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Commit | Line | Data |
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c34b1796 AL |
1 | //! Code related to processing overloaded binary and unary operators. |
2 | ||
7cac9316 | 3 | use super::method::MethodCallee; |
17df50a5 | 4 | use super::{has_expected_num_generic_args, FnCtxt}; |
2b03887a | 5 | use crate::Expectation; |
29967ef6 | 6 | use rustc_ast as ast; |
5e7ed085 | 7 | use rustc_errors::{self, struct_span_err, Applicability, Diagnostic}; |
dfeec247 | 8 | use rustc_hir as hir; |
74b04a01 | 9 | use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; |
064997fb | 10 | use rustc_infer::traits::ObligationCauseCode; |
ba9703b0 XL |
11 | use rustc_middle::ty::adjustment::{ |
12 | Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, | |
13 | }; | |
f2b60f7d | 14 | use rustc_middle::ty::print::with_no_trimmed_paths; |
353b0b11 | 15 | use rustc_middle::ty::{self, IsSuggestable, Ty, TyCtxt, TypeVisitableExt}; |
2b03887a | 16 | use rustc_session::errors::ExprParenthesesNeeded; |
29967ef6 | 17 | use rustc_span::source_map::Spanned; |
3dfed10e | 18 | use rustc_span::symbol::{sym, Ident}; |
dfeec247 | 19 | use rustc_span::Span; |
ba9703b0 | 20 | use rustc_trait_selection::infer::InferCtxtExt; |
2b03887a | 21 | use rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt as _; |
353b0b11 | 22 | use rustc_trait_selection::traits::{self, FulfillmentError, ObligationCtxt}; |
923072b8 | 23 | use rustc_type_ir::sty::TyKind::*; |
60c5eb7d | 24 | |
dc9dc135 | 25 | impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
9fa01778 | 26 | /// Checks a `a <op>= b` |
dc9dc135 XL |
27 | pub fn check_binop_assign( |
28 | &self, | |
dfeec247 | 29 | expr: &'tcx hir::Expr<'tcx>, |
dc9dc135 | 30 | op: hir::BinOp, |
dfeec247 XL |
31 | lhs: &'tcx hir::Expr<'tcx>, |
32 | rhs: &'tcx hir::Expr<'tcx>, | |
064997fb | 33 | expected: Expectation<'tcx>, |
dc9dc135 | 34 | ) -> Ty<'tcx> { |
abe05a73 | 35 | let (lhs_ty, rhs_ty, return_ty) = |
064997fb | 36 | self.check_overloaded_binop(expr, lhs, rhs, op, IsAssign::Yes, expected); |
a7813a04 | 37 | |
dfeec247 XL |
38 | let ty = |
39 | if !lhs_ty.is_ty_var() && !rhs_ty.is_ty_var() && is_builtin_binop(lhs_ty, rhs_ty, op) { | |
5e7ed085 | 40 | self.enforce_builtin_binop_types(lhs.span, lhs_ty, rhs.span, rhs_ty, op); |
dfeec247 XL |
41 | self.tcx.mk_unit() |
42 | } else { | |
43 | return_ty | |
44 | }; | |
45 | ||
923072b8 FG |
46 | self.check_lhs_assignable(lhs, "E0067", op.span, |err| { |
47 | if let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) { | |
48 | if self | |
49 | .lookup_op_method( | |
50 | lhs_deref_ty, | |
9c376795 | 51 | Some((rhs, rhs_ty)), |
923072b8 | 52 | Op::Binary(op, IsAssign::Yes), |
064997fb | 53 | expected, |
923072b8 FG |
54 | ) |
55 | .is_ok() | |
56 | { | |
f2b60f7d FG |
57 | // If LHS += RHS is an error, but *LHS += RHS is successful, then we will have |
58 | // emitted a better suggestion during error handling in check_overloaded_binop. | |
59 | if self | |
60 | .lookup_op_method( | |
61 | lhs_ty, | |
9c376795 | 62 | Some((rhs, rhs_ty)), |
f2b60f7d FG |
63 | Op::Binary(op, IsAssign::Yes), |
64 | expected, | |
65 | ) | |
66 | .is_err() | |
67 | { | |
68 | err.downgrade_to_delayed_bug(); | |
69 | } else { | |
70 | // Otherwise, it's valid to suggest dereferencing the LHS here. | |
71 | err.span_suggestion_verbose( | |
72 | lhs.span.shrink_to_lo(), | |
73 | "consider dereferencing the left-hand side of this operation", | |
74 | "*", | |
75 | Applicability::MaybeIncorrect, | |
76 | ); | |
77 | } | |
923072b8 FG |
78 | } |
79 | } | |
80 | }); | |
c34b1796 | 81 | |
9e0c209e | 82 | ty |
c34b1796 | 83 | } |
c34b1796 | 84 | |
9fa01778 | 85 | /// Checks a potentially overloaded binary operator. |
dc9dc135 XL |
86 | pub fn check_binop( |
87 | &self, | |
dfeec247 | 88 | expr: &'tcx hir::Expr<'tcx>, |
dc9dc135 | 89 | op: hir::BinOp, |
dfeec247 XL |
90 | lhs_expr: &'tcx hir::Expr<'tcx>, |
91 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
064997fb | 92 | expected: Expectation<'tcx>, |
dc9dc135 | 93 | ) -> Ty<'tcx> { |
a7813a04 XL |
94 | let tcx = self.tcx; |
95 | ||
dfeec247 XL |
96 | debug!( |
97 | "check_binop(expr.hir_id={}, expr={:?}, op={:?}, lhs_expr={:?}, rhs_expr={:?})", | |
98 | expr.hir_id, expr, op, lhs_expr, rhs_expr | |
99 | ); | |
a7813a04 | 100 | |
a7813a04 XL |
101 | match BinOpCategory::from(op) { |
102 | BinOpCategory::Shortcircuit => { | |
103 | // && and || are a simple case. | |
353b0b11 | 104 | self.check_expr_coercible_to_type(lhs_expr, tcx.types.bool, None); |
476ff2be | 105 | let lhs_diverges = self.diverges.get(); |
353b0b11 | 106 | self.check_expr_coercible_to_type(rhs_expr, tcx.types.bool, None); |
476ff2be SL |
107 | |
108 | // Depending on the LHS' value, the RHS can never execute. | |
109 | self.diverges.set(lhs_diverges); | |
110 | ||
abe05a73 | 111 | tcx.types.bool |
c34b1796 | 112 | } |
a7813a04 XL |
113 | _ => { |
114 | // Otherwise, we always treat operators as if they are | |
115 | // overloaded. This is the way to be most flexible w/r/t | |
116 | // types that get inferred. | |
064997fb FG |
117 | let (lhs_ty, rhs_ty, return_ty) = self.check_overloaded_binop( |
