| use crate::check::FnCtxt; |
| use rustc::infer::InferOk; |
| use rustc::traits::{self, ObligationCause, ObligationCauseCode}; |
| |
| use syntax::symbol::sym; |
| use syntax::util::parser::PREC_POSTFIX; |
| use syntax_pos::Span; |
| use rustc::hir; |
| use rustc::hir::Node; |
| use rustc::hir::{print, lowering::is_range_literal}; |
| use rustc::ty::{self, Ty, AssocItem}; |
| use rustc::ty::adjustment::AllowTwoPhase; |
| use errors::{Applicability, DiagnosticBuilder}; |
| |
| use super::method::probe; |
| |
| impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
| // 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>) { |
| self.demand_suptype_diag(sp, expected, actual).map(|mut e| e.emit()); |
| } |
| |
| pub fn demand_suptype_diag(&self, |
| sp: Span, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>) -> Option<DiagnosticBuilder<'tcx>> { |
| let cause = &self.misc(sp); |
| match self.at(cause, self.param_env).sup(expected, actual) { |
| Ok(InferOk { obligations, value: () }) => { |
| self.register_predicates(obligations); |
| None |
| }, |
| Err(e) => { |
| Some(self.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>> { |
| 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>> { |
| match self.at(cause, self.param_env).eq(expected, actual) { |
| Ok(InferOk { obligations, value: () }) => { |
| self.register_predicates(obligations); |
| None |
| } |
| Err(e) => { |
| Some(self.report_mismatched_types(cause, expected, actual, e)) |
| } |
| } |
| } |
| |
| pub fn demand_eqtype_pat( |
| &self, |
| cause_span: Span, |
| expected: Ty<'tcx>, |
| actual: Ty<'tcx>, |
| match_expr_span: Option<Span>, |
| ) { |
| let cause = if let Some(span) = match_expr_span { |
| self.cause( |
| cause_span, |
| ObligationCauseCode::MatchExpressionArmPattern { span, ty: expected }, |
| ) |
| } else { |
| self.misc(cause_span) |
| }; |
| self.demand_eqtype_with_origin(&cause, expected, actual).map(|mut err| err.emit()); |
| } |
| |
| |
| pub fn demand_coerce(&self, |
| expr: &hir::Expr, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| allow_two_phase: AllowTwoPhase) |
| -> Ty<'tcx> { |
| let (ty, err) = self.demand_coerce_diag(expr, checked_ty, expected, 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". |
| pub fn demand_coerce_diag(&self, |
| expr: &hir::Expr, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| allow_two_phase: AllowTwoPhase) |
| -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx>>) { |
| let expected = self.resolve_type_vars_with_obligations(expected); |
| |
| let e = match self.try_coerce(expr, checked_ty, expected, allow_two_phase) { |
| Ok(ty) => return (ty, None), |
| Err(e) => e |
| }; |
| |
| let cause = self.misc(expr.span); |
| let expr_ty = self.resolve_type_vars_with_obligations(checked_ty); |
| let mut err = self.report_mismatched_types(&cause, expected, expr_ty, e); |
| |
| if self.is_assign_to_bool(expr, expected) { |
| // Error reported in `check_assign` so avoid emitting error again. |
| err.delay_as_bug(); |
| return (expected, None) |
| } |
| |
| self.suggest_compatible_variants(&mut err, expr, expected, expr_ty); |
| self.suggest_ref_or_into(&mut err, expr, expected, expr_ty); |
| self.suggest_boxing_when_appropriate(&mut err, expr, expected, expr_ty); |
| self.suggest_missing_await(&mut err, expr, expected, expr_ty); |
| |
| (expected, Some(err)) |
| } |
| |
| /// Returns whether the expected type is `bool` and the expression is `x = y`. |
| pub fn is_assign_to_bool(&self, expr: &hir::Expr, expected: Ty<'tcx>) -> bool { |
| if let hir::ExprKind::Assign(..) = expr.node { |
| return expected == self.tcx.types.bool; |
| } |
| 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 DiagnosticBuilder<'_>, |
| expr: &hir::Expr, |
| expected: Ty<'tcx>, |
