]>
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}; |
29967ef6 | 5 | use rustc_ast as ast; |
74b04a01 | 6 | use rustc_errors::{self, struct_span_err, Applicability, DiagnosticBuilder}; |
dfeec247 | 7 | use rustc_hir as hir; |
74b04a01 | 8 | use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind}; |
ba9703b0 XL |
9 | use rustc_middle::ty::adjustment::{ |
10 | Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability, | |
11 | }; | |
f035d41b | 12 | use rustc_middle::ty::fold::TypeFolder; |
ba9703b0 | 13 | use rustc_middle::ty::TyKind::{Adt, Array, Char, FnDef, Never, Ref, Str, Tuple, Uint}; |
f035d41b XL |
14 | use rustc_middle::ty::{ |
15 | self, suggest_constraining_type_param, Ty, TyCtxt, TypeFoldable, TypeVisitor, | |
16 | }; | |
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; |
60c5eb7d | 21 | |
29967ef6 XL |
22 | use std::ops::ControlFlow; |
23 | ||
dc9dc135 | 24 | impl<'a, 'tcx> FnCtxt<'a, 'tcx> { |
9fa01778 | 25 | /// Checks a `a <op>= b` |
dc9dc135 XL |
26 | pub fn check_binop_assign( |
27 | &self, | |
dfeec247 | 28 | expr: &'tcx hir::Expr<'tcx>, |
dc9dc135 | 29 | op: hir::BinOp, |
dfeec247 XL |
30 | lhs: &'tcx hir::Expr<'tcx>, |
31 | rhs: &'tcx hir::Expr<'tcx>, | |
dc9dc135 | 32 | ) -> Ty<'tcx> { |
abe05a73 | 33 | let (lhs_ty, rhs_ty, return_ty) = |
dfeec247 | 34 | self.check_overloaded_binop(expr, lhs, rhs, op, IsAssign::Yes); |
a7813a04 | 35 | |
dfeec247 XL |
36 | let ty = |
37 | if !lhs_ty.is_ty_var() && !rhs_ty.is_ty_var() && is_builtin_binop(lhs_ty, rhs_ty, op) { | |
74b04a01 | 38 | self.enforce_builtin_binop_types(&lhs.span, lhs_ty, &rhs.span, rhs_ty, op); |
dfeec247 XL |
39 | self.tcx.mk_unit() |
40 | } else { | |
41 | return_ty | |
42 | }; | |
43 | ||
44 | self.check_lhs_assignable(lhs, "E0067", &op.span); | |
c34b1796 | 45 | |
9e0c209e | 46 | ty |
c34b1796 | 47 | } |
c34b1796 | 48 | |
9fa01778 | 49 | /// Checks a potentially overloaded binary operator. |
dc9dc135 XL |
50 | pub fn check_binop( |
51 | &self, | |
dfeec247 | 52 | expr: &'tcx hir::Expr<'tcx>, |
dc9dc135 | 53 | op: hir::BinOp, |
dfeec247 XL |
54 | lhs_expr: &'tcx hir::Expr<'tcx>, |
55 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
dc9dc135 | 56 | ) -> Ty<'tcx> { |
a7813a04 XL |
57 | let tcx = self.tcx; |
58 | ||
dfeec247 XL |
59 | debug!( |
60 | "check_binop(expr.hir_id={}, expr={:?}, op={:?}, lhs_expr={:?}, rhs_expr={:?})", | |
61 | expr.hir_id, expr, op, lhs_expr, rhs_expr | |
62 | ); | |
a7813a04 | 63 | |
a7813a04 XL |
64 | match BinOpCategory::from(op) { |
65 | BinOpCategory::Shortcircuit => { | |
66 | // && and || are a simple case. | |
f035d41b | 67 | self.check_expr_coercable_to_type(lhs_expr, tcx.types.bool, None); |
476ff2be | 68 | let lhs_diverges = self.diverges.get(); |
f035d41b | 69 | self.check_expr_coercable_to_type(rhs_expr, tcx.types.bool, None); |
476ff2be SL |
70 | |
71 | // Depending on the LHS' value, the RHS can never execute. | |
72 | self.diverges.set(lhs_diverges); | |
73 | ||
abe05a73 | 74 | tcx.types.bool |
c34b1796 | 75 | } |
a7813a04 XL |
76 | _ => { |
77 | // Otherwise, we always treat operators as if they are | |
78 | // overloaded. This is the way to be most flexible w/r/t | |
79 | // types that get inferred. | |
abe05a73 | 80 | let (lhs_ty, rhs_ty, return_ty) = |
dfeec247 | 81 | self.check_overloaded_binop(expr, lhs_expr, rhs_expr, op, IsAssign::No); |
a7813a04 XL |
82 | |
83 | // Supply type inference hints if relevant. Probably these | |
84 | // hints should be enforced during select as part of the | |
85 | // `consider_unification_despite_ambiguity` routine, but this | |
86 | // more convenient for now. | |
87 | // | |
88 | // The basic idea is to help type inference by taking | |
89 | // advantage of things we know about how the impls for | |
90 | // scalar types are arranged. This is important in a | |
91 | // scenario like `1_u32 << 2`, because it lets us quickly | |
92 | // deduce that the result type should be `u32`, even | |
93 | // though we don't know yet what type 2 has and hence | |
94 | // can't pin this down to a specific impl. | |
dfeec247 XL |
95 | if !lhs_ty.is_ty_var() |
96 | && !rhs_ty.is_ty_var() | |
97 | && is_builtin_binop(lhs_ty, rhs_ty, op) | |
a7813a04 | 98 | { |
74b04a01 XL |
99 | let builtin_return_ty = self.enforce_builtin_binop_types( |
100 | &lhs_expr.span, | |
101 | lhs_ty, | |
102 | &rhs_expr.span, | |
103 | rhs_ty, | |
104 | op, | |
105 | ); | |
a7813a04 XL |
106 | self.demand_suptype(expr.span, builtin_return_ty, return_ty); |
107 | } | |
c34b1796 | 108 | |
9e0c209e | 109 | return_ty |
a7813a04 | 110 | } |
c34b1796 AL |
111 | } |
112 | } | |
c34b1796 | 113 | |
dc9dc135 XL |
114 | fn enforce_builtin_binop_types( |
115 | &self, | |
74b04a01 | 116 | lhs_span: &Span, |
dc9dc135 | 117 | lhs_ty: Ty<'tcx>, |
74b04a01 | 118 | rhs_span: &Span, |
dc9dc135 XL |
119 | rhs_ty: Ty<'tcx>, |
120 | op: hir::BinOp, | |
121 | ) -> Ty<'tcx> { | |
a7813a04 XL |
122 | debug_assert!(is_builtin_binop(lhs_ty, rhs_ty, op)); |
123 | ||
74b04a01 XL |
124 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. |
125 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
126 | let (lhs_ty, rhs_ty) = (deref_ty_if_possible(lhs_ty), deref_ty_if_possible(rhs_ty)); | |
