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f20569fa XL |
1 | //! Contains utility functions to generate suggestions. |
2 | #![deny(clippy::missing_docs_in_private_items)] | |
3 | ||
a2a8927a | 4 | use crate::source::{snippet, snippet_opt, snippet_with_applicability, snippet_with_macro_callsite}; |
064997fb | 5 | use crate::ty::expr_sig; |
a2a8927a | 6 | use crate::{get_parent_expr_for_hir, higher}; |
f20569fa XL |
7 | use rustc_ast::util::parser::AssocOp; |
8 | use rustc_ast::{ast, token}; | |
9 | use rustc_ast_pretty::pprust::token_kind_to_string; | |
10 | use rustc_errors::Applicability; | |
11 | use rustc_hir as hir; | |
064997fb | 12 | use rustc_hir::{Closure, ExprKind, HirId, MutTy, TyKind}; |
a2a8927a | 13 | use rustc_infer::infer::TyCtxtInferExt; |
f20569fa | 14 | use rustc_lint::{EarlyContext, LateContext, LintContext}; |
a2a8927a XL |
15 | use rustc_middle::hir::place::ProjectionKind; |
16 | use rustc_middle::mir::{FakeReadCause, Mutability}; | |
17 | use rustc_middle::ty; | |
18 | use rustc_span::source_map::{BytePos, CharPos, Pos, Span, SyntaxContext}; | |
19 | use rustc_typeck::expr_use_visitor::{Delegate, ExprUseVisitor, PlaceBase, PlaceWithHirId}; | |
f20569fa | 20 | use std::borrow::Cow; |
04454e1e | 21 | use std::fmt::{Display, Write as _}; |
f20569fa XL |
22 | use std::ops::{Add, Neg, Not, Sub}; |
23 | ||
3c0e092e | 24 | /// A helper type to build suggestion correctly handling parentheses. |
f20569fa XL |
25 | #[derive(Clone, PartialEq)] |
26 | pub enum Sugg<'a> { | |
3c0e092e | 27 | /// An expression that never needs parentheses such as `1337` or `[0; 42]`. |
f20569fa XL |
28 | NonParen(Cow<'a, str>), |
29 | /// An expression that does not fit in other variants. | |
30 | MaybeParen(Cow<'a, str>), | |
31 | /// A binary operator expression, including `as`-casts and explicit type | |
32 | /// coercion. | |
a2a8927a | 33 | BinOp(AssocOp, Cow<'a, str>, Cow<'a, str>), |
f20569fa XL |
34 | } |
35 | ||
36 | /// Literal constant `0`, for convenience. | |
37 | pub const ZERO: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("0")); | |
38 | /// Literal constant `1`, for convenience. | |
39 | pub const ONE: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("1")); | |
40 | /// a constant represents an empty string, for convenience. | |
41 | pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("")); | |
42 | ||
43 | impl Display for Sugg<'_> { | |
44 | fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> { | |
45 | match *self { | |
a2a8927a XL |
46 | Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) => s.fmt(f), |
47 | Sugg::BinOp(op, ref lhs, ref rhs) => binop_to_string(op, lhs, rhs).fmt(f), | |
f20569fa XL |
48 | } |
49 | } | |
50 | } | |
51 | ||
923072b8 | 52 | #[expect(clippy::wrong_self_convention)] // ok, because of the function `as_ty` method |
f20569fa XL |
53 | impl<'a> Sugg<'a> { |
54 | /// Prepare a suggestion from an expression. | |
55 | pub fn hir_opt(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Self> { | |
a2a8927a XL |
56 | let get_snippet = |span| snippet(cx, span, ""); |
57 | snippet_opt(cx, expr.span).map(|_| Self::hir_from_snippet(expr, get_snippet)) | |
f20569fa XL |
58 | } |
59 | ||
60 | /// Convenience function around `hir_opt` for suggestions with a default | |
61 | /// text. | |
62 | pub fn hir(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self { | |
63 | Self::hir_opt(cx, expr).unwrap_or(Sugg::NonParen(Cow::Borrowed(default))) | |
64 | } | |
65 | ||
66 | /// Same as `hir`, but it adapts the applicability level by following rules: | |
67 | /// | |