118 | expr, | |
119 | lhs_expr, | |
120 | rhs_expr, | |
121 | op, | |
122 | IsAssign::No, | |
123 | expected, | |
124 | ); | |
a7813a04 XL |
125 | |
126 | // Supply type inference hints if relevant. Probably these | |
127 | // hints should be enforced during select as part of the | |
128 | // `consider_unification_despite_ambiguity` routine, but this | |
129 | // more convenient for now. | |
130 | // | |
131 | // The basic idea is to help type inference by taking | |
132 | // advantage of things we know about how the impls for | |
133 | // scalar types are arranged. This is important in a | |
134 | // scenario like `1_u32 << 2`, because it lets us quickly | |
135 | // deduce that the result type should be `u32`, even | |
136 | // though we don't know yet what type 2 has and hence | |
137 | // can't pin this down to a specific impl. | |
dfeec247 XL |
138 | if !lhs_ty.is_ty_var() |
139 | && !rhs_ty.is_ty_var() | |
140 | && is_builtin_binop(lhs_ty, rhs_ty, op) | |
a7813a04 | 141 | { |
74b04a01 | 142 | let builtin_return_ty = self.enforce_builtin_binop_types( |
5e7ed085 | 143 | lhs_expr.span, |
74b04a01 | 144 | lhs_ty, |
5e7ed085 | 145 | rhs_expr.span, |
74b04a01 XL |
146 | rhs_ty, |
147 | op, | |
148 | ); | |
353b0b11 FG |
149 | self.demand_eqtype(expr.span, builtin_return_ty, return_ty); |
150 | builtin_return_ty | |
151 | } else { | |
152 | return_ty | |
a7813a04 | 153 | } |
a7813a04 | 154 | } |
c34b1796 AL |
155 | } |
156 | } | |
c34b1796 | 157 | |
dc9dc135 XL |
158 | fn enforce_builtin_binop_types( |
159 | &self, | |
5e7ed085 | 160 | lhs_span: Span, |
dc9dc135 | 161 | lhs_ty: Ty<'tcx>, |
5e7ed085 | 162 | rhs_span: Span, |
dc9dc135 XL |
163 | rhs_ty: Ty<'tcx>, |
164 | op: hir::BinOp, | |
165 | ) -> Ty<'tcx> { | |
a7813a04 XL |
166 | debug_assert!(is_builtin_binop(lhs_ty, rhs_ty, op)); |
167 | ||
74b04a01 XL |
168 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. |
169 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
170 | let (lhs_ty, rhs_ty) = (deref_ty_if_possible(lhs_ty), deref_ty_if_possible(rhs_ty)); | |
171 | ||
a7813a04 XL |
172 | let tcx = self.tcx; |
173 | match BinOpCategory::from(op) { | |
174 | BinOpCategory::Shortcircuit => { | |
5e7ed085 FG |
175 | self.demand_suptype(lhs_span, tcx.types.bool, lhs_ty); |
176 | self.demand_suptype(rhs_span, tcx.types.bool, rhs_ty); | |
f9f354fc | 177 | tcx.types.bool |
a7813a04 | 178 | } |
c34b1796 | 179 | |
a7813a04 XL |
180 | BinOpCategory::Shift => { |
181 | // result type is same as LHS always | |
182 | lhs_ty | |
183 | } | |
c34b1796 | 184 | |
dfeec247 | 185 | BinOpCategory::Math | BinOpCategory::Bitwise => { |
a7813a04 | 186 | // both LHS and RHS and result will have the same type |
5e7ed085 | 187 | self.demand_suptype(rhs_span, lhs_ty, rhs_ty); |
a7813a04 XL |
188 | lhs_ty |
189 | } | |
c34b1796 | 190 | |
a7813a04 XL |
191 | BinOpCategory::Comparison => { |
192 | // both LHS and RHS and result will have the same type | |
5e7ed085 | 193 | self.demand_suptype(rhs_span, lhs_ty, rhs_ty); |
f9f354fc | 194 | tcx.types.bool |
a7813a04 | 195 | } |
c34b1796 AL |
196 | } |
197 | } | |
c34b1796 | 198 | |
dc9dc135 XL |
199 | fn check_overloaded_binop( |
200 | &self, | |
dfeec247 XL |
201 | expr: &'tcx hir::Expr<'tcx>, |
202 | lhs_expr: &'tcx hir::Expr<'tcx>, | |
203 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
dc9dc135 XL |
204 | op: hir::BinOp, |
205 | is_assign: IsAssign, | |
064997fb | 206 | expected: Expectation<'tcx>, |
dc9dc135 | 207 | ) -> (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>) { |
dfeec247 XL |
208 | debug!( |
209 | "check_overloaded_binop(expr.hir_id={}, op={:?}, is_assign={:?})", | |
210 | expr.hir_id, op, is_assign | |
211 | ); | |
a7813a04 | 212 | |
74d20737 XL |
213 | let lhs_ty = match is_assign { |
214 | IsAssign::No => { | |
215 | // Find a suitable supertype of the LHS expression's type, by coercing to | |
216 | // a type variable, to pass as the `Self` to the trait, avoiding invariant | |
217 | // trait matching creating lifetime constraints that are too strict. | |
0731742a | 218 | // e.g., adding `&'a T` and `&'b T`, given `&'x T: Add<&'x T>`, will result |
74d20737 | 219 | // in `&'a T <: &'x T` and `&'b T <: &'x T`, instead of `'a = 'b = 'x`. |
f035d41b | 220 | let lhs_ty = self.check_expr(lhs_expr); |
dc9dc135 XL |
221 | let fresh_var = self.next_ty_var(TypeVariableOrigin { |
222 | kind: TypeVariableOriginKind::MiscVariable, | |
223 | span: lhs_expr.span, | |
224 | }); | |
f035d41b | 225 | self.demand_coerce(lhs_expr, lhs_ty, fresh_var, Some(rhs_expr), AllowTwoPhase::No) |
74d20737 XL |
226 | } |
227 | IsAssign::Yes => { | |
228 | // rust-lang/rust#52126: We have to use strict | |
229 | // equivalence on the LHS of an assign-op like `+=`; | |
230 | // overwritten or mutably-borrowed places cannot be | |
231 | // coerced to a supertype. | |
f035d41b | 232 | self.check_expr(lhs_expr) |
74d20737 | 233 | } |
abe05a73 | 234 | }; |
e74abb32 | 235 | let lhs_ty = self.resolve_vars_with_obligations(lhs_ty); |
abe05a73 | 236 | |
0731742a | 237 | // N.B., as we have not yet type-checked the RHS, we don't have the |
a7813a04 XL |