127 | ||
a7813a04 XL |
128 | let tcx = self.tcx; |
129 | match BinOpCategory::from(op) { | |
130 | BinOpCategory::Shortcircuit => { | |
f9f354fc XL |
131 | self.demand_suptype(*lhs_span, tcx.types.bool, lhs_ty); |
132 | self.demand_suptype(*rhs_span, tcx.types.bool, rhs_ty); | |
133 | tcx.types.bool | |
a7813a04 | 134 | } |
c34b1796 | 135 | |
a7813a04 XL |
136 | BinOpCategory::Shift => { |
137 | // result type is same as LHS always | |
138 | lhs_ty | |
139 | } | |
c34b1796 | 140 | |
dfeec247 | 141 | BinOpCategory::Math | BinOpCategory::Bitwise => { |
a7813a04 | 142 | // both LHS and RHS and result will have the same type |
74b04a01 | 143 | self.demand_suptype(*rhs_span, lhs_ty, rhs_ty); |
a7813a04 XL |
144 | lhs_ty |
145 | } | |
c34b1796 | 146 | |
a7813a04 XL |
147 | BinOpCategory::Comparison => { |
148 | // both LHS and RHS and result will have the same type | |
74b04a01 | 149 | self.demand_suptype(*rhs_span, lhs_ty, rhs_ty); |
f9f354fc | 150 | tcx.types.bool |
a7813a04 | 151 | } |
c34b1796 AL |
152 | } |
153 | } | |
c34b1796 | 154 | |
dc9dc135 XL |
155 | fn check_overloaded_binop( |
156 | &self, | |
dfeec247 XL |
157 | expr: &'tcx hir::Expr<'tcx>, |
158 | lhs_expr: &'tcx hir::Expr<'tcx>, | |
159 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
dc9dc135 XL |
160 | op: hir::BinOp, |
161 | is_assign: IsAssign, | |
162 | ) -> (Ty<'tcx>, Ty<'tcx>, Ty<'tcx>) { | |
dfeec247 XL |
163 | debug!( |
164 | "check_overloaded_binop(expr.hir_id={}, op={:?}, is_assign={:?})", | |
165 | expr.hir_id, op, is_assign | |
166 | ); | |
a7813a04 | 167 | |
74d20737 XL |
168 | let lhs_ty = match is_assign { |
169 | IsAssign::No => { | |
170 | // Find a suitable supertype of the LHS expression's type, by coercing to | |
171 | // a type variable, to pass as the `Self` to the trait, avoiding invariant | |
172 | // trait matching creating lifetime constraints that are too strict. | |
0731742a | 173 | // e.g., adding `&'a T` and `&'b T`, given `&'x T: Add<&'x T>`, will result |
74d20737 | 174 | // in `&'a T <: &'x T` and `&'b T <: &'x T`, instead of `'a = 'b = 'x`. |
f035d41b | 175 | let lhs_ty = self.check_expr(lhs_expr); |
dc9dc135 XL |
176 | let fresh_var = self.next_ty_var(TypeVariableOrigin { |
177 | kind: TypeVariableOriginKind::MiscVariable, | |
178 | span: lhs_expr.span, | |
179 | }); | |
f035d41b | 180 | self.demand_coerce(lhs_expr, lhs_ty, fresh_var, Some(rhs_expr), AllowTwoPhase::No) |
74d20737 XL |
181 | } |
182 | IsAssign::Yes => { | |
183 | // rust-lang/rust#52126: We have to use strict | |
184 | // equivalence on the LHS of an assign-op like `+=`; | |
185 | // overwritten or mutably-borrowed places cannot be | |
186 | // coerced to a supertype. | |
f035d41b | 187 | self.check_expr(lhs_expr) |
74d20737 | 188 | } |
abe05a73 | 189 | }; |
e74abb32 | 190 | let lhs_ty = self.resolve_vars_with_obligations(lhs_ty); |
abe05a73 | 191 | |
0731742a | 192 | // N.B., as we have not yet type-checked the RHS, we don't have the |
a7813a04 XL |
193 | // type at hand. Make a variable to represent it. The whole reason |
194 | // for this indirection is so that, below, we can check the expr | |
195 | // using this variable as the expected type, which sometimes lets | |
196 | // us do better coercions than we would be able to do otherwise, | |
197 | // particularly for things like `String + &String`. | |
dc9dc135 XL |
198 | let rhs_ty_var = self.next_ty_var(TypeVariableOrigin { |
199 | kind: TypeVariableOriginKind::MiscVariable, | |
200 | span: rhs_expr.span, | |
201 | }); | |
a7813a04 | 202 | |
7cac9316 | 203 | let result = self.lookup_op_method(lhs_ty, &[rhs_ty_var], Op::Binary(op, is_assign)); |
8bb4bdeb XL |
204 | |
205 | // see `NB` above | |
f035d41b | 206 | let rhs_ty = self.check_expr_coercable_to_type(rhs_expr, rhs_ty_var, Some(lhs_expr)); |
e74abb32 | 207 | let rhs_ty = self.resolve_vars_with_obligations(rhs_ty); |
8bb4bdeb | 208 | |
7cac9316 XL |
209 | let return_ty = match result { |
210 | Ok(method) => { | |
211 | let by_ref_binop = !op.node.is_by_value(); | |
212 | if is_assign == IsAssign::Yes || by_ref_binop { | |
1b1a35ee | 213 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[0].kind() { |
94b46f34 | 214 | let mutbl = match mutbl { |
dfeec247 XL |
215 | hir::Mutability::Not => AutoBorrowMutability::Not, |
216 | hir::Mutability::Mut => AutoBorrowMutability::Mut { | |
0531ce1d XL |
217 | // Allow two-phase borrows for binops in initial deployment |
218 | // since they desugar to methods | |
83c7162d | 219 | allow_two_phase_borrow: AllowTwoPhase::Yes, |
dfeec247 | 220 | }, |
2c00a5a8 | 221 | }; |
7cac9316 | 222 | let autoref = Adjustment { |
2c00a5a8 | 223 | kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)), |
dfeec247 | 224 | target: method.sig.inputs()[0], |
7cac9316 XL |
225 | }; |
226 | self.apply_adjustments(lhs_expr, vec![autoref]); | |
227 | } | |
228 | } | |
229 | if by_ref_binop { | |
1b1a35ee | 230 | if let ty::Ref(region, _, mutbl) = method.sig.inputs()[1].kind() { |
94b46f34 | 231 | let mutbl = match mutbl { |
dfeec247 XL |
232 | hir::Mutability::Not => AutoBorrowMutability::Not, |
233 | hir::Mutability::Mut => AutoBorrowMutability::Mut { | |
0531ce1d XL |
234 | // Allow two-phase borrows for binops in initial deployment |