68 | /// - Applicability level `Unspecified` will never be changed. | |
69 | /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`. | |
70 | /// - If the default value is used and the applicability level is `MachineApplicable`, change it | |
71 | /// to | |
72 | /// `HasPlaceholders` | |
73 | pub fn hir_with_applicability( | |
74 | cx: &LateContext<'_>, | |
75 | expr: &hir::Expr<'_>, | |
76 | default: &'a str, | |
77 | applicability: &mut Applicability, | |
78 | ) -> Self { | |
79 | if *applicability != Applicability::Unspecified && expr.span.from_expansion() { | |
80 | *applicability = Applicability::MaybeIncorrect; | |
81 | } | |
82 | Self::hir_opt(cx, expr).unwrap_or_else(|| { | |
83 | if *applicability == Applicability::MachineApplicable { | |
84 | *applicability = Applicability::HasPlaceholders; | |
85 | } | |
86 | Sugg::NonParen(Cow::Borrowed(default)) | |
87 | }) | |
88 | } | |
89 | ||
90 | /// Same as `hir`, but will use the pre expansion span if the `expr` was in a macro. | |
91 | pub fn hir_with_macro_callsite(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self { | |
a2a8927a XL |
92 | let get_snippet = |span| snippet_with_macro_callsite(cx, span, default); |
93 | Self::hir_from_snippet(expr, get_snippet) | |
f20569fa XL |
94 | } |
95 | ||
17df50a5 XL |
96 | /// Same as `hir`, but first walks the span up to the given context. This will result in the |
97 | /// macro call, rather then the expansion, if the span is from a child context. If the span is | |
98 | /// not from a child context, it will be used directly instead. | |
99 | /// | |
100 | /// e.g. Given the expression `&vec![]`, getting a snippet from the span for `vec![]` as a HIR | |
101 | /// node would result in `box []`. If given the context of the address of expression, this | |
102 | /// function will correctly get a snippet of `vec![]`. | |
103 | pub fn hir_with_context( | |
104 | cx: &LateContext<'_>, | |
105 | expr: &hir::Expr<'_>, | |
106 | ctxt: SyntaxContext, | |
107 | default: &'a str, | |
108 | applicability: &mut Applicability, | |
109 | ) -> Self { | |
a2a8927a XL |
110 | if expr.span.ctxt() == ctxt { |
111 | Self::hir_from_snippet(expr, |span| snippet(cx, span, default)) | |
17df50a5 | 112 | } else { |
a2a8927a XL |
113 | let snip = snippet_with_applicability(cx, expr.span, default, applicability); |
114 | Sugg::NonParen(snip) | |
17df50a5 XL |
115 | } |
116 | } | |
117 | ||
f20569fa XL |
118 | /// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*` |
119 | /// function variants of `Sugg`, since these use different snippet functions. | |
a2a8927a | 120 | fn hir_from_snippet(expr: &hir::Expr<'_>, get_snippet: impl Fn(Span) -> Cow<'a, str>) -> Self { |
94222f64 | 121 | if let Some(range) = higher::Range::hir(expr) { |
f20569fa XL |
122 | let op = match range.limits { |
123 | ast::RangeLimits::HalfOpen => AssocOp::DotDot, | |
124 | ast::RangeLimits::Closed => AssocOp::DotDotEq, | |
125 | }; | |
a2a8927a XL |
126 | let start = range.start.map_or("".into(), |expr| get_snippet(expr.span)); |
127 | let end = range.end.map_or("".into(), |expr| get_snippet(expr.span)); | |
128 | ||
129 | return Sugg::BinOp(op, start, end); | |
f20569fa XL |
130 | } |
131 | ||
132 | match expr.kind { | |
133 | hir::ExprKind::AddrOf(..) | |
134 | | hir::ExprKind::Box(..) | |
135 | | hir::ExprKind::If(..) | |
94222f64 | 136 | | hir::ExprKind::Let(..) |
923072b8 | 137 | | hir::ExprKind::Closure { .. } |
f20569fa | 138 | | hir::ExprKind::Unary(..) |
a2a8927a | 139 | | hir::ExprKind::Match(..) => Sugg::MaybeParen(get_snippet(expr.span)), |