238 | // type at hand. Make a variable to represent it. The whole reason |
239 | // for this indirection is so that, below, we can check the expr | |
240 | // using this variable as the expected type, which sometimes lets | |
241 | // us do better coercions than we would be able to do otherwise, | |
242 | // particularly for things like `String + &String`. | |
dc9dc135 XL |
243 | let rhs_ty_var = self.next_ty_var(TypeVariableOrigin { |
244 | kind: TypeVariableOriginKind::MiscVariable, | |
245 | span: rhs_expr.span, | |
246 | }); | |
a7813a04 | 247 | |
5e7ed085 FG |
248 | let result = self.lookup_op_method( |
249 | lhs_ty, | |
9c376795 | 250 | Some((rhs_expr, rhs_ty_var)), |
5e7ed085 | 251 | Op::Binary(op, is_assign), |
064997fb | 252 | expected, |
5e7ed085 | 253 | ); |
8bb4bdeb XL |
254 | |
255 | // see `NB` above | |
353b0b11 | 256 | let rhs_ty = self.check_expr_coercible_to_type(rhs_expr, rhs_ty_var, Some(lhs_expr)); |
e74abb32 | 257 | let rhs_ty = self.resolve_vars_with_obligations(rhs_ty); |
8bb4bdeb | 258 | |
7cac9316 XL |
259 | let return_ty = match result { |
260 | Ok(method) => { | |
261 | let by_ref_binop = !op.node.is_by_value(); | |
262 | if is_assign == IsAssign::Yes || by_ref_binop { | |
1b1a35ee | 263 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].kind() { |
487cf647 | 264 | let mutbl = AutoBorrowMutability::new(*mutbl, AllowTwoPhase::Yes); |
7cac9316 | 265 | let autoref = Adjustment { |
5099ac24 | 266 | kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), |
dfeec247 | 267 | target: method.sig.inputs()[0], |
7cac9316 XL |
268 | }; |
269 | self.apply_adjustments(lhs_expr, vec![autoref]); | |
270 | } | |
271 | } | |
272 | if by_ref_binop { | |
1b1a35ee | 273 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[1].kind() { |
487cf647 FG |
274 | // Allow two-phase borrows for binops in initial deployment |
275 | // since they desugar to methods | |
276 | let mutbl = AutoBorrowMutability::new(*mutbl, AllowTwoPhase::Yes); | |
277 | ||
7cac9316 | 278 | let autoref = Adjustment { |
5099ac24 | 279 | kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), |
dfeec247 | 280 | target: method.sig.inputs()[1], |
7cac9316 XL |
281 | }; |
282 | // HACK(eddyb) Bypass checks due to reborrows being in | |
283 | // some cases applied on the RHS, on top of which we need | |
284 | // to autoref, which is not allowed by apply_adjustments. | |
285 | // self.apply_adjustments(rhs_expr, vec![autoref]); | |
3dfed10e | 286 | self.typeck_results |
3b2f2976 XL |
287 | .borrow_mut() |
288 | .adjustments_mut() | |
289 | .entry(rhs_expr.hir_id) | |
b7449926 | 290 | .or_default() |
3b2f2976 | 291 | .push(autoref); |
7cac9316 XL |
292 | } |
293 | } | |
3b2f2976 | 294 | self.write_method_call(expr.hir_id, method); |
7cac9316 XL |
295 | |
296 | method.sig.output() | |
297 | } | |
f035d41b | 298 | // error types are considered "builtin" |
9ffffee4 FG |
299 | Err(_) if lhs_ty.references_error() || rhs_ty.references_error() => { |
300 | self.tcx.ty_error_misc() | |
301 | } | |
c295e0f8 | 302 | Err(errors) => { |
f2b60f7d FG |
303 | let (_, trait_def_id) = |
304 | lang_item_for_op(self.tcx, Op::Binary(op, is_assign), op.span); | |
305 | let missing_trait = trait_def_id | |
306 | .map(|def_id| with_no_trimmed_paths!(self.tcx.def_path_str(def_id))); | |
307 | let (mut err, output_def_id) = match is_assign { | |
f035d41b XL |
308 | IsAssign::Yes => { |
309 | let mut err = struct_span_err!( | |
310 | self.tcx.sess, | |
311 | expr.span, | |
312 | E0368, | |
313 | "binary assignment operation `{}=` cannot be applied to type `{}`", | |
314 | op.node.as_str(), | |
315 | lhs_ty, | |
316 | ); | |
317 | err.span_label( | |
318 | lhs_expr.span, | |
319 | format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty), | |
320 | ); | |
c295e0f8 | 321 | self.note_unmet_impls_on_type(&mut err, errors); |
f2b60f7d | 322 | (err, None) |
f035d41b XL |
323 | } |
324 | IsAssign::No => { | |
f2b60f7d FG |
325 | let message = match op.node { |
326 | hir::BinOpKind::Add => { | |
327 | format!("cannot add `{rhs_ty}` to `{lhs_ty}`") | |
328 | } | |
329 | hir::BinOpKind::Sub => { | |
330 | format!("cannot subtract `{rhs_ty}` from `{lhs_ty}`") | |
331 | } | |
332 | hir::BinOpKind::Mul => { | |
333 | format!("cannot multiply `{lhs_ty}` by `{rhs_ty}`") | |
334 | } | |
335 | hir::BinOpKind::Div => { | |
336 | format!("cannot divide `{lhs_ty}` by `{rhs_ty}`") | |
337 | } | |
338 | hir::BinOpKind::Rem => { | |
9ffffee4 FG |
339 | format!( |
340 | "cannot calculate the remainder of `{lhs_ty}` divided by `{rhs_ty}`" | |
341 | ) | |
f2b60f7d FG |
342 | } |
343 | hir::BinOpKind::BitAnd => { | |
344 | format!("no implementation for `{lhs_ty} & {rhs_ty}`") | |
345 | } | |
346 | hir::BinOpKind::BitXor => { | |
347 | format!("no implementation for `{lhs_ty} ^ {rhs_ty}`") | |
348 | } | |
349 | hir::BinOpKind::BitOr => { | |
350 | format!("no implementation for `{lhs_ty} | {rhs_ty}`") | |
351 | } | |
352 | hir::BinOpKind::Shl => { | |
353 | format!("no implementation for `{lhs_ty} << {rhs_ty}`") | |
354 | } | |
355 | hir::BinOpKind::Shr => { | |
356 | format!("no implementation for `{lhs_ty} >> {rhs_ty}`") | |
357 | } | |
358 | _ => format!( | |
