: param_hir_id, .. })) = self.tcx.hir().find(local_parent) else { |
| return None; |
| }; |
| |
| let param_parent = self.tcx.hir().parent_id(*param_hir_id); |
| let Some(Node::Expr(hir::Expr { |
| hir_id: expr_hir_id, |
| kind: hir::ExprKind::Closure(hir::Closure { fn_decl: closure_fn_decl, .. }), |
| .. |
| })) = self.tcx.hir().find(param_parent) else { |
| return None; |
| }; |
| |
| let expr_parent = self.tcx.hir().parent_id(*expr_hir_id); |
| let hir = self.tcx.hir().find(expr_parent); |
| let closure_params_len = closure_fn_decl.inputs.len(); |
| let ( |
| Some(Node::Expr(hir::Expr { |
| kind: hir::ExprKind::MethodCall(method_path, receiver, ..), |
| .. |
| })), |
| 1, |
| ) = (hir, closure_params_len) else { |
| return None; |
| }; |
| |
| let self_ty = self.typeck_results.borrow().expr_ty(receiver); |
| let name = method_path.ident.name; |
| let is_as_ref_able = match self_ty.peel_refs().kind() { |
| ty::Adt(def, _) => { |
| (self.tcx.is_diagnostic_item(sym::Option, def.did()) |
| || self.tcx.is_diagnostic_item(sym::Result, def.did())) |
| && (name == sym::map || name == sym::and_then) |
| } |
| _ => false, |
| }; |
| match (is_as_ref_able, self.sess().source_map().span_to_snippet(method_path.ident.span)) { |
| (true, Ok(src)) => { |
| let suggestion = format!("as_ref().{}", src); |
| Some((method_path.ident.span, "consider using `as_ref` instead", suggestion)) |
| } |
| _ => None, |
| } |
| } |
| |
| pub(crate) fn maybe_get_struct_pattern_shorthand_field( |
| &self, |
| expr: &hir::Expr<'_>, |
| ) -> Option<Symbol> { |
| let hir = self.tcx.hir(); |
| let local = match expr { |
| hir::Expr { |
| kind: |
| hir::ExprKind::Path(hir::QPath::Resolved( |
| None, |
| hir::Path { |
| res: hir::def::Res::Local(_), |
| segments: [hir::PathSegment { ident, .. }], |
| .. |
| }, |
| )), |
| .. |
| } => Some(ident), |
| _ => None, |
| }?; |
| |
| match hir.find_parent(expr.hir_id)? { |
| Node::ExprField(field) => { |
| if field.ident.name == local.name && field.is_shorthand { |
| return Some(local.name); |
| } |
| } |
| _ => {} |
| } |
| |
| None |
| } |
| |
| /// If the given `HirId` corresponds to a block with a trailing expression, return that expression |
| pub(crate) fn maybe_get_block_expr( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| ) -> Option<&'tcx hir::Expr<'tcx>> { |
| match expr { |
| hir::Expr { kind: hir::ExprKind::Block(block, ..), .. } => block.expr, |
| _ => None, |
| } |
| } |
| |
| /// Returns whether the given expression is an `else if`. |
| pub(crate) fn is_else_if_block(&self, expr: &hir::Expr<'_>) -> bool { |
| if let hir::ExprKind::If(..) = expr.kind { |
| let parent_id = self.tcx.hir().parent_id(expr.hir_id); |
| if let Some(Node::Expr(hir::Expr { |
| kind: hir::ExprKind::If(_, _, Some(else_expr)), |
| .. |
| })) = self.tcx.hir().find(parent_id) |
| { |
| return else_expr.hir_id == expr.hir_id; |
| } |
| } |
| false |
| } |
| |
| /// This function is used to determine potential "simple" improvements or users' errors and |
| /// provide them useful help. For example: |
| /// |
| /// ```compile_fail,E0308 |
| /// fn some_fn(s: &str) {} |
| /// |
| /// let x = "hey!".to_owned(); |
| /// some_fn(x); // error |
| /// ``` |
| /// |
| /// No need to find every potential function which could make a coercion to transform a |
| /// `String` into a `&str` since a `&` would do the trick! |
| /// |
| /// In addition of this check, it also checks between references mutability state. If the |
| /// expected is mutable but the provided isn't, maybe we could just say "Hey, try with |
| /// `&mut`!". |
| pub fn check_ref( |
| &self, |
| expr: &hir::Expr<'tcx>, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| ) -> Option<( |
| Span, |
| String, |
| String, |
| Applicability, |
| bool, /* verbose */ |
| bool, /* suggest `&` or `&mut` type annotation */ |
| )> { |
| let sess = self.sess(); |
| let sp = expr.span; |
| |
| // If the span is from an external macro, there's no suggestion we can make. |
