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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 FG |
14 | use rustc_middle::ty::print::with_no_trimmed_paths; |
15 | use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt, TypeFolder, TypeSuperFoldable, TypeVisitable}; | |
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 _; |
c295e0f8 | 22 | use rustc_trait_selection::traits::{FulfillmentError, TraitEngine, TraitEngineExt}; |
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, | |
51 | Some(rhs_ty), | |
52 | Some(rhs), | |
53 | Op::Binary(op, IsAssign::Yes), | |
064997fb | 54 | expected, |
923072b8 FG |
55 | ) |
56 | .is_ok() | |
57 | { | |
f2b60f7d FG |
58 | // If LHS += RHS is an error, but *LHS += RHS is successful, then we will have |
59 | // emitted a better suggestion during error handling in check_overloaded_binop. | |
60 | if self | |
61 | .lookup_op_method( | |
62 | lhs_ty, | |
63 | Some(rhs_ty), | |
64 | Some(rhs), | |
65 | Op::Binary(op, IsAssign::Yes), | |
66 | expected, | |
67 | ) | |
68 | .is_err() | |
69 | { | |
70 | err.downgrade_to_delayed_bug(); | |
71 | } else { | |
72 | // Otherwise, it's valid to suggest dereferencing the LHS here. | |
73 | err.span_suggestion_verbose( | |
74 | lhs.span.shrink_to_lo(), | |
75 | "consider dereferencing the left-hand side of this operation", | |
76 | "*", | |
77 | Applicability::MaybeIncorrect, | |
78 | ); | |
79 | } | |
923072b8 FG |
80 | } |
81 | } | |
82 | }); | |
c34b1796 | 83 | |
9e0c209e | 84 | ty |
c34b1796 | 85 | } |
c34b1796 | 86 | |
9fa01778 | 87 | /// Checks a potentially overloaded binary operator. |
dc9dc135 XL |
88 | pub fn check_binop( |
89 | &self, | |
dfeec247 | 90 | expr: &'tcx hir::Expr<'tcx>, |
dc9dc135 | 91 | op: hir::BinOp, |
dfeec247 XL |
92 | lhs_expr: &'tcx hir::Expr<'tcx>, |
93 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
064997fb | 94 | expected: Expectation<'tcx>, |
dc9dc135 | 95 | ) -> Ty<'tcx> { |
a7813a04 XL |
96 | let tcx = self.tcx; |
97 | ||
dfeec247 XL |
98 | debug!( |
99 | "check_binop(expr.hir_id={}, expr={:?}, op={:?}, lhs_expr={:?}, rhs_expr={:?})", | |
100 | expr.hir_id, expr, op, lhs_expr, rhs_expr | |
101 | ); | |
a7813a04 | 102 | |
a7813a04 XL |
103 | match BinOpCategory::from(op) { |
104 | BinOpCategory::Shortcircuit => { | |
105 | // && and || are a simple case. | |
f035d41b | 106 | self.check_expr_coercable_to_type(lhs_expr, tcx.types.bool, None); |
476ff2be | 107 | let lhs_diverges = self.diverges.get(); |
f035d41b | 108 | self.check_expr_coercable_to_type(rhs_expr, tcx.types.bool, None); |
476ff2be SL |
109 | |
110 | // Depending on the LHS' value, the RHS can never execute. | |
111 | self.diverges.set(lhs_diverges); | |
112 | ||
abe05a73 | 113 | tcx.types.bool |
c34b1796 | 114 | } |
a7813a04 XL |
115 | _ => { |
116 | // Otherwise, we always treat operators as if they are | |
117 | // overloaded. This is the way to be most flexible w/r/t | |
118 | // types that get inferred. | |
064997fb FG |
119 | let (lhs_ty, rhs_ty, return_ty) = self.check_overloaded_binop( |
120 | expr, | |
121 | lhs_expr, | |
122 | rhs_expr, | |
123 | op, | |
124 | IsAssign::No, | |
125 | expected, | |
126 | ); | |
a7813a04 XL |
127 | |
128 | // Supply type inference hints if relevant. Probably these | |
129 | // hints should be enforced during select as part of the | |
130 | // `consider_unification_despite_ambiguity` routine, but this | |
131 | // more convenient for now. | |
132 | // | |
133 | // The basic idea is to help type inference by taking | |
134 | // advantage of things we know about how the impls for | |
135 | // scalar types are arranged. This is important in a | |
136 | // scenario like `1_u32 << 2`, because it lets us quickly | |
137 | // deduce that the result type should be `u32`, even | |
138 | // though we don't know yet what type 2 has and hence | |
139 | // can't pin this down to a specific impl. | |
dfeec247 XL |
140 | if !lhs_ty.is_ty_var() |
141 | && !rhs_ty.is_ty_var() | |
142 | && is_builtin_binop(lhs_ty, rhs_ty, op) | |
a7813a04 | 143 | { |
74b04a01 | 144 | let builtin_return_ty = self.enforce_builtin_binop_types( |
5e7ed085 | 145 | lhs_expr.span, |
74b04a01 | 146 | lhs_ty, |
5e7ed085 | 147 | rhs_expr.span, |
74b04a01 XL |
148 | rhs_ty, |
149 | op, | |
150 | ); | |
a7813a04 XL |
151 | self.demand_suptype(expr.span, builtin_return_ty, return_ty); |
152 | } | |
c34b1796 | 153 | |
9e0c209e | 154 | return_ty |
a7813a04 | 155 | } |
c34b1796 AL |
156 | } |
157 | } | |
c34b1796 | 158 | |
dc9dc135 XL |
159 | fn enforce_builtin_binop_types( |
160 | &self, | |
5e7ed085 | 161 | lhs_span: Span, |
dc9dc135 | 162 | lhs_ty: Ty<'tcx>, |
5e7ed085 | 163 | rhs_span: Span, |
dc9dc135 XL |
164 | rhs_ty: Ty<'tcx>, |
165 | op: hir::BinOp, | |
166 | ) -> Ty<'tcx> { | |
a7813a04 XL |
167 | debug_assert!(is_builtin_binop(lhs_ty, rhs_ty, op)); |