f20569fa XL |
140 | hir::ExprKind::Continue(..) |
141 | | hir::ExprKind::Yield(..) | |
142 | | hir::ExprKind::Array(..) | |
143 | | hir::ExprKind::Block(..) | |
144 | | hir::ExprKind::Break(..) | |
145 | | hir::ExprKind::Call(..) | |
146 | | hir::ExprKind::Field(..) | |
147 | | hir::ExprKind::Index(..) | |
148 | | hir::ExprKind::InlineAsm(..) | |
f20569fa XL |
149 | | hir::ExprKind::ConstBlock(..) |
150 | | hir::ExprKind::Lit(..) | |
151 | | hir::ExprKind::Loop(..) | |
152 | | hir::ExprKind::MethodCall(..) | |
153 | | hir::ExprKind::Path(..) | |
154 | | hir::ExprKind::Repeat(..) | |
155 | | hir::ExprKind::Ret(..) | |
156 | | hir::ExprKind::Struct(..) | |
157 | | hir::ExprKind::Tup(..) | |
158 | | hir::ExprKind::DropTemps(_) | |
a2a8927a XL |
159 | | hir::ExprKind::Err => Sugg::NonParen(get_snippet(expr.span)), |
160 | hir::ExprKind::Assign(lhs, rhs, _) => { | |
161 | Sugg::BinOp(AssocOp::Assign, get_snippet(lhs.span), get_snippet(rhs.span)) | |
162 | }, | |
163 | hir::ExprKind::AssignOp(op, lhs, rhs) => { | |
164 | Sugg::BinOp(hirbinop2assignop(op), get_snippet(lhs.span), get_snippet(rhs.span)) | |
165 | }, | |
166 | hir::ExprKind::Binary(op, lhs, rhs) => Sugg::BinOp( | |
167 | AssocOp::from_ast_binop(op.node.into()), | |
168 | get_snippet(lhs.span), | |
169 | get_snippet(rhs.span), | |
170 | ), | |
171 | hir::ExprKind::Cast(lhs, ty) => Sugg::BinOp(AssocOp::As, get_snippet(lhs.span), get_snippet(ty.span)), | |
172 | hir::ExprKind::Type(lhs, ty) => Sugg::BinOp(AssocOp::Colon, get_snippet(lhs.span), get_snippet(ty.span)), | |
f20569fa XL |
173 | } |
174 | } | |
175 | ||
176 | /// Prepare a suggestion from an expression. | |
177 | pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self { | |
178 | use rustc_ast::ast::RangeLimits; | |
179 | ||
a2a8927a XL |
180 | let get_whole_snippet = || { |
181 | if expr.span.from_expansion() { | |
182 | snippet_with_macro_callsite(cx, expr.span, default) | |
183 | } else { | |
184 | snippet(cx, expr.span, default) | |
185 | } | |
f20569fa XL |
186 | }; |
187 | ||
188 | match expr.kind { | |
189 | ast::ExprKind::AddrOf(..) | |
190 | | ast::ExprKind::Box(..) | |
923072b8 | 191 | | ast::ExprKind::Closure { .. } |
f20569fa XL |
192 | | ast::ExprKind::If(..) |
193 | | ast::ExprKind::Let(..) | |
194 | | ast::ExprKind::Unary(..) | |
a2a8927a | 195 | | ast::ExprKind::Match(..) => Sugg::MaybeParen(get_whole_snippet()), |
f20569fa XL |
196 | ast::ExprKind::Async(..) |
197 | | ast::ExprKind::Block(..) | |
198 | | ast::ExprKind::Break(..) | |
199 | | ast::ExprKind::Call(..) | |
200 | | ast::ExprKind::Continue(..) | |
201 | | ast::ExprKind::Yield(..) | |
202 | | ast::ExprKind::Field(..) | |
203 | | ast::ExprKind::ForLoop(..) | |
204 | | ast::ExprKind::Index(..) | |
205 | | ast::ExprKind::InlineAsm(..) | |
f20569fa XL |
206 | | ast::ExprKind::ConstBlock(..) |
207 | | ast::ExprKind::Lit(..) | |
208 | | ast::ExprKind::Loop(..) | |
209 | | ast::ExprKind::MacCall(..) | |
210 | | ast::ExprKind::MethodCall(..) | |
211 | | ast::ExprKind::Paren(..) | |
212 | | ast::ExprKind::Underscore | |
213 | | ast::ExprKind::Path(..) | |
214 | | ast::ExprKind::Repeat(..) | |
215 | | ast::ExprKind::Ret(..) | |
04454e1e | 216 | | ast::ExprKind::Yeet(..) |
f20569fa XL |
217 | | ast::ExprKind::Struct(..) |
218 | | ast::ExprKind::Try(..) | |
219 | | ast::ExprKind::TryBlock(..) | |
220 | | ast::ExprKind::Tup(..) | |
221 | | ast::ExprKind::Array(..) | |
222 | | ast::ExprKind::While(..) | |
223 | | ast::ExprKind::Await(..) | |
a2a8927a XL |
224 | | ast::ExprKind::Err => Sugg::NonParen(get_whole_snippet()), |