| if in_external_macro(sess, sp) { |
| return None; |
| } |
| |
| let sm = sess.source_map(); |
| |
| let replace_prefix = |s: &str, old: &str, new: &str| { |
| s.strip_prefix(old).map(|stripped| new.to_string() + stripped) |
| }; |
| |
| // `ExprKind::DropTemps` is semantically irrelevant for these suggestions. |
| let expr = expr.peel_drop_temps(); |
| |
| match (&expr.kind, expected.kind(), checked_ty.kind()) { |
| (_, &ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (exp.kind(), check.kind()) { |
| (&ty::Str, &ty::Array(arr, _) | &ty::Slice(arr)) if arr == self.tcx.types.u8 => { |
| if let hir::ExprKind::Lit(_) = expr.kind |
| && let Ok(src) = sm.span_to_snippet(sp) |
| && replace_prefix(&src, "b\"", "\"").is_some() |
| { |
| let pos = sp.lo() + BytePos(1); |
| return Some(( |
| sp.with_hi(pos), |
| "consider removing the leading `b`".to_string(), |
| String::new(), |
| Applicability::MachineApplicable, |
| true, |
| false, |
| )); |
| } |
| } |
| (&ty::Array(arr, _) | &ty::Slice(arr), &ty::Str) if arr == self.tcx.types.u8 => { |
| if let hir::ExprKind::Lit(_) = expr.kind |
| && let Ok(src) = sm.span_to_snippet(sp) |
| && replace_prefix(&src, "\"", "b\"").is_some() |
| { |
| return Some(( |
| sp.shrink_to_lo(), |
| "consider adding a leading `b`".to_string(), |
| "b".to_string(), |
| Applicability::MachineApplicable, |
| true, |
| false, |
| )); |
| } |
| } |
| _ => {} |
| }, |
| (_, &ty::Ref(_, _, mutability), _) => { |
| // Check if it can work when put into a ref. For example: |
| // |
| // ``` |
| // fn bar(x: &mut i32) {} |
| // |
| // let x = 0u32; |
| // bar(&x); // error, expected &mut |
| // ``` |
| let ref_ty = match mutability { |
| hir::Mutability::Mut => { |
| self.tcx.mk_mut_ref(self.tcx.lifetimes.re_static, checked_ty) |
| } |
| hir::Mutability::Not => { |
| self.tcx.mk_imm_ref(self.tcx.lifetimes.re_static, checked_ty) |
| } |
| }; |
| if self.can_coerce(ref_ty, expected) { |
| let mut sugg_sp = sp; |
| if let hir::ExprKind::MethodCall(ref segment, receiver, args, _) = expr.kind { |
| let clone_trait = |
| self.tcx.require_lang_item(LangItem::Clone, Some(segment.ident.span)); |
| if args.is_empty() |
| && self.typeck_results.borrow().type_dependent_def_id(expr.hir_id).map( |
| |did| { |
| let ai = self.tcx.associated_item(did); |
| ai.trait_container(self.tcx) == Some(clone_trait) |
| }, |
| ) == Some(true) |
| && segment.ident.name == sym::clone |
| { |
| // If this expression had a clone call when suggesting borrowing |
| // we want to suggest removing it because it'd now be unnecessary. |
| sugg_sp = receiver.span; |
| } |
| } |
| |
| if let hir::ExprKind::Unary(hir::UnOp::Deref, ref inner) = expr.kind |
| && let Some(1) = self.deref_steps(expected, checked_ty) { |
| // We have `*&T`, check if what was expected was `&T`. |
| // If so, we may want to suggest removing a `*`. |
| sugg_sp = sugg_sp.with_hi(inner.span.lo()); |
| return Some(( |
| sugg_sp, |
| "consider removing deref here".to_string(), |
| "".to_string(), |
| Applicability::MachineApplicable, |
| true, |
| false, |
| )); |
| } |
| |
| if let Ok(src) = sm.span_to_snippet(sugg_sp) { |
| let needs_parens = match expr.kind { |
| // parenthesize if needed (Issue #46756) |
| hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true, |
| // parenthesize borrows of range literals (Issue #54505) |
| _ if is_range_literal(expr) => true, |
| _ => false, |
| }; |
| |
| if let Some(sugg) = self.can_use_as_ref(expr) { |
| return Some(( |
| sugg.0, |
| sugg.1.to_string(), |
| sugg.2, |
| Applicability::MachineApplicable, |
| false, |
| false, |
| )); |
| } |
| |
| let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { |
| Some(ident) => format!("{ident}: "), |
| None => String::new(), |
| }; |
| |
| if let Some(hir::Node::Expr(hir::Expr { |
| kind: hir::ExprKind::Assign(..), |
| .. |
| })) = self.tcx.hir().find_parent(expr.hir_id) |
| { |
| if mutability.is_mut() { |
| // Suppressing this diagnostic, we'll properly print it in `check_expr_assign` |