359 | "binary operation `{}` cannot be applied to type `{}`", | |
360 | op.node.as_str(), | |
361 | lhs_ty | |
f035d41b XL |
362 | ), |
363 | }; | |
f2b60f7d FG |
364 | let output_def_id = trait_def_id.and_then(|def_id| { |
365 | self.tcx | |
366 | .associated_item_def_ids(def_id) | |
367 | .iter() | |
368 | .find(|item_def_id| { | |
369 | self.tcx.associated_item(*item_def_id).name == sym::Output | |
370 | }) | |
371 | .cloned() | |
372 | }); | |
064997fb | 373 | let mut err = struct_span_err!(self.tcx.sess, op.span, E0369, "{message}"); |
f035d41b | 374 | if !lhs_expr.span.eq(&rhs_expr.span) { |
f2b60f7d FG |
375 | err.span_label(lhs_expr.span, lhs_ty.to_string()); |
376 | err.span_label(rhs_expr.span, rhs_ty.to_string()); | |
32a655c1 | 377 | } |
c295e0f8 | 378 | self.note_unmet_impls_on_type(&mut err, errors); |
f2b60f7d | 379 | (err, output_def_id) |
f035d41b XL |
380 | } |
381 | }; | |
923072b8 FG |
382 | |
383 | let mut suggest_deref_binop = |lhs_deref_ty: Ty<'tcx>| { | |
384 | if self | |
385 | .lookup_op_method( | |
386 | lhs_deref_ty, | |
9c376795 | 387 | Some((rhs_expr, rhs_ty)), |
923072b8 | 388 | Op::Binary(op, is_assign), |
064997fb | 389 | expected, |
923072b8 FG |
390 | ) |
391 | .is_ok() | |
3c0e092e | 392 | { |
49aad941 | 393 | let msg = format!( |
f2b60f7d FG |
394 | "`{}{}` can be used on `{}` if you dereference the left-hand side", |
395 | op.node.as_str(), | |
396 | match is_assign { | |
397 | IsAssign::Yes => "=", | |
398 | IsAssign::No => "", | |
399 | }, | |
400 | lhs_deref_ty, | |
401 | ); | |
402 | err.span_suggestion_verbose( | |
403 | lhs_expr.span.shrink_to_lo(), | |
404 | msg, | |
405 | "*", | |
406 | rustc_errors::Applicability::MachineApplicable, | |
407 | ); | |
f035d41b | 408 | } |
923072b8 FG |
409 | }; |
410 | ||
49aad941 | 411 | let is_compatible_after_call = |lhs_ty, rhs_ty| { |
f2b60f7d FG |
412 | self.lookup_op_method( |
413 | lhs_ty, | |
9c376795 | 414 | Some((rhs_expr, rhs_ty)), |
f2b60f7d FG |
415 | Op::Binary(op, is_assign), |
416 | expected, | |
417 | ) | |
418 | .is_ok() | |
49aad941 FG |
419 | // Suggest calling even if, after calling, the types don't |
420 | // implement the operator, since it'll lead to better | |
421 | // diagnostics later. | |
422 | || self.can_eq(self.param_env, lhs_ty, rhs_ty) | |
f2b60f7d FG |
423 | }; |
424 | ||
923072b8 FG |
425 | // We should suggest `a + b` => `*a + b` if `a` is copy, and suggest |
426 | // `a += b` => `*a += b` if a is a mut ref. | |
f2b60f7d FG |
427 | if !op.span.can_be_used_for_suggestions() { |
428 | // Suppress suggestions when lhs and rhs are not in the same span as the error | |
429 | } else if is_assign == IsAssign::Yes | |
430 | && let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) | |
431 | { | |
432 | suggest_deref_binop(lhs_deref_ty); | |
923072b8 | 433 | } else if is_assign == IsAssign::No |
f2b60f7d FG |
434 | && let Ref(_, lhs_deref_ty, _) = lhs_ty.kind() |
435 | { | |
436 | if self.type_is_copy_modulo_regions( | |
437 | self.param_env, | |
438 | *lhs_deref_ty, | |
f2b60f7d | 439 | ) { |
923072b8 FG |
440 | suggest_deref_binop(*lhs_deref_ty); |
441 | } | |
f2b60f7d | 442 | } else if self.suggest_fn_call(&mut err, lhs_expr, lhs_ty, |lhs_ty| { |
49aad941 | 443 | is_compatible_after_call(lhs_ty, rhs_ty) |
f2b60f7d | 444 | }) || self.suggest_fn_call(&mut err, rhs_expr, rhs_ty, |rhs_ty| { |
49aad941 | 445 | is_compatible_after_call(lhs_ty, rhs_ty) |
f2b60f7d FG |
446 | }) || self.suggest_two_fn_call( |
447 | &mut err, | |
448 | rhs_expr, | |
449 | rhs_ty, | |
450 | lhs_expr, | |
451 | lhs_ty, | |
49aad941 | 452 | |lhs_ty, rhs_ty| is_compatible_after_call(lhs_ty, rhs_ty), |
f2b60f7d FG |
453 | ) { |
454 | // Cool | |
f035d41b | 455 | } |
f035d41b | 456 | |
f2b60f7d | 457 | if let Some(missing_trait) = missing_trait { |
f035d41b XL |
458 | if op.node == hir::BinOpKind::Add |
459 | && self.check_str_addition( | |
460 | lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, is_assign, op, | |
461 | ) | |
462 | { | |
463 | // This has nothing here because it means we did string | |
464 | // concatenation (e.g., "Hello " + "World!"). This means | |
465 | // we don't want the note in the else clause to be emitted | |
2b03887a | 466 | } else if lhs_ty.has_non_region_param() { |
04454e1e FG |
467 | // Look for a TraitPredicate in the Fulfillment errors, |
468 | // and use it to generate a suggestion. | |
469 | // | |
470 | // Note that lookup_op_method must be called again but | |
471 | // with a specific rhs_ty instead of a placeholder so | |
472 | // the resulting predicate generates a more specific | |
473 | // suggestion for the user. | |
474 | let errors = self | |
475 | .lookup_op_method( | |
476 | lhs_ty, | |
9c376795 | 477 | Some((rhs_expr, rhs_ty)), |
04454e1e | 478 | Op::Binary(op, is_assign), |
064997fb | 479 | expected, |
04454e1e FG |
480 | ) |
481 | .unwrap_err(); | |
064997fb FG |
482 | if !errors.is_empty() { |
483 | for error in errors { | |
484 | if let Some(trait_pred) = | |
485 | error.obligation.predicate.to_opt_poly_trait_pred() | |
486 | { | |
f2b60f7d FG |
487 | let output_associated_item = match error.obligation.cause.code() |
488 | { | |
