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1 | //! Contains utility functions to generate suggestions. |
2 | #![deny(clippy::missing_docs_in_private_items)] | |
3 | ||
4 | use crate::{higher, snippet, snippet_opt, snippet_with_macro_callsite}; | |
5 | use rustc_ast::util::parser::AssocOp; | |
6 | use rustc_ast::{ast, token}; | |
7 | use rustc_ast_pretty::pprust::token_kind_to_string; | |
8 | use rustc_errors::Applicability; | |
9 | use rustc_hir as hir; | |
10 | use rustc_lint::{EarlyContext, LateContext, LintContext}; | |
11 | use rustc_span::source_map::{CharPos, Span}; | |
12 | use rustc_span::{BytePos, Pos}; | |
13 | use std::borrow::Cow; | |
14 | use std::convert::TryInto; | |
15 | use std::fmt::Display; | |
16 | use std::ops::{Add, Neg, Not, Sub}; | |
17 | ||
18 | /// A helper type to build suggestion correctly handling parenthesis. | |
19 | #[derive(Clone, PartialEq)] | |
20 | pub enum Sugg<'a> { | |
21 | /// An expression that never needs parenthesis such as `1337` or `[0; 42]`. | |
22 | NonParen(Cow<'a, str>), | |
23 | /// An expression that does not fit in other variants. | |
24 | MaybeParen(Cow<'a, str>), | |
25 | /// A binary operator expression, including `as`-casts and explicit type | |
26 | /// coercion. | |
27 | BinOp(AssocOp, Cow<'a, str>), | |
28 | } | |
29 | ||
30 | /// Literal constant `0`, for convenience. | |
31 | pub const ZERO: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("0")); | |
32 | /// Literal constant `1`, for convenience. | |
33 | pub const ONE: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("1")); | |
34 | /// a constant represents an empty string, for convenience. | |
35 | pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("")); | |
36 | ||
37 | impl Display for Sugg<'_> { | |
38 | fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> { | |
39 | match *self { | |
40 | Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) | Sugg::BinOp(_, ref s) => s.fmt(f), | |
41 | } | |
42 | } | |
43 | } | |
44 | ||
45 | #[allow(clippy::wrong_self_convention)] // ok, because of the function `as_ty` method | |
46 | impl<'a> Sugg<'a> { | |
47 | /// Prepare a suggestion from an expression. | |
48 | pub fn hir_opt(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Self> { | |
49 | snippet_opt(cx, expr.span).map(|snippet| { | |
50 | let snippet = Cow::Owned(snippet); | |
51 | Self::hir_from_snippet(expr, snippet) | |
52 | }) | |
53 | } | |
54 | ||
55 | /// Convenience function around `hir_opt` for suggestions with a default | |
56 | /// text. | |
57 | pub fn hir(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self { | |
58 | Self::hir_opt(cx, expr).unwrap_or(Sugg::NonParen(Cow::Borrowed(default))) | |
59 | } | |
60 | ||
61 | /// Same as `hir`, but it adapts the applicability level by following rules: | |
62 | /// | |
63 | /// - Applicability level `Unspecified` will never be changed. | |
64 | /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`. | |
65 | /// - If the default value is used and the applicability level is `MachineApplicable`, change it | |
66 | /// to | |
67 | /// `HasPlaceholders` | |
68 | pub fn hir_with_applicability( | |
69 | cx: &LateContext<'_>, | |
70 | expr: &hir::Expr<'_>, | |
71 | default: &'a str, | |
72 | applicability: &mut Applicability, | |
73 | ) -> Self { | |
74 | if *applicability != Applicability::Unspecified && expr.span.from_expansion() { | |
