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