235 | // since they desugar to methods | |
83c7162d | 236 | allow_two_phase_borrow: AllowTwoPhase::Yes, |
dfeec247 | 237 | }, |
2c00a5a8 | 238 | }; |
7cac9316 | 239 | let autoref = Adjustment { |
2c00a5a8 | 240 | kind: Adjust::Borrow(AutoBorrow::Ref(region, mutbl)), |
dfeec247 | 241 | target: method.sig.inputs()[1], |
7cac9316 XL |
242 | }; |
243 | // HACK(eddyb) Bypass checks due to reborrows being in | |
244 | // some cases applied on the RHS, on top of which we need | |
245 | // to autoref, which is not allowed by apply_adjustments. | |
246 | // self.apply_adjustments(rhs_expr, vec![autoref]); | |
3dfed10e | 247 | self.typeck_results |
3b2f2976 XL |
248 | .borrow_mut() |
249 | .adjustments_mut() | |
250 | .entry(rhs_expr.hir_id) | |
b7449926 | 251 | .or_default() |
3b2f2976 | 252 | .push(autoref); |
7cac9316 XL |
253 | } |
254 | } | |
3b2f2976 | 255 | self.write_method_call(expr.hir_id, method); |
7cac9316 XL |
256 | |
257 | method.sig.output() | |
258 | } | |
f035d41b XL |
259 | // error types are considered "builtin" |
260 | Err(()) if lhs_ty.references_error() || rhs_ty.references_error() => { | |
261 | self.tcx.ty_error() | |
262 | } | |
a7813a04 | 263 | Err(()) => { |
f035d41b XL |
264 | let source_map = self.tcx.sess.source_map(); |
265 | let (mut err, missing_trait, use_output, involves_fn) = match is_assign { | |
266 | IsAssign::Yes => { | |
267 | let mut err = struct_span_err!( | |
268 | self.tcx.sess, | |
269 | expr.span, | |
270 | E0368, | |
271 | "binary assignment operation `{}=` cannot be applied to type `{}`", | |
272 | op.node.as_str(), | |
273 | lhs_ty, | |
274 | ); | |
275 | err.span_label( | |
276 | lhs_expr.span, | |
277 | format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty), | |
278 | ); | |
279 | let missing_trait = match op.node { | |
280 | hir::BinOpKind::Add => Some("std::ops::AddAssign"), | |
281 | hir::BinOpKind::Sub => Some("std::ops::SubAssign"), | |
282 | hir::BinOpKind::Mul => Some("std::ops::MulAssign"), | |
283 | hir::BinOpKind::Div => Some("std::ops::DivAssign"), | |
284 | hir::BinOpKind::Rem => Some("std::ops::RemAssign"), | |
285 | hir::BinOpKind::BitAnd => Some("std::ops::BitAndAssign"), | |
286 | hir::BinOpKind::BitXor => Some("std::ops::BitXorAssign"), | |
287 | hir::BinOpKind::BitOr => Some("std::ops::BitOrAssign"), | |
288 | hir::BinOpKind::Shl => Some("std::ops::ShlAssign"), | |
289 | hir::BinOpKind::Shr => Some("std::ops::ShrAssign"), | |
290 | _ => None, | |
291 | }; | |
292 | (err, missing_trait, false, false) | |
293 | } | |
294 | IsAssign::No => { | |
295 | let (message, missing_trait, use_output) = match op.node { | |
296 | hir::BinOpKind::Add => ( | |
297 | format!("cannot add `{}` to `{}`", rhs_ty, lhs_ty), | |
298 | Some("std::ops::Add"), | |
299 | true, | |
300 | ), | |
301 | hir::BinOpKind::Sub => ( | |
302 | format!("cannot subtract `{}` from `{}`", rhs_ty, lhs_ty), | |
303 | Some("std::ops::Sub"), | |
304 | true, | |
305 | ), | |
306 | hir::BinOpKind::Mul => ( | |
29967ef6 | 307 | format!("cannot multiply `{}` by `{}`", lhs_ty, rhs_ty), |
f035d41b XL |
308 | Some("std::ops::Mul"), |
309 | true, | |
310 | ), | |
311 | hir::BinOpKind::Div => ( | |
312 | format!("cannot divide `{}` by `{}`", lhs_ty, rhs_ty), | |
313 | Some("std::ops::Div"), | |
314 | true, | |
315 | ), | |
316 | hir::BinOpKind::Rem => ( | |
317 | format!("cannot mod `{}` by `{}`", lhs_ty, rhs_ty), | |
318 | Some("std::ops::Rem"), | |
319 | true, | |
320 | ), | |
321 | hir::BinOpKind::BitAnd => ( | |
322 | format!("no implementation for `{} & {}`", lhs_ty, rhs_ty), | |
323 | Some("std::ops::BitAnd"), | |
324 | true, | |
325 | ), | |
326 | hir::BinOpKind::BitXor => ( | |
327 | format!("no implementation for `{} ^ {}`", lhs_ty, rhs_ty), | |
328 | Some("std::ops::BitXor"), | |
329 | true, | |
330 | ), | |
331 | hir::BinOpKind::BitOr => ( | |
332 | format!("no implementation for `{} | {}`", lhs_ty, rhs_ty), | |
333 | Some("std::ops::BitOr"), | |
334 | true, | |
335 | ), | |
336 | hir::BinOpKind::Shl => ( | |
337 | format!("no implementation for `{} << {}`", lhs_ty, rhs_ty), | |
338 | Some("std::ops::Shl"), | |
339 | true, | |
340 | ), | |
341 | hir::BinOpKind::Shr => ( | |
342 | format!("no implementation for `{} >> {}`", lhs_ty, rhs_ty), | |
343 | Some("std::ops::Shr"), | |
344 | true, | |
345 | ), | |
346 | hir::BinOpKind::Eq | hir::BinOpKind::Ne => ( | |
347 | format!( | |
348 | "binary operation `{}` cannot be applied to type `{}`", | |
349 | op.node.as_str(), | |
350 | lhs_ty | |
351 | ), | |
352 | Some("std::cmp::PartialEq"), | |
353 | false, | |
354 | ), | |
355 | hir::BinOpKind::Lt | |
356 | | hir::BinOpKind::Le | |
357 | | hir::BinOpKind::Gt | |
358 | | hir::BinOpKind::Ge => ( | |
359 | format!( | |
360 | "binary operation `{}` cannot be applied to type `{}`", | |
361 | op.node.as_str(), | |
362 | lhs_ty | |
363 | ), | |
364 | Some("std::cmp::PartialOrd"), | |
365 | false, | |
366 | ), | |
367 | _ => ( | |
368 | format!( | |
369 | "binary operation `{}` cannot be applied to type `{}`", | |
370 | op.node.as_str(), | |
371 | lhs_ty | |
372 | ), | |
373 | None, | |
374 | false, | |
375 | ), | |
376 | }; | |
377 | let mut err = | |