75 | *applicability = Applicability::MaybeIncorrect; | |
76 | } | |
77 | Self::hir_opt(cx, expr).unwrap_or_else(|| { | |
78 | if *applicability == Applicability::MachineApplicable { | |
79 | *applicability = Applicability::HasPlaceholders; | |
80 | } | |
81 | Sugg::NonParen(Cow::Borrowed(default)) | |
82 | }) | |
83 | } | |
84 | ||
85 | /// Same as `hir`, but will use the pre expansion span if the `expr` was in a macro. | |
86 | pub fn hir_with_macro_callsite(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self { | |
87 | let snippet = snippet_with_macro_callsite(cx, expr.span, default); | |
88 | ||
89 | Self::hir_from_snippet(expr, snippet) | |
90 | } | |
91 | ||
92 | /// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*` | |
93 | /// function variants of `Sugg`, since these use different snippet functions. | |
94 | fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self { | |
95 | if let Some(range) = higher::range(expr) { | |
96 | let op = match range.limits { | |
97 | ast::RangeLimits::HalfOpen => AssocOp::DotDot, | |
98 | ast::RangeLimits::Closed => AssocOp::DotDotEq, | |
99 | }; | |
100 | return Sugg::BinOp(op, snippet); | |
101 | } | |
102 | ||
103 | match expr.kind { | |
104 | hir::ExprKind::AddrOf(..) | |
105 | | hir::ExprKind::Box(..) | |
106 | | hir::ExprKind::If(..) | |
107 | | hir::ExprKind::Closure(..) | |
108 | | hir::ExprKind::Unary(..) | |
109 | | hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet), | |
110 | hir::ExprKind::Continue(..) | |
111 | | hir::ExprKind::Yield(..) | |
112 | | hir::ExprKind::Array(..) | |
113 | | hir::ExprKind::Block(..) | |
114 | | hir::ExprKind::Break(..) | |
115 | | hir::ExprKind::Call(..) | |
116 | | hir::ExprKind::Field(..) | |
117 | | hir::ExprKind::Index(..) | |
118 | | hir::ExprKind::InlineAsm(..) | |
119 | | hir::ExprKind::LlvmInlineAsm(..) | |
120 | | hir::ExprKind::ConstBlock(..) | |
121 | | hir::ExprKind::Lit(..) | |
122 | | hir::ExprKind::Loop(..) | |
123 | | hir::ExprKind::MethodCall(..) | |
124 | | hir::ExprKind::Path(..) | |
125 | | hir::ExprKind::Repeat(..) | |
126 | | hir::ExprKind::Ret(..) | |
127 | | hir::ExprKind::Struct(..) | |
128 | | hir::ExprKind::Tup(..) | |
129 | | hir::ExprKind::DropTemps(_) | |
130 | | hir::ExprKind::Err => Sugg::NonParen(snippet), | |
131 | hir::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet), | |
132 | hir::ExprKind::AssignOp(op, ..) => Sugg::BinOp(hirbinop2assignop(op), snippet), | |
133 | hir::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(higher::binop(op.node)), snippet), | |
134 | hir::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet), | |
135 | hir::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet), | |
136 | } | |
137 | } | |
138 | ||
139 | /// Prepare a suggestion from an expression. | |
140 | pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self { | |
141 | use rustc_ast::ast::RangeLimits; | |
142 | ||
143 | let snippet = if expr.span.from_expansion() { | |
144 | snippet_with_macro_callsite(cx, expr.span, default) | |
145 | } else { | |
146 | snippet(cx, expr.span, default) | |
147 | }; | |
148 | ||
149 | match expr.kind { | |
150 | ast::ExprKind::AddrOf(..) | |
151 | | ast::ExprKind::Box(..) | |
152 | | ast::ExprKind::Closure(..) | |
153 | | ast::ExprKind::If(..) | |
154 | | ast::ExprKind::Let(..) | |