| return None; |
| } |
| } |
| |
| let sugg_expr = if needs_parens { format!("({src})") } else { src }; |
| return Some(( |
| sp, |
| format!("consider {}borrowing here", mutability.mutably_str()), |
| format!("{prefix}{}{sugg_expr}", mutability.ref_prefix_str()), |
| Applicability::MachineApplicable, |
| false, |
| false, |
| )); |
| } |
| } |
| } |
| ( |
| hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, ref expr), |
| _, |
| &ty::Ref(_, checked, _), |
| ) if self.can_sub(self.param_env, checked, expected) => { |
| // We have `&T`, check if what was expected was `T`. If so, |
| // we may want to suggest removing a `&`. |
| if sm.is_imported(expr.span) { |
| // Go through the spans from which this span was expanded, |
| // and find the one that's pointing inside `sp`. |
| // |
| // E.g. for `&format!("")`, where we want the span to the |
| // `format!()` invocation instead of its expansion. |
| if let Some(call_span) = |
| iter::successors(Some(expr.span), |s| s.parent_callsite()) |
| .find(|&s| sp.contains(s)) |
| && sm.is_span_accessible(call_span) |
| { |
| return Some(( |
| sp.with_hi(call_span.lo()), |
| "consider removing the borrow".to_string(), |
| String::new(), |
| Applicability::MachineApplicable, |
| true, |
| true |
| )); |
| } |
| return None; |
| } |
| if sp.contains(expr.span) |
| && sm.is_span_accessible(expr.span) |
| { |
| return Some(( |
| sp.with_hi(expr.span.lo()), |
| "consider removing the borrow".to_string(), |
| String::new(), |
| Applicability::MachineApplicable, |
| true, |
| true, |
| )); |
| } |
| } |
| ( |
| _, |
| &ty::RawPtr(TypeAndMut { ty: ty_b, mutbl: mutbl_b }), |
| &ty::Ref(_, ty_a, mutbl_a), |
| ) => { |
| if let Some(steps) = self.deref_steps(ty_a, ty_b) |
| // Only suggest valid if dereferencing needed. |
| && steps > 0 |
| // The pointer type implements `Copy` trait so the suggestion is always valid. |
| && let Ok(src) = sm.span_to_snippet(sp) |
| { |
| let derefs = "*".repeat(steps); |
| let old_prefix = mutbl_a.ref_prefix_str(); |
| let new_prefix = mutbl_b.ref_prefix_str().to_owned() + &derefs; |
| |
| let suggestion = replace_prefix(&src, old_prefix, &new_prefix).map(|_| { |
| // skip `&` or `&mut ` if both mutabilities are mutable |
| let lo = sp.lo() + BytePos(min(old_prefix.len(), mutbl_b.ref_prefix_str().len()) as _); |
| // skip `&` or `&mut ` |
| let hi = sp.lo() + BytePos(old_prefix.len() as _); |
| let sp = sp.with_lo(lo).with_hi(hi); |
| |
| ( |
| sp, |
| format!("{}{derefs}", if mutbl_a != mutbl_b { mutbl_b.prefix_str() } else { "" }), |
| if mutbl_b <= mutbl_a { Applicability::MachineApplicable } else { Applicability::MaybeIncorrect } |
| ) |
| }); |
| |
| if let Some((span, src, applicability)) = suggestion { |
| return Some(( |
| span, |
| "consider dereferencing".to_string(), |
| src, |
| applicability, |
| true, |
| false, |
| )); |
| } |
| } |
| } |
| _ if sp == expr.span => { |
| if let Some(mut steps) = self.deref_steps(checked_ty, expected) { |
| let mut expr = expr.peel_blocks(); |
| let mut prefix_span = expr.span.shrink_to_lo(); |
| let mut remove = String::new(); |
| |
| // Try peeling off any existing `&` and `&mut` to reach our target type |
| while steps > 0 { |
| if let hir::ExprKind::AddrOf(_, mutbl, inner) = expr.kind { |
| // If the expression has `&`, removing it would fix the error |
| prefix_span = prefix_span.with_hi(inner.span.lo()); |
| expr = inner; |
| remove.push_str(mutbl.ref_prefix_str()); |
| steps -= 1; |
| } else { |
| break; |
| } |
| } |
| // If we've reached our target type with just removing `&`, then just print now. |
| if steps == 0 && !remove.trim().is_empty() { |
| return Some(( |
| prefix_span, |
| format!("consider removing the `{}`", remove.trim()), |
| String::new(), |
| // Do not remove `&&` to get to bool, because it might be something like |
| // { a } && b, which we have a separate fixup suggestion that is more |
| // likely correct... |