378 | struct_span_err!(self.tcx.sess, op.span, E0369, "{}", message.as_str()); | |
379 | let mut involves_fn = false; | |
380 | if !lhs_expr.span.eq(&rhs_expr.span) { | |
381 | involves_fn |= self.add_type_neq_err_label( | |
382 | &mut err, | |
383 | lhs_expr.span, | |
b7449926 | 384 | lhs_ty, |
f035d41b XL |
385 | rhs_ty, |
386 | op, | |
387 | is_assign, | |
b7449926 | 388 | ); |
f035d41b XL |
389 | involves_fn |= self.add_type_neq_err_label( |
390 | &mut err, | |
391 | rhs_expr.span, | |
392 | rhs_ty, | |
393 | lhs_ty, | |
394 | op, | |
395 | is_assign, | |
b7449926 | 396 | ); |
32a655c1 | 397 | } |
f035d41b XL |
398 | (err, missing_trait, use_output, involves_fn) |
399 | } | |
400 | }; | |
401 | let mut suggested_deref = false; | |
1b1a35ee | 402 | if let Ref(_, rty, _) = lhs_ty.kind() { |
f035d41b XL |
403 | if { |
404 | self.infcx.type_is_copy_modulo_regions(self.param_env, rty, lhs_expr.span) | |
405 | && self | |
406 | .lookup_op_method(rty, &[rhs_ty], Op::Binary(op, is_assign)) | |
407 | .is_ok() | |
408 | } { | |
409 | if let Ok(lstring) = source_map.span_to_snippet(lhs_expr.span) { | |
410 | let msg = &format!( | |
411 | "`{}{}` can be used on `{}`, you can dereference `{}`", | |
412 | op.node.as_str(), | |
413 | match is_assign { | |
414 | IsAssign::Yes => "=", | |
415 | IsAssign::No => "", | |
416 | }, | |
417 | rty.peel_refs(), | |
418 | lstring, | |
dfeec247 | 419 | ); |
f035d41b XL |
420 | err.span_suggestion_verbose( |
421 | lhs_expr.span.shrink_to_lo(), | |
422 | msg, | |
423 | "*".to_string(), | |
424 | rustc_errors::Applicability::MachineApplicable, | |
425 | ); | |
426 | suggested_deref = true; | |
427 | } | |
428 | } | |
429 | } | |
430 | if let Some(missing_trait) = missing_trait { | |
431 | let mut visitor = TypeParamVisitor(vec![]); | |
432 | visitor.visit_ty(lhs_ty); | |
433 | ||
434 | if op.node == hir::BinOpKind::Add | |
435 | && self.check_str_addition( | |
436 | lhs_expr, rhs_expr, lhs_ty, rhs_ty, &mut err, is_assign, op, | |
437 | ) | |
438 | { | |
439 | // This has nothing here because it means we did string | |
440 | // concatenation (e.g., "Hello " + "World!"). This means | |
441 | // we don't want the note in the else clause to be emitted | |
442 | } else if let [ty] = &visitor.0[..] { | |
1b1a35ee | 443 | if let ty::Param(p) = *ty.kind() { |
f035d41b XL |
444 | // Check if the method would be found if the type param wasn't |
445 | // involved. If so, it means that adding a trait bound to the param is | |
446 | // enough. Otherwise we do not give the suggestion. | |
447 | let mut eraser = TypeParamEraser(&self, expr.span); | |
448 | let needs_bound = self | |
449 | .lookup_op_method( | |
450 | eraser.fold_ty(lhs_ty), | |
451 | &[eraser.fold_ty(rhs_ty)], | |
452 | Op::Binary(op, is_assign), | |
453 | ) | |
454 | .is_ok(); | |
455 | if needs_bound { | |
456 | suggest_constraining_param( | |
457 | self.tcx, | |
458 | self.body_id, | |
48663c56 | 459 | &mut err, |
f035d41b | 460 | ty, |
48663c56 | 461 | rhs_ty, |
f035d41b XL |
462 | missing_trait, |
463 | p, | |
464 | use_output, | |
48663c56 | 465 | ); |
f035d41b XL |
466 | } else if *ty != lhs_ty { |
467 | // When we know that a missing bound is responsible, we don't show | |
468 | // this note as it is redundant. | |
469 | err.note(&format!( | |
470 | "the trait `{}` is not implemented for `{}`", | |
471 | missing_trait, lhs_ty | |
472 | )); | |
532ac7d7 | 473 | } |
f035d41b | 474 | } else { |
1b1a35ee | 475 | bug!("type param visitor stored a non type param: {:?}", ty.kind()); |
a7813a04 | 476 | } |
f035d41b XL |
477 | } else if !suggested_deref && !involves_fn { |
478 | suggest_impl_missing(&mut err, lhs_ty, &missing_trait); | |
b039eaaf SL |
479 | } |
480 | } | |
f035d41b XL |
481 | err.emit(); |
482 | self.tcx.ty_error() | |
c34b1796 | 483 | } |
a7813a04 | 484 | }; |
c34b1796 | 485 | |
abe05a73 | 486 | (lhs_ty, rhs_ty, return_ty) |
a7813a04 | 487 | } |
c34b1796 | 488 | |
48663c56 | 489 | /// If one of the types is an uncalled function and calling it would yield the other type, |
ba9703b0 | 490 | /// suggest calling the function. Returns `true` if suggestion would apply (even if not given). |
48663c56 XL |
491 | fn add_type_neq_err_label( |
492 | &self, | |
dfeec247 | 493 | err: &mut rustc_errors::DiagnosticBuilder<'_>, |
48663c56 XL |
494 | span: Span, |
495 | ty: Ty<'tcx>, | |
496 | other_ty: Ty<'tcx>, | |
497 | op: hir::BinOp, | |
498 | is_assign: IsAssign, | |
499 | ) -> bool /* did we suggest to call a function because of missing parenthesis? */ { | |
500 | err.span_label(span, ty.to_string()); | |
1b1a35ee | 501 | if let FnDef(def_id, _) = *ty.kind() { |
48663c56 | 502 | let source_map = self.tcx.sess.source_map(); |
3dfed10e | 503 | if !self.tcx.has_typeck_results(def_id) { |
48663c56 XL |
504 | return false; |
505 | } | |
fc512014 XL |
506 | // FIXME: Instead of exiting early when encountering bound vars in |
507 | // the function signature, consider keeping the binder here and | |
508 | // propagating it downwards. | |
509 | let fn_sig = if let Some(fn_sig) = self.tcx.fn_sig(def_id).no_bound_vars() { | |
510 | fn_sig | |
511 | } else { | |
512 | return false; | |
513 | }; | |
48663c56 | 514 | |
1b1a35ee | 515 | let other_ty = if let FnDef(def_id, _) = *other_ty.kind() { |