168 | ||
74b04a01 XL |
169 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. |
170 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
171 | let (lhs_ty, rhs_ty) = (deref_ty_if_possible(lhs_ty), deref_ty_if_possible(rhs_ty)); | |
172 | ||
a7813a04 XL |
173 | let tcx = self.tcx; |
174 | match BinOpCategory::from(op) { | |
175 | BinOpCategory::Shortcircuit => { | |
5e7ed085 FG |
176 | self.demand_suptype(lhs_span, tcx.types.bool, lhs_ty); |
177 | self.demand_suptype(rhs_span, tcx.types.bool, rhs_ty); | |
f9f354fc | 178 | tcx.types.bool |
a7813a04 | 179 | } |
c34b1796 | 180 | |
a7813a04 XL |
181 | BinOpCategory::Shift => { |
182 | // result type is same as LHS always | |
183 | lhs_ty | |
184 | } | |
c34b1796 | 185 | |
dfeec247 | 186 | BinOpCategory::Math | BinOpCategory::Bitwise => { |
a7813a04 | 187 | // both LHS and RHS and result will have the same type |
5e7ed085 | 188 | self.demand_suptype(rhs_span, lhs_ty, rhs_ty); |
a7813a04 XL |
189 | lhs_ty |
190 | } | |
c34b1796 | 191 | |
a7813a04 XL |
192 | BinOpCategory::Comparison => { |
193 | // both LHS and RHS and result will have the same type | |
5e7ed085 | 194 | self.demand_suptype(rhs_span, lhs_ty, rhs_ty); |
f9f354fc | 195 | tcx.types.bool |
a7813a04 | 196 | } |
c34b1796 AL |
197 | } |
198 | } | |
c34b1796 | 199 | |
dc9dc135 XL |
200 | fn check_overloaded_binop( |
201 | &self, | |
dfeec247 XL |
202 | expr: &'tcx hir::Expr<'tcx>, |
203 | lhs_expr: &'tcx hir::Expr<'tcx>, | |
204 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
dc9dc135 XL |
205 | op: hir::BinOp, |
206 | is_assign: IsAssign, | |
064997fb | 207 | expected: Expectation<'tcx>, |
dc9dc135 | 208 | ) -> (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>) { |
dfeec247 XL |
209 | debug!( |
210 | "check_overloaded_binop(expr.hir_id={}, op={:?}, is_assign={:?})", | |
211 | expr.hir_id, op, is_assign | |
212 | ); | |
a7813a04 | 213 | |
74d20737 XL |
214 | let lhs_ty = match is_assign { |
215 | IsAssign::No => { | |
216 | // Find a suitable supertype of the LHS expression's type, by coercing to | |
217 | // a type variable, to pass as the `Self` to the trait, avoiding invariant | |
218 | // trait matching creating lifetime constraints that are too strict. | |
0731742a | 219 | // e.g., adding `&'a T` and `&'b T`, given `&'x T: Add<&'x T>`, will result |
74d20737 | 220 | // in `&'a T <: &'x T` and `&'b T <: &'x T`, instead of `'a = 'b = 'x`. |
f035d41b | 221 | let lhs_ty = self.check_expr(lhs_expr); |
dc9dc135 XL |
222 | let fresh_var = self.next_ty_var(TypeVariableOrigin { |
223 | kind: TypeVariableOriginKind::MiscVariable, | |
224 | span: lhs_expr.span, | |
225 | }); | |
f035d41b | 226 | self.demand_coerce(lhs_expr, lhs_ty, fresh_var, Some(rhs_expr), AllowTwoPhase::No) |
74d20737 XL |
227 | } |
228 | IsAssign::Yes => { | |
229 | // rust-lang/rust#52126: We have to use strict | |
230 | // equivalence on the LHS of an assign-op like `+=`; | |
231 | // overwritten or mutably-borrowed places cannot be | |
232 | // coerced to a supertype. | |
f035d41b | 233 | self.check_expr(lhs_expr) |
74d20737 | 234 | } |
abe05a73 | 235 | }; |
e74abb32 | 236 | let lhs_ty = self.resolve_vars_with_obligations(lhs_ty); |
abe05a73 | 237 | |
0731742a | 238 | // N.B., as we have not yet type-checked the RHS, we don't have the |
a7813a04 XL |
239 | // type at hand. Make a variable to represent it. The whole reason |
240 | // for this indirection is so that, below, we can check the expr | |
241 | // using this variable as the expected type, which sometimes lets | |
242 | // us do better coercions than we would be able to do otherwise, | |
243 | // particularly for things like `String + &String`. | |
dc9dc135 XL |
244 | let rhs_ty_var = self.next_ty_var(TypeVariableOrigin { |
245 | kind: TypeVariableOriginKind::MiscVariable, | |
246 | span: rhs_expr.span, | |
247 | }); | |
a7813a04 | 248 | |
5e7ed085 FG |
249 | let result = self.lookup_op_method( |
250 | lhs_ty, | |
251 | Some(rhs_ty_var), | |
252 | Some(rhs_expr), | |
253 | Op::Binary(op, is_assign), | |
064997fb | 254 | expected, |
5e7ed085 | 255 | ); |
8bb4bdeb XL |
256 | |
257 | // see `NB` above | |
f035d41b | 258 | let rhs_ty = self.check_expr_coercable_to_type(rhs_expr, rhs_ty_var, Some(lhs_expr)); |
e74abb32 | 259 | let rhs_ty = self.resolve_vars_with_obligations(rhs_ty); |
8bb4bdeb | 260 | |
7cac9316 XL |
261 | let return_ty = match result { |
262 | Ok(method) => { | |
263 | let by_ref_binop = !op.node.is_by_value(); | |
264 | if is_assign == IsAssign::Yes || by_ref_binop { | |
1b1a35ee | 265 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].kind() { |
94b46f34 | 266 | let mutbl = match mutbl { |
dfeec247 XL |
267 | hir::Mutability::Not => AutoBorrowMutability::Not, |
268 | hir::Mutability::Mut => AutoBorrowMutability::Mut { | |
0531ce1d XL |