| if remove.trim() == "&&" && expected == self.tcx.types.bool { |
| Applicability::MaybeIncorrect |
| } else { |
| Applicability::MachineApplicable |
| }, |
| true, |
| false, |
| )); |
| } |
| |
| // For this suggestion to make sense, the type would need to be `Copy`, |
| // or we have to be moving out of a `Box<T>` |
| if self.type_is_copy_modulo_regions(self.param_env, expected, sp) |
| // FIXME(compiler-errors): We can actually do this if the checked_ty is |
| // `steps` layers of boxes, not just one, but this is easier and most likely. |
| || (checked_ty.is_box() && steps == 1) |
| { |
| let deref_kind = if checked_ty.is_box() { |
| "unboxing the value" |
| } else if checked_ty.is_region_ptr() { |
| "dereferencing the borrow" |
| } else { |
| "dereferencing the type" |
| }; |
| |
| // Suggest removing `&` if we have removed any, otherwise suggest just |
| // dereferencing the remaining number of steps. |
| let message = if remove.is_empty() { |
| format!("consider {deref_kind}") |
| } else { |
| format!( |
| "consider removing the `{}` and {} instead", |
| remove.trim(), |
| deref_kind |
| ) |
| }; |
| |
| let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { |
| Some(ident) => format!("{ident}: "), |
| None => String::new(), |
| }; |
| |
| let (span, suggestion) = if self.is_else_if_block(expr) { |
| // Don't suggest nonsense like `else *if` |
| return None; |
| } else if let Some(expr) = self.maybe_get_block_expr(expr) { |
| // prefix should be empty here.. |
| (expr.span.shrink_to_lo(), "*".to_string()) |
| } else { |
| (prefix_span, format!("{}{}", prefix, "*".repeat(steps))) |
| }; |
| if suggestion.trim().is_empty() { |
| return None; |
| } |
| |
| return Some(( |
| span, |
| message, |
| suggestion, |
| Applicability::MachineApplicable, |
| true, |
| false, |
| )); |
| } |
| } |
| } |
| _ => {} |
| } |
| None |
| } |
| |
| pub fn check_for_cast( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| checked_ty: Ty<'tcx>, |
| expected_ty: Ty<'tcx>, |
| expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
| ) -> bool { |
| if self.tcx.sess.source_map().is_imported(expr.span) { |
| // Ignore if span is from within a macro. |
| return false; |
| } |
| |
| let Ok(src) = self.tcx.sess.source_map().span_to_snippet(expr.span) else { |
| return false; |
| }; |
| |
| // If casting this expression to a given numeric type would be appropriate in case of a type |
| // mismatch. |
| // |
| // We want to minimize the amount of casting operations that are suggested, as it can be a |
| // lossy operation with potentially bad side effects, so we only suggest when encountering |
| // an expression that indicates that the original type couldn't be directly changed. |
| // |
| // For now, don't suggest casting with `as`. |
| let can_cast = false; |
| |
| let mut sugg = vec![]; |
| |
| if let Some(hir::Node::ExprField(field)) = self.tcx.hir().find_parent(expr.hir_id) { |
| // `expr` is a literal field for a struct, only suggest if appropriate |
| if field.is_shorthand { |
| // This is a field literal |
| sugg.push((field.ident.span.shrink_to_lo(), format!("{}: ", field.ident))); |
| } else { |
| // Likely a field was meant, but this field wasn't found. Do not suggest anything. |
| return false; |
| } |
| }; |
| |
| if let hir::ExprKind::Call(path, args) = &expr.kind |
| && let (hir::ExprKind::Path(hir::QPath::TypeRelative(base_ty, path_segment)), 1) = |
| (&path.kind, args.len()) |
| // `expr` is a conversion like `u32::from(val)`, do not suggest anything (#63697). |
| && let (hir::TyKind::Path(hir::QPath::Resolved(None, base_ty_path)), sym::from) = |
| (&base_ty.kind, path_segment.ident.name) |
| { |
| if let Some(ident) = &base_ty_path.segments.iter().map(|s| s.ident).next() { |
| match ident.name { |
| sym::i128 |
| | sym::i64 |
| | sym::i32 |
| | sym::i16 |
| | sym::i8 |
| | sym::u128 |
| | sym::u64 |
| | sym::u32 |
| | sym::u16 |
| | sym::u8 |
| | sym::isize |
| | sym::usize |
| if base_ty_path.segments.len() == 1 => |
| { |