3dfed10e | 516 | if !self.tcx.has_typeck_results(def_id) { |
48663c56 XL |
517 | return false; |
518 | } | |
ba9703b0 XL |
519 | // We're emitting a suggestion, so we can just ignore regions |
520 | self.tcx.fn_sig(def_id).skip_binder().output() | |
48663c56 XL |
521 | } else { |
522 | other_ty | |
523 | }; | |
524 | ||
dfeec247 XL |
525 | if self |
526 | .lookup_op_method(fn_sig.output(), &[other_ty], Op::Binary(op, is_assign)) | |
527 | .is_ok() | |
528 | { | |
ba9703b0 XL |
529 | if let Ok(snippet) = source_map.span_to_snippet(span) { |
530 | let (variable_snippet, applicability) = if !fn_sig.inputs().is_empty() { | |
531 | (format!("{}( /* arguments */ )", snippet), Applicability::HasPlaceholders) | |
532 | } else { | |
533 | (format!("{}()", snippet), Applicability::MaybeIncorrect) | |
534 | }; | |
48663c56 | 535 | |
ba9703b0 XL |
536 | err.span_suggestion( |
537 | span, | |
538 | "you might have forgotten to call this function", | |
539 | variable_snippet, | |
540 | applicability, | |
541 | ); | |
542 | } | |
48663c56 XL |
543 | return true; |
544 | } | |
545 | } | |
546 | false | |
547 | } | |
548 | ||
549 | /// Provide actionable suggestions when trying to add two strings with incorrect types, | |
550 | /// like `&str + &str`, `String + String` and `&str + &String`. | |
551 | /// | |
552 | /// If this function returns `true` it means a note was printed, so we don't need | |
553 | /// to print the normal "implementation of `std::ops::Add` might be missing" note | |
8faf50e0 XL |
554 | fn check_str_addition( |
555 | &self, | |
dfeec247 XL |
556 | lhs_expr: &'tcx hir::Expr<'tcx>, |
557 | rhs_expr: &'tcx hir::Expr<'tcx>, | |
8faf50e0 XL |
558 | lhs_ty: Ty<'tcx>, |
559 | rhs_ty: Ty<'tcx>, | |
dfeec247 | 560 | err: &mut rustc_errors::DiagnosticBuilder<'_>, |
f035d41b | 561 | is_assign: IsAssign, |
532ac7d7 | 562 | op: hir::BinOp, |
8faf50e0 | 563 | ) -> bool { |
b7449926 | 564 | let source_map = self.tcx.sess.source_map(); |
48663c56 XL |
565 | let remove_borrow_msg = "String concatenation appends the string on the right to the \ |
566 | string on the left and may require reallocation. This \ | |
567 | requires ownership of the string on the left"; | |
568 | ||
0531ce1d XL |
569 | let msg = "`to_owned()` can be used to create an owned `String` \ |
570 | from a string reference. String concatenation \ | |
571 | appends the string on the right to the string \ | |
572 | on the left and may require reallocation. This \ | |
573 | requires ownership of the string on the left"; | |
48663c56 | 574 | |
3dfed10e XL |
575 | let string_type = self.tcx.get_diagnostic_item(sym::string_type); |
576 | let is_std_string = |ty: Ty<'tcx>| match ty.ty_adt_def() { | |
577 | Some(ty_def) => Some(ty_def.did) == string_type, | |
578 | None => false, | |
579 | }; | |
48663c56 | 580 | |
1b1a35ee | 581 | match (lhs_ty.kind(), rhs_ty.kind()) { |
48663c56 | 582 | (&Ref(_, l_ty, _), &Ref(_, r_ty, _)) // &str or &String + &str, &String or &&str |
1b1a35ee XL |
583 | if (*l_ty.kind() == Str || is_std_string(l_ty)) && ( |
584 | *r_ty.kind() == Str || is_std_string(r_ty) || | |
48663c56 XL |
585 | &format!("{:?}", rhs_ty) == "&&str" |
586 | ) => | |
587 | { | |
f035d41b | 588 | if let IsAssign::No = is_assign { // Do not supply this message if `&str += &str` |
48663c56 XL |
589 | err.span_label( |
590 | op.span, | |
591 | "`+` cannot be used to concatenate two `&str` strings", | |
592 | ); | |
b7449926 | 593 | match source_map.span_to_snippet(lhs_expr.span) { |
48663c56 XL |
594 | Ok(lstring) => { |
595 | err.span_suggestion( | |
596 | lhs_expr.span, | |
74b04a01 | 597 | if lstring.starts_with('&') { |
48663c56 XL |
598 | remove_borrow_msg |
599 | } else { | |
600 | msg | |
601 | }, | |
1b1a35ee | 602 | if let Some(stripped) = lstring.strip_prefix('&') { |
48663c56 XL |
603 | // let a = String::new(); |
604 | // let _ = &a + "bar"; | |
1b1a35ee | 605 | stripped.to_string() |
48663c56 XL |
606 | } else { |
607 | format!("{}.to_owned()", lstring) | |
608 | }, | |
609 | Applicability::MachineApplicable, | |
610 | ) | |
611 | } | |
8faf50e0 XL |
612 | _ => err.help(msg), |
613 | }; | |
614 | } | |
0531ce1d | 615 | true |
8bb4bdeb | 616 | } |
48663c56 | 617 | (&Ref(_, l_ty, _), &Adt(..)) // Handle `&str` & `&String` + `String` |
1b1a35ee | 618 | if (*l_ty.kind() == Str || is_std_string(l_ty)) && is_std_string(rhs_ty) => |
48663c56 XL |
619 | { |
620 | err.span_label( | |
621 | op.span, | |
622 | "`+` cannot be used to concatenate a `&str` with a `String`", | |
623 | ); | |
8faf50e0 | 624 | match ( |
b7449926 XL |
625 | source_map.span_to_snippet(lhs_expr.span), |
626 | source_map.span_to_snippet(rhs_expr.span), | |
8faf50e0 XL |
627 | is_assign, |
628 | ) { | |
f035d41b | 629 | (Ok(l), Ok(r), IsAssign::No) => { |
1b1a35ee | 630 | let to_string = if let Some(stripped) = l.strip_prefix('&') { |
48663c56 XL |
631 | // let a = String::new(); let b = String::new(); |
632 | // let _ = &a + b; | |
1b1a35ee | 633 | stripped.to_string() |
48663c56 XL |
634 | } else { |
635 | format!("{}.to_owned()", l) | |
636 | }; | |
9fa01778 | 637 | err.multipart_suggestion( |
0bf4aa26 XL |
638 | msg, |
639 | vec![ | |
48663c56 | 640 | (lhs_expr.span, to_string), |
