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Commit | Line | Data |
---|---|---|
9fa01778 | 1 | use crate::check::FnCtxt; |
74b04a01 | 2 | use rustc_infer::infer::InferOk; |
ba9703b0 | 3 | use rustc_trait_selection::infer::InferCtxtExt as _; |
f9f354fc | 4 | use rustc_trait_selection::traits::ObligationCause; |
1a4d82fc | 5 | |
74b04a01 | 6 | use rustc_ast::util::parser::PREC_POSTFIX; |
5e7ed085 | 7 | use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed}; |
dfeec247 | 8 | use rustc_hir as hir; |
3dfed10e | 9 | use rustc_hir::lang_items::LangItem; |
ba9703b0 | 10 | use rustc_hir::{is_range_literal, Node}; |
17df50a5 | 11 | use rustc_middle::lint::in_external_macro; |
ba9703b0 | 12 | use rustc_middle::ty::adjustment::AllowTwoPhase; |
3c0e092e | 13 | use rustc_middle::ty::error::{ExpectedFound, TypeError}; |
136023e0 | 14 | use rustc_middle::ty::print::with_no_trimmed_paths; |
f9f354fc | 15 | use rustc_middle::ty::{self, AssocItem, Ty, TypeAndMut}; |
5099ac24 | 16 | use rustc_span::symbol::{sym, Symbol}; |
94222f64 | 17 | use rustc_span::{BytePos, Span}; |
32a655c1 SL |
18 | |
19 | use super::method::probe; | |
1a4d82fc | 20 | |
17df50a5 | 21 | use std::iter; |
f035d41b | 22 | |
dc9dc135 | 23 | impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
60c5eb7d XL |
24 | pub fn emit_coerce_suggestions( |
25 | &self, | |
5e7ed085 | 26 | err: &mut Diagnostic, |
5099ac24 | 27 | expr: &hir::Expr<'tcx>, |
60c5eb7d | 28 | expr_ty: Ty<'tcx>, |
dfeec247 | 29 | expected: Ty<'tcx>, |
f035d41b | 30 | expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
3c0e092e | 31 | error: TypeError<'tcx>, |
60c5eb7d | 32 | ) { |
3c0e092e | 33 | self.annotate_expected_due_to_let_ty(err, expr, error); |
f035d41b | 34 | self.suggest_deref_ref_or_into(err, expr, expected, expr_ty, expected_ty_expr); |
5099ac24 | 35 | self.suggest_compatible_variants(err, expr, expected, expr_ty); |
74b04a01 XL |
36 | if self.suggest_calling_boxed_future_when_appropriate(err, expr, expected, expr_ty) { |
37 | return; | |
38 | } | |
5869c6ff | 39 | self.suggest_no_capture_closure(err, expected, expr_ty); |
60c5eb7d | 40 | self.suggest_boxing_when_appropriate(err, expr, expected, expr_ty); |
3dfed10e | 41 | self.suggest_missing_parentheses(err, expr); |
5e7ed085 | 42 | self.suggest_block_to_brackets_peeling_refs(err, expr, expr_ty, expected); |
f035d41b | 43 | self.note_need_for_fn_pointer(err, expected, expr_ty); |
3dfed10e | 44 | self.note_internal_mutation_in_method(err, expr, expected, expr_ty); |
94222f64 | 45 | self.report_closure_inferred_return_type(err, expected); |
60c5eb7d XL |
46 | } |
47 | ||
a7813a04 XL |
48 | // Requires that the two types unify, and prints an error message if |
49 | // they don't. | |
50 | pub fn demand_suptype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) { | |
f9f354fc XL |
51 | if let Some(mut e) = self.demand_suptype_diag(sp, expected, actual) { |
52 | e.emit(); | |
53 | } | |
041b39d2 XL |
54 | } |
55 | ||
dfeec247 XL |
56 | pub fn demand_suptype_diag( |
57 | &self, | |
58 | sp: Span, | |
59 | expected: Ty<'tcx>, | |
60 | actual: Ty<'tcx>, | |
5e7ed085 | 61 | ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
74b04a01 XL |
62 | self.demand_suptype_with_origin(&self.misc(sp), expected, actual) |
63 | } | |
64 | ||
c295e0f8 | 65 | #[instrument(skip(self), level = "debug")] |
74b04a01 XL |
66 | pub fn demand_suptype_with_origin( |
67 | &self, | |
68 | cause: &ObligationCause<'tcx>, | |
69 | expected: Ty<'tcx>, | |
70 | actual: Ty<'tcx>, | |
5e7ed085 | 71 | ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
7cac9316 | 72 | match self.at(cause, self.param_env).sup(expected, actual) { |
476ff2be SL |
73 | Ok(InferOk { obligations, value: () }) => { |
74 | self.register_predicates(obligations); | |
041b39d2 | 75 | None |
a7813a04 | 76 | } |
dfeec247 | 77 | Err(e) => Some(self.report_mismatched_types(&cause, expected, actual, e)), |
54a0048b | 78 | } |
1a4d82fc | 79 | } |
1a4d82fc | 80 | |
a7813a04 | 81 | pub fn demand_eqtype(&self, sp: Span, expected: Ty<'tcx>, actual: Ty<'tcx>) { |
32a655c1 SL |
82 | if let Some(mut err) = self.demand_eqtype_diag(sp, expected, actual) { |
83 | err.emit(); | |
84 | } | |
85 | } | |
86 | ||
dfeec247 XL |
87 | pub fn demand_eqtype_diag( |
88 | &self, | |
89 | sp: Span, | |
90 | expected: Ty<'tcx>, | |
91 | actual: Ty<'tcx>, | |
5e7ed085 | 92 | ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
32a655c1 | 93 | self.demand_eqtype_with_origin(&self.misc(sp), expected, actual) |
5bcae85e SL |
94 | } |
95 | ||
dfeec247 XL |
96 | pub fn demand_eqtype_with_origin( |
97 | &self, | |
98 | cause: &ObligationCause<'tcx>, | |
99 | expected: Ty<'tcx>, | |
100 | actual: Ty<'tcx>, | |
5e7ed085 | 101 | ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> { |
7cac9316 | 102 | match self.at(cause, self.param_env).eq(expected, actual) { |
476ff2be SL |
103 | Ok(InferOk { obligations, value: () }) => { |
104 | self.register_predicates(obligations); | |
32a655c1 | 105 | None |
3b2f2976 | 106 | } |
dfeec247 | 107 | Err(e) => Some(self.report_mismatched_types(cause, expected, actual, e)), |
54a0048b | 108 | } |
1a4d82fc | 109 | } |
1a4d82fc | 110 | |
dfeec247 | 111 | pub fn demand_coerce( |
e74abb32 | 112 | &self, |
5099ac24 | 113 | expr: &hir::Expr<'tcx>, |
dfeec247 | 114 | checked_ty: Ty<'tcx>, |
e74abb32 | 115 | expected: Ty<'tcx>, |
f035d41b | 116 | expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
dfeec247 XL |
117 | allow_two_phase: AllowTwoPhase, |
118 | ) -> Ty<'tcx> { | |
f035d41b XL |
119 | let (ty, err) = |
120 | self.demand_coerce_diag(expr, checked_ty, expected, expected_ty_expr, allow_two_phase); | |
abe05a73 | 121 | if let Some(mut err) = err { |
041b39d2 XL |
122 | err.emit(); |
123 | } | |
abe05a73 | 124 | ty |
041b39d2 XL |
125 | } |
126 | ||
1b1a35ee XL |
127 | /// Checks that the type of `expr` can be coerced to `expected`. |
128 | /// | |
129 | /// N.B., this code relies on `self.diverges` to be accurate. In particular, assignments to `!` | |
130 | /// will be permitted if the diverges flag is currently "always". | |
60c5eb7d XL |
131 | pub fn demand_coerce_diag( |
132 | &self, | |
5099ac24 | 133 | expr: &hir::Expr<'tcx>, |
60c5eb7d XL |
134 | checked_ty: Ty<'tcx>, |
135 | expected: Ty<'tcx>, | |
f035d41b | 136 | expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
60c5eb7d | 137 | allow_two_phase: AllowTwoPhase, |
5e7ed085 | 138 | ) -> (Ty<'tcx>, Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>>) { |
e74abb32 | 139 | let expected = self.resolve_vars_with_obligations(expected); |
cc61c64b | 140 | |
c295e0f8 | 141 | let e = match self.try_coerce(expr, checked_ty, expected, allow_two_phase, None) { |
abe05a73 | 142 | Ok(ty) => return (ty, None), |
dfeec247 | 143 | Err(e) => e, |
abe05a73 XL |
144 | }; |
145 | ||
c295e0f8 | 146 | self.set_tainted_by_errors(); |
e74abb32 | 147 | let expr = expr.peel_drop_temps(); |
abe05a73 | 148 | let cause = self.misc(expr.span); |
e74abb32 | 149 | let expr_ty = self.resolve_vars_with_obligations(checked_ty); |