269 | // Allow two-phase borrows for binops in initial deployment |
270 | // since they desugar to methods | |
83c7162d | 271 | allow_two_phase_borrow: AllowTwoPhase::Yes, |
dfeec247 | 272 | }, |
2c00a5a8 | 273 | }; |
7cac9316 | 274 | let autoref = Adjustment { |
5099ac24 | 275 | kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), |
dfeec247 | 276 | target: method.sig.inputs()[0], |
7cac9316 XL |
277 | }; |
278 | self.apply_adjustments(lhs_expr, vec![autoref]); | |
279 | } | |
280 | } | |
281 | if by_ref_binop { | |
1b1a35ee | 282 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[1].kind() { |
94b46f34 | 283 | let mutbl = match mutbl { |
dfeec247 XL |
284 | hir::Mutability::Not => AutoBorrowMutability::Not, |
285 | hir::Mutability::Mut => AutoBorrowMutability::Mut { | |
0531ce1d XL |
286 | // Allow two-phase borrows for binops in initial deployment |
287 | // since they desugar to methods | |
83c7162d | 288 | allow_two_phase_borrow: AllowTwoPhase::Yes, |
dfeec247 | 289 | }, |
2c00a5a8 | 290 | }; |
7cac9316 | 291 | let autoref = Adjustment { |
5099ac24 | 292 | kind: Adjust::Borrow(AutoBorrow::Ref(*region, mutbl)), |
dfeec247 | 293 | target: method.sig.inputs()[1], |
7cac9316 XL |
294 | }; |
295 | // HACK(eddyb) Bypass checks due to reborrows being in | |
296 | // some cases applied on the RHS, on top of which we need | |
297 | // to autoref, which is not allowed by apply_adjustments. | |
298 | // self.apply_adjustments(rhs_expr, vec![autoref]); | |
3dfed10e | 299 | self.typeck_results |
3b2f2976 XL |
300 | .borrow_mut() |
301 | .adjustments_mut() | |
302 | .entry(rhs_expr.hir_id) | |
b7449926 | 303 | .or_default() |
3b2f2976 | 304 | .push(autoref); |
7cac9316 XL |
305 | } |
306 | } | |
3b2f2976 | 307 | self.write_method_call(expr.hir_id, method); |
7cac9316 XL |
308 | |
309 | method.sig.output() | |
310 | } | |
f035d41b | 311 | // error types are considered "builtin" |
c295e0f8 XL |
312 | Err(_) if lhs_ty.references_error() || rhs_ty.references_error() => self.tcx.ty_error(), |
313 | Err(errors) => { | |
f2b60f7d FG |
314 | let (_, trait_def_id) = |
315 | lang_item_for_op(self.tcx, Op::Binary(op, is_assign), op.span); | |
316 | let missing_trait = trait_def_id | |
317 | .map(|def_id| with_no_trimmed_paths!(self.tcx.def_path_str(def_id))); | |
318 | let (mut err, output_def_id) = match is_assign { | |
f035d41b XL |
319 | IsAssign::Yes => { |
320 | let mut err = struct_span_err!( | |
321 | self.tcx.sess, | |
322 | expr.span, | |
323 | E0368, | |
324 | "binary assignment operation `{}=` cannot be applied to type `{}`", | |
325 | op.node.as_str(), | |
326 | lhs_ty, | |
327 | ); | |
328 | err.span_label( | |
329 | lhs_expr.span, | |
330 | format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty), | |
331 | ); | |
c295e0f8 | 332 | self.note_unmet_impls_on_type(&mut err, errors); |
f2b60f7d | 333 | (err, None) |
f035d41b XL |
334 | } |
335 | IsAssign::No => { | |
f2b60f7d FG |
336 | let message = match op.node { |
337 | hir::BinOpKind::Add => { | |
338 | format!("cannot add `{rhs_ty}` to `{lhs_ty}`") | |
339 | } | |
340 | hir::BinOpKind::Sub => { | |
341 | format!("cannot subtract `{rhs_ty}` from `{lhs_ty}`") | |
342 | } | |
343 | hir::BinOpKind::Mul => { | |
344 | format!("cannot multiply `{lhs_ty}` by `{rhs_ty}`") | |
345 | } | |
346 | hir::BinOpKind::Div => { | |
347 | format!("cannot divide `{lhs_ty}` by `{rhs_ty}`") | |
348 | } | |
349 | hir::BinOpKind::Rem => { | |
350 | format!("cannot mod `{lhs_ty}` by `{rhs_ty}`") | |
351 | } | |
352 | hir::BinOpKind::BitAnd => { | |
353 | format!("no implementation for `{lhs_ty} & {rhs_ty}`") | |
354 | } | |
355 | hir::BinOpKind::BitXor => { | |
356 | format!("no implementation for `{lhs_ty} ^ {rhs_ty}`") | |
357 | } | |
358 | hir::BinOpKind::BitOr => { | |
359 | format!("no implementation for `{lhs_ty} | {rhs_ty}`") | |
360 | } | |
361 | hir::BinOpKind::Shl => { | |
362 | format!("no implementation for `{lhs_ty} << {rhs_ty}`") | |
363 | } | |
364 | hir::BinOpKind::Shr => { | |
365 | format!("no implementation for `{lhs_ty} >> {rhs_ty}`") | |
366 | } | |
367 | _ => format!( | |
368 | "binary operation `{}` cannot be applied to type `{}`", | |
369 | op.node.as_str(), | |
370 | lhs_ty | |
f035d41b XL |
371 | ), |
372 | }; | |
f2b60f7d FG |
373 | let output_def_id = trait_def_id.and_then(|def_id| { |
374 | self.tcx | |
375 | .associated_item_def_ids(def_id) | |
376 | .iter() | |
377 | .find(|item_def_id| { | |
378 | self.tcx.associated_item(*item_def_id).name == sym::Output | |
379 | }) | |
380 | .cloned() | |
381 | }); | |
064997fb | 382 | let mut err = struct_span_err!(self.tcx.sess, op.span, E0369, "{message}"); |
f035d41b | 383 | if !lhs_expr.span.eq(&rhs_expr.span) { |
f2b60f7d FG |
384 | err.span_label(lhs_expr.span, lhs_ty.to_string()); |
385 | err.span_label(rhs_expr.span, rhs_ty.to_string()); | |