0bf4aa26 XL |
641 | (rhs_expr.span, format!("&{}", r)), |
642 | ], | |
643 | Applicability::MachineApplicable, | |
644 | ); | |
8faf50e0 XL |
645 | } |
646 | _ => { | |
647 | err.help(msg); | |
0531ce1d | 648 | } |
0531ce1d XL |
649 | }; |
650 | true | |
651 | } | |
652 | _ => false, | |
8bb4bdeb | 653 | } |
8bb4bdeb XL |
654 | } |
655 | ||
dc9dc135 XL |
656 | pub fn check_user_unop( |
657 | &self, | |
dfeec247 | 658 | ex: &'tcx hir::Expr<'tcx>, |
dc9dc135 XL |
659 | operand_ty: Ty<'tcx>, |
660 | op: hir::UnOp, | |
661 | ) -> Ty<'tcx> { | |
a7813a04 | 662 | assert!(op.is_by_value()); |
7cac9316 XL |
663 | match self.lookup_op_method(operand_ty, &[], Op::Unary(op, ex.span)) { |
664 | Ok(method) => { | |
3b2f2976 | 665 | self.write_method_call(ex.hir_id, method); |
7cac9316 XL |
666 | method.sig.output() |
667 | } | |
a7813a04 | 668 | Err(()) => { |
fc512014 | 669 | let actual = self.resolve_vars_if_possible(operand_ty); |
7cac9316 | 670 | if !actual.references_error() { |
dfeec247 XL |
671 | let mut err = struct_span_err!( |
672 | self.tcx.sess, | |
673 | ex.span, | |
674 | E0600, | |
675 | "cannot apply unary operator `{}` to type `{}`", | |
676 | op.as_str(), | |
677 | actual | |
678 | ); | |
679 | err.span_label( | |
680 | ex.span, | |
f035d41b | 681 | format!("cannot apply unary operator `{}`", op.as_str()), |
dfeec247 | 682 | ); |
1b1a35ee | 683 | match actual.kind() { |
6a06907d | 684 | Uint(_) if op == hir::UnOp::Neg => { |
8faf50e0 | 685 | err.note("unsigned values cannot be negated"); |
29967ef6 XL |
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!( | |
702 | "you may have meant the maximum value of `{}`", | |
703 | actual | |
704 | ), | |
705 | format!("{}::MAX", actual), | |
706 | Applicability::MaybeIncorrect, | |
707 | ); | |
708 | } | |
dfeec247 XL |
709 | } |
710 | Str | Never | Char | Tuple(_) | Array(_, _) => {} | |
1b1a35ee | 711 | Ref(_, ref lty, _) if *lty.kind() == Str => {} |
94b46f34 XL |
712 | _ => { |
713 | let missing_trait = match op { | |
6a06907d XL |
714 | hir::UnOp::Neg => "std::ops::Neg", |
715 | hir::UnOp::Not => "std::ops::Not", | |
716 | hir::UnOp::Deref => "std::ops::UnDerf", | |
94b46f34 | 717 | }; |
74b04a01 | 718 | suggest_impl_missing(&mut err, operand_ty, &missing_trait); |
94b46f34 XL |
719 | } |
720 | } | |
721 | err.emit(); | |
7cac9316 | 722 | } |
f035d41b | 723 | self.tcx.ty_error() |
a7813a04 | 724 | } |
c34b1796 AL |
725 | } |
726 | } | |
c34b1796 | 727 | |
dfeec247 XL |
728 | fn lookup_op_method( |
729 | &self, | |
730 | lhs_ty: Ty<'tcx>, | |
731 | other_tys: &[Ty<'tcx>], | |
732 | op: Op, | |
733 | ) -> Result<MethodCallee<'tcx>, ()> { | |
ea8adc8c | 734 | let lang = self.tcx.lang_items(); |
a7813a04 | 735 | |
7cac9316 XL |
736 | let span = match op { |
737 | Op::Binary(op, _) => op.span, | |
dfeec247 | 738 | Op::Unary(_, span) => span, |
7cac9316 XL |
739 | }; |
740 | let (opname, trait_did) = if let Op::Binary(op, IsAssign::Yes) = op { | |
a7813a04 | 741 | match op.node { |
3dfed10e XL |
742 | hir::BinOpKind::Add => (sym::add_assign, lang.add_assign_trait()), |
743 | hir::BinOpKind::Sub => (sym::sub_assign, lang.sub_assign_trait()), | |
744 | hir::BinOpKind::Mul => (sym::mul_assign, lang.mul_assign_trait()), | |
745 | hir::BinOpKind::Div => (sym::div_assign, lang.div_assign_trait()), | |
746 | hir::BinOpKind::Rem => (sym::rem_assign, lang.rem_assign_trait()), | |
747 | hir::BinOpKind::BitXor => (sym::bitxor_assign, lang.bitxor_assign_trait()), | |
748 | hir::BinOpKind::BitAnd => (sym::bitand_assign, lang.bitand_assign_trait()), | |
749 | hir::BinOpKind::BitOr => (sym::bitor_assign, lang.bitor_assign_trait()), | |
750 | hir::BinOpKind::Shl => (sym::shl_assign, lang.shl_assign_trait()), | |
751 | hir::BinOpKind::Shr => (sym::shr_assign, lang.shr_assign_trait()), | |
dfeec247 XL |
752 | hir::BinOpKind::Lt |
753 | | hir::BinOpKind::Le | |
754 | | hir::BinOpKind::Ge | |
755 | | hir::BinOpKind::Gt | |
756 | | hir::BinOpKind::Eq | |
757 | | hir::BinOpKind::Ne | |
758 | | hir::BinOpKind::And | |
759 | | hir::BinOpKind::Or => { | |
760 | span_bug!(span, "impossible assignment operation: {}=", op.node.as_str()) | |
a7813a04 | 761 | } |
b039eaaf | 762 | } |
7cac9316 | 763 | } else if let Op::Binary(op, IsAssign::No) = op { |
a7813a04 | 764 | match op.node { |
3dfed10e XL |
765 | hir::BinOpKind::Add => (sym::add, lang.add_trait()), |
766 | hir::BinOpKind::Sub => (sym::sub, lang.sub_trait()), | |
767 | hir::BinOpKind::Mul => (sym::mul, lang.mul_trait()), | |
768 | hir::BinOpKind::Div => (sym::div, lang.div_trait()), | |
769 | hir::BinOpKind::Rem => (sym::rem, lang.rem_trait()), | |
770 | hir::BinOpKind::BitXor => (sym::bitxor, lang.bitxor_trait()), | |
771 | hir::BinOpKind::BitAnd => (sym::bitand, lang.bitand_trait()), | |
772 | hir::BinOpKind::BitOr => (sym::bitor, lang.bitor_trait()), | |
773 | hir::BinOpKind::Shl => (sym::shl, lang.shl_trait()), | |
774 | hir::BinOpKind::Shr => (sym::shr, lang.shr_trait()), | |
775 | hir::BinOpKind::Lt => (sym::lt, lang.partial_ord_trait()), | |
776 | hir::BinOpKind::Le => (sym::le, lang.partial_ord_trait()), | |
777 | hir::BinOpKind::Ge => (sym::ge, lang.partial_ord_trait()), | |