064997fb | 489 | ObligationCauseCode::BinOp { |
f2b60f7d | 490 | output_ty: Some(output_ty), |
064997fb | 491 | .. |
f2b60f7d FG |
492 | } => { |
493 | // Make sure that we're attaching `Output = ..` to the right trait predicate | |
494 | if let Some(output_def_id) = output_def_id | |
495 | && let Some(trait_def_id) = trait_def_id | |
496 | && self.tcx.parent(output_def_id) == trait_def_id | |
9ffffee4 | 497 | && let Some(output_ty) = output_ty.make_suggestable(self.tcx, false) |
f2b60f7d | 498 | { |
9ffffee4 | 499 | Some(("Output", output_ty)) |
f2b60f7d FG |
500 | } else { |
501 | None | |
502 | } | |
064997fb FG |
503 | } |
504 | _ => None, | |
505 | }; | |
506 | ||
2b03887a | 507 | self.err_ctxt().suggest_restricting_param_bound( |
064997fb FG |
508 | &mut err, |
509 | trait_pred, | |
f2b60f7d | 510 | output_associated_item, |
064997fb FG |
511 | self.body_id, |
512 | ); | |
513 | } | |
532ac7d7 | 514 | } |
f2b60f7d | 515 | } else { |
04454e1e FG |
516 | // When we know that a missing bound is responsible, we don't show |
517 | // this note as it is redundant. | |
49aad941 | 518 | err.note(format!( |
04454e1e FG |
519 | "the trait `{missing_trait}` is not implemented for `{lhs_ty}`" |
520 | )); | |
a7813a04 | 521 | } |
b039eaaf SL |
522 | } |
523 | } | |
487cf647 | 524 | let reported = err.emit(); |
9ffffee4 | 525 | self.tcx.ty_error(reported) |
c34b1796 | 526 | } |
a7813a04 | 527 | }; |
c34b1796 | 528 | |
abe05a73 | 529 | (lhs_ty, rhs_ty, return_ty) |
a7813a04 | 530 | } |
c34b1796 | 531 | |
48663c56 XL |
532 | /// Provide actionable suggestions when trying to add two strings with incorrect types, |
533 | /// like `&str + &str`, `String + String` and `&str + &String`. | |
534 | /// | |
535 | /// If this function returns `true` it means a note was printed, so we don't need | |
536 | /// to print the normal "implementation of `std::ops::Add` might be missing" note | |
8faf50e0 XL |
537 | fn check_str_addition( |
538 | &self, | |
dfeec247 XL |
539 | lhs_expr: &'tcx hir::Expr<'tcx>, |
540 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
8faf50e0 XL |
541 | lhs_ty: Ty<'tcx>, |
542 | rhs_ty: Ty<'tcx>, | |
5e7ed085 | 543 | err: &mut Diagnostic, |
f035d41b | 544 | is_assign: IsAssign, |
532ac7d7 | 545 | op: hir::BinOp, |
8faf50e0 | 546 | ) -> bool { |
5099ac24 FG |
547 | let str_concat_note = "string concatenation requires an owned `String` on the left"; |
548 | let rm_borrow_msg = "remove the borrow to obtain an owned `String`"; | |
549 | let to_owned_msg = "create an owned `String` from a string reference"; | |
48663c56 | 550 | |
487cf647 | 551 | let string_type = self.tcx.lang_items().string(); |
49aad941 FG |
552 | let is_std_string = |
553 | |ty: Ty<'tcx>| ty.ty_adt_def().is_some_and(|ty_def| Some(ty_def.did()) == string_type); | |
48663c56 | 554 | |
1b1a35ee | 555 | match (lhs_ty.kind(), rhs_ty.kind()) { |
48663c56 | 556 | (&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str |
064997fb FG |
557 | if (*l_ty.kind() == Str || is_std_string(l_ty)) |
558 | && (*r_ty.kind() == Str | |
559 | || is_std_string(r_ty) | |
560 | || matches!( | |
561 | r_ty.kind(), Ref(_, inner_ty, _) if *inner_ty.kind() == Str | |
562 | )) => | |
48663c56 | 563 | { |
f035d41b | 564 | if let IsAssign::No = is_assign { // Do not supply this message if `&str += &str` |
5099ac24 FG |
565 | err.span_label(op.span, "`+` cannot be used to concatenate two `&str` strings"); |
566 | err.note(str_concat_note); | |
567 | if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { | |
568 | err.span_suggestion_verbose( | |
569 | lhs_expr.span.until(lhs_inner_expr.span), | |
570 | rm_borrow_msg, | |
923072b8 | 571 | "", |
5099ac24 FG |
572 | Applicability::MachineApplicable |
573 | ); | |
574 | } else { | |
575 | err.span_suggestion_verbose( | |
576 | lhs_expr.span.shrink_to_hi(), | |
577 | to_owned_msg, | |
923072b8 | 578 | ".to_owned()", |
5099ac24 FG |
579 | Applicability::MachineApplicable |
580 | ); | |
581 | } | |
8faf50e0 | 582 | } |
0531ce1d | 583 | true |
8bb4bdeb | 584 | } |
48663c56 | 585 | (&Ref(_, l_ty, _), &Adt(..)) // Handle `&str` & `&String` + `String` |
1b1a35ee | 586 | if (*l_ty.kind() == Str || is_std_string(l_ty)) && is_std_string(rhs_ty) => |
48663c56 XL |
587 | { |
588 | err.span_label( | |
589 | op.span, | |
590 | "`+` cannot be used to concatenate a `&str` with a `String`", | |
591 | ); | |
5099ac24 FG |
592 | match is_assign { |
593 | IsAssign::No => { | |
594 | let sugg_msg; | |
595 | let lhs_sugg = if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { | |
596 | sugg_msg = "remove the borrow on the left and add one on the right"; | |
597 | (lhs_expr.span.until(lhs_inner_expr.span), "".to_owned()) | |
48663c56 | 598 | } else { |
5099ac24 FG |
599 | sugg_msg = "create an owned `String` on the left and add a borrow on the right"; |
600 | (lhs_expr.span.shrink_to_hi(), ".to_owned()".to_owned()) | |
48663c56 | 601 | }; |
5099ac24 FG |
602 | let suggestions = vec![ |
603 | lhs_sugg, | |
604 | (rhs_expr.span.shrink_to_lo(), "&".to_owned()), | |
605 | ]; | |
606 | err.multipart_suggestion_verbose( | |
607 | sugg_msg, | |
608 | suggestions, | |
0bf4aa26 XL |
609 | Applicability::MachineApplicable, |