| expr_ty: Ty<'tcx>, |
| ) { |
| if let ty::Adt(expected_adt, substs) = expected.sty { |
| if !expected_adt.is_enum() { |
| return; |
| } |
| |
| let mut compatible_variants = expected_adt.variants |
| .iter() |
| .filter(|variant| variant.fields.len() == 1) |
| .filter_map(|variant| { |
| let sole_field = &variant.fields[0]; |
| let sole_field_ty = sole_field.ty(self.tcx, substs); |
| if self.can_coerce(expr_ty, sole_field_ty) { |
| let variant_path = self.tcx.def_path_str(variant.def_id); |
| // FIXME #56861: DRYer prelude filtering |
| Some(variant_path.trim_start_matches("std::prelude::v1::").to_string()) |
| } else { |
| None |
| } |
| }).peekable(); |
| |
| if compatible_variants.peek().is_some() { |
| let expr_text = print::to_string(print::NO_ANN, |s| s.print_expr(expr)); |
| let suggestions = compatible_variants |
| .map(|v| format!("{}({})", v, expr_text)); |
| let msg = "try using a variant of the expected type"; |
| err.span_suggestions(expr.span, msg, suggestions, Applicability::MaybeIncorrect); |
| } |
| } |
| } |
| |
| pub fn get_conversion_methods(&self, span: Span, expected: Ty<'tcx>, checked_ty: Ty<'tcx>) |
| -> Vec<AssocItem> { |
| let mut methods = self.probe_for_return_type(span, |
| probe::Mode::MethodCall, |
| expected, |
| checked_ty, |
| hir::DUMMY_HIR_ID); |
| methods.retain(|m| { |
| self.has_no_input_arg(m) && |
| self.tcx.get_attrs(m.def_id).iter() |
| // This special internal attribute is used to whitelist |
| // "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`? |
| .find(|a| a.check_name(sym::rustc_conversion_suggestion)).is_some() |
| }); |
| |
| methods |
| } |
| |
| // This function checks if the method isn't static and takes other arguments than `self`. |
| fn has_no_input_arg(&self, method: &AssocItem) -> bool { |
| match method.kind { |
| ty::AssocKind::Method => { |
| self.tcx.fn_sig(method.def_id).inputs().skip_binder().len() == 1 |
| } |
| _ => false, |
| } |
| } |
| |
| /// Identify some cases where `as_ref()` would be appropriate and suggest it. |
| /// |
| /// Given the following code: |
| /// ``` |
| /// struct Foo; |
| /// fn takes_ref(_: &Foo) {} |
| /// let ref opt = Some(Foo); |
| /// |
| /// opt.map(|arg| takes_ref(arg)); |
| /// ``` |
| /// Suggest using `opt.as_ref().map(|arg| takes_ref(arg));` instead. |
| /// |
| /// It only checks for `Option` and `Result` and won't work with |
| /// ``` |
| /// opt.map(|arg| { takes_ref(arg) }); |
| /// ``` |
| fn can_use_as_ref( |
| &self, |
| expr: &hir::Expr, |
| ) -> Option<(Span, &'static str, String)> { |
| let path = match expr.node { |
| hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) => path, |
| _ => return None |
| }; |
| |
| let local_id = match path.res { |
| hir::def::Res::Local(id) => id, |
| _ => return None |
| }; |
| |
| let local_parent = self.tcx.hir().get_parent_node(local_id); |
| let arg_hir_id = match self.tcx.hir().find(local_parent) { |
| Some(Node::Arg(hir::Arg { hir_id, .. })) => hir_id, |
| _ => return None |
| }; |
| |
| let arg_parent = self.tcx.hir().get_parent_node(*arg_hir_id); |
| let (expr_hir_id, closure_fn_decl) = match self.tcx.hir().find(arg_parent) { |
| Some(Node::Expr( |
| hir::Expr { hir_id, node: hir::ExprKind::Closure(_, decl, ..), .. } |
| )) => (hir_id, decl), |
| _ => return None |
| }; |
| |
| let expr_parent = self.tcx.hir().get_parent_node(*expr_hir_id); |
| let hir = self.tcx.hir().find(expr_parent); |
| let closure_params_len = closure_fn_decl.inputs.len(); |
| let (method_path, method_span, method_expr) = match (hir, closure_params_len) { |
| (Some(Node::Expr( |
| hir::Expr { node: hir::ExprKind::MethodCall(path, span, expr), .. } |
| )), 1) => (path, span, expr), |
| _ => return None |
| }; |
| |
| let self_ty = self.tables.borrow().node_type(method_expr[0].hir_id); |