| return false; |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| let msg = format!( |
| "you can convert {} `{}` to {} `{}`", |
| checked_ty.kind().article(), |
| checked_ty, |
| expected_ty.kind().article(), |
| expected_ty, |
| ); |
| let cast_msg = format!( |
| "you can cast {} `{}` to {} `{}`", |
| checked_ty.kind().article(), |
| checked_ty, |
| expected_ty.kind().article(), |
| expected_ty, |
| ); |
| let lit_msg = format!( |
| "change the type of the numeric literal from `{checked_ty}` to `{expected_ty}`", |
| ); |
| |
| let close_paren = if expr.precedence().order() < PREC_POSTFIX { |
| sugg.push((expr.span.shrink_to_lo(), "(".to_string())); |
| ")" |
| } else { |
| "" |
| }; |
| |
| let mut cast_suggestion = sugg.clone(); |
| cast_suggestion.push((expr.span.shrink_to_hi(), format!("{close_paren} as {expected_ty}"))); |
| let mut into_suggestion = sugg.clone(); |
| into_suggestion.push((expr.span.shrink_to_hi(), format!("{close_paren}.into()"))); |
| let mut suffix_suggestion = sugg.clone(); |
| suffix_suggestion.push(( |
| if matches!( |
| (&expected_ty.kind(), &checked_ty.kind()), |
| (ty::Int(_) | ty::Uint(_), ty::Float(_)) |
| ) { |
| // Remove fractional part from literal, for example `42.0f32` into `42` |
| let src = src.trim_end_matches(&checked_ty.to_string()); |
| let len = src.split('.').next().unwrap().len(); |
| expr.span.with_lo(expr.span.lo() + BytePos(len as u32)) |
| } else { |
| let len = src.trim_end_matches(&checked_ty.to_string()).len(); |
| expr.span.with_lo(expr.span.lo() + BytePos(len as u32)) |
| }, |
| if expr.precedence().order() < PREC_POSTFIX { |
| // Readd `)` |
| format!("{expected_ty})") |
| } else { |
| expected_ty.to_string() |
| }, |
| )); |
| let literal_is_ty_suffixed = |expr: &hir::Expr<'_>| { |
| if let hir::ExprKind::Lit(lit) = &expr.kind { lit.node.is_suffixed() } else { false } |
| }; |
| let is_negative_int = |
| |expr: &hir::Expr<'_>| matches!(expr.kind, hir::ExprKind::Unary(hir::UnOp::Neg, ..)); |
| let is_uint = |ty: Ty<'_>| matches!(ty.kind(), ty::Uint(..)); |
| |
| let in_const_context = self.tcx.hir().is_inside_const_context(expr.hir_id); |
| |
| let suggest_fallible_into_or_lhs_from = |
| |err: &mut Diagnostic, exp_to_found_is_fallible: bool| { |
| // If we know the expression the expected type is derived from, we might be able |
| // to suggest a widening conversion rather than a narrowing one (which may |
| // panic). For example, given x: u8 and y: u32, if we know the span of "x", |
| // x > y |
| // can be given the suggestion "u32::from(x) > y" rather than |
| // "x > y.try_into().unwrap()". |
| let lhs_expr_and_src = expected_ty_expr.and_then(|expr| { |
| self.tcx |
| .sess |
| .source_map() |
| .span_to_snippet(expr.span) |
| .ok() |
| .map(|src| (expr, src)) |
| }); |
| let (msg, suggestion) = if let (Some((lhs_expr, lhs_src)), false) = |
| (lhs_expr_and_src, exp_to_found_is_fallible) |
| { |
| let msg = format!( |
| "you can convert `{lhs_src}` from `{expected_ty}` to `{checked_ty}`, matching the type of `{src}`", |
| ); |
| let suggestion = vec![ |
| (lhs_expr.span.shrink_to_lo(), format!("{checked_ty}::from(")), |
| (lhs_expr.span.shrink_to_hi(), ")".to_string()), |
| ]; |
| (msg, suggestion) |
| } else { |
| let msg = format!("{msg} and panic if the converted value doesn't fit"); |
| let mut suggestion = sugg.clone(); |
| suggestion.push(( |
| expr.span.shrink_to_hi(), |
| format!("{close_paren}.try_into().unwrap()"), |
| )); |
| (msg, suggestion) |
| }; |
| err.multipart_suggestion_verbose( |
| &msg, |
| suggestion, |
| Applicability::MachineApplicable, |
| ); |
| }; |
| |
| let suggest_to_change_suffix_or_into = |
| |err: &mut Diagnostic, |
| found_to_exp_is_fallible: bool, |
| exp_to_found_is_fallible: bool| { |
| let exp_is_lhs = |
| expected_ty_expr.map(|e| self.tcx.hir().is_lhs(e.hir_id)).unwrap_or(false); |
| |
| if exp_is_lhs { |
| return; |
| } |
| |
| let always_fallible = found_to_exp_is_fallible |