3c0e092e | 150 | let mut err = self.report_mismatched_types(&cause, expected, expr_ty, e.clone()); |
abe05a73 | 151 | |
3c0e092e | 152 | self.emit_coerce_suggestions(&mut err, expr, expr_ty, expected, expected_ty_expr, e); |
8faf50e0 | 153 | |
abe05a73 | 154 | (expected, Some(err)) |
32a655c1 SL |
155 | } |
156 | ||
dfeec247 XL |
157 | fn annotate_expected_due_to_let_ty( |
158 | &self, | |
5e7ed085 | 159 | err: &mut Diagnostic, |
dfeec247 | 160 | expr: &hir::Expr<'_>, |
3c0e092e | 161 | error: TypeError<'_>, |
dfeec247 | 162 | ) { |
60c5eb7d | 163 | let parent = self.tcx.hir().get_parent_node(expr.hir_id); |
3c0e092e XL |
164 | match (self.tcx.hir().find(parent), error) { |
165 | (Some(hir::Node::Local(hir::Local { ty: Some(ty), init: Some(init), .. })), _) | |
166 | if init.hir_id == expr.hir_id => | |
167 | { | |
60c5eb7d XL |
168 | // Point at `let` assignment type. |
169 | err.span_label(ty.span, "expected due to this"); | |
170 | } | |
3c0e092e XL |
171 | ( |
172 | Some(hir::Node::Expr(hir::Expr { | |
173 | kind: hir::ExprKind::Assign(lhs, rhs, _), .. | |
174 | })), | |
175 | TypeError::Sorts(ExpectedFound { expected, .. }), | |
176 | ) if rhs.hir_id == expr.hir_id && !expected.is_closure() => { | |
177 | // We ignore closures explicitly because we already point at them elsewhere. | |
178 | // Point at the assigned-to binding. | |
179 | let mut primary_span = lhs.span; | |
180 | let mut secondary_span = lhs.span; | |
181 | let mut post_message = ""; | |
182 | match lhs.kind { | |
183 | hir::ExprKind::Path(hir::QPath::Resolved( | |
184 | None, | |
185 | hir::Path { | |
186 | res: | |
187 | hir::def::Res::Def( | |
5e7ed085 | 188 | hir::def::DefKind::Static(_) | hir::def::DefKind::Const, |
3c0e092e XL |
189 | def_id, |
190 | ), | |
191 | .. | |
192 | }, | |
193 | )) => { | |
194 | if let Some(hir::Node::Item(hir::Item { | |
195 | ident, | |
196 | kind: hir::ItemKind::Static(ty, ..) | hir::ItemKind::Const(ty, ..), | |
197 | .. | |
198 | })) = self.tcx.hir().get_if_local(*def_id) | |
199 | { | |
200 | primary_span = ty.span; | |
201 | secondary_span = ident.span; | |
202 | post_message = " type"; | |
203 | } | |
204 | } | |
205 | hir::ExprKind::Path(hir::QPath::Resolved( | |
206 | None, | |
207 | hir::Path { res: hir::def::Res::Local(hir_id), .. }, | |
208 | )) => { | |
209 | if let Some(hir::Node::Binding(pat)) = self.tcx.hir().find(*hir_id) { | |
210 | let parent = self.tcx.hir().get_parent_node(pat.hir_id); | |
211 | primary_span = pat.span; | |
212 | secondary_span = pat.span; | |
213 | match self.tcx.hir().find(parent) { | |
214 | Some(hir::Node::Local(hir::Local { ty: Some(ty), .. })) => { | |
215 | primary_span = ty.span; | |
216 | post_message = " type"; | |
217 | } | |
218 | Some(hir::Node::Local(hir::Local { init: Some(init), .. })) => { | |
219 | primary_span = init.span; | |
220 | post_message = " value"; | |
221 | } | |
222 | Some(hir::Node::Param(hir::Param { ty_span, .. })) => { | |
223 | primary_span = *ty_span; | |
224 | post_message = " parameter type"; | |
225 | } | |
226 | _ => {} | |
227 | } | |
228 | } | |
229 | } | |
230 | _ => {} | |
231 | } | |
232 | ||
233 | if primary_span != secondary_span | |
234 | && self | |
235 | .tcx | |
236 | .sess | |
237 | .source_map() | |
238 | .is_multiline(secondary_span.shrink_to_hi().until(primary_span)) | |
239 | { | |
240 | // We are pointing at the binding's type or initializer value, but it's pattern | |
241 | // is in a different line, so we point at both. | |
242 | err.span_label(secondary_span, "expected due to the type of this binding"); | |
243 | err.span_label(primary_span, &format!("expected due to this{}", post_message)); | |
244 | } else if post_message == "" { | |
245 | // We are pointing at either the assignment lhs or the binding def pattern. | |
246 | err.span_label(primary_span, "expected due to the type of this binding"); | |
247 | } else { | |
248 | // We are pointing at the binding's type or initializer value. | |
249 | err.span_label(primary_span, &format!("expected due to this{}", post_message)); | |
250 | } | |
251 | ||
252 | if !lhs.is_syntactic_place_expr() { | |
253 | // We already emitted E0070 "invalid left-hand side of assignment", so we | |
254 | // silence this. | |
5e7ed085 | 255 | err.downgrade_to_delayed_bug(); |
3c0e092e XL |
256 | } |
257 | } | |
258 | _ => {} | |
259 | } | |
260 | } | |
261 | ||
532ac7d7 XL |
262 | /// If the expected type is an enum (Issue #55250) with any variants whose |
263 | /// sole field is of the found type, suggest such variants. (Issue #42764) | |
264 | fn suggest_compatible_variants( | |
265 | &self, | |
5e7ed085 | 266 | err: &mut Diagnostic, |
dfeec247 | 267 | expr: &hir::Expr<'_>, |
532ac7d7 XL |
268 | expected: Ty<'tcx>, |
269 | expr_ty: Ty<'tcx>, | |
270 | ) { | |
1b1a35ee | 271 | if let ty::Adt(expected_adt, substs) = expected.kind() { |
3c0e092e XL |
272 | // If the expression is of type () and it's the return expression of a block, |
273 | // we suggest adding a separate return expression instead. | |
274 | // (To avoid things like suggesting `Ok(while .. { .. })`.) | |
275 | if expr_ty.is_unit() { | |
5e7ed085 FG |
276 | let mut id = expr.hir_id; |
277 | let mut parent; | |
278 | ||
279 | // Unroll desugaring, to make sure this works for `for` loops etc. | |
280 | loop { | |
281 | parent = self.tcx.hir().get_parent_node(id); | |
282 | if let Some(parent_span) = self.tcx.hir().opt_span(parent) { | |
283 | if parent_span.find_ancestor_inside(expr.span).is_some() { | |
284 | // The parent node is part of the same span, so is the result of the | |
285 | // same expansion/desugaring and not the 'real' parent node. | |
286 | id = parent; | |
287 | continue; | |
288 | } | |
289 | } | |
290 | break; | |
291 | } | |
292 | ||
3c0e092e XL |
293 | if let Some(hir::Node::Block(&hir::Block { |
294 | span: block_span, expr: Some(e), .. | |
5e7ed085 | 295 | })) = self.tcx.hir().find(parent) |
3c0e092e | 296 | { |
5e7ed085 | 297 | if e.hir_id == id { |
3c0e092e | 298 | if let Some(span) = expr.span.find_ancestor_inside(block_span) { |
5e7ed085 FG |
299 | let return_suggestions = if self |
300 | .tcx | |
301 | .is_diagnostic_item(sym::Result, expected_adt.did()) | |
302 | { | |
303 | vec!["Ok(())".to_string()] | |
304 | } else if self.tcx.is_diagnostic_item(sym::Option, expected_adt.did()) { | |
305 | vec!["None".to_string(), "Some(())".to_string()] | |
306 | } else { | |
307 | return; | |
308 | }; | |
3c0e092e XL |
309 | if let Some(indent) = |
310 | self.tcx.sess.source_map().indentation_before(span.shrink_to_lo()) | |
311 | { | |
312 | // Add a semicolon, except after `}`. | |
313 | let semicolon = | |
314 | match self.tcx.sess.source_map().span_to_snippet(span) { | |
315 | Ok(s) if s.ends_with('}') => "", | |
316 | _ => ";", | |
317 | }; | |
318 | err.span_suggestions( | |
319 | span.shrink_to_hi(), | |
320 | "try adding an expression at the end of the block", | |
321 | return_suggestions | |
322 | .into_iter() | |