155 | | ast::ExprKind::Unary(..) | |
156 | | ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet), | |
157 | ast::ExprKind::Async(..) | |
158 | | ast::ExprKind::Block(..) | |
159 | | ast::ExprKind::Break(..) | |
160 | | ast::ExprKind::Call(..) | |
161 | | ast::ExprKind::Continue(..) | |
162 | | ast::ExprKind::Yield(..) | |
163 | | ast::ExprKind::Field(..) | |
164 | | ast::ExprKind::ForLoop(..) | |
165 | | ast::ExprKind::Index(..) | |
166 | | ast::ExprKind::InlineAsm(..) | |
167 | | ast::ExprKind::LlvmInlineAsm(..) | |
168 | | ast::ExprKind::ConstBlock(..) | |
169 | | ast::ExprKind::Lit(..) | |
170 | | ast::ExprKind::Loop(..) | |
171 | | ast::ExprKind::MacCall(..) | |
172 | | ast::ExprKind::MethodCall(..) | |
173 | | ast::ExprKind::Paren(..) | |
174 | | ast::ExprKind::Underscore | |
175 | | ast::ExprKind::Path(..) | |
176 | | ast::ExprKind::Repeat(..) | |
177 | | ast::ExprKind::Ret(..) | |
178 | | ast::ExprKind::Struct(..) | |
179 | | ast::ExprKind::Try(..) | |
180 | | ast::ExprKind::TryBlock(..) | |
181 | | ast::ExprKind::Tup(..) | |
182 | | ast::ExprKind::Array(..) | |
183 | | ast::ExprKind::While(..) | |
184 | | ast::ExprKind::Await(..) | |
185 | | ast::ExprKind::Err => Sugg::NonParen(snippet), | |
186 | ast::ExprKind::Range(.., RangeLimits::HalfOpen) => Sugg::BinOp(AssocOp::DotDot, snippet), | |
187 | ast::ExprKind::Range(.., RangeLimits::Closed) => Sugg::BinOp(AssocOp::DotDotEq, snippet), | |
188 | ast::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet), | |
189 | ast::ExprKind::AssignOp(op, ..) => Sugg::BinOp(astbinop2assignop(op), snippet), | |
190 | ast::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node), snippet), | |
191 | ast::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet), | |
192 | ast::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet), | |
193 | } | |
194 | } | |
195 | ||
196 | /// Convenience method to create the `<lhs> && <rhs>` suggestion. | |
197 | pub fn and(self, rhs: &Self) -> Sugg<'static> { | |
198 | make_binop(ast::BinOpKind::And, &self, rhs) | |
199 | } | |
200 | ||
201 | /// Convenience method to create the `<lhs> & <rhs>` suggestion. | |
202 | pub fn bit_and(self, rhs: &Self) -> Sugg<'static> { | |
203 | make_binop(ast::BinOpKind::BitAnd, &self, rhs) | |
204 | } | |
205 | ||
206 | /// Convenience method to create the `<lhs> as <rhs>` suggestion. | |
207 | pub fn as_ty<R: Display>(self, rhs: R) -> Sugg<'static> { | |
208 | make_assoc(AssocOp::As, &self, &Sugg::NonParen(rhs.to_string().into())) | |
209 | } | |
210 | ||
211 | /// Convenience method to create the `&<expr>` suggestion. | |
212 | pub fn addr(self) -> Sugg<'static> { | |
213 | make_unop("&", self) | |
214 | } | |
215 | ||
216 | /// Convenience method to create the `&mut <expr>` suggestion. | |
217 | pub fn mut_addr(self) -> Sugg<'static> { | |
218 | make_unop("&mut ", self) | |
219 | } | |
220 | ||
221 | /// Convenience method to create the `*<expr>` suggestion. | |
222 | pub fn deref(self) -> Sugg<'static> { | |
223 | make_unop("*", self) | |
224 | } | |
225 | ||
226 | /// Convenience method to create the `&*<expr>` suggestion. Currently this | |
227 | /// is needed because `sugg.deref().addr()` produces an unnecessary set of | |
228 | /// parentheses around the deref. | |
229 | pub fn addr_deref(self) -> Sugg<'static> { | |
230 | make_unop("&*", self) | |
231 | } | |
232 | ||