32a655c1 | 386 | } |
c295e0f8 | 387 | self.note_unmet_impls_on_type(&mut err, errors); |
f2b60f7d | 388 | (err, output_def_id) |
f035d41b XL |
389 | } |
390 | }; | |
923072b8 FG |
391 | |
392 | let mut suggest_deref_binop = |lhs_deref_ty: Ty<'tcx>| { | |
393 | if self | |
394 | .lookup_op_method( | |
395 | lhs_deref_ty, | |
396 | Some(rhs_ty), | |
397 | Some(rhs_expr), | |
398 | Op::Binary(op, is_assign), | |
064997fb | 399 | expected, |
923072b8 FG |
400 | ) |
401 | .is_ok() | |
3c0e092e | 402 | { |
f2b60f7d FG |
403 | let msg = &format!( |
404 | "`{}{}` can be used on `{}` if you dereference the left-hand side", | |
405 | op.node.as_str(), | |
406 | match is_assign { | |
407 | IsAssign::Yes => "=", | |
408 | IsAssign::No => "", | |
409 | }, | |
410 | lhs_deref_ty, | |
411 | ); | |
412 | err.span_suggestion_verbose( | |
413 | lhs_expr.span.shrink_to_lo(), | |
414 | msg, | |
415 | "*", | |
416 | rustc_errors::Applicability::MachineApplicable, | |
417 | ); | |
f035d41b | 418 | } |
923072b8 FG |
419 | }; |
420 | ||
f2b60f7d FG |
421 | let is_compatible = |lhs_ty, rhs_ty| { |
422 | self.lookup_op_method( | |
423 | lhs_ty, | |
424 | Some(rhs_ty), | |
425 | Some(rhs_expr), | |
426 | Op::Binary(op, is_assign), | |
427 | expected, | |
428 | ) | |
429 | .is_ok() | |
430 | }; | |
431 | ||
923072b8 FG |
432 | // We should suggest `a + b` => `*a + b` if `a` is copy, and suggest |
433 | // `a += b` => `*a += b` if a is a mut ref. | |
f2b60f7d FG |
434 | if !op.span.can_be_used_for_suggestions() { |
435 | // Suppress suggestions when lhs and rhs are not in the same span as the error | |
436 | } else if is_assign == IsAssign::Yes | |
437 | && let Some(lhs_deref_ty) = self.deref_once_mutably_for_diagnostic(lhs_ty) | |
438 | { | |
439 | suggest_deref_binop(lhs_deref_ty); | |
923072b8 | 440 | } else if is_assign == IsAssign::No |
f2b60f7d FG |
441 | && let Ref(_, lhs_deref_ty, _) = lhs_ty.kind() |
442 | { | |
443 | if self.type_is_copy_modulo_regions( | |
444 | self.param_env, | |
445 | *lhs_deref_ty, | |
446 | lhs_expr.span, | |
447 | ) { | |
923072b8 FG |
448 | suggest_deref_binop(*lhs_deref_ty); |
449 | } | |
f2b60f7d FG |
450 | } else if self.suggest_fn_call(&mut err, lhs_expr, lhs_ty, |lhs_ty| { |
451 | is_compatible(lhs_ty, rhs_ty) | |
452 | }) || self.suggest_fn_call(&mut err, rhs_expr, rhs_ty, |rhs_ty| { | |
453 | is_compatible(lhs_ty, rhs_ty) | |
454 | }) || self.suggest_two_fn_call( | |
455 | &mut err, | |
456 | rhs_expr, | |
457 | rhs_ty, | |
458 | lhs_expr, | |
459 | lhs_ty, | |
460 | |lhs_ty, rhs_ty| is_compatible(lhs_ty, rhs_ty), | |
461 | ) { | |
462 | // Cool | |
f035d41b | 463 | } |
f035d41b | 464 | |
f2b60f7d | 465 | if let Some(missing_trait) = missing_trait { |
f035d41b XL |
466 | if op.node == hir::BinOpKind::Add |
467 | && self.check_str_addition( | |
468 | lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, is_assign, op, | |
469 | ) | |
470 | { | |
471 | // This has nothing here because it means we did string | |
472 | // concatenation (e.g., "Hello " + "World!"). This means | |
473 | // we don't want the note in the else clause to be emitted | |
2b03887a | 474 | } else if lhs_ty.has_non_region_param() { |
04454e1e FG |
475 | // Look for a TraitPredicate in the Fulfillment errors, |
476 | // and use it to generate a suggestion. | |
477 | // | |
478 | // Note that lookup_op_method must be called again but | |
479 | // with a specific rhs_ty instead of a placeholder so | |
480 | // the resulting predicate generates a more specific | |
481 | // suggestion for the user. | |
482 | let errors = self | |
483 | .lookup_op_method( | |
484 | lhs_ty, | |
485 | Some(rhs_ty), | |
486 | Some(rhs_expr), | |
487 | Op::Binary(op, is_assign), | |
064997fb | 488 | expected, |
04454e1e FG |
489 | ) |
490 | .unwrap_err(); | |
064997fb FG |
491 | if !errors.is_empty() { |
492 | for error in errors { | |
493 | if let Some(trait_pred) = | |
494 | error.obligation.predicate.to_opt_poly_trait_pred() | |
495 | { | |
f2b60f7d FG |
496 | let output_associated_item = match error.obligation.cause.code() |
497 | { | |
064997fb | 498 | ObligationCauseCode::BinOp { |
f2b60f7d | 499 | output_ty: Some(output_ty), |
064997fb | 500 | .. |
f2b60f7d FG |
501 | } => { |
502 | // Make sure that we're attaching `Output = ..` to the right trait predicate | |
503 | if let Some(output_def_id) = output_def_id | |
504 | && let Some(trait_def_id) = trait_def_id | |
505 | && self.tcx.parent(output_def_id) == trait_def_id | |
506 | { | |
507 | Some(("Output", *output_ty)) | |
508 | } else { | |
509 | None | |
510 | } | |
064997fb FG |
511 | } |
512 | _ => None, | |
513 | }; | |
514 | ||
2b03887a | 515 | self.err_ctxt().suggest_restricting_param_bound( |
064997fb FG |
516 | &mut err, |
517 | trait_pred, | |
f2b60f7d | 518 | output_associated_item, |