323 | .map(|r| format!("{}\n{}{}", semicolon, indent, r)), | |
324 | Applicability::MaybeIncorrect, | |
325 | ); | |
326 | } | |
327 | return; | |
328 | } | |
329 | } | |
330 | } | |
331 | } | |
332 | ||
333 | let compatible_variants: Vec<String> = expected_adt | |
5e7ed085 | 334 | .variants() |
532ac7d7 | 335 | .iter() |
5e7ed085 FG |
336 | .filter(|variant| { |
337 | variant.fields.len() == 1 && variant.ctor_kind == hir::def::CtorKind::Fn | |
338 | }) | |
532ac7d7 XL |
339 | .filter_map(|variant| { |
340 | let sole_field = &variant.fields[0]; | |
341 | let sole_field_ty = sole_field.ty(self.tcx, substs); | |
342 | if self.can_coerce(expr_ty, sole_field_ty) { | |
136023e0 | 343 | let variant_path = |
5e7ed085 | 344 | with_no_trimmed_paths!(self.tcx.def_path_str(variant.def_id)); |
532ac7d7 | 345 | // FIXME #56861: DRYer prelude filtering |
6a06907d XL |
346 | if let Some(path) = variant_path.strip_prefix("std::prelude::") { |
347 | if let Some((_, path)) = path.split_once("::") { | |
348 | return Some(path.to_string()); | |
349 | } | |
350 | } | |
351 | Some(variant_path) | |
532ac7d7 XL |
352 | } else { |
353 | None | |
354 | } | |
dfeec247 | 355 | }) |
3c0e092e XL |
356 | .collect(); |
357 | ||
5099ac24 FG |
358 | let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { |
359 | Some(ident) => format!("{}: ", ident), | |
360 | None => String::new(), | |
361 | }; | |
362 | ||
363 | match &compatible_variants[..] { | |
364 | [] => { /* No variants to format */ } | |
365 | [variant] => { | |
366 | // Just a single matching variant. | |
367 | err.multipart_suggestion_verbose( | |
368 | &format!("try wrapping the expression in `{}`", variant), | |
3c0e092e | 369 | vec![ |
5099ac24 | 370 | (expr.span.shrink_to_lo(), format!("{}{}(", prefix, variant)), |
3c0e092e | 371 | (expr.span.shrink_to_hi(), ")".to_string()), |
5099ac24 FG |
372 | ], |
373 | Applicability::MaybeIncorrect, | |
374 | ); | |
375 | } | |
376 | _ => { | |
377 | // More than one matching variant. | |
378 | err.multipart_suggestions( | |
379 | &format!( | |
380 | "try wrapping the expression in a variant of `{}`", | |
5e7ed085 | 381 | self.tcx.def_path_str(expected_adt.did()) |
5099ac24 FG |
382 | ), |
383 | compatible_variants.into_iter().map(|variant| { | |
384 | vec![ | |
385 | (expr.span.shrink_to_lo(), format!("{}{}(", prefix, variant)), | |
386 | (expr.span.shrink_to_hi(), ")".to_string()), | |
387 | ] | |
388 | }), | |
389 | Applicability::MaybeIncorrect, | |
390 | ); | |
391 | } | |
532ac7d7 XL |
392 | } |
393 | } | |
394 | } | |
395 | ||
dfeec247 XL |
396 | pub fn get_conversion_methods( |
397 | &self, | |
398 | span: Span, | |
399 | expected: Ty<'tcx>, | |
400 | checked_ty: Ty<'tcx>, | |
ba9703b0 | 401 | hir_id: hir::HirId, |
dfeec247 | 402 | ) -> Vec<AssocItem> { |
ba9703b0 XL |
403 | let mut methods = |
404 | self.probe_for_return_type(span, probe::Mode::MethodCall, expected, checked_ty, hir_id); | |
2c00a5a8 | 405 | methods.retain(|m| { |
ba9703b0 | 406 | self.has_only_self_parameter(m) |
dfeec247 XL |
407 | && self |
408 | .tcx | |
409 | .get_attrs(m.def_id) | |
410 | .iter() | |
f035d41b | 411 | // This special internal attribute is used to permit |
dfeec247 XL |
412 | // "identity-like" conversion methods to be suggested here. |
413 | // | |
414 | // FIXME (#46459 and #46460): ideally | |
415 | // `std::convert::Into::into` and `std::borrow:ToOwned` would | |
416 | // also be `#[rustc_conversion_suggestion]`, if not for | |
417 | // method-probing false-positives and -negatives (respectively). | |
418 | // | |
419 | // FIXME? Other potential candidate methods: `as_ref` and | |
420 | // `as_mut`? | |
94222f64 | 421 | .any(|a| a.has_name(sym::rustc_conversion_suggestion)) |
2c00a5a8 | 422 | }); |
32a655c1 | 423 | |
2c00a5a8 | 424 | methods |
32a655c1 SL |
425 | } |
426 | ||
ba9703b0 XL |
427 | /// This function checks whether the method is not static and does not accept other parameters than `self`. |
428 | fn has_only_self_parameter(&self, method: &AssocItem) -> bool { | |
48663c56 | 429 | match method.kind { |
ba9703b0 XL |
430 | ty::AssocKind::Fn => { |
431 | method.fn_has_self_parameter | |
432 | && self.tcx.fn_sig(method.def_id).inputs().skip_binder().len() == 1 | |
32a655c1 SL |
433 | } |
434 | _ => false, | |
a7813a04 XL |
435 | } |
436 | } | |
cc61c64b | 437 | |
94b46f34 XL |
438 | /// Identify some cases where `as_ref()` would be appropriate and suggest it. |
439 | /// | |
440 | /// Given the following code: | |
441 | /// ``` | |
442 | /// struct Foo; | |
443 | /// fn takes_ref(_: &Foo) {} | |
444 | /// let ref opt = Some(Foo); | |
445 | /// | |
e1599b0c | 446 | /// opt.map(|param| takes_ref(param)); |
94b46f34 | 447 | /// ``` |
e1599b0c | 448 | /// Suggest using `opt.as_ref().map(|param| takes_ref(param));` instead. |
94b46f34 XL |
449 | /// |
450 | /// It only checks for `Option` and `Result` and won't work with | |
451 | /// ``` | |
e1599b0c | 452 | /// opt.map(|param| { takes_ref(param) }); |
94b46f34 | 453 | /// ``` |
dfeec247 | 454 | fn can_use_as_ref(&self, expr: &hir::Expr<'_>) -> Option<(Span, &'static str, String)> { |
5e7ed085 FG |
455 | let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.kind else { |
456 | return None; | |
416331ca XL |
457 | }; |
458 | ||
5e7ed085 FG |
459 | let hir::def::Res::Local(local_id) = path.res else { |
460 | return None; | |
416331ca XL |
461 | }; |
462 | ||
463 | let local_parent = self.tcx.hir().get_parent_node(local_id); | |
5e7ed085 FG |
464 | let Some(Node::Param(hir::Param { hir_id: param_hir_id, .. })) = self.tcx.hir().find(local_parent) else { |
465 | return None; | |
416331ca XL |
466 | }; |
467 | ||
e1599b0c | 468 | let param_parent = self.tcx.hir().get_parent_node(*param_hir_id); |
5e7ed085 FG |
469 | let Some(Node::Expr(hir::Expr { |
470 | hir_id: expr_hir_id, | |
471 | kind: hir::ExprKind::Closure(_, closure_fn_decl, ..), | |
472 | .. | |
473 | })) = self.tcx.hir().find(param_parent) else { | |
474 | return None; | |
416331ca XL |
475 | }; |
476 | ||
477 | let expr_parent = self.tcx.hir().get_parent_node(*expr_hir_id); | |
478 | let hir = self.tcx.hir().find(expr_parent); | |
479 | let closure_params_len = closure_fn_decl.inputs.len(); | |
5e7ed085 FG |
480 | let ( |
481 | Some(Node::Expr(hir::Expr { | |
482 | kind: hir::ExprKind::MethodCall(method_path, method_expr, _), | |
483 | .. | |
484 | })), | |
485 | 1, | |
486 | ) = (hir, closure_params_len) else { | |
487 | return None; | |
416331ca XL |
488 | }; |
489 | ||
5099ac24 | 490 | let self_ty = self.typeck_results.borrow().expr_ty(&method_expr[0]); |
416331ca | 491 | let self_ty = format!("{:?}", self_ty); |
3dfed10e | 492 | let name = method_path.ident.name; |
dfeec247 XL |
493 | let is_as_ref_able = (self_ty.starts_with("&std::option::Option") |
494 | || self_ty.starts_with("&std::result::Result") | |
495 | || self_ty.starts_with("std::option::Option") | |
496 | || self_ty.starts_with("std::result::Result")) | |
3dfed10e | 497 | && (name == sym::map || name == sym::and_then); |