| let self_ty = format!("{:?}", self_ty); |
| let name = method_path.ident.as_str(); |
| let is_as_ref_able = ( |
| self_ty.starts_with("&std::option::Option") || |
| self_ty.starts_with("&std::result::Result") || |
| self_ty.starts_with("std::option::Option") || |
| self_ty.starts_with("std::result::Result") |
| ) && (name == "map" || name == "and_then"); |
| match (is_as_ref_able, self.sess().source_map().span_to_snippet(*method_span)) { |
| (true, Ok(src)) => { |
| let suggestion = format!("as_ref().{}", src); |
| Some((*method_span, "consider using `as_ref` instead", suggestion)) |
| }, |
| _ => None |
| } |
| } |
| |
| crate fn is_hir_id_from_struct_pattern_shorthand_field( |
| &self, |
| hir_id: hir::HirId, |
| sp: Span, |
| ) -> bool { |
| let cm = self.sess().source_map(); |
| let parent_id = self.tcx.hir().get_parent_node(hir_id); |
| if let Some(parent) = self.tcx.hir().find(parent_id) { |
| // Account for fields |
| if let Node::Expr(hir::Expr { |
| node: hir::ExprKind::Struct(_, fields, ..), .. |
| }) = parent { |
| if let Ok(src) = cm.span_to_snippet(sp) { |
| for field in fields { |
| if field.ident.as_str() == src.as_str() && field.is_shorthand { |
| return true; |
| } |
| } |
| } |
| } |
| } |
| false |
| } |
| |
| /// This function is used to determine potential "simple" improvements or users' errors and |
| /// provide them useful help. For example: |
| /// |
| /// ``` |
| /// 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, |
| checked_ty: Ty<'tcx>, |
| expected: Ty<'tcx>, |
| ) -> Option<(Span, &'static str, String)> { |
| let cm = self.sess().source_map(); |
| let sp = expr.span; |
| if !cm.span_to_filename(sp).is_real() { |
| // Ignore if span is from within a macro #41858, #58298. We previously used the macro |
| // call span, but that breaks down when the type error comes from multiple calls down. |
| return None; |
| } |
| |
| let is_struct_pat_shorthand_field = self.is_hir_id_from_struct_pattern_shorthand_field( |
| expr.hir_id, |
| sp, |
| ); |
| |
| // Check the `expn_info()` to see if this is a macro; if so, it's hard to |
| // extract the text and make a good suggestion, so don't bother. |
| let is_macro = sp.ctxt().outer_expn_info().is_some(); |
| |
| match (&expr.node, &expected.sty, &checked_ty.sty) { |
| (_, &ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (&exp.sty, &check.sty) { |
| (&ty::Str, &ty::Array(arr, _)) | |
| (&ty::Str, &ty::Slice(arr)) if arr == self.tcx.types.u8 => { |
| if let hir::ExprKind::Lit(_) = expr.node { |
| if let Ok(src) = cm.span_to_snippet(sp) { |
| if src.starts_with("b\"") { |
| return Some((sp, |
| "consider removing the leading `b`", |
| src[1..].to_string())); |
| } |
| } |
| } |
| }, |
| (&ty::Array(arr, _), &ty::Str) | |
| (&ty::Slice(arr), &ty::Str) if arr == self.tcx.types.u8 => { |
| if let hir::ExprKind::Lit(_) = expr.node { |
| if let Ok(src) = cm.span_to_snippet(sp) { |
| if src.starts_with("\"") { |
| return Some((sp, |
| "consider adding a leading `b`", |
| format!("b{}", src))); |
| } |
| } |
| } |
| } |
| _ => {} |
| }, |
| (_, &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::MutMutable => { |
| self.tcx.mk_mut_ref(self.tcx.mk_region(ty::ReStatic), checked_ty) |
| } |
| hir::Mutability::MutImmutable => { |
| self.tcx.mk_imm_ref(self.tcx.mk_region(ty::ReStatic), checked_ty) |
| } |
| }; |
| if self.can_coerce(ref_ty, expected) { |
| let mut sugg_sp = sp; |
| if let hir::ExprKind::MethodCall(segment, _sp, args) = &expr.node { |
| let clone_trait = self.tcx.lang_items().clone_trait().unwrap(); |
| if let ([arg], Some(true), "clone") = ( |
| &args[..], |
| self.tables.borrow().type_dependent_def_id(expr.hir_id).map(|did| { |
| let ai = self.tcx.associated_item(did); |