233 | /// Convenience method to create the `&mut *<expr>` suggestion. Currently | |
234 | /// this is needed because `sugg.deref().mut_addr()` produces an unnecessary | |
235 | /// set of parentheses around the deref. | |
236 | pub fn mut_addr_deref(self) -> Sugg<'static> { | |
237 | make_unop("&mut *", self) | |
238 | } | |
239 | ||
240 | /// Convenience method to transform suggestion into a return call | |
241 | pub fn make_return(self) -> Sugg<'static> { | |
242 | Sugg::NonParen(Cow::Owned(format!("return {}", self))) | |
243 | } | |
244 | ||
245 | /// Convenience method to transform suggestion into a block | |
246 | /// where the suggestion is a trailing expression | |
247 | pub fn blockify(self) -> Sugg<'static> { | |
248 | Sugg::NonParen(Cow::Owned(format!("{{ {} }}", self))) | |
249 | } | |
250 | ||
251 | /// Convenience method to create the `<lhs>..<rhs>` or `<lhs>...<rhs>` | |
252 | /// suggestion. | |
253 | #[allow(dead_code)] | |
254 | pub fn range(self, end: &Self, limit: ast::RangeLimits) -> Sugg<'static> { | |
255 | match limit { | |
256 | ast::RangeLimits::HalfOpen => make_assoc(AssocOp::DotDot, &self, end), | |
257 | ast::RangeLimits::Closed => make_assoc(AssocOp::DotDotEq, &self, end), | |
258 | } | |
259 | } | |
260 | ||
261 | /// Adds parenthesis to any expression that might need them. Suitable to the | |
262 | /// `self` argument of a method call | |
263 | /// (e.g., to build `bar.foo()` or `(1 + 2).foo()`). | |
264 | pub fn maybe_par(self) -> Self { | |
265 | match self { | |
266 | Sugg::NonParen(..) => self, | |
267 | // `(x)` and `(x).y()` both don't need additional parens. | |
268 | Sugg::MaybeParen(sugg) => { | |
269 | if sugg.starts_with('(') && sugg.ends_with(')') { | |
270 | Sugg::MaybeParen(sugg) | |
271 | } else { | |
272 | Sugg::NonParen(format!("({})", sugg).into()) | |
273 | } | |
274 | }, | |
275 | Sugg::BinOp(_, sugg) => Sugg::NonParen(format!("({})", sugg).into()), | |
276 | } | |
277 | } | |
278 | } | |
279 | ||
280 | // Copied from the rust standart library, and then edited | |
281 | macro_rules! forward_binop_impls_to_ref { | |
282 | (impl $imp:ident, $method:ident for $t:ty, type Output = $o:ty) => { | |
283 | impl $imp<$t> for &$t { | |
284 | type Output = $o; | |
285 | ||
286 | fn $method(self, other: $t) -> $o { | |
287 | $imp::$method(self, &other) | |
288 | } | |
289 | } | |
290 | ||
291 | impl $imp<&$t> for $t { | |
292 | type Output = $o; | |
293 | ||
294 | fn $method(self, other: &$t) -> $o { | |
295 | $imp::$method(&self, other) | |
296 | } | |
297 | } | |
298 | ||
299 | impl $imp for $t { | |
300 | type Output = $o; | |
301 | ||
302 | fn $method(self, other: $t) -> $o { | |
303 | $imp::$method(&self, &other) | |
304 | } | |
305 | } | |
306 | }; | |
307 | } | |
308 | ||
309 | impl Add for &Sugg<'_> { | |
310 | type Output = Sugg<'static>; | |
311 | fn add(self, rhs: &Sugg<'_>) -> Sugg<'static> { | |
312 | make_binop(ast::BinOpKind::Add, self, rhs) | |
313 | } | |
314 | } | |
315 | ||
316 | impl Sub for &Sugg<'_> { | |
317 | type Output = Sugg<'static>; | |
318 | fn sub(self, rhs: &Sugg<'_>) -> Sugg<'static> { | |
319 | make_binop(ast::BinOpKind::Sub, self, rhs) | |
320 | } | |
321 | } | |
322 | ||
323 | forward_binop_impls_to_ref!(impl Add, add for Sugg<'_>, type Output = Sugg<'static>); | |
324 | forward_binop_impls_to_ref!(impl Sub, sub for Sugg<'_>, type Output = Sugg<'static>); | |