5099ac24 | 498 | match (is_as_ref_able, self.sess().source_map().span_to_snippet(method_path.ident.span)) { |
416331ca XL |
499 | (true, Ok(src)) => { |
500 | let suggestion = format!("as_ref().{}", src); | |
5099ac24 | 501 | Some((method_path.ident.span, "consider using `as_ref` instead", suggestion)) |
dfeec247 XL |
502 | } |
503 | _ => None, | |
94b46f34 | 504 | } |
94b46f34 XL |
505 | } |
506 | ||
5099ac24 | 507 | crate fn maybe_get_struct_pattern_shorthand_field( |
dc9dc135 | 508 | &self, |
5099ac24 FG |
509 | expr: &hir::Expr<'_>, |
510 | ) -> Option<Symbol> { | |
511 | let hir = self.tcx.hir(); | |
512 | let local = match expr { | |
513 | hir::Expr { | |
514 | kind: | |
515 | hir::ExprKind::Path(hir::QPath::Resolved( | |
516 | None, | |
517 | hir::Path { | |
518 | res: hir::def::Res::Local(_), | |
519 | segments: [hir::PathSegment { ident, .. }], | |
520 | .. | |
521 | }, | |
522 | )), | |
523 | .. | |
524 | } => Some(ident), | |
525 | _ => None, | |
526 | }?; | |
527 | ||
528 | match hir.find(hir.get_parent_node(expr.hir_id))? { | |
529 | Node::Expr(hir::Expr { kind: hir::ExprKind::Struct(_, fields, ..), .. }) => { | |
530 | for field in *fields { | |
531 | if field.ident.name == local.name && field.is_shorthand { | |
532 | return Some(local.name); | |
532ac7d7 XL |
533 | } |
534 | } | |
535 | } | |
5099ac24 | 536 | _ => {} |
532ac7d7 | 537 | } |
5099ac24 FG |
538 | |
539 | None | |
532ac7d7 XL |
540 | } |
541 | ||
cdc7bbd5 | 542 | /// If the given `HirId` corresponds to a block with a trailing expression, return that expression |
5099ac24 FG |
543 | crate fn maybe_get_block_expr(&self, expr: &hir::Expr<'tcx>) -> Option<&'tcx hir::Expr<'tcx>> { |
544 | match expr { | |
545 | hir::Expr { kind: hir::ExprKind::Block(block, ..), .. } => block.expr, | |
cdc7bbd5 XL |
546 | _ => None, |
547 | } | |
548 | } | |
549 | ||
550 | /// Returns whether the given expression is an `else if`. | |
551 | crate fn is_else_if_block(&self, expr: &hir::Expr<'_>) -> bool { | |
552 | if let hir::ExprKind::If(..) = expr.kind { | |
553 | let parent_id = self.tcx.hir().get_parent_node(expr.hir_id); | |
554 | if let Some(Node::Expr(hir::Expr { | |
555 | kind: hir::ExprKind::If(_, _, Some(else_expr)), | |
556 | .. | |
557 | })) = self.tcx.hir().find(parent_id) | |
558 | { | |
559 | return else_expr.hir_id == expr.hir_id; | |
560 | } | |
561 | } | |
562 | false | |
563 | } | |
564 | ||
cc61c64b XL |
565 | /// This function is used to determine potential "simple" improvements or users' errors and |
566 | /// provide them useful help. For example: | |
567 | /// | |
568 | /// ``` | |
569 | /// fn some_fn(s: &str) {} | |
570 | /// | |
571 | /// let x = "hey!".to_owned(); | |
572 | /// some_fn(x); // error | |
573 | /// ``` | |
574 | /// | |
575 | /// No need to find every potential function which could make a coercion to transform a | |
576 | /// `String` into a `&str` since a `&` would do the trick! | |
577 | /// | |
578 | /// In addition of this check, it also checks between references mutability state. If the | |
579 | /// expected is mutable but the provided isn't, maybe we could just say "Hey, try with | |
580 | /// `&mut`!". | |
dc9dc135 XL |
581 | pub fn check_ref( |
582 | &self, | |
5099ac24 | 583 | expr: &hir::Expr<'tcx>, |
dc9dc135 XL |
584 | checked_ty: Ty<'tcx>, |
585 | expected: Ty<'tcx>, | |
5e7ed085 | 586 | ) -> Option<(Span, String, String, Applicability, bool /* verbose */)> { |
17df50a5 | 587 | let sess = self.sess(); |
532ac7d7 | 588 | let sp = expr.span; |
17df50a5 XL |
589 | |
590 | // If the span is from an external macro, there's no suggestion we can make. | |
591 | if in_external_macro(sess, sp) { | |
8faf50e0 XL |
592 | return None; |
593 | } | |
594 | ||
17df50a5 XL |
595 | let sm = sess.source_map(); |
596 | ||
fc512014 XL |
597 | let replace_prefix = |s: &str, old: &str, new: &str| { |
598 | s.strip_prefix(old).map(|stripped| new.to_string() + stripped) | |
599 | }; | |
600 | ||
e74abb32 XL |
601 | // `ExprKind::DropTemps` is semantically irrelevant for these suggestions. |
602 | let expr = expr.peel_drop_temps(); | |
48663c56 | 603 | |
1b1a35ee XL |
604 | match (&expr.kind, expected.kind(), checked_ty.kind()) { |
605 | (_, &ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (exp.kind(), check.kind()) { | |
ba9703b0 | 606 | (&ty::Str, &ty::Array(arr, _) | &ty::Slice(arr)) if arr == self.tcx.types.u8 => { |
5e7ed085 FG |
607 | if let hir::ExprKind::Lit(_) = expr.kind |
608 | && let Ok(src) = sm.span_to_snippet(sp) | |
609 | && replace_prefix(&src, "b\"", "\"").is_some() | |
610 | { | |
94222f64 | 611 | let pos = sp.lo() + BytePos(1); |
dfeec247 | 612 | return Some(( |
94222f64 | 613 | sp.with_hi(pos), |
5e7ed085 | 614 | "consider removing the leading `b`".to_string(), |
94222f64 | 615 | String::new(), |
f9f354fc | 616 | Applicability::MachineApplicable, |
94222f64 | 617 | true, |
dfeec247 | 618 | )); |
8faf50e0 | 619 | } |
ea8adc8c | 620 | } |
ba9703b0 | 621 | (&ty::Array(arr, _) | &ty::Slice(arr), &ty::Str) if arr == self.tcx.types.u8 => { |
5e7ed085 FG |
622 | if let hir::ExprKind::Lit(_) = expr.kind |
623 | && let Ok(src) = sm.span_to_snippet(sp) | |
624 | && replace_prefix(&src, "\"", "b\"").is_some() | |
625 | { | |
dfeec247 | 626 | return Some(( |
94222f64 | 627 | sp.shrink_to_lo(), |
5e7ed085 | 628 | "consider adding a leading `b`".to_string(), |
94222f64 | 629 | "b".to_string(), |
f9f354fc | 630 | Applicability::MachineApplicable, |
94222f64 | 631 | true, |
dfeec247 | 632 | )); |
5e7ed085 | 633 | |
ea8adc8c | 634 | } |
ea8adc8c | 635 | } |
94b46f34 | 636 | _ => {} |
ea8adc8c | 637 | }, |
48663c56 | 638 | (_, &ty::Ref(_, _, mutability), _) => { |
cc61c64b XL |
639 | // Check if it can work when put into a ref. For example: |
640 | // | |
641 | // ``` | |
642 | // fn bar(x: &mut i32) {} | |
643 | // | |
644 | // let x = 0u32; | |
645 | // bar(&x); // error, expected &mut | |
646 | // ``` | |
94b46f34 | 647 | let ref_ty = match mutability { |
dfeec247 | 648 | hir::Mutability::Mut => { |
532ac7d7 XL |
649 | self.tcx.mk_mut_ref(self.tcx.mk_region(ty::ReStatic), checked_ty) |
650 | } | |
dfeec247 | 651 | hir::Mutability::Not => { |
532ac7d7 XL |
652 | self.tcx.mk_imm_ref(self.tcx.mk_region(ty::ReStatic), checked_ty) |
653 | } | |
cc61c64b XL |
654 | }; |
655 | if self.can_coerce(ref_ty, expected) { | |
dc9dc135 | 656 | let mut sugg_sp = sp; |
5099ac24 FG |
657 | if let hir::ExprKind::MethodCall(ref segment, ref args, _) = expr.kind { |
658 | let clone_trait = | |
659 | self.tcx.require_lang_item(LangItem::Clone, Some(segment.ident.span)); | |
60c5eb7d | 660 | if let ([arg], Some(true), sym::clone) = ( |
dc9dc135 | 661 | &args[..], |
3dfed10e XL |
662 | self.typeck_results.borrow().type_dependent_def_id(expr.hir_id).map( |
663 | |did| { | |
664 | let ai = self.tcx.associated_item(did); | |
665 | ai.container == ty::TraitContainer(clone_trait) | |
666 | }, | |
667 | ), | |
60c5eb7d | 668 | segment.ident.name, |
dc9dc135 XL |
669 | ) { |