064997fb FG |
519 | self.body_id, |
520 | ); | |
521 | } | |
532ac7d7 | 522 | } |
f2b60f7d | 523 | } else { |
04454e1e FG |
524 | // When we know that a missing bound is responsible, we don't show |
525 | // this note as it is redundant. | |
526 | err.note(&format!( | |
527 | "the trait `{missing_trait}` is not implemented for `{lhs_ty}`" | |
528 | )); | |
a7813a04 | 529 | } |
b039eaaf SL |
530 | } |
531 | } | |
f035d41b XL |
532 | err.emit(); |
533 | self.tcx.ty_error() | |
c34b1796 | 534 | } |
a7813a04 | 535 | }; |
c34b1796 | 536 | |
abe05a73 | 537 | (lhs_ty, rhs_ty, return_ty) |
a7813a04 | 538 | } |
c34b1796 | 539 | |
48663c56 XL |
540 | /// Provide actionable suggestions when trying to add two strings with incorrect types, |
541 | /// like `&str + &str`, `String + String` and `&str + &String`. | |
542 | /// | |
543 | /// If this function returns `true` it means a note was printed, so we don't need | |
544 | /// to print the normal "implementation of `std::ops::Add` might be missing" note | |
8faf50e0 XL |
545 | fn check_str_addition( |
546 | &self, | |
dfeec247 XL |
547 | lhs_expr: &'tcx hir::Expr<'tcx>, |
548 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
8faf50e0 XL |
549 | lhs_ty: Ty<'tcx>, |
550 | rhs_ty: Ty<'tcx>, | |
5e7ed085 | 551 | err: &mut Diagnostic, |
f035d41b | 552 | is_assign: IsAssign, |
532ac7d7 | 553 | op: hir::BinOp, |
8faf50e0 | 554 | ) -> bool { |
5099ac24 FG |
555 | let str_concat_note = "string concatenation requires an owned `String` on the left"; |
556 | let rm_borrow_msg = "remove the borrow to obtain an owned `String`"; | |
557 | let to_owned_msg = "create an owned `String` from a string reference"; | |
48663c56 | 558 | |
064997fb FG |
559 | let is_std_string = |ty: Ty<'tcx>| { |
560 | ty.ty_adt_def() | |
561 | .map_or(false, |ty_def| self.tcx.is_diagnostic_item(sym::String, ty_def.did())) | |
3dfed10e | 562 | }; |
48663c56 | 563 | |
1b1a35ee | 564 | match (lhs_ty.kind(), rhs_ty.kind()) { |
48663c56 | 565 | (&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str |
064997fb FG |
566 | if (*l_ty.kind() == Str || is_std_string(l_ty)) |
567 | && (*r_ty.kind() == Str | |
568 | || is_std_string(r_ty) | |
569 | || matches!( | |
570 | r_ty.kind(), Ref(_, inner_ty, _) if *inner_ty.kind() == Str | |
571 | )) => | |
48663c56 | 572 | { |
f035d41b | 573 | if let IsAssign::No = is_assign { // Do not supply this message if `&str += &str` |
5099ac24 FG |
574 | err.span_label(op.span, "`+` cannot be used to concatenate two `&str` strings"); |
575 | err.note(str_concat_note); | |
576 | if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { | |
577 | err.span_suggestion_verbose( | |
578 | lhs_expr.span.until(lhs_inner_expr.span), | |
579 | rm_borrow_msg, | |
923072b8 | 580 | "", |
5099ac24 FG |
581 | Applicability::MachineApplicable |
582 | ); | |
583 | } else { | |
584 | err.span_suggestion_verbose( | |
585 | lhs_expr.span.shrink_to_hi(), | |
586 | to_owned_msg, | |
923072b8 | 587 | ".to_owned()", |
5099ac24 FG |
588 | Applicability::MachineApplicable |
589 | ); | |
590 | } | |
8faf50e0 | 591 | } |
0531ce1d | 592 | true |
8bb4bdeb | 593 | } |
48663c56 | 594 | (&Ref(_, l_ty, _), &Adt(..)) // Handle `&str` & `&String` + `String` |
1b1a35ee | 595 | if (*l_ty.kind() == Str || is_std_string(l_ty)) && is_std_string(rhs_ty) => |
48663c56 XL |
596 | { |
597 | err.span_label( | |
598 | op.span, | |
599 | "`+` cannot be used to concatenate a `&str` with a `String`", | |
600 | ); | |
5099ac24 FG |
601 | match is_assign { |
602 | IsAssign::No => { | |
603 | let sugg_msg; | |
604 | let lhs_sugg = if let hir::ExprKind::AddrOf(_, _, lhs_inner_expr) = lhs_expr.kind { | |
605 | sugg_msg = "remove the borrow on the left and add one on the right"; | |
606 | (lhs_expr.span.until(lhs_inner_expr.span), "".to_owned()) | |
48663c56 | 607 | } else { |
5099ac24 FG |
608 | sugg_msg = "create an owned `String` on the left and add a borrow on the right"; |
609 | (lhs_expr.span.shrink_to_hi(), ".to_owned()".to_owned()) | |
48663c56 | 610 | }; |
5099ac24 FG |
611 | let suggestions = vec![ |
612 | lhs_sugg, | |
613 | (rhs_expr.span.shrink_to_lo(), "&".to_owned()), | |
614 | ]; | |
615 | err.multipart_suggestion_verbose( | |
616 | sugg_msg, | |
617 | suggestions, | |
0bf4aa26 XL |
618 | Applicability::MachineApplicable, |
619 | ); | |
8faf50e0 | 620 | } |
5099ac24 FG |
621 | IsAssign::Yes => { |
622 | err.note(str_concat_note); | |
0531ce1d | 623 | } |
5099ac24 | 624 | } |
0531ce1d XL |
625 | true |
626 | } | |
627 | _ => false, | |
8bb4bdeb | 628 | } |
8bb4bdeb XL |
629 | } |
630 | ||
dc9dc135 XL |
631 | pub fn check_user_unop( |
632 | &self, | |
dfeec247 | 633 | ex: &'tcx hir::Expr<'tcx>, |
dc9dc135 XL |
634 | operand_ty: Ty<'tcx>, |
635 | op: hir::UnOp, | |
064997fb | 636 | expected: Expectation<'tcx>, |
dc9dc135 | 637 | ) -> Ty<'tcx> { |