778 | hir::BinOpKind::Gt => (sym::gt, lang.partial_ord_trait()), | |
779 | hir::BinOpKind::Eq => (sym::eq, lang.eq_trait()), | |
780 | hir::BinOpKind::Ne => (sym::ne, lang.eq_trait()), | |
8faf50e0 | 781 | hir::BinOpKind::And | hir::BinOpKind::Or => { |
7cac9316 | 782 | span_bug!(span, "&& and || are not overloadable") |
a7813a04 | 783 | } |
b039eaaf | 784 | } |
6a06907d | 785 | } else if let Op::Unary(hir::UnOp::Not, _) = op { |
3dfed10e | 786 | (sym::not, lang.not_trait()) |
6a06907d | 787 | } else if let Op::Unary(hir::UnOp::Neg, _) = op { |
3dfed10e | 788 | (sym::neg, lang.neg_trait()) |
7cac9316 XL |
789 | } else { |
790 | bug!("lookup_op_method: op not supported: {:?}", op) | |
791 | }; | |
c34b1796 | 792 | |
dfeec247 XL |
793 | debug!( |
794 | "lookup_op_method(lhs_ty={:?}, op={:?}, opname={:?}, trait_did={:?})", | |
795 | lhs_ty, op, opname, trait_did | |
796 | ); | |
7cac9316 | 797 | |
17df50a5 XL |
798 | // Catches cases like #83893, where a lang item is declared with the |
799 | // wrong number of generic arguments. Should have yielded an error | |
800 | // elsewhere by now, but we have to catch it here so that we do not | |
801 | // index `other_tys` out of bounds (if the lang item has too many | |
802 | // generic arguments, `other_tys` is too short). | |
803 | if !has_expected_num_generic_args( | |
804 | self.tcx, | |
805 | trait_did, | |
806 | match op { | |
807 | // Binary ops have a generic right-hand side, unary ops don't | |
808 | Op::Binary(..) => 1, | |
809 | Op::Unary(..) => 0, | |
810 | }, | |
811 | ) { | |
812 | return Err(()); | |
813 | } | |
814 | ||
7cac9316 | 815 | let method = trait_did.and_then(|trait_did| { |
3dfed10e | 816 | let opname = Ident::with_dummy_span(opname); |
7cac9316 XL |
817 | self.lookup_method_in_trait(span, opname, trait_did, lhs_ty, Some(other_tys)) |
818 | }); | |
c34b1796 | 819 | |
a7813a04 | 820 | match method { |
cc61c64b XL |
821 | Some(ok) => { |
822 | let method = self.register_infer_ok_obligations(ok); | |
e1599b0c | 823 | self.select_obligations_where_possible(false, |_| {}); |
cc61c64b | 824 | |
7cac9316 | 825 | Ok(method) |
a7813a04 | 826 | } |
dfeec247 | 827 | None => Err(()), |
c34b1796 AL |
828 | } |
829 | } | |
830 | } | |
831 | ||
832 | // Binary operator categories. These categories summarize the behavior | |
833 | // with respect to the builtin operationrs supported. | |
834 | enum BinOpCategory { | |
835 | /// &&, || -- cannot be overridden | |
836 | Shortcircuit, | |
837 | ||
838 | /// <<, >> -- when shifting a single integer, rhs can be any | |
839 | /// integer type. For simd, types must match. | |
840 | Shift, | |
841 | ||
842 | /// +, -, etc -- takes equal types, produces same type as input, | |
843 | /// applicable to ints/floats/simd | |
844 | Math, | |
845 | ||
846 | /// &, |, ^ -- takes equal types, produces same type as input, | |
847 | /// applicable to ints/floats/simd/bool | |
848 | Bitwise, | |
849 | ||
850 | /// ==, !=, etc -- takes equal types, produces bools, except for simd, | |
851 | /// which produce the input type | |
852 | Comparison, | |
853 | } | |
854 | ||
855 | impl BinOpCategory { | |
e9174d1e | 856 | fn from(op: hir::BinOp) -> BinOpCategory { |
c34b1796 | 857 | match op.node { |
dfeec247 XL |
858 | hir::BinOpKind::Shl | hir::BinOpKind::Shr => BinOpCategory::Shift, |
859 | ||
860 | hir::BinOpKind::Add | |
861 | | hir::BinOpKind::Sub | |
862 | | hir::BinOpKind::Mul | |
863 | | hir::BinOpKind::Div | |
864 | | hir::BinOpKind::Rem => BinOpCategory::Math, | |
865 | ||
866 | hir::BinOpKind::BitXor | hir::BinOpKind::BitAnd | hir::BinOpKind::BitOr => { | |
867 | BinOpCategory::Bitwise | |
868 | } | |
869 | ||
870 | hir::BinOpKind::Eq | |
871 | | hir::BinOpKind::Ne | |
872 | | hir::BinOpKind::Lt | |
873 | | hir::BinOpKind::Le | |
874 | | hir::BinOpKind::Ge | |
875 | | hir::BinOpKind::Gt => BinOpCategory::Comparison, | |
876 | ||
877 | hir::BinOpKind::And | hir::BinOpKind::Or => BinOpCategory::Shortcircuit, | |
c34b1796 AL |
878 | } |
879 | } | |
880 | } | |
881 | ||
b039eaaf | 882 | /// Whether the binary operation is an assignment (`a += b`), or not (`a + b`) |
7cac9316 | 883 | #[derive(Clone, Copy, Debug, PartialEq)] |
b039eaaf SL |
884 | enum IsAssign { |
885 | No, | |
886 | Yes, | |
887 | } | |
888 | ||
7cac9316 XL |
889 | #[derive(Clone, Copy, Debug)] |
890 | enum Op { | |
891 | Binary(hir::BinOp, IsAssign), | |
892 | Unary(hir::UnOp, Span), | |
893 | } | |
894 | ||
74b04a01 | 895 | /// Dereferences a single level of immutable referencing. |
ba9703b0 | 896 | fn deref_ty_if_possible(ty: Ty<'tcx>) -> Ty<'tcx> { |
1b1a35ee | 897 | match ty.kind() { |
74b04a01 XL |
898 | ty::Ref(_, ty, hir::Mutability::Not) => ty, |
899 | _ => ty, | |
900 | } | |
901 | } | |
902 | ||
9fa01778 | 903 | /// Returns `true` if this is a built-in arithmetic operation (e.g., u32 |
c34b1796 AL |
904 | /// + u32, i16x4 == i16x4) and false if these types would have to be |
905 | /// overloaded to be legal. There are two reasons that we distinguish | |
906 | /// builtin operations from overloaded ones (vs trying to drive | |
907 | /// everything uniformly through the trait system and intrinsics or | |
908 | /// something like that): | |
909 | /// | |