670 | // If this expression had a clone call when suggesting borrowing | |
60c5eb7d | 671 | // we want to suggest removing it because it'd now be unnecessary. |
dc9dc135 XL |
672 | sugg_sp = arg.span; |
673 | } | |
674 | } | |
74b04a01 | 675 | if let Ok(src) = sm.span_to_snippet(sugg_sp) { |
e74abb32 | 676 | let needs_parens = match expr.kind { |
0bf4aa26 | 677 | // parenthesize if needed (Issue #46756) |
dfeec247 | 678 | hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true, |
0bf4aa26 | 679 | // parenthesize borrows of range literals (Issue #54505) |
3dfed10e | 680 | _ if is_range_literal(expr) => true, |
0bf4aa26 XL |
681 | _ => false, |
682 | }; | |
dfeec247 | 683 | let sugg_expr = if needs_parens { format!("({})", src) } else { src }; |
0bf4aa26 | 684 | |
94b46f34 | 685 | if let Some(sugg) = self.can_use_as_ref(expr) { |
f9f354fc XL |
686 | return Some(( |
687 | sugg.0, | |
5e7ed085 | 688 | sugg.1.to_string(), |
f9f354fc XL |
689 | sugg.2, |
690 | Applicability::MachineApplicable, | |
94222f64 | 691 | false, |
f9f354fc | 692 | )); |
94b46f34 | 693 | } |
5099ac24 FG |
694 | |
695 | let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { | |
696 | Some(ident) => format!("{}: ", ident), | |
697 | None => String::new(), | |
532ac7d7 | 698 | }; |
5099ac24 | 699 | |
dc9dc135 | 700 | if let Some(hir::Node::Expr(hir::Expr { |
dfeec247 | 701 | kind: hir::ExprKind::Assign(left_expr, ..), |
dc9dc135 | 702 | .. |
dfeec247 XL |
703 | })) = self.tcx.hir().find(self.tcx.hir().get_parent_node(expr.hir_id)) |
704 | { | |
705 | if mutability == hir::Mutability::Mut { | |
dc9dc135 XL |
706 | // Found the following case: |
707 | // fn foo(opt: &mut Option<String>){ opt = None } | |
708 | // --- ^^^^ | |
709 | // | | | |
710 | // consider dereferencing here: `*opt` | | |
711 | // expected mutable reference, found enum `Option` | |
94222f64 | 712 | if sm.span_to_snippet(left_expr.span).is_ok() { |
dc9dc135 | 713 | return Some(( |
94222f64 | 714 | left_expr.span.shrink_to_lo(), |
dc9dc135 | 715 | "consider dereferencing here to assign to the mutable \ |
5e7ed085 FG |
716 | borrowed piece of memory" |
717 | .to_string(), | |
94222f64 | 718 | "*".to_string(), |
f9f354fc | 719 | Applicability::MachineApplicable, |
94222f64 | 720 | true, |
dc9dc135 XL |
721 | )); |
722 | } | |
723 | } | |
724 | } | |
725 | ||
94b46f34 | 726 | return Some(match mutability { |
dfeec247 | 727 | hir::Mutability::Mut => ( |
532ac7d7 | 728 | sp, |
5e7ed085 | 729 | "consider mutably borrowing here".to_string(), |
5099ac24 | 730 | format!("{}&mut {}", prefix, sugg_expr), |
f9f354fc | 731 | Applicability::MachineApplicable, |
94222f64 | 732 | false, |
532ac7d7 | 733 | ), |
dfeec247 | 734 | hir::Mutability::Not => ( |
532ac7d7 | 735 | sp, |
5e7ed085 | 736 | "consider borrowing here".to_string(), |
5099ac24 | 737 | format!("{}&{}", prefix, sugg_expr), |
f9f354fc | 738 | Applicability::MachineApplicable, |
94222f64 | 739 | false, |
532ac7d7 | 740 | ), |
ff7c6d11 | 741 | }); |
cc61c64b XL |
742 | } |
743 | } | |
dfeec247 | 744 | } |
60c5eb7d XL |
745 | ( |
746 | hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, ref expr), | |
747 | _, | |
dfeec247 | 748 | &ty::Ref(_, checked, _), |
5099ac24 | 749 | ) if self.infcx.can_sub(self.param_env, checked, expected).is_ok() => { |
ea8adc8c | 750 | // We have `&T`, check if what was expected was `T`. If so, |
48663c56 | 751 | // we may want to suggest removing a `&`. |
ba9703b0 | 752 | if sm.is_imported(expr.span) { |
17df50a5 XL |
753 | // Go through the spans from which this span was expanded, |
754 | // and find the one that's pointing inside `sp`. | |
755 | // | |
756 | // E.g. for `&format!("")`, where we want the span to the | |
757 | // `format!()` invocation instead of its expansion. | |
758 | if let Some(call_span) = | |
c295e0f8 XL |
759 | iter::successors(Some(expr.span), |s| s.parent_callsite()) |
760 | .find(|&s| sp.contains(s)) | |
17df50a5 | 761 | { |
94222f64 | 762 | if sm.span_to_snippet(call_span).is_ok() { |
48663c56 | 763 | return Some(( |
94222f64 | 764 | sp.with_hi(call_span.lo()), |
5e7ed085 | 765 | "consider removing the borrow".to_string(), |
94222f64 | 766 | String::new(), |
f9f354fc | 767 | Applicability::MachineApplicable, |
94222f64 | 768 | true, |
48663c56 | 769 | )); |
2c00a5a8 | 770 | } |
ea8adc8c | 771 | } |
48663c56 | 772 | return None; |
ea8adc8c | 773 | } |
17df50a5 | 774 | if sp.contains(expr.span) { |
94222f64 | 775 | if sm.span_to_snippet(expr.span).is_ok() { |
17df50a5 | 776 | return Some(( |
94222f64 | 777 | sp.with_hi(expr.span.lo()), |
5e7ed085 | 778 | "consider removing the borrow".to_string(), |
94222f64 | 779 | String::new(), |
17df50a5 | 780 | Applicability::MachineApplicable, |
94222f64 | 781 | true, |
17df50a5 XL |
782 | )); |
783 | } | |
f9f354fc XL |
784 | } |
785 | } | |
786 | ( | |
787 | _, | |
788 | &ty::RawPtr(TypeAndMut { ty: ty_b, mutbl: mutbl_b }), | |
789 | &ty::Ref(_, ty_a, mutbl_a), | |
790 | ) => { | |
791 | if let Some(steps) = self.deref_steps(ty_a, ty_b) { | |
792 | // Only suggest valid if dereferencing needed. | |
793 | if steps > 0 { | |
794 | // The pointer type implements `Copy` trait so the suggestion is always valid. | |
795 | if let Ok(src) = sm.span_to_snippet(sp) { | |
94222f64 XL |
796 | let derefs = "*".repeat(steps); |
797 | if let Some((span, src, applicability)) = match mutbl_b { | |
f9f354fc | 798 | hir::Mutability::Mut => { |
94222f64 | 799 | let new_prefix = "&mut ".to_owned() + &derefs; |
f9f354fc XL |
800 | match mutbl_a { |
801 | hir::Mutability::Mut => { | |
94222f64 XL |
802 | replace_prefix(&src, "&mut ", &new_prefix).map(|_| { |
803 | let pos = sp.lo() + BytePos(5); | |
804 | let sp = sp.with_lo(pos).with_hi(pos); | |
805 | (sp, derefs, Applicability::MachineApplicable) | |
806 | }) | |
f9f354fc XL |
807 | } |
808 | hir::Mutability::Not => { | |
94222f64 XL |
809 | replace_prefix(&src, "&", &new_prefix).map(|_| { |
810 | let pos = sp.lo() + BytePos(1); | |
811 | let sp = sp.with_lo(pos).with_hi(pos); | |
812 | ( | |
813 | sp, | |
814 | format!("mut {}", derefs), | |
815 | Applicability::Unspecified, | |
816 | ) | |
817 | }) | |
f9f354fc XL |
818 | } |
819 | } | |
820 | } | |
821 | hir::Mutability::Not => { | |
94222f64 | 822 | let new_prefix = "&".to_owned() + &derefs; |
f9f354fc XL |
823 | match mutbl_a { |
824 | hir::Mutability::Mut => { | |
94222f64 XL |
825 | replace_prefix(&src, "&mut ", &new_prefix).map(|_| { |
826 | let lo = sp.lo() + BytePos(1); | |
827 | let hi = sp.lo() + BytePos(5); | |
828 | let sp = sp.with_lo(lo).with_hi(hi); | |
829 | (sp, derefs, Applicability::MachineApplicable) | |
830 | }) | |
f9f354fc XL |
831 | } |
832 | hir::Mutability::Not => { | |
94222f64 XL |
833 | replace_prefix(&src, "&", &new_prefix).map(|_| { |
834 | let pos = sp.lo() + BytePos(1); | |
835 | let sp = sp.with_lo(pos).with_hi(pos); | |
836 | (sp, derefs, Applicability::MachineApplicable) | |
837 | }) | |
f9f354fc XL |
838 | } |
839 | } | |
840 | } | |
841 | } { | |
94222f64 XL |
842 | return Some(( |
843 | span, | |