a7813a04 | 638 | assert!(op.is_by_value()); |
064997fb | 639 | match self.lookup_op_method(operand_ty, None, None, Op::Unary(op, ex.span), expected) { |
7cac9316 | 640 | Ok(method) => { |
3b2f2976 | 641 | self.write_method_call(ex.hir_id, method); |
7cac9316 XL |
642 | method.sig.output() |
643 | } | |
c295e0f8 | 644 | Err(errors) => { |
fc512014 | 645 | let actual = self.resolve_vars_if_possible(operand_ty); |
7cac9316 | 646 | if !actual.references_error() { |
dfeec247 XL |
647 | let mut err = struct_span_err!( |
648 | self.tcx.sess, | |
649 | ex.span, | |
650 | E0600, | |
651 | "cannot apply unary operator `{}` to type `{}`", | |
652 | op.as_str(), | |
653 | actual | |
654 | ); | |
655 | err.span_label( | |
656 | ex.span, | |
f035d41b | 657 | format!("cannot apply unary operator `{}`", op.as_str()), |
dfeec247 | 658 | ); |
04454e1e | 659 | |
2b03887a | 660 | if operand_ty.has_non_region_param() { |
f2b60f7d FG |
661 | let predicates = errors.iter().filter_map(|error| { |
662 | error.obligation.predicate.to_opt_poly_trait_pred() | |
663 | }); | |
04454e1e | 664 | for pred in predicates { |
2b03887a | 665 | self.err_ctxt().suggest_restricting_param_bound( |
04454e1e FG |
666 | &mut err, |
667 | pred, | |
064997fb | 668 | None, |
04454e1e FG |
669 | self.body_id, |
670 | ); | |
671 | } | |
5e7ed085 | 672 | } |
c295e0f8 XL |
673 | |
674 | let sp = self.tcx.sess.source_map().start_point(ex.span); | |
675 | if let Some(sp) = | |
676 | self.tcx.sess.parse_sess.ambiguous_block_expr_parse.borrow().get(&sp) | |
677 | { | |
678 | // If the previous expression was a block expression, suggest parentheses | |
679 | // (turning this into a binary subtraction operation instead.) | |
680 | // for example, `{2} - 2` -> `({2}) - 2` (see src\test\ui\parser\expr-as-stmt.rs) | |
2b03887a | 681 | err.subdiagnostic(ExprParenthesesNeeded::surrounding(*sp)); |
c295e0f8 XL |
682 | } else { |
683 | match actual.kind() { | |
684 | Uint(_) if op == hir::UnOp::Neg => { | |
685 | err.note("unsigned values cannot be negated"); | |
686 | ||
687 | if let hir::ExprKind::Unary( | |
688 | _, | |
689 | hir::Expr { | |
690 | kind: | |
691 | hir::ExprKind::Lit(Spanned { | |
692 | node: ast::LitKind::Int(1, _), | |
693 | .. | |
694 | }), | |
695 | .. | |
696 | }, | |
697 | ) = ex.kind | |
698 | { | |
699 | err.span_suggestion( | |
700 | ex.span, | |
701 | &format!( | |
5e7ed085 | 702 | "you may have meant the maximum value of `{actual}`", |
c295e0f8 | 703 | ), |
5e7ed085 | 704 | format!("{actual}::MAX"), |
c295e0f8 XL |
705 | Applicability::MaybeIncorrect, |
706 | ); | |
707 | } | |
708 | } | |
709 | Str | Never | Char | Tuple(_) | Array(_, _) => {} | |
710 | Ref(_, lty, _) if *lty.kind() == Str => {} | |
711 | _ => { | |
712 | self.note_unmet_impls_on_type(&mut err, errors); | |
29967ef6 | 713 | } |
94b46f34 XL |
714 | } |
715 | } | |
716 | err.emit(); | |
7cac9316 | 717 | } |
f035d41b | 718 | self.tcx.ty_error() |
a7813a04 | 719 | } |
c34b1796 AL |
720 | } |
721 | } | |
c34b1796 | 722 | |
dfeec247 XL |
723 | fn lookup_op_method( |
724 | &self, | |
725 | lhs_ty: Ty<'tcx>, | |
5e7ed085 FG |
726 | other_ty: Option<Ty<'tcx>>, |
727 | other_ty_expr: Option<&'tcx hir::Expr<'tcx>>, | |
dfeec247 | 728 | op: Op, |
064997fb | 729 | expected: Expectation<'tcx>, |
c295e0f8 | 730 | ) -> Result<MethodCallee<'tcx>, Vec<FulfillmentError<'tcx>>> { |
7cac9316 XL |
731 | let span = match op { |
732 | Op::Binary(op, _) => op.span, | |
dfeec247 | 733 | Op::Unary(_, span) => span, |
7cac9316 | 734 | }; |
f2b60f7d | 735 | let (opname, trait_did) = lang_item_for_op(self.tcx, op, span); |
c34b1796 | 736 | |
dfeec247 XL |
737 | debug!( |
738 | "lookup_op_method(lhs_ty={:?}, op={:?}, opname={:?}, trait_did={:?})", | |
739 | lhs_ty, op, opname, trait_did | |
740 | ); | |
7cac9316 | 741 | |
17df50a5 XL |
742 | // Catches cases like #83893, where a lang item is declared with the |
743 | // wrong number of generic arguments. Should have yielded an error | |
744 | // elsewhere by now, but we have to catch it here so that we do not | |
745 | // index `other_tys` out of bounds (if the lang item has too many | |
746 | // generic arguments, `other_tys` is too short). | |
747 | if !has_expected_num_generic_args( | |
748 | self.tcx, | |
749 | trait_did, | |
750 | match op { | |
751 | // Binary ops have a generic right-hand side, unary ops don't | |
752 | Op::Binary(..) => 1, | |
753 | Op::Unary(..) => 0, | |
754 | }, | |
755 | ) { | |
c295e0f8 | 756 | return Err(vec![]); |
17df50a5 XL |
757 | } |
758 | ||
c295e0f8 | 759 | let opname = Ident::with_dummy_span(opname); |
7cac9316 | 760 | let method = trait_did.and_then(|trait_did| { |
064997fb FG |
761 | self.lookup_op_method_in_trait( |
762 | span, | |
763 | opname, | |
764 | trait_did, | |
765 | lhs_ty, | |
766 | other_ty, | |
767 | other_ty_expr, | |