225 | ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::HalfOpen) => Sugg::BinOp( | |
226 | AssocOp::DotDot, | |
227 | lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)), | |
228 | rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)), | |
229 | ), | |
230 | ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::Closed) => Sugg::BinOp( | |
231 | AssocOp::DotDotEq, | |
232 | lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)), | |
233 | rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)), | |
234 | ), | |
235 | ast::ExprKind::Assign(ref lhs, ref rhs, _) => Sugg::BinOp( | |
236 | AssocOp::Assign, | |
237 | snippet(cx, lhs.span, default), | |
238 | snippet(cx, rhs.span, default), | |
239 | ), | |
240 | ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => Sugg::BinOp( | |
241 | astbinop2assignop(op), | |
242 | snippet(cx, lhs.span, default), | |
243 | snippet(cx, rhs.span, default), | |
244 | ), | |
245 | ast::ExprKind::Binary(op, ref lhs, ref rhs) => Sugg::BinOp( | |
246 | AssocOp::from_ast_binop(op.node), | |
247 | snippet(cx, lhs.span, default), | |
248 | snippet(cx, rhs.span, default), | |
249 | ), | |
250 | ast::ExprKind::Cast(ref lhs, ref ty) => Sugg::BinOp( | |
251 | AssocOp::As, | |
252 | snippet(cx, lhs.span, default), | |
253 | snippet(cx, ty.span, default), | |
254 | ), | |
255 | ast::ExprKind::Type(ref lhs, ref ty) => Sugg::BinOp( | |
256 | AssocOp::Colon, | |
257 | snippet(cx, lhs.span, default), | |
258 | snippet(cx, ty.span, default), | |
259 | ), | |
f20569fa XL |
260 | } |
261 | } | |
262 | ||
263 | /// Convenience method to create the `<lhs> && <rhs>` suggestion. | |
264 | pub fn and(self, rhs: &Self) -> Sugg<'static> { | |
265 | make_binop(ast::BinOpKind::And, &self, rhs) | |
266 | } | |
267 | ||
268 | /// Convenience method to create the `<lhs> & <rhs>` suggestion. | |
269 | pub fn bit_and(self, rhs: &Self) -> Sugg<'static> { | |
270 | make_binop(ast::BinOpKind::BitAnd, &self, rhs) | |
271 | } | |
272 | ||
273 | /// Convenience method to create the `<lhs> as <rhs>` suggestion. | |
274 | pub fn as_ty<R: Display>(self, rhs: R) -> Sugg<'static> { | |
275 | make_assoc(AssocOp::As, &self, &Sugg::NonParen(rhs.to_string().into())) | |
276 | } | |
277 | ||
278 | /// Convenience method to create the `&<expr>` suggestion. | |
279 | pub fn addr(self) -> Sugg<'static> { | |
280 | make_unop("&", self) | |
281 | } | |
282 | ||
283 | /// Convenience method to create the `&mut <expr>` suggestion. | |
284 | pub fn mut_addr(self) -> Sugg<'static> { | |
285 | make_unop("&mut ", self) | |
286 | } | |
287 | ||
288 | /// Convenience method to create the `*<expr>` suggestion. | |
289 | pub fn deref(self) -> Sugg<'static> { | |
290 | make_unop("*", self) | |
291 | } | |
292 | ||
293 | /// Convenience method to create the `&*<expr>` suggestion. Currently this | |
294 | /// is needed because `sugg.deref().addr()` produces an unnecessary set of | |
295 | /// parentheses around the deref. | |
296 | pub fn addr_deref(self) -> Sugg<'static> { | |
297 | make_unop("&*", self) | |
298 | } | |
299 | ||
300 | /// Convenience method to create the `&mut *<expr>` suggestion. Currently | |
301 | /// this is needed because `sugg.deref().mut_addr()` produces an unnecessary | |
302 | /// set of parentheses around the deref. | |
303 | pub fn mut_addr_deref(self) -> Sugg<'static> { | |
304 | make_unop("&mut *", self) | |
305 | } | |
306 | ||
307 | /// Convenience method to transform suggestion into a return call | |
308 | pub fn make_return(self) -> Sugg<'static> { | |
309 | Sugg::NonParen(Cow::Owned(format!("return {}", self))) | |