5e7ed085 | 844 | "consider dereferencing".to_string(), |
94222f64 XL |
845 | src, |
846 | applicability, | |
847 | true, | |
848 | )); | |
f9f354fc XL |
849 | } |
850 | } | |
851 | } | |
9fa01778 | 852 | } |
dfeec247 | 853 | } |
17df50a5 | 854 | _ if sp == expr.span => { |
5e7ed085 FG |
855 | if let Some(mut steps) = self.deref_steps(checked_ty, expected) { |
856 | let mut expr = expr.peel_blocks(); | |
857 | let mut prefix_span = expr.span.shrink_to_lo(); | |
858 | let mut remove = String::new(); | |
6a06907d | 859 | |
5e7ed085 FG |
860 | // Try peeling off any existing `&` and `&mut` to reach our target type |
861 | while steps > 0 { | |
6a06907d XL |
862 | if let hir::ExprKind::AddrOf(_, mutbl, inner) = expr.kind { |
863 | // If the expression has `&`, removing it would fix the error | |
5e7ed085 FG |
864 | prefix_span = prefix_span.with_hi(inner.span.lo()); |
865 | expr = inner; | |
866 | remove += match mutbl { | |
867 | hir::Mutability::Not => "&", | |
868 | hir::Mutability::Mut => "&mut ", | |
6a06907d | 869 | }; |
5e7ed085 FG |
870 | steps -= 1; |
871 | } else { | |
872 | break; | |
5099ac24 | 873 | } |
5e7ed085 FG |
874 | } |
875 | // If we've reached our target type with just removing `&`, then just print now. | |
876 | if steps == 0 { | |
877 | return Some(( | |
878 | prefix_span, | |
879 | format!("consider removing the `{}`", remove.trim()), | |
880 | String::new(), | |
881 | // Do not remove `&&` to get to bool, because it might be something like | |
882 | // { a } && b, which we have a separate fixup suggestion that is more | |
883 | // likely correct... | |
884 | if remove.trim() == "&&" && expected == self.tcx.types.bool { | |
885 | Applicability::MaybeIncorrect | |
5099ac24 | 886 | } else { |
5e7ed085 FG |
887 | Applicability::MachineApplicable |
888 | }, | |
889 | true, | |
890 | )); | |
891 | } | |
892 | ||
893 | // For this suggestion to make sense, the type would need to be `Copy`, | |
894 | // or we have to be moving out of a `Box<T>` | |
895 | if self.infcx.type_is_copy_modulo_regions(self.param_env, expected, sp) | |
896 | // FIXME(compiler-errors): We can actually do this if the checked_ty is | |
897 | // `steps` layers of boxes, not just one, but this is easier and most likely. | |
898 | || (checked_ty.is_box() && steps == 1) | |
899 | { | |
900 | let deref_kind = if checked_ty.is_box() { | |
901 | "unboxing the value" | |
902 | } else if checked_ty.is_region_ptr() { | |
903 | "dereferencing the borrow" | |
904 | } else { | |
905 | "dereferencing the type" | |
906 | }; | |
907 | ||
908 | // Suggest removing `&` if we have removed any, otherwise suggest just | |
909 | // dereferencing the remaining number of steps. | |
910 | let message = if remove.is_empty() { | |
911 | format!("consider {}", deref_kind) | |
912 | } else { | |
913 | format!( | |
914 | "consider removing the `{}` and {} instead", | |
915 | remove.trim(), | |
916 | deref_kind | |
917 | ) | |
918 | }; | |
919 | ||
920 | let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) { | |
921 | Some(ident) => format!("{}: ", ident), | |
922 | None => String::new(), | |
923 | }; | |
924 | ||
925 | let (span, suggestion) = if self.is_else_if_block(expr) { | |
926 | // Don't suggest nonsense like `else *if` | |
927 | return None; | |
928 | } else if let Some(expr) = self.maybe_get_block_expr(expr) { | |
929 | // prefix should be empty here.. | |
930 | (expr.span.shrink_to_lo(), "*".to_string()) | |
931 | } else { | |
932 | (prefix_span, format!("{}{}", prefix, "*".repeat(steps))) | |
933 | }; | |
934 | ||
935 | return Some(( | |
936 | span, | |
937 | message, | |
938 | suggestion, | |
939 | Applicability::MachineApplicable, | |
940 | true, | |
941 | )); | |
0bf4aa26 XL |
942 | } |
943 | } | |
944 | } | |
0bf4aa26 XL |
945 | _ => {} |
946 | } | |
48663c56 | 947 | None |
0bf4aa26 XL |
948 | } |
949 | ||
9fa01778 XL |
950 | pub fn check_for_cast( |
951 | &self, | |
5e7ed085 | 952 | err: &mut Diagnostic, |
dfeec247 | 953 | expr: &hir::Expr<'_>, |
9fa01778 XL |
954 | checked_ty: Ty<'tcx>, |
955 | expected_ty: Ty<'tcx>, | |
f035d41b | 956 | expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>, |
9fa01778 | 957 | ) -> bool { |
ba9703b0 | 958 | if self.tcx.sess.source_map().is_imported(expr.span) { |
e1599b0c XL |
959 | // Ignore if span is from within a macro. |
960 | return false; | |
961 | } | |
2c00a5a8 | 962 | |
3c0e092e | 963 | let Ok(src) = self.tcx.sess.source_map().span_to_snippet(expr.span) else { |
f035d41b XL |
964 | return false; |
965 | }; | |
966 | ||
2c00a5a8 XL |
967 | // If casting this expression to a given numeric type would be appropriate in case of a type |
968 | // mismatch. | |
969 | // | |
970 | // We want to minimize the amount of casting operations that are suggested, as it can be a | |
971 | // lossy operation with potentially bad side effects, so we only suggest when encountering | |
972 | // an expression that indicates that the original type couldn't be directly changed. | |
973 | // | |
974 | // For now, don't suggest casting with `as`. | |
975 | let can_cast = false; | |
976 | ||
c295e0f8 XL |
977 | let mut sugg = vec![]; |
978 | ||
979 | if let Some(hir::Node::Expr(hir::Expr { | |
980 | kind: hir::ExprKind::Struct(_, fields, _), .. | |
dfeec247 XL |
981 | })) = self.tcx.hir().find(self.tcx.hir().get_parent_node(expr.hir_id)) |
982 | { | |
9fa01778 | 983 | // `expr` is a literal field for a struct, only suggest if appropriate |
f9f354fc XL |
984 | match (*fields) |
985 | .iter() | |
986 | .find(|field| field.expr.hir_id == expr.hir_id && field.is_shorthand) | |
987 | { | |
988 | // This is a field literal | |
c295e0f8 XL |
989 | Some(field) => { |
990 | sugg.push((field.ident.span.shrink_to_lo(), format!("{}: ", field.ident))); | |
991 | } | |
9fa01778 | 992 | // Likely a field was meant, but this field wasn't found. Do not suggest anything. |
f9f354fc | 993 | None => return false, |
9fa01778 | 994 | } |
f9f354fc | 995 | }; |
f035d41b | 996 | |
e74abb32 | 997 | if let hir::ExprKind::Call(path, args) = &expr.kind { |
dfeec247 XL |
998 | if let (hir::ExprKind::Path(hir::QPath::TypeRelative(base_ty, path_segment)), 1) = |
999 | (&path.kind, args.len()) | |
1000 | { | |
e1599b0c | 1001 | // `expr` is a conversion like `u32::from(val)`, do not suggest anything (#63697). |
dfeec247 XL |
1002 | if let (hir::TyKind::Path(hir::QPath::Resolved(None, base_ty_path)), sym::from) = |
1003 | (&base_ty.kind, path_segment.ident.name) | |
1004 | { | |
e1599b0c XL |
1005 | if let Some(ident) = &base_ty_path.segments.iter().map(|s| s.ident).next() { |
1006 | match ident.name { | |
dfeec247 XL |
1007 | sym::i128 |
1008 | | sym::i64 | |
1009 | | sym::i32 | |
1010 | | sym::i16 | |
1011 | | sym::i8 | |
1012 | | sym::u128 | |
1013 | | sym::u64 | |
1014 | | sym::u32 | |
1015 | | sym::u16 | |
1016 | | sym::u8 | |
1017 | | sym::isize | |
1018 | | sym::usize | |
1019 | if base_ty_path.segments.len() == 1 => | |
1020 | { | |
e1599b0c XL |
1021 | return false; |
1022 | } | |
1023 | _ => {} | |