325 | ||
326 | impl Neg for Sugg<'_> { | |
327 | type Output = Sugg<'static>; | |
328 | fn neg(self) -> Sugg<'static> { | |
329 | make_unop("-", self) | |
330 | } | |
331 | } | |
332 | ||
333 | impl Not for Sugg<'_> { | |
334 | type Output = Sugg<'static>; | |
335 | fn not(self) -> Sugg<'static> { | |
336 | make_unop("!", self) | |
337 | } | |
338 | } | |
339 | ||
340 | /// Helper type to display either `foo` or `(foo)`. | |
341 | struct ParenHelper<T> { | |
342 | /// `true` if parentheses are needed. | |
343 | paren: bool, | |
344 | /// The main thing to display. | |
345 | wrapped: T, | |
346 | } | |
347 | ||
348 | impl<T> ParenHelper<T> { | |
349 | /// Builds a `ParenHelper`. | |
350 | fn new(paren: bool, wrapped: T) -> Self { | |
351 | Self { paren, wrapped } | |
352 | } | |
353 | } | |
354 | ||
355 | impl<T: Display> Display for ParenHelper<T> { | |
356 | fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> { | |
357 | if self.paren { | |
358 | write!(f, "({})", self.wrapped) | |
359 | } else { | |
360 | self.wrapped.fmt(f) | |
361 | } | |
362 | } | |
363 | } | |
364 | ||
365 | /// Builds the string for `<op><expr>` adding parenthesis when necessary. | |
366 | /// | |
367 | /// For convenience, the operator is taken as a string because all unary | |
368 | /// operators have the same | |
369 | /// precedence. | |
370 | pub fn make_unop(op: &str, expr: Sugg<'_>) -> Sugg<'static> { | |
371 | Sugg::MaybeParen(format!("{}{}", op, expr.maybe_par()).into()) | |
372 | } | |
373 | ||
374 | /// Builds the string for `<lhs> <op> <rhs>` adding parenthesis when necessary. | |
375 | /// | |
376 | /// Precedence of shift operator relative to other arithmetic operation is | |
377 | /// often confusing so | |
378 | /// parenthesis will always be added for a mix of these. | |
379 | pub fn make_assoc(op: AssocOp, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> { | |
380 | /// Returns `true` if the operator is a shift operator `<<` or `>>`. | |
381 | fn is_shift(op: AssocOp) -> bool { | |
382 | matches!(op, AssocOp::ShiftLeft | AssocOp::ShiftRight) | |
383 | } | |
384 | ||
385 | /// Returns `true` if the operator is a arithmetic operator | |
386 | /// (i.e., `+`, `-`, `*`, `/`, `%`). | |
387 | fn is_arith(op: AssocOp) -> bool { | |
388 | matches!( | |
389 | op, | |
390 | AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide | AssocOp::Modulus | |
391 | ) | |
392 | } | |
393 | ||
394 | /// Returns `true` if the operator `op` needs parenthesis with the operator | |
395 | /// `other` in the direction `dir`. | |
396 | fn needs_paren(op: AssocOp, other: AssocOp, dir: Associativity) -> bool { | |
397 | other.precedence() < op.precedence() | |
398 | || (other.precedence() == op.precedence() | |
399 | && ((op != other && associativity(op) != dir) | |
400 | || (op == other && associativity(op) != Associativity::Both))) | |
401 | || is_shift(op) && is_arith(other) | |
402 | || is_shift(other) && is_arith(op) | |
403 | } | |
404 | ||
405 | let lhs_paren = if let Sugg::BinOp(lop, _) = *lhs { | |
406 | needs_paren(op, lop, Associativity::Left) | |
407 | } else { | |
408 | false | |
409 | }; | |
410 | ||
411 | let rhs_paren = if let Sugg::BinOp(rop, _) = *rhs { | |
412 | needs_paren(op, rop, Associativity::Right) | |
413 | } else { | |
414 | false | |
415 | }; | |
416 | ||