310 | } | |
311 | ||
312 | /// Convenience method to transform suggestion into a block | |
313 | /// where the suggestion is a trailing expression | |
314 | pub fn blockify(self) -> Sugg<'static> { | |
315 | Sugg::NonParen(Cow::Owned(format!("{{ {} }}", self))) | |
316 | } | |
317 | ||
318 | /// Convenience method to create the `<lhs>..<rhs>` or `<lhs>...<rhs>` | |
319 | /// suggestion. | |
f20569fa XL |
320 | pub fn range(self, end: &Self, limit: ast::RangeLimits) -> Sugg<'static> { |
321 | match limit { | |
322 | ast::RangeLimits::HalfOpen => make_assoc(AssocOp::DotDot, &self, end), | |
323 | ast::RangeLimits::Closed => make_assoc(AssocOp::DotDotEq, &self, end), | |
324 | } | |
325 | } | |
326 | ||
3c0e092e | 327 | /// Adds parentheses to any expression that might need them. Suitable to the |
f20569fa XL |
328 | /// `self` argument of a method call |
329 | /// (e.g., to build `bar.foo()` or `(1 + 2).foo()`). | |
a2a8927a | 330 | #[must_use] |
f20569fa XL |
331 | pub fn maybe_par(self) -> Self { |
332 | match self { | |
333 | Sugg::NonParen(..) => self, | |
334 | // `(x)` and `(x).y()` both don't need additional parens. | |
335 | Sugg::MaybeParen(sugg) => { | |
cdc7bbd5 | 336 | if has_enclosing_paren(&sugg) { |
f20569fa XL |
337 | Sugg::MaybeParen(sugg) |
338 | } else { | |
339 | Sugg::NonParen(format!("({})", sugg).into()) | |
340 | } | |
341 | }, | |
a2a8927a XL |
342 | Sugg::BinOp(op, lhs, rhs) => { |
343 | let sugg = binop_to_string(op, &lhs, &rhs); | |
344 | Sugg::NonParen(format!("({})", sugg).into()) | |
cdc7bbd5 | 345 | }, |
f20569fa XL |
346 | } |
347 | } | |
348 | } | |
349 | ||
a2a8927a XL |
350 | /// Generates a string from the operator and both sides. |
351 | fn binop_to_string(op: AssocOp, lhs: &str, rhs: &str) -> String { | |
352 | match op { | |
353 | AssocOp::Add | |
354 | | AssocOp::Subtract | |
355 | | AssocOp::Multiply | |
356 | | AssocOp::Divide | |
357 | | AssocOp::Modulus | |
358 | | AssocOp::LAnd | |
359 | | AssocOp::LOr | |
360 | | AssocOp::BitXor | |
361 | | AssocOp::BitAnd | |
362 | | AssocOp::BitOr | |
363 | | AssocOp::ShiftLeft | |
364 | | AssocOp::ShiftRight | |
365 | | AssocOp::Equal | |
366 | | AssocOp::Less | |
367 | | AssocOp::LessEqual | |
368 | | AssocOp::NotEqual | |
369 | | AssocOp::Greater | |
370 | | AssocOp::GreaterEqual => format!( | |
371 | "{} {} {}", | |
372 | lhs, | |
373 | op.to_ast_binop().expect("Those are AST ops").to_string(), | |
374 | rhs | |
375 | ), | |
376 | AssocOp::Assign => format!("{} = {}", lhs, rhs), | |
377 | AssocOp::AssignOp(op) => { | |
378 | format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs) | |
379 | }, | |
380 | AssocOp::As => format!("{} as {}", lhs, rhs), | |
381 | AssocOp::DotDot => format!("{}..{}", lhs, rhs), | |
382 | AssocOp::DotDotEq => format!("{}..={}", lhs, rhs), | |
383 | AssocOp::Colon => format!("{}: {}", lhs, rhs), | |
384 | } | |
385 | } | |
386 | ||
cdc7bbd5 | 387 | /// Return `true` if `sugg` is enclosed in parenthesis. |
5099ac24 | 388 | pub fn has_enclosing_paren(sugg: impl AsRef<str>) -> bool { |
cdc7bbd5 | 389 | let mut chars = sugg.as_ref().chars(); |
c295e0f8 | 390 | if chars.next() == Some('(') { |
cdc7bbd5 | 391 | let mut depth = 1; |
17df50a5 | 392 | for c in &mut chars { |
cdc7bbd5 XL |
393 | if c == '(' { |
394 | depth += 1; | |
395 | } else if c == ')' { | |
396 | depth -= 1; | |
397 | } | |
398 | if depth == 0 { | |
399 | break; | |
400 | } | |
401 | } | |
402 | chars.next().is_none() | |
403 | } else { | |
404 | false | |
405 | } | |
406 | } | |
407 | ||
c295e0f8 | 408 | /// Copied from the rust standard library, and then edited |