1024 | } | |
1025 | } | |
1026 | } | |
1027 | } | |
1028 | } | |
9fa01778 | 1029 | |
29967ef6 XL |
1030 | let msg = format!( |
1031 | "you can convert {} `{}` to {} `{}`", | |
1032 | checked_ty.kind().article(), | |
1033 | checked_ty, | |
1034 | expected_ty.kind().article(), | |
1035 | expected_ty, | |
1036 | ); | |
1037 | let cast_msg = format!( | |
1038 | "you can cast {} `{}` to {} `{}`", | |
1039 | checked_ty.kind().article(), | |
1040 | checked_ty, | |
1041 | expected_ty.kind().article(), | |
1042 | expected_ty, | |
1043 | ); | |
48663c56 XL |
1044 | let lit_msg = format!( |
1045 | "change the type of the numeric literal from `{}` to `{}`", | |
dfeec247 | 1046 | checked_ty, expected_ty, |
48663c56 XL |
1047 | ); |
1048 | ||
c295e0f8 XL |
1049 | let close_paren = if expr.precedence().order() < PREC_POSTFIX { |
1050 | sugg.push((expr.span.shrink_to_lo(), "(".to_string())); | |
1051 | ")" | |
1052 | } else { | |
1053 | "" | |
1054 | }; | |
f035d41b | 1055 | |
c295e0f8 XL |
1056 | let mut cast_suggestion = sugg.clone(); |
1057 | cast_suggestion | |
1058 | .push((expr.span.shrink_to_hi(), format!("{} as {}", close_paren, expected_ty))); | |
1059 | let mut into_suggestion = sugg.clone(); | |
1060 | into_suggestion.push((expr.span.shrink_to_hi(), format!("{}.into()", close_paren))); | |
1061 | let mut suffix_suggestion = sugg.clone(); | |
1062 | suffix_suggestion.push(( | |
f035d41b | 1063 | if matches!( |
1b1a35ee | 1064 | (&expected_ty.kind(), &checked_ty.kind()), |
f035d41b XL |
1065 | (ty::Int(_) | ty::Uint(_), ty::Float(_)) |
1066 | ) { | |
1067 | // Remove fractional part from literal, for example `42.0f32` into `42` | |
1068 | let src = src.trim_end_matches(&checked_ty.to_string()); | |
c295e0f8 XL |
1069 | let len = src.split('.').next().unwrap().len(); |
1070 | expr.span.with_lo(expr.span.lo() + BytePos(len as u32)) | |
f035d41b | 1071 | } else { |
c295e0f8 XL |
1072 | let len = src.trim_end_matches(&checked_ty.to_string()).len(); |
1073 | expr.span.with_lo(expr.span.lo() + BytePos(len as u32)) | |
1074 | }, | |
1075 | if expr.precedence().order() < PREC_POSTFIX { | |
1076 | // Readd `)` | |
1077 | format!("{})", expected_ty) | |
1078 | } else { | |
1079 | expected_ty.to_string() | |
f035d41b | 1080 | }, |
f035d41b XL |
1081 | )); |
1082 | let literal_is_ty_suffixed = |expr: &hir::Expr<'_>| { | |
1083 | if let hir::ExprKind::Lit(lit) = &expr.kind { lit.node.is_suffixed() } else { false } | |
1084 | }; | |
1085 | let is_negative_int = | |
6a06907d | 1086 | |expr: &hir::Expr<'_>| matches!(expr.kind, hir::ExprKind::Unary(hir::UnOp::Neg, ..)); |
1b1a35ee | 1087 | let is_uint = |ty: Ty<'_>| matches!(ty.kind(), ty::Uint(..)); |
f035d41b XL |
1088 | |
1089 | let in_const_context = self.tcx.hir().is_inside_const_context(expr.hir_id); | |
1090 | ||
1091 | let suggest_fallible_into_or_lhs_from = | |
5e7ed085 | 1092 | |err: &mut Diagnostic, exp_to_found_is_fallible: bool| { |
f035d41b XL |
1093 | // If we know the expression the expected type is derived from, we might be able |
1094 | // to suggest a widening conversion rather than a narrowing one (which may | |
1095 | // panic). For example, given x: u8 and y: u32, if we know the span of "x", | |
1096 | // x > y | |
1097 | // can be given the suggestion "u32::from(x) > y" rather than | |
1098 | // "x > y.try_into().unwrap()". | |
1099 | let lhs_expr_and_src = expected_ty_expr.and_then(|expr| { | |
fc512014 XL |
1100 | self.tcx |
1101 | .sess | |
1102 | .source_map() | |
1103 | .span_to_snippet(expr.span) | |
1104 | .ok() | |
1105 | .map(|src| (expr, src)) | |
f035d41b | 1106 | }); |
c295e0f8 | 1107 | let (msg, suggestion) = if let (Some((lhs_expr, lhs_src)), false) = |
f035d41b | 1108 | (lhs_expr_and_src, exp_to_found_is_fallible) |
dfeec247 | 1109 | { |
f035d41b XL |
1110 | let msg = format!( |
1111 | "you can convert `{}` from `{}` to `{}`, matching the type of `{}`", | |
1112 | lhs_src, expected_ty, checked_ty, src | |
1113 | ); | |
c295e0f8 XL |
1114 | let suggestion = vec![ |
1115 | (lhs_expr.span.shrink_to_lo(), format!("{}::from(", checked_ty)), | |
1116 | (lhs_expr.span.shrink_to_hi(), ")".to_string()), | |
1117 | ]; | |
1118 | (msg, suggestion) | |
48663c56 | 1119 | } else { |
29967ef6 | 1120 | let msg = format!("{} and panic if the converted value doesn't fit", msg); |
c295e0f8 XL |
1121 | let mut suggestion = sugg.clone(); |
1122 | suggestion.push(( | |
1123 | expr.span.shrink_to_hi(), | |
1124 | format!("{}.try_into().unwrap()", close_paren), | |
1125 | )); | |
1126 | (msg, suggestion) | |
f035d41b | 1127 | }; |
c295e0f8 XL |
1128 | err.multipart_suggestion_verbose( |
1129 | &msg, | |
1130 | suggestion, | |
1131 | Applicability::MachineApplicable, | |
1132 | ); | |
f035d41b XL |
1133 | }; |
1134 | ||
1135 | let suggest_to_change_suffix_or_into = | |
5e7ed085 | 1136 | |err: &mut Diagnostic, |
f035d41b XL |
1137 | found_to_exp_is_fallible: bool, |
1138 | exp_to_found_is_fallible: bool| { | |
5869c6ff XL |
1139 | let exp_is_lhs = |
1140 | expected_ty_expr.map(|e| self.tcx.hir().is_lhs(e.hir_id)).unwrap_or(false); | |
1141 | ||
1142 | if exp_is_lhs { | |
1143 | return; | |
1144 | } | |
1145 | ||
f035d41b XL |
1146 | let always_fallible = found_to_exp_is_fallible |
1147 | && (exp_to_found_is_fallible || expected_ty_expr.is_none()); | |
1148 | let msg = if literal_is_ty_suffixed(expr) { | |
1149 | &lit_msg | |
1150 | } else if always_fallible && (is_negative_int(expr) && is_uint(expected_ty)) { | |
1151 | // We now know that converting either the lhs or rhs is fallible. Before we | |
1152 | // suggest a fallible conversion, check if the value can never fit in the | |
1153 | // expected type. | |
1154 | let msg = format!("`{}` cannot fit into type `{}`", src, expected_ty); | |
1155 | err.note(&msg); | |
1156 | return; | |
1157 | } else if in_const_context { | |
1158 | // Do not recommend `into` or `try_into` in const contexts. | |
1159 | return; | |
1160 | } else if found_to_exp_is_fallible { | |
1161 | return suggest_fallible_into_or_lhs_from(err, exp_to_found_is_fallible); | |
0bf4aa26 | 1162 | } else { |
f035d41b XL |
1163 | &msg |
1164 | }; | |
1165 | let suggestion = if literal_is_ty_suffixed(expr) { | |
1166 | suffix_suggestion.clone() | |
1167 | } else { | |
1168 | into_suggestion.clone() | |
1169 | }; | |
c295e0f8 | 1170 | err.multipart_suggestion_verbose(msg, suggestion, Applicability::MachineApplicable); |
0bf4aa26 XL |
1171 | }; |
1172 | ||
1b1a35ee | 1173 | match (&expected_ty.kind(), &checked_ty.kind()) { |
f035d41b XL |
1174 | (&ty::Int(ref exp), &ty::Int(ref found)) => { |
1175 | let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) | |
1176 | { | |
1177 | (Some(exp), Some(found)) if exp < found => (true, false), | |
1178 | (Some(exp), Some(found)) if exp > found => (false, true), | |
1179 | (None, Some(8 | 16)) => (false, true), | |
1180 | (Some(8 | 16), None) => (true, false), | |
1181 | (None, _) | (_, None) => (true, true), | |
1182 | _ => (false, false), | |
1183 | }; | |