| && (exp_to_found_is_fallible || expected_ty_expr.is_none()); |
| let msg = if literal_is_ty_suffixed(expr) { |
| &lit_msg |
| } else if always_fallible && (is_negative_int(expr) && is_uint(expected_ty)) { |
| // We now know that converting either the lhs or rhs is fallible. Before we |
| // suggest a fallible conversion, check if the value can never fit in the |
| // expected type. |
| let msg = format!("`{src}` cannot fit into type `{expected_ty}`"); |
| err.note(&msg); |
| return; |
| } else if in_const_context { |
| // Do not recommend `into` or `try_into` in const contexts. |
| return; |
| } else if found_to_exp_is_fallible { |
| return suggest_fallible_into_or_lhs_from(err, exp_to_found_is_fallible); |
| } else { |
| &msg |
| }; |
| let suggestion = if literal_is_ty_suffixed(expr) { |
| suffix_suggestion.clone() |
| } else { |
| into_suggestion.clone() |
| }; |
| err.multipart_suggestion_verbose(msg, suggestion, Applicability::MachineApplicable); |
| }; |
| |
| match (&expected_ty.kind(), &checked_ty.kind()) { |
| (ty::Int(exp), ty::Int(found)) => { |
| let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) |
| { |
| (Some(exp), Some(found)) if exp < found => (true, false), |
| (Some(exp), Some(found)) if exp > found => (false, true), |
| (None, Some(8 | 16)) => (false, true), |
| (Some(8 | 16), None) => (true, false), |
| (None, _) | (_, None) => (true, true), |
| _ => (false, false), |
| }; |
| suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); |
| true |
| } |
| (ty::Uint(exp), ty::Uint(found)) => { |
| let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) |
| { |
| (Some(exp), Some(found)) if exp < found => (true, false), |
| (Some(exp), Some(found)) if exp > found => (false, true), |
| (None, Some(8 | 16)) => (false, true), |
| (Some(8 | 16), None) => (true, false), |
| (None, _) | (_, None) => (true, true), |
| _ => (false, false), |
| }; |
| suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); |
| true |
| } |
| (&ty::Int(exp), &ty::Uint(found)) => { |
| let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) |
| { |
| (Some(exp), Some(found)) if found < exp => (false, true), |
| (None, Some(8)) => (false, true), |
| _ => (true, true), |
| }; |
| suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); |
| true |
| } |
| (&ty::Uint(exp), &ty::Int(found)) => { |
| let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) |
| { |
| (Some(exp), Some(found)) if found > exp => (true, false), |
| (Some(8), None) => (true, false), |
| _ => (true, true), |
| }; |
| suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); |
| true |
| } |
| (ty::Float(exp), ty::Float(found)) => { |
| if found.bit_width() < exp.bit_width() { |
| suggest_to_change_suffix_or_into(err, false, true); |
| } else if literal_is_ty_suffixed(expr) { |
| err.multipart_suggestion_verbose( |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if can_cast { |
| // Missing try_into implementation for `f64` to `f32` |
| err.multipart_suggestion_verbose( |
| &format!("{cast_msg}, producing the closest possible value"), |
| cast_suggestion, |
| Applicability::MaybeIncorrect, // lossy conversion |
| ); |
| } |
| true |
| } |
| (&ty::Uint(_) | &ty::Int(_), &ty::Float(_)) => { |
| if literal_is_ty_suffixed(expr) { |
| err.multipart_suggestion_verbose( |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if can_cast { |
| // Missing try_into implementation for `{float}` to `{integer}` |
| err.multipart_suggestion_verbose( |
| &format!("{msg}, rounding the float towards zero"), |
| cast_suggestion, |
| Applicability::MaybeIncorrect, // lossy conversion |
| ); |
| } |
| true |
| } |
| (ty::Float(exp), ty::Uint(found)) => { |
| // if `found` is `None` (meaning found is `usize`), don't suggest `.into()` |
| if exp.bit_width() > found.bit_width().unwrap_or(256) { |
| err.multipart_suggestion_verbose( |
| &format!( |
| "{msg}, producing the floating point representation of the integer", |
| ), |
| into_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if literal_is_ty_suffixed(expr) { |