610 | ); | |
8faf50e0 | 611 | } |
5099ac24 FG |
612 | IsAssign::Yes => { |
613 | err.note(str_concat_note); | |
0531ce1d | 614 | } |
5099ac24 | 615 | } |
0531ce1d XL |
616 | true |
617 | } | |
618 | _ => false, | |
8bb4bdeb | 619 | } |
8bb4bdeb XL |
620 | } |
621 | ||
dc9dc135 XL |
622 | pub fn check_user_unop( |
623 | &self, | |
dfeec247 | 624 | ex: &'tcx hir::Expr<'tcx>, |
dc9dc135 XL |
625 | operand_ty: Ty<'tcx>, |
626 | op: hir::UnOp, | |
064997fb | 627 | expected: Expectation<'tcx>, |
dc9dc135 | 628 | ) -> Ty<'tcx> { |
a7813a04 | 629 | assert!(op.is_by_value()); |
9c376795 | 630 | match self.lookup_op_method(operand_ty, None, Op::Unary(op, ex.span), expected) { |
7cac9316 | 631 | Ok(method) => { |
3b2f2976 | 632 | self.write_method_call(ex.hir_id, method); |
7cac9316 XL |
633 | method.sig.output() |
634 | } | |
c295e0f8 | 635 | Err(errors) => { |
fc512014 | 636 | let actual = self.resolve_vars_if_possible(operand_ty); |
9ffffee4 | 637 | let guar = actual.error_reported().err().unwrap_or_else(|| { |
dfeec247 XL |
638 | let mut err = struct_span_err!( |
639 | self.tcx.sess, | |
640 | ex.span, | |
641 | E0600, | |
642 | "cannot apply unary operator `{}` to type `{}`", | |
643 | op.as_str(), | |
644 | actual | |
645 | ); | |
646 | err.span_label( | |
647 | ex.span, | |
f035d41b | 648 | format!("cannot apply unary operator `{}`", op.as_str()), |
dfeec247 | 649 | ); |
04454e1e | 650 | |
2b03887a | 651 | if operand_ty.has_non_region_param() { |
f2b60f7d FG |
652 | let predicates = errors.iter().filter_map(|error| { |
653 | error.obligation.predicate.to_opt_poly_trait_pred() | |
654 | }); | |
04454e1e | 655 | for pred in predicates { |
2b03887a | 656 | self.err_ctxt().suggest_restricting_param_bound( |
04454e1e FG |
657 | &mut err, |
658 | pred, | |
064997fb | 659 | None, |
04454e1e FG |
660 | self.body_id, |
661 | ); | |
662 | } | |
5e7ed085 | 663 | } |
c295e0f8 | 664 | |
9c376795 | 665 | let sp = self.tcx.sess.source_map().start_point(ex.span).with_parent(None); |
c295e0f8 XL |
666 | if let Some(sp) = |
667 | self.tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp) | |
668 | { | |
669 | // If the previous expression was a block expression, suggest parentheses | |
670 | // (turning this into a binary subtraction operation instead.) | |
671 | // for example, `{2} - 2` -> `({2}) - 2` (see src\test\ui\parser\expr-as-stmt.rs) | |
2b03887a | 672 | err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp)); |
c295e0f8 XL |
673 | } else { |
674 | match actual.kind() { | |
675 | Uint(_) if op == hir::UnOp::Neg => { | |
676 | err.note("unsigned values cannot be negated"); | |
677 | ||
678 | if let hir::ExprKind::Unary( | |
679 | _, | |
680 | hir::Expr { | |
681 | kind: | |
682 | hir::ExprKind::Lit(Spanned { | |
683 | node: ast::LitKind::Int(1, _), | |
684 | .. | |
685 | }), | |
686 | .. | |
687 | }, | |
688 | ) = ex.kind | |
689 | { | |
690 | err.span_suggestion( | |
691 | ex.span, | |
49aad941 | 692 | format!( |
5e7ed085 | 693 | "you may have meant the maximum value of `{actual}`", |
c295e0f8 | 694 | ), |
5e7ed085 | 695 | format!("{actual}::MAX"), |
c295e0f8 XL |
696 | Applicability::MaybeIncorrect, |
697 | ); | |
698 | } | |
699 | } | |
700 | Str | Never | Char | Tuple(_) | Array(_, _) => {} | |
701 | Ref(_, lty, _) if *lty.kind() == Str => {} | |
702 | _ => { | |
703 | self.note_unmet_impls_on_type(&mut err, errors); | |
29967ef6 | 704 | } |
94b46f34 XL |
705 | } |
706 | } | |
9ffffee4 FG |
707 | err.emit() |
708 | }); | |
709 | self.tcx.ty_error(guar) | |
a7813a04 | 710 | } |
c34b1796 AL |
711 | } |
712 | } | |
c34b1796 | 713 | |
dfeec247 XL |
714 | fn lookup_op_method( |
715 | &self, | |
716 | lhs_ty: Ty<'tcx>, | |
9c376795 | 717 | opt_rhs: Option<(&'tcx hir::Expr<'tcx>, Ty<'tcx>)>, |
dfeec247 | 718 | op: Op, |
064997fb | 719 | expected: Expectation<'tcx>, |
c295e0f8 | 720 | ) -> Result<MethodCallee<'tcx>, Vec<FulfillmentError<'tcx>>> { |
7cac9316 XL |
721 | let span = match op { |
722 | Op::Binary(op, _) => op.span, | |
dfeec247 | 723 | Op::Unary(_, span) => span, |
7cac9316 | 724 | }; |
49aad941 FG |
725 | let (opname, Some(trait_did)) = lang_item_for_op(self.tcx, op, span) else { |
726 | // Bail if the operator trait is not defined. | |
727 | return Err(vec![]); | |
728 | }; | |
c34b1796 | 729 | |
dfeec247 XL |
730 | debug!( |
731 | "lookup_op_method(lhs_ty={:?}, op={:?}, opname={:?}, trait_did={:?})", | |
732 | lhs_ty, op, opname, trait_did | |
733 | ); | |
7cac9316 | 734 | |
17df50a5 XL |
735 | // Catches cases like #83893, where a lang item is declared with the |
736 | // wrong number of generic arguments. Should have yielded an error | |
737 | // elsewhere by now, but we have to catch it here so that we do not | |
738 | // index `other_tys` out of bounds (if the lang item has too many | |
739 | // generic arguments, `other_tys` is too short). | |
740 | if !has_expected_num_generic_args( | |
741 | self.tcx, | |
742 | trait_did, | |
743 | match op { | |
744 | // Binary ops have a generic right-hand side, unary ops don't | |
745 | Op::Binary(..) => 1, | |
746 | Op::Unary(..) => 0, | |
747 | }, | |
748 | ) { | |
9c376795 FG |
749 | self.tcx |