417 | let lhs = ParenHelper::new(lhs_paren, lhs); | |
418 | let rhs = ParenHelper::new(rhs_paren, rhs); | |
419 | let sugg = match op { | |
420 | AssocOp::Add | |
421 | | AssocOp::BitAnd | |
422 | | AssocOp::BitOr | |
423 | | AssocOp::BitXor | |
424 | | AssocOp::Divide | |
425 | | AssocOp::Equal | |
426 | | AssocOp::Greater | |
427 | | AssocOp::GreaterEqual | |
428 | | AssocOp::LAnd | |
429 | | AssocOp::LOr | |
430 | | AssocOp::Less | |
431 | | AssocOp::LessEqual | |
432 | | AssocOp::Modulus | |
433 | | AssocOp::Multiply | |
434 | | AssocOp::NotEqual | |
435 | | AssocOp::ShiftLeft | |
436 | | AssocOp::ShiftRight | |
437 | | AssocOp::Subtract => format!( | |
438 | "{} {} {}", | |
439 | lhs, | |
440 | op.to_ast_binop().expect("Those are AST ops").to_string(), | |
441 | rhs | |
442 | ), | |
443 | AssocOp::Assign => format!("{} = {}", lhs, rhs), | |
444 | AssocOp::AssignOp(op) => format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs), | |
445 | AssocOp::As => format!("{} as {}", lhs, rhs), | |
446 | AssocOp::DotDot => format!("{}..{}", lhs, rhs), | |
447 | AssocOp::DotDotEq => format!("{}..={}", lhs, rhs), | |
448 | AssocOp::Colon => format!("{}: {}", lhs, rhs), | |
449 | }; | |
450 | ||
451 | Sugg::BinOp(op, sugg.into()) | |
452 | } | |
453 | ||
454 | /// Convenience wrapper around `make_assoc` and `AssocOp::from_ast_binop`. | |
455 | pub fn make_binop(op: ast::BinOpKind, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> { | |
456 | make_assoc(AssocOp::from_ast_binop(op), lhs, rhs) | |
457 | } | |
458 | ||
459 | #[derive(PartialEq, Eq, Clone, Copy)] | |
460 | /// Operator associativity. | |
461 | enum Associativity { | |
462 | /// The operator is both left-associative and right-associative. | |
463 | Both, | |
464 | /// The operator is left-associative. | |
465 | Left, | |
466 | /// The operator is not associative. | |
467 | None, | |
468 | /// The operator is right-associative. | |
469 | Right, | |
470 | } | |
471 | ||
472 | /// Returns the associativity/fixity of an operator. The difference with | |
473 | /// `AssocOp::fixity` is that an operator can be both left and right associative | |
474 | /// (such as `+`: `a + b + c == (a + b) + c == a + (b + c)`. | |
475 | /// | |
476 | /// Chained `as` and explicit `:` type coercion never need inner parenthesis so | |
477 | /// they are considered | |
478 | /// associative. | |
479 | #[must_use] | |
480 | fn associativity(op: AssocOp) -> Associativity { | |
481 | use rustc_ast::util::parser::AssocOp::{ | |
482 | Add, As, Assign, AssignOp, BitAnd, BitOr, BitXor, Colon, Divide, DotDot, DotDotEq, Equal, Greater, | |
483 | GreaterEqual, LAnd, LOr, Less, LessEqual, Modulus, Multiply, NotEqual, ShiftLeft, ShiftRight, Subtract, | |
484 | }; | |
485 | ||
486 | match op { | |
487 | Assign | AssignOp(_) => Associativity::Right, | |
488 | Add | BitAnd | BitOr | BitXor | LAnd | LOr | Multiply | As | Colon => Associativity::Both, | |
489 | Divide | Equal | Greater | GreaterEqual | Less | LessEqual | Modulus | NotEqual | ShiftLeft | ShiftRight | |
490 | | Subtract => Associativity::Left, | |
491 | DotDot | DotDotEq => Associativity::None, | |
492 | } | |
493 | } | |
494 | ||
495 | /// Converts a `hir::BinOp` to the corresponding assigning binary operator. | |
496 | fn hirbinop2assignop(op: hir::BinOp) -> AssocOp { | |