1184 | suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); | |
1185 | true | |
1186 | } | |
1187 | (&ty::Uint(ref exp), &ty::Uint(ref found)) => { | |
1188 | let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) | |
1189 | { | |
1190 | (Some(exp), Some(found)) if exp < found => (true, false), | |
1191 | (Some(exp), Some(found)) if exp > found => (false, true), | |
1192 | (None, Some(8 | 16)) => (false, true), | |
1193 | (Some(8 | 16), None) => (true, false), | |
1194 | (None, _) | (_, None) => (true, true), | |
1195 | _ => (false, false), | |
1196 | }; | |
1197 | suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); | |
1198 | true | |
1199 | } | |
1200 | (&ty::Int(exp), &ty::Uint(found)) => { | |
1201 | let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) | |
1202 | { | |
1203 | (Some(exp), Some(found)) if found < exp => (false, true), | |
1204 | (None, Some(8)) => (false, true), | |
1205 | _ => (true, true), | |
1206 | }; | |
1207 | suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); | |
1208 | true | |
1209 | } | |
1210 | (&ty::Uint(exp), &ty::Int(found)) => { | |
1211 | let (f2e_is_fallible, e2f_is_fallible) = match (exp.bit_width(), found.bit_width()) | |
1212 | { | |
1213 | (Some(exp), Some(found)) if found > exp => (true, false), | |
1214 | (Some(8), None) => (true, false), | |
1215 | _ => (true, true), | |
1216 | }; | |
1217 | suggest_to_change_suffix_or_into(err, f2e_is_fallible, e2f_is_fallible); | |
1218 | true | |
1219 | } | |
1220 | (&ty::Float(ref exp), &ty::Float(ref found)) => { | |
1221 | if found.bit_width() < exp.bit_width() { | |
1222 | suggest_to_change_suffix_or_into(err, false, true); | |
1223 | } else if literal_is_ty_suffixed(expr) { | |
c295e0f8 | 1224 | err.multipart_suggestion_verbose( |
f035d41b XL |
1225 | &lit_msg, |
1226 | suffix_suggestion, | |
dfeec247 XL |
1227 | Applicability::MachineApplicable, |
1228 | ); | |
f035d41b XL |
1229 | } else if can_cast { |
1230 | // Missing try_into implementation for `f64` to `f32` | |
c295e0f8 | 1231 | err.multipart_suggestion_verbose( |
f035d41b XL |
1232 | &format!("{}, producing the closest possible value", cast_msg), |
1233 | cast_suggestion, | |
1234 | Applicability::MaybeIncorrect, // lossy conversion | |
1235 | ); | |
2c00a5a8 | 1236 | } |
f035d41b XL |
1237 | true |
1238 | } | |
1239 | (&ty::Uint(_) | &ty::Int(_), &ty::Float(_)) => { | |
1240 | if literal_is_ty_suffixed(expr) { | |
c295e0f8 | 1241 | err.multipart_suggestion_verbose( |
f035d41b XL |
1242 | &lit_msg, |
1243 | suffix_suggestion, | |
1244 | Applicability::MachineApplicable, | |
1245 | ); | |
1246 | } else if can_cast { | |
1247 | // Missing try_into implementation for `{float}` to `{integer}` | |
c295e0f8 | 1248 | err.multipart_suggestion_verbose( |
f035d41b XL |
1249 | &format!("{}, rounding the float towards zero", msg), |
1250 | cast_suggestion, | |
1251 | Applicability::MaybeIncorrect, // lossy conversion | |
1252 | ); | |
2c00a5a8 | 1253 | } |
f035d41b XL |
1254 | true |
1255 | } | |
1256 | (&ty::Float(ref exp), &ty::Uint(ref found)) => { | |
1257 | // if `found` is `None` (meaning found is `usize`), don't suggest `.into()` | |
1258 | if exp.bit_width() > found.bit_width().unwrap_or(256) { | |
c295e0f8 | 1259 | err.multipart_suggestion_verbose( |
f035d41b XL |
1260 | &format!( |
1261 | "{}, producing the floating point representation of the integer", | |
1262 | msg, | |
1263 | ), | |
1264 | into_suggestion, | |
1265 | Applicability::MachineApplicable, | |
1266 | ); | |
1267 | } else if literal_is_ty_suffixed(expr) { | |
c295e0f8 | 1268 | err.multipart_suggestion_verbose( |
f035d41b XL |
1269 | &lit_msg, |
1270 | suffix_suggestion, | |
1271 | Applicability::MachineApplicable, | |
1272 | ); | |
1273 | } else { | |
1274 | // Missing try_into implementation for `{integer}` to `{float}` | |
c295e0f8 | 1275 | err.multipart_suggestion_verbose( |
f035d41b | 1276 | &format!( |
a2a8927a | 1277 | "{}, producing the floating point representation of the integer, \ |
48663c56 | 1278 | rounded if necessary", |
f035d41b XL |
1279 | cast_msg, |
1280 | ), | |
1281 | cast_suggestion, | |
1282 | Applicability::MaybeIncorrect, // lossy conversion | |
1283 | ); | |
2c00a5a8 | 1284 | } |
f035d41b XL |
1285 | true |
1286 | } | |
1287 | (&ty::Float(ref exp), &ty::Int(ref found)) => { | |
1288 | // if `found` is `None` (meaning found is `isize`), don't suggest `.into()` | |
1289 | if exp.bit_width() > found.bit_width().unwrap_or(256) { | |
c295e0f8 | 1290 | err.multipart_suggestion_verbose( |
f035d41b XL |
1291 | &format!( |
1292 | "{}, producing the floating point representation of the integer", | |
1293 | &msg, | |
1294 | ), | |
1295 | into_suggestion, | |
1296 | Applicability::MachineApplicable, | |
1297 | ); | |
1298 | } else if literal_is_ty_suffixed(expr) { | |
c295e0f8 | 1299 | err.multipart_suggestion_verbose( |
f035d41b XL |
1300 | &lit_msg, |
1301 | suffix_suggestion, | |
1302 | Applicability::MachineApplicable, | |
1303 | ); | |
1304 | } else { | |
1305 | // Missing try_into implementation for `{integer}` to `{float}` | |
c295e0f8 | 1306 | err.multipart_suggestion_verbose( |
f035d41b XL |
1307 | &format!( |
1308 | "{}, producing the floating point representation of the integer, \ | |
1309 | rounded if necessary", | |
1310 | &msg, | |
1311 | ), | |
1312 | cast_suggestion, | |
1313 | Applicability::MaybeIncorrect, // lossy conversion | |
1314 | ); | |
2c00a5a8 | 1315 | } |
f035d41b | 1316 | true |
2c00a5a8 | 1317 | } |
a2a8927a XL |
1318 | ( |
1319 | &ty::Uint(ty::UintTy::U32 | ty::UintTy::U64 | ty::UintTy::U128) | |
1320 | | &ty::Int(ty::IntTy::I32 | ty::IntTy::I64 | ty::IntTy::I128), | |
1321 | &ty::Char, | |
1322 | ) => { | |
1323 | err.multipart_suggestion_verbose( | |
1324 | &format!("{}, since a `char` always occupies 4 bytes", cast_msg,), | |
1325 | cast_suggestion, | |
1326 | Applicability::MachineApplicable, | |
1327 | ); | |
1328 | true | |
1329 | } | |
f035d41b | 1330 | _ => false, |
2c00a5a8 XL |
1331 | } |
1332 | } | |
cdc7bbd5 XL |
1333 | |
1334 | // Report the type inferred by the return statement. | |
5e7ed085 | 1335 | fn report_closure_inferred_return_type(&self, err: &mut Diagnostic, expected: Ty<'tcx>) { |
cdc7bbd5 | 1336 | if let Some(sp) = self.ret_coercion_span.get() { |
94222f64 XL |
1337 | // If the closure has an explicit return type annotation, or if |
1338 | // the closure's return type has been inferred from outside | |
1339 | // requirements (such as an Fn* trait bound), then a type error | |
1340 | // may occur at the first return expression we see in the closure | |
1341 | // (if it conflicts with the declared return type). Skip adding a | |
1342 | // note in this case, since it would be incorrect. | |
1343 | if !self.return_type_pre_known { | |
1344 | err.span_note( | |
1345 | sp, | |
1346 | &format!( | |
1347 | "return type inferred to be `{}` here", | |
1348 | self.resolve_vars_if_possible(expected) | |
1349 | ), | |
1350 | ); | |
cdc7bbd5 XL |
1351 | } |
1352 | } | |
1353 | } | |
1a4d82fc | 1354 | } |