750 | .sess | |
751 | .delay_span_bug(span, "operator didn't have the right number of generic args"); | |
c295e0f8 | 752 | return Err(vec![]); |
17df50a5 XL |
753 | } |
754 | ||
c295e0f8 | 755 | let opname = Ident::with_dummy_span(opname); |
9ffffee4 FG |
756 | let (opt_rhs_expr, opt_rhs_ty) = opt_rhs.unzip(); |
757 | let input_types = opt_rhs_ty.as_slice(); | |
9c376795 FG |
758 | let cause = self.cause( |
759 | span, | |
760 | traits::BinOp { | |
9ffffee4 | 761 | rhs_span: opt_rhs_expr.map(|expr| expr.span), |
49aad941 | 762 | is_lit: opt_rhs_expr.is_some_and(|expr| matches!(expr.kind, hir::ExprKind::Lit(_))), |
9c376795 FG |
763 | output_ty: expected.only_has_type(self), |
764 | }, | |
765 | ); | |
766 | ||
49aad941 FG |
767 | let method = self.lookup_method_in_trait( |
768 | cause.clone(), | |
769 | opname, | |
770 | trait_did, | |
771 | lhs_ty, | |
772 | Some(input_types), | |
773 | ); | |
774 | match method { | |
775 | Some(ok) => { | |
cc61c64b | 776 | let method = self.register_infer_ok_obligations(ok); |
487cf647 | 777 | self.select_obligations_where_possible(|_| {}); |
7cac9316 | 778 | Ok(method) |
a7813a04 | 779 | } |
49aad941 FG |
780 | None => { |
781 | // This path may do some inference, so make sure we've really | |
782 | // doomed compilation so as to not accidentally stabilize new | |
783 | // inference or something here... | |
784 | self.tcx.sess.delay_span_bug(span, "this path really should be doomed..."); | |
785 | // Guide inference for the RHS expression if it's provided -- | |
786 | // this will allow us to better error reporting, at the expense | |
787 | // of making some error messages a bit more specific. | |
788 | if let Some((rhs_expr, rhs_ty)) = opt_rhs | |
789 | && rhs_ty.is_ty_var() | |
790 | { | |
791 | self.check_expr_coercible_to_type(rhs_expr, rhs_ty, None); | |
792 | } | |
793 | ||
9c376795 FG |
794 | let (obligation, _) = |
795 | self.obligation_for_method(cause, trait_did, lhs_ty, Some(input_types)); | |
353b0b11 FG |
796 | // FIXME: This should potentially just add the obligation to the `FnCtxt` |
797 | let ocx = ObligationCtxt::new(&self.infcx); | |
798 | ocx.register_obligation(obligation); | |
799 | Err(ocx.select_all_or_error()) | |
c295e0f8 | 800 | } |
c34b1796 AL |
801 | } |
802 | } | |
803 | } | |
804 | ||
f2b60f7d FG |
805 | fn lang_item_for_op( |
806 | tcx: TyCtxt<'_>, | |
807 | op: Op, | |
808 | span: Span, | |
809 | ) -> (rustc_span::Symbol, Option<hir::def_id::DefId>) { | |
810 | let lang = tcx.lang_items(); | |
811 | if let Op::Binary(op, IsAssign::Yes) = op { | |
812 | match op.node { | |
813 | hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()), | |
814 | hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()), | |
815 | hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()), | |
816 | hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()), | |
817 | hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()), | |
818 | hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()), | |
819 | hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()), | |
820 | hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()), | |
821 | hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()), | |
822 | hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()), | |
823 | hir::BinOpKind::Lt | |
824 | | hir::BinOpKind::Le | |
825 | | hir::BinOpKind::Ge | |
826 | | hir::BinOpKind::Gt | |
827 | | hir::BinOpKind::Eq | |
828 | | hir::BinOpKind::Ne | |
829 | | hir::BinOpKind::And | |
830 | | hir::BinOpKind::Or => { | |
831 | span_bug!(span, "impossible assignment operation: {}=", op.node.as_str()) | |
832 | } | |
833 | } | |
834 | } else if let Op::Binary(op, IsAssign::No) = op { | |
835 | match op.node { | |
836 | hir::BinOpKind::Add => (sym::add, lang.add_trait()), | |
837 | hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()), | |
838 | hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()), | |
839 | hir::BinOpKind::Div => (sym::div, lang.div_trait()), | |
840 | hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()), | |
841 | hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()), | |
842 | hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()), | |
843 | hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()), | |
844 | hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()), | |
845 | hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()), | |
846 | hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()), | |
847 | hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()), | |
848 | hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()), | |
849 | hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()), | |
850 | hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()), | |
851 | hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()), | |
852 | hir::BinOpKind::And | hir::BinOpKind::Or => { | |
853 | span_bug!(span, "&& and || are not overloadable") | |
854 | } | |
855 | } | |
856 | } else if let Op::Unary(hir::UnOp::Not, _) = op { | |
857 | (sym::not, lang.not_trait()) | |
858 | } else if let Op::Unary(hir::UnOp::Neg, _) = op { | |
859 | (sym::neg, lang.neg_trait()) | |
860 | } else { | |