497 | use rustc_ast::token::BinOpToken::{And, Caret, Minus, Or, Percent, Plus, Shl, Shr, Slash, Star}; | |
498 | ||
499 | AssocOp::AssignOp(match op.node { | |
500 | hir::BinOpKind::Add => Plus, | |
501 | hir::BinOpKind::BitAnd => And, | |
502 | hir::BinOpKind::BitOr => Or, | |
503 | hir::BinOpKind::BitXor => Caret, | |
504 | hir::BinOpKind::Div => Slash, | |
505 | hir::BinOpKind::Mul => Star, | |
506 | hir::BinOpKind::Rem => Percent, | |
507 | hir::BinOpKind::Shl => Shl, | |
508 | hir::BinOpKind::Shr => Shr, | |
509 | hir::BinOpKind::Sub => Minus, | |
510 | ||
511 | hir::BinOpKind::And | |
512 | | hir::BinOpKind::Eq | |
513 | | hir::BinOpKind::Ge | |
514 | | hir::BinOpKind::Gt | |
515 | | hir::BinOpKind::Le | |
516 | | hir::BinOpKind::Lt | |
517 | | hir::BinOpKind::Ne | |
518 | | hir::BinOpKind::Or => panic!("This operator does not exist"), | |
519 | }) | |
520 | } | |
521 | ||
522 | /// Converts an `ast::BinOp` to the corresponding assigning binary operator. | |
523 | fn astbinop2assignop(op: ast::BinOp) -> AssocOp { | |
524 | use rustc_ast::ast::BinOpKind::{ | |
525 | Add, And, BitAnd, BitOr, BitXor, Div, Eq, Ge, Gt, Le, Lt, Mul, Ne, Or, Rem, Shl, Shr, Sub, | |
526 | }; | |
527 | use rustc_ast::token::BinOpToken; | |
528 | ||
529 | AssocOp::AssignOp(match op.node { | |
530 | Add => BinOpToken::Plus, | |
531 | BitAnd => BinOpToken::And, | |
532 | BitOr => BinOpToken::Or, | |
533 | BitXor => BinOpToken::Caret, | |
534 | Div => BinOpToken::Slash, | |
535 | Mul => BinOpToken::Star, | |
536 | Rem => BinOpToken::Percent, | |
537 | Shl => BinOpToken::Shl, | |
538 | Shr => BinOpToken::Shr, | |
539 | Sub => BinOpToken::Minus, | |
540 | And | Eq | Ge | Gt | Le | Lt | Ne | Or => panic!("This operator does not exist"), | |
541 | }) | |
542 | } | |
543 | ||
544 | /// Returns the indentation before `span` if there are nothing but `[ \t]` | |
545 | /// before it on its line. | |
546 | fn indentation<T: LintContext>(cx: &T, span: Span) -> Option<String> { | |
547 | let lo = cx.sess().source_map().lookup_char_pos(span.lo()); | |
548 | lo.file | |
549 | .get_line(lo.line - 1 /* line numbers in `Loc` are 1-based */) | |
550 | .and_then(|line| { | |
551 | if let Some((pos, _)) = line.char_indices().find(|&(_, c)| c != ' ' && c != '\t') { | |
552 | // We can mix char and byte positions here because we only consider `[ \t]`. | |
553 | if lo.col == CharPos(pos) { | |
554 | Some(line[..pos].into()) | |
555 | } else { | |
556 | None | |
557 | } | |
558 | } else { | |
559 | None | |
560 | } | |
561 | }) | |
562 | } | |
563 | ||
564 | /// Convenience extension trait for `DiagnosticBuilder`. | |
565 | pub trait DiagnosticBuilderExt<T: LintContext> { | |
566 | /// Suggests to add an attribute to an item. | |
567 | /// | |
568 | /// Correctly handles indentation of the attribute and item. | |
569 | /// | |
570 | /// # Example | |
571 | /// | |
572 | /// ```rust,ignore | |
573 | /// diag.suggest_item_with_attr(cx, item, "#[derive(Default)]"); | |
574 | /// ``` | |
575 | fn suggest_item_with_attr<D: Display + ?Sized>( | |
576 | &mut self, | |
577 | cx: &T, | |
578 | item: Span, | |
579 | msg: &str, | |
580 | attr: &D, | |
581 | applicability: Applicability, | |
582 | ); | |
583 | ||
584 | /// Suggest to add an item before another. | |
585 | /// | |
586 | /// The item should not be indented (except for inner indentation). | |
587 | /// | |
588 | /// # Example | |