f20569fa XL |
409 | macro_rules! forward_binop_impls_to_ref { |
410 | (impl $imp:ident, $method:ident for $t:ty, type Output = $o:ty) => { | |
411 | impl $imp<$t> for &$t { | |
412 | type Output = $o; | |
413 | ||
414 | fn $method(self, other: $t) -> $o { | |
415 | $imp::$method(self, &other) | |
416 | } | |
417 | } | |
418 | ||
419 | impl $imp<&$t> for $t { | |
420 | type Output = $o; | |
421 | ||
422 | fn $method(self, other: &$t) -> $o { | |
423 | $imp::$method(&self, other) | |
424 | } | |
425 | } | |
426 | ||
427 | impl $imp for $t { | |
428 | type Output = $o; | |
429 | ||
430 | fn $method(self, other: $t) -> $o { | |
431 | $imp::$method(&self, &other) | |
432 | } | |
433 | } | |
434 | }; | |
435 | } | |
436 | ||
437 | impl Add for &Sugg<'_> { | |
438 | type Output = Sugg<'static>; | |
439 | fn add(self, rhs: &Sugg<'_>) -> Sugg<'static> { | |
440 | make_binop(ast::BinOpKind::Add, self, rhs) | |
441 | } | |
442 | } | |
443 | ||
444 | impl Sub for &Sugg<'_> { | |
445 | type Output = Sugg<'static>; | |
446 | fn sub(self, rhs: &Sugg<'_>) -> Sugg<'static> { | |
447 | make_binop(ast::BinOpKind::Sub, self, rhs) | |
448 | } | |
449 | } | |
450 | ||
451 | forward_binop_impls_to_ref!(impl Add, add for Sugg<'_>, type Output = Sugg<'static>); | |
452 | forward_binop_impls_to_ref!(impl Sub, sub for Sugg<'_>, type Output = Sugg<'static>); | |
453 | ||
454 | impl Neg for Sugg<'_> { | |
455 | type Output = Sugg<'static>; | |
456 | fn neg(self) -> Sugg<'static> { | |
457 | make_unop("-", self) | |
458 | } | |
459 | } | |
460 | ||
5099ac24 | 461 | impl<'a> Not for Sugg<'a> { |
a2a8927a XL |
462 | type Output = Sugg<'a>; |
463 | fn not(self) -> Sugg<'a> { | |
464 | use AssocOp::{Equal, Greater, GreaterEqual, Less, LessEqual, NotEqual}; | |
465 | ||
466 | if let Sugg::BinOp(op, lhs, rhs) = self { | |
467 | let to_op = match op { | |
468 | Equal => NotEqual, | |
469 | NotEqual => Equal, | |
470 | Less => GreaterEqual, | |
471 | GreaterEqual => Less, | |
472 | Greater => LessEqual, | |
473 | LessEqual => Greater, | |
474 | _ => return make_unop("!", Sugg::BinOp(op, lhs, rhs)), | |
475 | }; | |
476 | Sugg::BinOp(to_op, lhs, rhs) | |
477 | } else { | |
478 | make_unop("!", self) | |
479 | } | |
f20569fa XL |
480 | } |
481 | } | |
482 | ||
483 | /// Helper type to display either `foo` or `(foo)`. | |
484 | struct ParenHelper<T> { | |
485 | /// `true` if parentheses are needed. | |
486 | paren: bool, | |
487 | /// The main thing to display. | |
488 | wrapped: T, | |
489 | } | |
490 | ||
491 | impl<T> ParenHelper<T> { | |
492 | /// Builds a `ParenHelper`. | |
493 | fn new(paren: bool, wrapped: T) -> Self { | |
494 | Self { paren, wrapped } | |
495 | } | |
496 | } | |
497 | ||
498 | impl<T: Display> Display for ParenHelper<T> { | |
499 | fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> { | |
500 | if self.paren { | |
501 | write!(f, "({})", self.wrapped) | |
502 | } else { | |
503 | self.wrapped.fmt(f) | |
504 | } | |
505 | } | |
506 | } | |
507 | ||
508 | /// Builds the string for `<op><expr>` adding parenthesis when necessary. | |
509 | /// | |
510 | /// For convenience, the operator is taken as a string because all unary | |
511 | /// operators have the same | |
512 | /// precedence. | |
513 | pub fn make_unop(op: &str, expr: Sugg<'_>) -> Sugg<'static> { | |
514 | Sugg::MaybeParen(format!("{}{}", op, expr.maybe_par()).into()) | |
515 | } | |
516 | ||
517 | /// Builds the string for `<lhs> <op> <rhs>` adding parenthesis when necessary. | |
518 | /// | |