| ai.container == ty::TraitContainer(clone_trait) |
| }), |
| &segment.ident.as_str()[..], |
| ) { |
| // If this expression had a clone call when suggesting borrowing |
| // we want to suggest removing it because it'd now be unecessary. |
| sugg_sp = arg.span; |
| } |
| } |
| if let Ok(src) = cm.span_to_snippet(sugg_sp) { |
| let needs_parens = match expr.node { |
| // parenthesize if needed (Issue #46756) |
| hir::ExprKind::Cast(_, _) | |
| hir::ExprKind::Binary(_, _, _) => true, |
| // parenthesize borrows of range literals (Issue #54505) |
| _ if is_range_literal(self.tcx.sess, expr) => true, |
| _ => false, |
| }; |
| let sugg_expr = if needs_parens { |
| format!("({})", src) |
| } else { |
| src |
| }; |
| |
| if let Some(sugg) = self.can_use_as_ref(expr) { |
| return Some(sugg); |
| } |
| let field_name = if is_struct_pat_shorthand_field { |
| format!("{}: ", sugg_expr) |
| } else { |
| String::new() |
| }; |
| if let Some(hir::Node::Expr(hir::Expr { |
| node: hir::ExprKind::Assign(left_expr, _), |
| .. |
| })) = self.tcx.hir().find( |
| self.tcx.hir().get_parent_node(expr.hir_id), |
| ) { |
| if mutability == hir::Mutability::MutMutable { |
| // Found the following case: |
| // fn foo(opt: &mut Option<String>){ opt = None } |
| // --- ^^^^ |
| // | | |
| // consider dereferencing here: `*opt` | |
| // expected mutable reference, found enum `Option` |
| if let Ok(src) = cm.span_to_snippet(left_expr.span) { |
| return Some(( |
| left_expr.span, |
| "consider dereferencing here to assign to the mutable \ |
| borrowed piece of memory", |
| format!("*{}", src), |
| )); |
| } |
| } |
| } |
| |
| return Some(match mutability { |
| hir::Mutability::MutMutable => ( |
| sp, |
| "consider mutably borrowing here", |
| format!("{}&mut {}", field_name, sugg_expr), |
| ), |
| hir::Mutability::MutImmutable => ( |
| sp, |
| "consider borrowing here", |
| format!("{}&{}", field_name, sugg_expr), |
| ), |
| }); |
| } |
| } |
| }, |
| (hir::ExprKind::AddrOf(_, ref expr), _, &ty::Ref(_, checked, _)) if { |
| self.infcx.can_sub(self.param_env, checked, &expected).is_ok() && !is_macro |
| } => { |
| // We have `&T`, check if what was expected was `T`. If so, |
| // we may want to suggest removing a `&`. |
| if !cm.span_to_filename(expr.span).is_real() { |
| if let Ok(code) = cm.span_to_snippet(sp) { |
| if code.chars().next() == Some('&') { |
| return Some(( |
| sp, |
| "consider removing the borrow", |
| code[1..].to_string(), |
| )); |
| } |
| } |
| return None; |
| } |
| if let Ok(code) = cm.span_to_snippet(expr.span) { |
| return Some((sp, "consider removing the borrow", code)); |
| } |
| }, |
| _ if sp == expr.span && !is_macro => { |
| // Check for `Deref` implementations by constructing a predicate to |
| // prove: `<T as Deref>::Output == U` |
| let deref_trait = self.tcx.lang_items().deref_trait().unwrap(); |
| let item_def_id = self.tcx.associated_items(deref_trait).next().unwrap().def_id; |
| let predicate = ty::Predicate::Projection(ty::Binder::bind(ty::ProjectionPredicate { |
| // `<T as Deref>::Output` |
| projection_ty: ty::ProjectionTy { |
| // `T` |
| substs: self.tcx.mk_substs_trait( |
| checked_ty, |
| self.fresh_substs_for_item(sp, item_def_id), |
| ), |
| // `Deref::Output` |
| item_def_id, |
| }, |
| // `U` |
| ty: expected, |
| })); |
| let obligation = traits::Obligation::new(self.misc(sp), self.param_env, predicate); |
| let impls_deref = self.infcx.predicate_may_hold(&obligation); |
| |
| // For a suggestion to make sense, the type would need to be `Copy`. |
| let is_copy = self.infcx.type_is_copy_modulo_regions(self.param_env, expected, sp); |
| |
| if is_copy && impls_deref { |
| if let Ok(code) = cm.span_to_snippet(sp) { |
| let message = if checked_ty.is_region_ptr() { |