768 | expected, | |
769 | ) | |
7cac9316 | 770 | }); |
c34b1796 | 771 | |
c295e0f8 XL |
772 | match (method, trait_did) { |
773 | (Some(ok), _) => { | |
cc61c64b | 774 | let method = self.register_infer_ok_obligations(ok); |
e1599b0c | 775 | self.select_obligations_where_possible(false, |_| {}); |
7cac9316 | 776 | Ok(method) |
a7813a04 | 777 | } |
c295e0f8 XL |
778 | (None, None) => Err(vec![]), |
779 | (None, Some(trait_did)) => { | |
064997fb FG |
780 | let (obligation, _) = self.obligation_for_op_method( |
781 | span, | |
782 | trait_did, | |
783 | lhs_ty, | |
784 | other_ty, | |
785 | other_ty_expr, | |
786 | expected, | |
787 | ); | |
c295e0f8 XL |
788 | let mut fulfill = <dyn TraitEngine<'_>>::new(self.tcx); |
789 | fulfill.register_predicate_obligation(self, obligation); | |
3c0e092e | 790 | Err(fulfill.select_where_possible(&self.infcx)) |
c295e0f8 | 791 | } |
c34b1796 AL |
792 | } |
793 | } | |
794 | } | |
795 | ||
f2b60f7d FG |
796 | fn lang_item_for_op( |
797 | tcx: TyCtxt<'_>, | |
798 | op: Op, | |
799 | span: Span, | |
800 | ) -> (rustc_span::Symbol, Option<hir::def_id::DefId>) { | |
801 | let lang = tcx.lang_items(); | |
802 | if let Op::Binary(op, IsAssign::Yes) = op { | |
803 | match op.node { | |
804 | hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()), | |
805 | hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()), | |
806 | hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()), | |
807 | hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()), | |
808 | hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()), | |
809 | hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()), | |
810 | hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()), | |
811 | hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()), | |
812 | hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()), | |
813 | hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()), | |
814 | hir::BinOpKind::Lt | |
815 | | hir::BinOpKind::Le | |
816 | | hir::BinOpKind::Ge | |
817 | | hir::BinOpKind::Gt | |
818 | | hir::BinOpKind::Eq | |
819 | | hir::BinOpKind::Ne | |
820 | | hir::BinOpKind::And | |
821 | | hir::BinOpKind::Or => { | |
822 | span_bug!(span, "impossible assignment operation: {}=", op.node.as_str()) | |
823 | } | |
824 | } | |
825 | } else if let Op::Binary(op, IsAssign::No) = op { | |
826 | match op.node { | |
827 | hir::BinOpKind::Add => (sym::add, lang.add_trait()), | |
828 | hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()), | |
829 | hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()), | |
830 | hir::BinOpKind::Div => (sym::div, lang.div_trait()), | |
831 | hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()), | |
832 | hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()), | |
833 | hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()), | |
834 | hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()), | |
835 | hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()), | |
836 | hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()), | |
837 | hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()), | |
838 | hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()), | |
839 | hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()), | |
840 | hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()), | |
841 | hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()), | |
842 | hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()), | |
843 | hir::BinOpKind::And | hir::BinOpKind::Or => { | |
844 | span_bug!(span, "&& and || are not overloadable") | |
845 | } | |
846 | } | |
847 | } else if let Op::Unary(hir::UnOp::Not, _) = op { | |
848 | (sym::not, lang.not_trait()) | |
849 | } else if let Op::Unary(hir::UnOp::Neg, _) = op { | |
850 | (sym::neg, lang.neg_trait()) | |
851 | } else { | |
852 | bug!("lookup_op_method: op not supported: {:?}", op) | |
853 | } | |
854 | } | |
855 | ||
c34b1796 | 856 | // Binary operator categories. These categories summarize the behavior |
5e7ed085 | 857 | // with respect to the builtin operations supported. |
c34b1796 AL |
858 | enum BinOpCategory { |
859 | /// &&, || -- cannot be overridden | |
860 | Shortcircuit, | |
861 | ||
862 | /// <<, >> -- when shifting a single integer, rhs can be any | |
863 | /// integer type. For simd, types must match. | |
864 | Shift, | |
865 | ||
866 | /// +, -, etc -- takes equal types, produces same type as input, | |
867 | /// applicable to ints/floats/simd | |
868 | Math, | |
869 | ||
870 | /// &, |, ^ -- takes equal types, produces same type as input, | |
871 | /// applicable to ints/floats/simd/bool | |
872 | Bitwise, | |
873 | ||
874 | /// ==, !=, etc -- takes equal types, produces bools, except for simd, | |
875 | /// which produce the input type | |
876 | Comparison, | |
877 | } | |
878 | ||