519 | /// Precedence of shift operator relative to other arithmetic operation is | |
520 | /// often confusing so | |
521 | /// parenthesis will always be added for a mix of these. | |
522 | pub fn make_assoc(op: AssocOp, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> { | |
523 | /// Returns `true` if the operator is a shift operator `<<` or `>>`. | |
524 | fn is_shift(op: AssocOp) -> bool { | |
525 | matches!(op, AssocOp::ShiftLeft | AssocOp::ShiftRight) | |
526 | } | |
527 | ||
94222f64 | 528 | /// Returns `true` if the operator is an arithmetic operator |
f20569fa XL |
529 | /// (i.e., `+`, `-`, `*`, `/`, `%`). |
530 | fn is_arith(op: AssocOp) -> bool { | |
531 | matches!( | |
532 | op, | |
533 | AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide | AssocOp::Modulus | |
534 | ) | |
535 | } | |
536 | ||
537 | /// Returns `true` if the operator `op` needs parenthesis with the operator | |
538 | /// `other` in the direction `dir`. | |
539 | fn needs_paren(op: AssocOp, other: AssocOp, dir: Associativity) -> bool { | |
540 | other.precedence() < op.precedence() | |
541 | || (other.precedence() == op.precedence() | |
542 | && ((op != other && associativity(op) != dir) | |
543 | || (op == other && associativity(op) != Associativity::Both))) | |
544 | || is_shift(op) && is_arith(other) | |
545 | || is_shift(other) && is_arith(op) | |
546 | } | |
547 | ||
a2a8927a | 548 | let lhs_paren = if let Sugg::BinOp(lop, _, _) = *lhs { |
f20569fa XL |
549 | needs_paren(op, lop, Associativity::Left) |
550 | } else { | |
551 | false | |
552 | }; | |
553 | ||
a2a8927a | 554 | let rhs_paren = if let Sugg::BinOp(rop, _, _) = *rhs { |
f20569fa XL |
555 | needs_paren(op, rop, Associativity::Right) |
556 | } else { | |
557 | false | |
558 | }; | |
559 | ||
a2a8927a XL |
560 | let lhs = ParenHelper::new(lhs_paren, lhs).to_string(); |
561 | let rhs = ParenHelper::new(rhs_paren, rhs).to_string(); | |
562 | Sugg::BinOp(op, lhs.into(), rhs.into()) | |
f20569fa XL |
563 | } |
564 | ||
565 | /// Convenience wrapper around `make_assoc` and `AssocOp::from_ast_binop`. | |
566 | pub fn make_binop(op: ast::BinOpKind, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static> { | |
567 | make_assoc(AssocOp::from_ast_binop(op), lhs, rhs) | |
568 | } | |
569 | ||
570 | #[derive(PartialEq, Eq, Clone, Copy)] | |
571 | /// Operator associativity. | |
572 | enum Associativity { | |
573 | /// The operator is both left-associative and right-associative. | |
574 | Both, | |
575 | /// The operator is left-associative. | |
576 | Left, | |
577 | /// The operator is not associative. | |
578 | None, | |
579 | /// The operator is right-associative. | |
580 | Right, | |
581 | } | |
582 | ||
583 | /// Returns the associativity/fixity of an operator. The difference with | |
584 | /// `AssocOp::fixity` is that an operator can be both left and right associative | |
585 | /// (such as `+`: `a + b + c == (a + b) + c == a + (b + c)`. | |
586 | /// | |
587 | /// Chained `as` and explicit `:` type coercion never need inner parenthesis so | |
588 | /// they are considered | |
589 | /// associative. | |
590 | #[must_use] | |
591 | fn associativity(op: AssocOp) -> Associativity { | |
592 | use rustc_ast::util::parser::AssocOp::{ | |
593 | Add, As, Assign, AssignOp, BitAnd, BitOr, BitXor, Colon, Divide, DotDot, DotDotEq, Equal, Greater, | |
594 | GreaterEqual, LAnd, LOr, Less, LessEqual, Modulus, Multiply, NotEqual, ShiftLeft, ShiftRight, Subtract, | |
595 | }; | |
596 | ||
597 | match op { | |
598 | Assign | AssignOp(_) => Associativity::Right, | |
599 | Add | BitAnd | BitOr | BitXor | LAnd | LOr | Multiply | As | Colon => Associativity::Both, | |