| err.multipart_suggestion_verbose( |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| // Missing try_into implementation for `{integer}` to `{float}` |
| err.multipart_suggestion_verbose( |
| &format!( |
| "{cast_msg}, producing the floating point representation of the integer, \ |
| rounded if necessary", |
| ), |
| cast_suggestion, |
| Applicability::MaybeIncorrect, // lossy conversion |
| ); |
| } |
| true |
| } |
| (ty::Float(exp), ty::Int(found)) => { |
| // if `found` is `None` (meaning found is `isize`), don't suggest `.into()` |
| if exp.bit_width() > found.bit_width().unwrap_or(256) { |
| err.multipart_suggestion_verbose( |
| &format!( |
| "{}, producing the floating point representation of the integer", |
| &msg, |
| ), |
| into_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if literal_is_ty_suffixed(expr) { |
| err.multipart_suggestion_verbose( |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| // Missing try_into implementation for `{integer}` to `{float}` |
| err.multipart_suggestion_verbose( |
| &format!( |
| "{}, producing the floating point representation of the integer, \ |
| rounded if necessary", |
| &msg, |
| ), |
| cast_suggestion, |
| Applicability::MaybeIncorrect, // lossy conversion |
| ); |
| } |
| true |
| } |
| ( |
| &ty::Uint(ty::UintTy::U32 | ty::UintTy::U64 | ty::UintTy::U128) |
| | &ty::Int(ty::IntTy::I32 | ty::IntTy::I64 | ty::IntTy::I128), |
| &ty::Char, |
| ) => { |
| err.multipart_suggestion_verbose( |
| &format!("{cast_msg}, since a `char` always occupies 4 bytes"), |
| cast_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| true |
| } |
| _ => false, |
| } |
| } |
| |
| /// Identify when the user has written `foo..bar()` instead of `foo.bar()`. |
| pub fn check_for_range_as_method_call( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'tcx>, |
| checked_ty: Ty<'tcx>, |
| expected_ty: Ty<'tcx>, |
| ) { |
| if !hir::is_range_literal(expr) { |
| return; |
| } |
| let hir::ExprKind::Struct( |
| hir::QPath::LangItem(LangItem::Range, ..), |
| [start, end], |
| _, |
| ) = expr.kind else { return; }; |
| let parent = self.tcx.hir().parent_id(expr.hir_id); |
| if let Some(hir::Node::ExprField(_)) = self.tcx.hir().find(parent) { |
| // Ignore `Foo { field: a..Default::default() }` |
| return; |
| } |
| let mut expr = end.expr; |
| let mut expectation = Some(expected_ty); |
| while let hir::ExprKind::MethodCall(_, rcvr, ..) = expr.kind { |
| // Getting to the root receiver and asserting it is a fn call let's us ignore cases in |
| // `tests/ui/methods/issues/issue-90315.stderr`. |
| expr = rcvr; |
| // If we have more than one layer of calls, then the expected ty |
| // cannot guide the method probe. |
| expectation = None; |
| } |
| let hir::ExprKind::Call(method_name, _) = expr.kind else { return; }; |
| let ty::Adt(adt, _) = checked_ty.kind() else { return; }; |
| if self.tcx.lang_items().range_struct() != Some(adt.did()) { |
| return; |
| } |
| if let ty::Adt(adt, _) = expected_ty.kind() |
| && self.tcx.lang_items().range_struct() == Some(adt.did()) |
| { |
| return; |
| } |
| // Check if start has method named end. |
| let hir::ExprKind::Path(hir::QPath::Resolved(None, p)) = method_name.kind else { return; }; |
| let [hir::PathSegment { ident, .. }] = p.segments else { return; }; |
| let self_ty = self.typeck_results.borrow().expr_ty(start.expr); |
| let Ok(_pick) = self.lookup_probe_for_diagnostic( |
| *ident, |
| self_ty, |
| expr, |
| probe::ProbeScope::AllTraits, |
| expectation, |
| ) else { return; }; |
| let mut sugg = "."; |
| let mut span = start.expr.span.between(end.expr.span); |
| if span.lo() + BytePos(2) == span.hi() { |
| // There's no space between the start, the range op and the end, suggest removal which |
| // will be more noticeable than the replacement of `..` with `.`. |
| span = span.with_lo(span.lo() + BytePos(1)); |
| sugg = ""; |
| } |
| err.span_suggestion_verbose( |
| span, |