589 | /// | |
590 | /// ```rust,ignore | |
591 | /// diag.suggest_prepend_item(cx, item, | |
592 | /// "fn foo() { | |
593 | /// bar(); | |
594 | /// }"); | |
595 | /// ``` | |
596 | fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability); | |
597 | ||
598 | /// Suggest to completely remove an item. | |
599 | /// | |
600 | /// This will remove an item and all following whitespace until the next non-whitespace | |
601 | /// character. This should work correctly if item is on the same indentation level as the | |
602 | /// following item. | |
603 | /// | |
604 | /// # Example | |
605 | /// | |
606 | /// ```rust,ignore | |
607 | /// diag.suggest_remove_item(cx, item, "remove this") | |
608 | /// ``` | |
609 | fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability); | |
610 | } | |
611 | ||
612 | impl<T: LintContext> DiagnosticBuilderExt<T> for rustc_errors::DiagnosticBuilder<'_> { | |
613 | fn suggest_item_with_attr<D: Display + ?Sized>( | |
614 | &mut self, | |
615 | cx: &T, | |
616 | item: Span, | |
617 | msg: &str, | |
618 | attr: &D, | |
619 | applicability: Applicability, | |
620 | ) { | |
621 | if let Some(indent) = indentation(cx, item) { | |
622 | let span = item.with_hi(item.lo()); | |
623 | ||
624 | self.span_suggestion(span, msg, format!("{}\n{}", attr, indent), applicability); | |
625 | } | |
626 | } | |
627 | ||
628 | fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability) { | |
629 | if let Some(indent) = indentation(cx, item) { | |
630 | let span = item.with_hi(item.lo()); | |
631 | ||
632 | let mut first = true; | |
633 | let new_item = new_item | |
634 | .lines() | |
635 | .map(|l| { | |
636 | if first { | |
637 | first = false; | |
638 | format!("{}\n", l) | |
639 | } else { | |
640 | format!("{}{}\n", indent, l) | |
641 | } | |
642 | }) | |
643 | .collect::<String>(); | |
644 | ||
645 | self.span_suggestion(span, msg, format!("{}\n{}", new_item, indent), applicability); | |
646 | } | |
647 | } | |
648 | ||
649 | fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability) { | |
650 | let mut remove_span = item; | |
651 | let hi = cx.sess().source_map().next_point(remove_span).hi(); | |
652 | let fmpos = cx.sess().source_map().lookup_byte_offset(hi); | |
653 | ||
654 | if let Some(ref src) = fmpos.sf.src { | |
655 | let non_whitespace_offset = src[fmpos.pos.to_usize()..].find(|c| c != ' ' && c != '\t' && c != '\n'); | |
656 | ||
657 | if let Some(non_whitespace_offset) = non_whitespace_offset { | |
658 | remove_span = remove_span | |
659 | .with_hi(remove_span.hi() + BytePos(non_whitespace_offset.try_into().expect("offset too large"))) | |
660 | } | |
661 | } | |
662 | ||
663 | self.span_suggestion(remove_span, msg, String::new(), applicability); | |
664 | } | |
665 | } | |
666 | ||
667 | #[cfg(test)] | |
668 | mod test { | |
669 | use super::Sugg; | |
670 | use std::borrow::Cow; | |
671 | ||
672 | const SUGGESTION: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("function_call()")); | |
673 | ||
674 | #[test] | |
675 | fn make_return_transform_sugg_into_a_return_call() { | |
676 | assert_eq!("return function_call()", SUGGESTION.make_return().to_string()); | |
677 | } | |
678 | ||
679 | #[test] | |
680 | fn blockify_transforms_sugg_into_a_block() { | |
681 | assert_eq!("{ function_call() }", SUGGESTION.blockify().to_string()); | |
682 | } | |
683 | } |