879 | impl BinOpCategory { | |
e9174d1e | 880 | fn from(op: hir::BinOp) -> BinOpCategory { |
c34b1796 | 881 | match op.node { |
dfeec247 XL |
882 | hir::BinOpKind::Shl | hir::BinOpKind::Shr => BinOpCategory::Shift, |
883 | ||
884 | hir::BinOpKind::Add | |
885 | | hir::BinOpKind::Sub | |
886 | | hir::BinOpKind::Mul | |
887 | | hir::BinOpKind::Div | |
888 | | hir::BinOpKind::Rem => BinOpCategory::Math, | |
889 | ||
890 | hir::BinOpKind::BitXor | hir::BinOpKind::BitAnd | hir::BinOpKind::BitOr => { | |
891 | BinOpCategory::Bitwise | |
892 | } | |
893 | ||
894 | hir::BinOpKind::Eq | |
895 | | hir::BinOpKind::Ne | |
896 | | hir::BinOpKind::Lt | |
897 | | hir::BinOpKind::Le | |
898 | | hir::BinOpKind::Ge | |
899 | | hir::BinOpKind::Gt => BinOpCategory::Comparison, | |
900 | ||
901 | hir::BinOpKind::And | hir::BinOpKind::Or => BinOpCategory::Shortcircuit, | |
c34b1796 AL |
902 | } |
903 | } | |
904 | } | |
905 | ||
b039eaaf | 906 | /// Whether the binary operation is an assignment (`a += b`), or not (`a + b`) |
7cac9316 | 907 | #[derive(Clone, Copy, Debug, PartialEq)] |
b039eaaf SL |
908 | enum IsAssign { |
909 | No, | |
910 | Yes, | |
911 | } | |
912 | ||
7cac9316 XL |
913 | #[derive(Clone, Copy, Debug)] |
914 | enum Op { | |
915 | Binary(hir::BinOp, IsAssign), | |
916 | Unary(hir::UnOp, Span), | |
917 | } | |
918 | ||
74b04a01 | 919 | /// Dereferences a single level of immutable referencing. |
a2a8927a | 920 | fn deref_ty_if_possible<'tcx>(ty: Ty<'tcx>) -> Ty<'tcx> { |
1b1a35ee | 921 | match ty.kind() { |
5099ac24 | 922 | ty::Ref(_, ty, hir::Mutability::Not) => *ty, |
74b04a01 XL |
923 | _ => ty, |
924 | } | |
925 | } | |
926 | ||
9fa01778 | 927 | /// Returns `true` if this is a built-in arithmetic operation (e.g., u32 |
c34b1796 AL |
928 | /// + u32, i16x4 == i16x4) and false if these types would have to be |
929 | /// overloaded to be legal. There are two reasons that we distinguish | |
930 | /// builtin operations from overloaded ones (vs trying to drive | |
931 | /// everything uniformly through the trait system and intrinsics or | |
932 | /// something like that): | |
933 | /// | |
934 | /// 1. Builtin operations can trivially be evaluated in constants. | |
935 | /// 2. For comparison operators applied to SIMD types the result is | |
9fa01778 | 936 | /// not of type `bool`. For example, `i16x4 == i16x4` yields a |
c34b1796 AL |
937 | /// type like `i16x4`. This means that the overloaded trait |
938 | /// `PartialEq` is not applicable. | |
939 | /// | |
940 | /// Reason #2 is the killer. I tried for a while to always use | |
94b46f34 | 941 | /// overloaded logic and just check the types in constants/codegen after |
c34b1796 | 942 | /// the fact, and it worked fine, except for SIMD types. -nmatsakis |
74b04a01 XL |
943 | fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>, rhs: Ty<'tcx>, op: hir::BinOp) -> bool { |
944 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. | |
945 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
946 | let (lhs, rhs) = (deref_ty_if_possible(lhs), deref_ty_if_possible(rhs)); | |
947 | ||
c34b1796 | 948 | match BinOpCategory::from(op) { |
dfeec247 | 949 | BinOpCategory::Shortcircuit => true, |
c34b1796 AL |
950 | |
951 | BinOpCategory::Shift => { | |
dfeec247 XL |
952 | lhs.references_error() |
953 | || rhs.references_error() | |
954 | || lhs.is_integral() && rhs.is_integral() | |
c34b1796 AL |
955 | } |
956 | ||
957 | BinOpCategory::Math => { | |
dfeec247 XL |
958 | lhs.references_error() |
959 | || rhs.references_error() | |
960 | || lhs.is_integral() && rhs.is_integral() | |
961 | || lhs.is_floating_point() && rhs.is_floating_point() | |
c34b1796 AL |
962 | } |
963 | ||
964 | BinOpCategory::Bitwise => { | |
dfeec247 XL |
965 | lhs.references_error() |
966 | || rhs.references_error() | |
967 | || lhs.is_integral() && rhs.is_integral() | |
968 | || lhs.is_floating_point() && rhs.is_floating_point() | |
969 | || lhs.is_bool() && rhs.is_bool() | |
c34b1796 AL |
970 | } |
971 | ||
972 | BinOpCategory::Comparison => { | |
dfeec247 | 973 | lhs.references_error() || rhs.references_error() || lhs.is_scalar() && rhs.is_scalar() |
c34b1796 AL |
974 | } |
975 | } | |
976 | } | |
74b04a01 | 977 | |
f035d41b XL |
978 | struct TypeParamEraser<'a, 'tcx>(&'a FnCtxt<'a, 'tcx>, Span); |
979 | ||
a2a8927a | 980 | impl<'tcx> TypeFolder<'tcx> for TypeParamEraser<'_, 'tcx> { |
f035d41b XL |
981 | fn tcx(&self) -> TyCtxt<'tcx> { |
982 | self.0.tcx | |
983 | } | |
984 | ||
985 | fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
1b1a35ee | 986 | match ty.kind() { |
f035d41b XL |
987 | ty::Param(_) => self.0.next_ty_var(TypeVariableOrigin { |
988 | kind: TypeVariableOriginKind::MiscVariable, | |
989 | span: self.1, | |
990 | }), | |
991 | _ => ty.super_fold_with(self), | |
992 | } | |
993 | } | |
994 | } |