910 | /// 1. Builtin operations can trivially be evaluated in constants. | |
911 | /// 2. For comparison operators applied to SIMD types the result is | |
9fa01778 | 912 | /// not of type `bool`. For example, `i16x4 == i16x4` yields a |
c34b1796 AL |
913 | /// type like `i16x4`. This means that the overloaded trait |
914 | /// `PartialEq` is not applicable. | |
915 | /// | |
916 | /// Reason #2 is the killer. I tried for a while to always use | |
94b46f34 | 917 | /// overloaded logic and just check the types in constants/codegen after |
c34b1796 | 918 | /// the fact, and it worked fine, except for SIMD types. -nmatsakis |
74b04a01 XL |
919 | fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>, rhs: Ty<'tcx>, op: hir::BinOp) -> bool { |
920 | // Special-case a single layer of referencing, so that things like `5.0 + &6.0f32` work. | |
921 | // (See https://github.com/rust-lang/rust/issues/57447.) | |
922 | let (lhs, rhs) = (deref_ty_if_possible(lhs), deref_ty_if_possible(rhs)); | |
923 | ||
c34b1796 | 924 | match BinOpCategory::from(op) { |
dfeec247 | 925 | BinOpCategory::Shortcircuit => true, |
c34b1796 AL |
926 | |
927 | BinOpCategory::Shift => { | |
dfeec247 XL |
928 | lhs.references_error() |
929 | || rhs.references_error() | |
930 | || lhs.is_integral() && rhs.is_integral() | |
c34b1796 AL |
931 | } |
932 | ||
933 | BinOpCategory::Math => { | |
dfeec247 XL |
934 | lhs.references_error() |
935 | || rhs.references_error() | |
936 | || lhs.is_integral() && rhs.is_integral() | |
937 | || lhs.is_floating_point() && rhs.is_floating_point() | |
c34b1796 AL |
938 | } |
939 | ||
940 | BinOpCategory::Bitwise => { | |
dfeec247 XL |
941 | lhs.references_error() |
942 | || rhs.references_error() | |
943 | || lhs.is_integral() && rhs.is_integral() | |
944 | || lhs.is_floating_point() && rhs.is_floating_point() | |
945 | || lhs.is_bool() && rhs.is_bool() | |
c34b1796 AL |
946 | } |
947 | ||
948 | BinOpCategory::Comparison => { | |
dfeec247 | 949 | lhs.references_error() || rhs.references_error() || lhs.is_scalar() && rhs.is_scalar() |
c34b1796 AL |
950 | } |
951 | } | |
952 | } | |
74b04a01 XL |
953 | |
954 | /// If applicable, note that an implementation of `trait` for `ty` may fix the error. | |
955 | fn suggest_impl_missing(err: &mut DiagnosticBuilder<'_>, ty: Ty<'_>, missing_trait: &str) { | |
1b1a35ee | 956 | if let Adt(def, _) = ty.peel_refs().kind() { |
74b04a01 XL |
957 | if def.did.is_local() { |
958 | err.note(&format!( | |
f035d41b | 959 | "an implementation of `{}` might be missing for `{}`", |
74b04a01 XL |
960 | missing_trait, ty |
961 | )); | |
962 | } | |
963 | } | |
964 | } | |
f9f354fc XL |
965 | |
966 | fn suggest_constraining_param( | |
967 | tcx: TyCtxt<'_>, | |
968 | body_id: hir::HirId, | |
969 | mut err: &mut DiagnosticBuilder<'_>, | |
970 | lhs_ty: Ty<'_>, | |
971 | rhs_ty: Ty<'_>, | |
972 | missing_trait: &str, | |
973 | p: ty::ParamTy, | |
974 | set_output: bool, | |
975 | ) { | |
976 | let hir = tcx.hir(); | |
977 | let msg = &format!("`{}` might need a bound for `{}`", lhs_ty, missing_trait); | |
978 | // Try to find the def-id and details for the parameter p. We have only the index, | |
979 | // so we have to find the enclosing function's def-id, then look through its declared | |
980 | // generic parameters to get the declaration. | |
981 | let def_id = hir.body_owner_def_id(hir::BodyId { hir_id: body_id }); | |
982 | let generics = tcx.generics_of(def_id); | |
983 | let param_def_id = generics.type_param(&p, tcx).def_id; | |
984 | if let Some(generics) = param_def_id | |
985 | .as_local() | |
3dfed10e | 986 | .map(|id| hir.local_def_id_to_hir_id(id)) |
f9f354fc XL |
987 | .and_then(|id| hir.find(hir.get_parent_item(id))) |
988 | .as_ref() | |
989 | .and_then(|node| node.generics()) | |
990 | { | |
991 | let output = if set_output { format!("<Output = {}>", rhs_ty) } else { String::new() }; | |
992 | suggest_constraining_type_param( | |
993 | tcx, | |
994 | generics, | |
995 | &mut err, | |
996 | &format!("{}", lhs_ty), | |
997 | &format!("{}{}", missing_trait, output), | |
998 | None, | |
999 | ); | |
1000 | } else { | |
1001 | let span = tcx.def_span(param_def_id); | |
1002 | err.span_label(span, msg); | |
1003 | } | |
1004 | } | |
f035d41b XL |
1005 | |
1006 | struct TypeParamVisitor<'tcx>(Vec<Ty<'tcx>>); | |
1007 | ||
1008 | impl<'tcx> TypeVisitor<'tcx> for TypeParamVisitor<'tcx> { | |
fc512014 | 1009 | fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { |
1b1a35ee | 1010 | if let ty::Param(_) = ty.kind() { |
f035d41b XL |
1011 | self.0.push(ty); |
1012 | } | |
1013 | ty.super_visit_with(self) | |
1014 | } | |
1015 | } | |
1016 | ||
1017 | struct TypeParamEraser<'a, 'tcx>(&'a FnCtxt<'a, 'tcx>, Span); | |
1018 | ||
1019 | impl TypeFolder<'tcx> for TypeParamEraser<'_, 'tcx> { | |
1020 | fn tcx(&self) -> TyCtxt<'tcx> { | |
1021 | self.0.tcx | |
1022 | } | |
1023 | ||
1024 | fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
1b1a35ee | 1025 | match ty.kind() { |
f035d41b XL |
1026 | ty::Param(_) => self.0.next_ty_var(TypeVariableOrigin { |
1027 | kind: TypeVariableOriginKind::MiscVariable, | |
1028 | span: self.1, | |
1029 | }), | |
1030 | _ => ty.super_fold_with(self), | |
1031 | } | |
1032 | } | |
1033 | } |