861 | bug!("lookup_op_method: op not supported: {:?}", op) | |
862 | } | |
863 | } | |
864 | ||
c34b1796 | 865 | // Binary operator categories. These categories summarize the behavior |
5e7ed085 | 866 | // with respect to the builtin operations supported. |
c34b1796 AL |
867 | enum BinOpCategory { |
868 | /// &&, || -- cannot be overridden | |
869 | Shortcircuit, | |
870 | ||
871 | /// <<, >> -- when shifting a single integer, rhs can be any | |
872 | /// integer type. For simd, types must match. | |
873 | Shift, | |
874 | ||
875 | /// +, -, etc -- takes equal types, produces same type as input, | |
876 | /// applicable to ints/floats/simd | |
877 | Math, | |
878 | ||
879 | /// &, |, ^ -- takes equal types, produces same type as input, | |
880 | /// applicable to ints/floats/simd/bool | |
881 | Bitwise, | |
882 | ||
883 | /// ==, !=, etc -- takes equal types, produces bools, except for simd, | |
884 | /// which produce the input type | |
885 | Comparison, | |
886 | } | |
887 | ||
888 | impl BinOpCategory { | |
e9174d1e | 889 | fn from(op: hir::BinOp) -> BinOpCategory { |
c34b1796 | 890 | match op.node { |
dfeec247 XL |
891 | hir::BinOpKind::Shl | hir::BinOpKind::Shr => BinOpCategory::Shift, |
892 | ||
893 | hir::BinOpKind::Add | |
894 | | hir::BinOpKind::Sub | |
895 | | hir::BinOpKind::Mul | |
896 | | hir::BinOpKind::Div | |
897 | | hir::BinOpKind::Rem => BinOpCategory::Math, | |
898 | ||
899 | hir::BinOpKind::BitXor | hir::BinOpKind::BitAnd | hir::BinOpKind::BitOr => { | |
900 | BinOpCategory::Bitwise | |
901 | } | |
902 | ||
903 | hir::BinOpKind::Eq | |
904 | | hir::BinOpKind::Ne | |
905 | | hir::BinOpKind::Lt | |
906 | | hir::BinOpKind::Le | |
907 | | hir::BinOpKind::Ge | |
908 | | hir::BinOpKind::Gt => BinOpCategory::Comparison, | |
909 | ||
910 | hir::BinOpKind::And | hir::BinOpKind::Or => BinOpCategory::Shortcircuit, | |
c34b1796 AL |
911 | } |
912 | } | |
913 | } | |
914 | ||
b039eaaf | 915 | /// Whether the binary operation is an assignment (`a += b`), or not (`a + b`) |
7cac9316 | 916 | #[derive(Clone, Copy, Debug, PartialEq)] |
b039eaaf SL |
917 | enum IsAssign { |
918 | No, | |
919 | Yes, | |
920 | } | |
921 | ||
7cac9316 XL |
922 | #[derive(Clone, Copy, Debug)] |
923 | enum Op { | |
924 | Binary(hir::BinOp, IsAssign), | |
925 | Unary(hir::UnOp, Span), | |
926 | } | |
927 | ||
74b04a01 | 928 | /// Dereferences a single level of immutable referencing. |
9c376795 | 929 | fn deref_ty_if_possible(ty: Ty<'_>) -> Ty<'_> { |
1b1a35ee | 930 | match ty.kind() { |
5099ac24 | 931 | ty::Ref(_, ty, hir::Mutability::Not) => *ty, |
74b04a01 XL |
932 | _ => ty, |
933 | } | |
934 | } | |
935 | ||
9fa01778 | 936 | /// Returns `true` if this is a built-in arithmetic operation (e.g., u32 |
c34b1796 AL |
937 | /// + u32, i16x4 == i16x4) and false if these types would have to be |
938 | /// overloaded to be legal. There are two reasons that we distinguish | |
939 | /// builtin operations from overloaded ones (vs trying to drive | |
940 | /// everything uniformly through the trait system and intrinsics or | |
941 | /// something like that): | |
942 | /// | |
943 | /// 1. Builtin operations can trivially be evaluated in constants. | |
944 | /// 2. For comparison operators applied to SIMD types the result is | |
9fa01778 | 945 | /// not of type `bool`. For example, `i16x4 == i16x4` yields a |
c34b1796 AL |
946 | /// type like `i16x4`. This means that the overloaded trait |
947 | /// `PartialEq` is not applicable. | |
948 | /// | |
949 | /// Reason #2 is the killer. I tried for a while to always use | |
94b46f34 | 950 | /// overloaded logic and just check the types in constants/codegen after |
c34b1796 | 951 | /// the fact, and it worked fine, except for SIMD types. -nmatsakis |
74b04a01 XL |
952 | fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>, rhs: Ty<'tcx>, op: hir::BinOp) -> bool { |
953 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. | |
954 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
955 | let (lhs, rhs) = (deref_ty_if_possible(lhs), deref_ty_if_possible(rhs)); | |
956 | ||
c34b1796 | 957 | match BinOpCategory::from(op) { |
dfeec247 | 958 | BinOpCategory::Shortcircuit => true, |
c34b1796 AL |
959 | |
960 | BinOpCategory::Shift => { | |
dfeec247 XL |
961 | lhs.references_error() |
962 | || rhs.references_error() | |
963 | || lhs.is_integral() && rhs.is_integral() | |
c34b1796 AL |
964 | } |
965 | ||
966 | BinOpCategory::Math => { | |
dfeec247 XL |
967 | lhs.references_error() |
968 | || rhs.references_error() | |
969 | || lhs.is_integral() && rhs.is_integral() | |
970 | || lhs.is_floating_point() && rhs.is_floating_point() | |
c34b1796 AL |
971 | } |
972 | ||
973 | BinOpCategory::Bitwise => { | |
dfeec247 XL |
974 | lhs.references_error() |
975 | || rhs.references_error() | |
976 | || lhs.is_integral() && rhs.is_integral() | |
977 | || lhs.is_floating_point() && rhs.is_floating_point() | |
978 | || lhs.is_bool() && rhs.is_bool() | |
c34b1796 AL |
979 | } |
980 | ||
981 | BinOpCategory::Comparison => { | |
dfeec247 | 982 | lhs.references_error() || rhs.references_error() || lhs.is_scalar() && rhs.is_scalar() |
c34b1796 AL |
983 | } |
984 | } | |
985 | } |