| "consider dereferencing the borrow" |
| } else { |
| "consider dereferencing the type" |
| }; |
| let suggestion = if is_struct_pat_shorthand_field { |
| format!("{}: *{}", code, code) |
| } else { |
| format!("*{}", code) |
| }; |
| return Some((sp, message, suggestion)); |
| } |
| } |
| } |
| _ => {} |
| } |
| None |
| } |
| |
| pub fn check_for_cast( |
| &self, |
| err: &mut DiagnosticBuilder<'tcx>, |
| expr: &hir::Expr, |
| checked_ty: Ty<'tcx>, |
| expected_ty: Ty<'tcx>, |
| ) -> bool { |
| if self.tcx.hir().is_const_context(expr.hir_id) { |
| // Shouldn't suggest `.into()` on `const`s. |
| // FIXME(estebank): modify once we decide to suggest `as` casts |
| 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 prefix = String::new(); |
| if let Some(hir::Node::Expr(hir::Expr { |
| node: hir::ExprKind::Struct(_, fields, _), |
| .. |
| })) = self.tcx.hir().find(self.tcx.hir().get_parent_node(expr.hir_id)) { |
| // `expr` is a literal field for a struct, only suggest if appropriate |
| for field in fields { |
| if field.expr.hir_id == expr.hir_id && field.is_shorthand { |
| // This is a field literal |
| prefix = format!("{}: ", field.ident); |
| break; |
| } |
| } |
| if &prefix == "" { |
| // Likely a field was meant, but this field wasn't found. Do not suggest anything. |
| return false; |
| } |
| } |
| |
| let msg = format!("you can convert an `{}` to `{}`", checked_ty, expected_ty); |
| let cast_msg = format!("you can cast an `{} to `{}`", checked_ty, expected_ty); |
| let try_msg = format!("{} and panic if the converted value wouldn't fit", msg); |
| let lit_msg = format!( |
| "change the type of the numeric literal from `{}` to `{}`", |
| checked_ty, |
| expected_ty, |
| ); |
| |
| let needs_paren = expr.precedence().order() < (PREC_POSTFIX as i8); |
| |
| if let Ok(src) = self.tcx.sess.source_map().span_to_snippet(expr.span) { |
| let cast_suggestion = format!( |
| "{}{}{}{} as {}", |
| prefix, |
| if needs_paren { "(" } else { "" }, |
| src, |
| if needs_paren { ")" } else { "" }, |
| expected_ty, |
| ); |
| let try_into_suggestion = format!( |
| "{}{}{}{}.try_into().unwrap()", |
| prefix, |
| if needs_paren { "(" } else { "" }, |
| src, |
| if needs_paren { ")" } else { "" }, |
| ); |
| let into_suggestion = format!( |
| "{}{}{}{}.into()", |
| prefix, |
| if needs_paren { "(" } else { "" }, |
| src, |
| if needs_paren { ")" } else { "" }, |
| ); |
| let suffix_suggestion = format!( |
| "{}{}{}{}", |
| if needs_paren { "(" } else { "" }, |
| if let (ty::Int(_), ty::Float(_)) | (ty::Uint(_), ty::Float(_)) = ( |
| &expected_ty.sty, |
| &checked_ty.sty, |
| ) { |
| // Remove fractional part from literal, for example `42.0f32` into `42` |
| let src = src.trim_end_matches(&checked_ty.to_string()); |
| src.split(".").next().unwrap() |
| } else { |
| src.trim_end_matches(&checked_ty.to_string()) |
| }, |
| expected_ty, |
| if needs_paren { ")" } else { "" }, |
| ); |
| let literal_is_ty_suffixed = |expr: &hir::Expr| { |
| if let hir::ExprKind::Lit(lit) = &expr.node { |
| lit.node.is_suffixed() |
| } else { |
| false |
| } |
| }; |
| |
| let suggest_to_change_suffix_or_into = | |
| err: &mut DiagnosticBuilder<'_>, |
| is_fallible: bool, |
| | { |
| let into_sugg = into_suggestion.clone(); |
| err.span_suggestion( |
| expr.span, |
| if literal_is_ty_suffixed(expr) { |
| &lit_msg |
| } else if is_fallible { |
| &try_msg |
| } else { |
| &msg |
| }, |
| if literal_is_ty_suffixed(expr) { |
| suffix_suggestion.clone() |
| } else if is_fallible { |
| try_into_suggestion |
| } else { |
| into_sugg |
| }, |
| Applicability::MachineApplicable, |
| ); |
| }; |
| |
| match (&expected_ty.sty, &checked_ty.sty) { |
| (&ty::Int(ref exp), &ty::Int(ref found)) => { |
| let is_fallible = match (found.bit_width(), exp.bit_width()) { |