| "you likely meant to write a method call instead of a range", |
| sugg, |
| Applicability::MachineApplicable, |
| ); |
| } |
| |
| /// Identify when the type error is because `()` is found in a binding that was assigned a |
| /// block without a tail expression. |
| fn check_for_binding_assigned_block_without_tail_expression( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| checked_ty: Ty<'tcx>, |
| expected_ty: Ty<'tcx>, |
| ) { |
| if !checked_ty.is_unit() { |
| return; |
| } |
| let hir::ExprKind::Path(hir::QPath::Resolved(None, path)) = expr.kind else { return; }; |
| let hir::def::Res::Local(hir_id) = path.res else { return; }; |
| let Some(hir::Node::Pat(pat)) = self.tcx.hir().find(hir_id) else { |
| return; |
| }; |
| let Some(hir::Node::Local(hir::Local { |
| ty: None, |
| init: Some(init), |
| .. |
| })) = self.tcx.hir().find_parent(pat.hir_id) else { return; }; |
| let hir::ExprKind::Block(block, None) = init.kind else { return; }; |
| if block.expr.is_some() { |
| return; |
| } |
| let [.., stmt] = block.stmts else { |
| err.span_label(block.span, "this empty block is missing a tail expression"); |
| return; |
| }; |
| let hir::StmtKind::Semi(tail_expr) = stmt.kind else { return; }; |
| let Some(ty) = self.node_ty_opt(tail_expr.hir_id) else { return; }; |
| if self.can_eq(self.param_env, expected_ty, ty) { |
| err.span_suggestion_short( |
| stmt.span.with_lo(tail_expr.span.hi()), |
| "remove this semicolon", |
| "", |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| err.span_label(block.span, "this block is missing a tail expression"); |
| } |
| } |
| |
| fn check_wrong_return_type_due_to_generic_arg( |
| &self, |
| err: &mut Diagnostic, |
| expr: &hir::Expr<'_>, |
| checked_ty: Ty<'tcx>, |
| ) { |
| let Some(hir::Node::Expr(parent_expr)) = self.tcx.hir().find_parent(expr.hir_id) else { return; }; |
| enum CallableKind { |
| Function, |
| Method, |
| Constructor, |
| } |
| let mut maybe_emit_help = |def_id: hir::def_id::DefId, |
| callable: rustc_span::symbol::Ident, |
| args: &[hir::Expr<'_>], |
| kind: CallableKind| { |
| let arg_idx = args.iter().position(|a| a.hir_id == expr.hir_id).unwrap(); |
| let fn_ty = self.tcx.type_of(def_id).skip_binder(); |
| if !fn_ty.is_fn() { |
| return; |
| } |
| let fn_sig = fn_ty.fn_sig(self.tcx).skip_binder(); |
| let Some(&arg) = fn_sig.inputs().get(arg_idx + if matches!(kind, CallableKind::Method) { 1 } else { 0 }) else { return; }; |
| if matches!(arg.kind(), ty::Param(_)) |
| && fn_sig.output().contains(arg) |
| && self.node_ty(args[arg_idx].hir_id) == checked_ty |
| { |
| let mut multi_span: MultiSpan = parent_expr.span.into(); |
| multi_span.push_span_label( |
| args[arg_idx].span, |
| format!( |
| "this argument influences the {} of `{}`", |
| if matches!(kind, CallableKind::Constructor) { |
| "type" |
| } else { |
| "return type" |
| }, |
| callable |
| ), |
| ); |
| err.span_help( |
| multi_span, |
| format!( |
| "the {} `{}` due to the type of the argument passed", |
| match kind { |
| CallableKind::Function => "return type of this call is", |
| CallableKind::Method => "return type of this call is", |
| CallableKind::Constructor => "type constructed contains", |
| }, |
| checked_ty |
| ), |
| ); |
| } |
| }; |
| match parent_expr.kind { |
| hir::ExprKind::Call(fun, args) => { |
| let hir::ExprKind::Path(hir::QPath::Resolved(_, path)) = fun.kind else { return; }; |
| let hir::def::Res::Def(kind, def_id) = path.res else { return; }; |
| let callable_kind = if matches!(kind, hir::def::DefKind::Ctor(_, _)) { |
| CallableKind::Constructor |
| } else { |
| CallableKind::Function |
| }; |
| maybe_emit_help(def_id, path.segments[0].ident, args, callable_kind); |
| } |
| hir::ExprKind::MethodCall(method, _receiver, args, _span) => { |
| let Some(def_id) = self.typeck_results.borrow().type_dependent_def_id(parent_expr.hir_id) else { return; }; |
| maybe_emit_help(def_id, method.ident, args, CallableKind::Method) |
| } |
| _ => return, |
| } |
| } |
| } |