| (Some(found), Some(exp)) if found > exp => true, |
| (None, _) | (_, None) => true, |
| _ => false, |
| }; |
| suggest_to_change_suffix_or_into(err, is_fallible); |
| true |
| } |
| (&ty::Uint(ref exp), &ty::Uint(ref found)) => { |
| let is_fallible = match (found.bit_width(), exp.bit_width()) { |
| (Some(found), Some(exp)) if found > exp => true, |
| (None, _) | (_, None) => true, |
| _ => false, |
| }; |
| suggest_to_change_suffix_or_into(err, is_fallible); |
| true |
| } |
| (&ty::Int(_), &ty::Uint(_)) | (&ty::Uint(_), &ty::Int(_)) => { |
| suggest_to_change_suffix_or_into(err, true); |
| true |
| } |
| (&ty::Float(ref exp), &ty::Float(ref found)) => { |
| if found.bit_width() < exp.bit_width() { |
| suggest_to_change_suffix_or_into(err, false); |
| } else if literal_is_ty_suffixed(expr) { |
| err.span_suggestion( |
| expr.span, |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if can_cast { // Missing try_into implementation for `f64` to `f32` |
| err.span_suggestion( |
| expr.span, |
| &format!("{}, producing the closest possible value", cast_msg), |
| cast_suggestion, |
| Applicability::MaybeIncorrect, // lossy conversion |
| ); |
| } |
| true |
| } |
| (&ty::Uint(_), &ty::Float(_)) | (&ty::Int(_), &ty::Float(_)) => { |
| if literal_is_ty_suffixed(expr) { |
| err.span_suggestion( |
| expr.span, |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else if can_cast { |
| // Missing try_into implementation for `{float}` to `{integer}` |
| err.span_suggestion( |
| expr.span, |
| &format!("{}, rounding the float towards zero", msg), |
| cast_suggestion, |
| Applicability::MaybeIncorrect // lossy conversion |
| ); |
| err.warn("if the rounded value cannot be represented by the target \ |
| integer type, including `Inf` and `NaN`, casting will cause \ |
| undefined behavior \ |
| (https://github.com/rust-lang/rust/issues/10184)"); |
| } |
| true |
| } |
| (&ty::Float(ref exp), &ty::Uint(ref found)) => { |
| // if `found` is `None` (meaning found is `usize`), don't suggest `.into()` |
| if exp.bit_width() > found.bit_width().unwrap_or(256) { |
| err.span_suggestion( |
| expr.span, |
| &format!( |
| "{}, producing the floating point representation of the integer", |
| msg, |
| ), |
| into_suggestion, |
| Applicability::MachineApplicable |
| ); |
| } else if literal_is_ty_suffixed(expr) { |
| err.span_suggestion( |
| expr.span, |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| // Missing try_into implementation for `{integer}` to `{float}` |
| err.span_suggestion( |
| expr.span, |
| &format!( |
| "{}, producing the floating point representation of the integer, |
| rounded if necessary", |
| cast_msg, |
| ), |
| cast_suggestion, |
| Applicability::MaybeIncorrect // lossy conversion |
| ); |
| } |
| true |
| } |
| (&ty::Float(ref exp), &ty::Int(ref found)) => { |
| // if `found` is `None` (meaning found is `isize`), don't suggest `.into()` |
| if exp.bit_width() > found.bit_width().unwrap_or(256) { |
| err.span_suggestion( |
| expr.span, |
| &format!( |
| "{}, producing the floating point representation of the integer", |
| &msg, |
| ), |
| into_suggestion, |
| Applicability::MachineApplicable |
| ); |
| } else if literal_is_ty_suffixed(expr) { |
| err.span_suggestion( |
| expr.span, |
| &lit_msg, |
| suffix_suggestion, |
| Applicability::MachineApplicable, |
| ); |
| } else { |
| // Missing try_into implementation for `{integer}` to `{float}` |
| err.span_suggestion( |
| expr.span, |
| &format!( |
| "{}, producing the floating point representation of the integer, \ |
| rounded if necessary", |
| &msg, |
| ), |
| cast_suggestion, |
| Applicability::MaybeIncorrect // lossy conversion |
| ); |
| } |
| true |
| } |
| _ => false, |
| } |
| } else { |
| false |
| } |
| } |
| } |