600 | Divide | Equal | Greater | GreaterEqual | Less | LessEqual | Modulus | NotEqual | ShiftLeft | ShiftRight | |
601 | | Subtract => Associativity::Left, | |
602 | DotDot | DotDotEq => Associativity::None, | |
603 | } | |
604 | } | |
605 | ||
606 | /// Converts a `hir::BinOp` to the corresponding assigning binary operator. | |
607 | fn hirbinop2assignop(op: hir::BinOp) -> AssocOp { | |
608 | use rustc_ast::token::BinOpToken::{And, Caret, Minus, Or, Percent, Plus, Shl, Shr, Slash, Star}; | |
609 | ||
610 | AssocOp::AssignOp(match op.node { | |
611 | hir::BinOpKind::Add => Plus, | |
612 | hir::BinOpKind::BitAnd => And, | |
613 | hir::BinOpKind::BitOr => Or, | |
614 | hir::BinOpKind::BitXor => Caret, | |
615 | hir::BinOpKind::Div => Slash, | |
616 | hir::BinOpKind::Mul => Star, | |
617 | hir::BinOpKind::Rem => Percent, | |
618 | hir::BinOpKind::Shl => Shl, | |
619 | hir::BinOpKind::Shr => Shr, | |
620 | hir::BinOpKind::Sub => Minus, | |
621 | ||
622 | hir::BinOpKind::And | |
623 | | hir::BinOpKind::Eq | |
624 | | hir::BinOpKind::Ge | |
625 | | hir::BinOpKind::Gt | |
626 | | hir::BinOpKind::Le | |
627 | | hir::BinOpKind::Lt | |
628 | | hir::BinOpKind::Ne | |
629 | | hir::BinOpKind::Or => panic!("This operator does not exist"), | |
630 | }) | |
631 | } | |
632 | ||
633 | /// Converts an `ast::BinOp` to the corresponding assigning binary operator. | |
634 | fn astbinop2assignop(op: ast::BinOp) -> AssocOp { | |
635 | use rustc_ast::ast::BinOpKind::{ | |
636 | Add, And, BitAnd, BitOr, BitXor, Div, Eq, Ge, Gt, Le, Lt, Mul, Ne, Or, Rem, Shl, Shr, Sub, | |
637 | }; | |
638 | use rustc_ast::token::BinOpToken; | |
639 | ||
640 | AssocOp::AssignOp(match op.node { | |
641 | Add => BinOpToken::Plus, | |
642 | BitAnd => BinOpToken::And, | |
643 | BitOr => BinOpToken::Or, | |
644 | BitXor => BinOpToken::Caret, | |
645 | Div => BinOpToken::Slash, | |
646 | Mul => BinOpToken::Star, | |
647 | Rem => BinOpToken::Percent, | |
648 | Shl => BinOpToken::Shl, | |
649 | Shr => BinOpToken::Shr, | |
650 | Sub => BinOpToken::Minus, | |
651 | And | Eq | Ge | Gt | Le | Lt | Ne | Or => panic!("This operator does not exist"), | |
652 | }) | |
653 | } | |
654 | ||
655 | /// Returns the indentation before `span` if there are nothing but `[ \t]` | |
656 | /// before it on its line. | |
657 | fn indentation<T: LintContext>(cx: &T, span: Span) -> Option<String> { | |
658 | let lo = cx.sess().source_map().lookup_char_pos(span.lo()); | |
659 | lo.file | |
660 | .get_line(lo.line - 1 /* line numbers in `Loc` are 1-based */) | |
661 | .and_then(|line| { | |
662 | if let Some((pos, _)) = line.char_indices().find(|&(_, c)| c != ' ' && c != '\t') { | |
663 | // We can mix char and byte positions here because we only consider `[ \t]`. | |
664 | if lo.col == CharPos(pos) { | |
665 | Some(line[..pos].into()) | |
666 | } else { | |
667 | None | |
668 | } | |
669 | } else { | |
670 | None | |
671 | } | |
672 | }) | |
673 | } | |
674 | ||
5e7ed085 FG |
675 | /// Convenience extension trait for `Diagnostic`. |
676 | pub trait DiagnosticExt<T: LintContext> { | |
f20569fa XL |
677 | /// Suggests to add an attribute to an item. |
678 | /// | |
679 | /// Correctly handles indentation of the attribute and item. | |
680 | /// | |
681 | /// # Example | |
682 | /// | |
683 | /// ```rust,ignore | |
684 | /// diag.suggest_item_with_attr(cx, item, "#[derive(Default)]"); | |
685 | /// ``` | |
686 | fn suggest_item_with_attr<D: Display + ?Sized>( | |
687 | &mut self, | |
688 | cx: &T, | |
689 | item: Span, | |
690 | msg: &str, | |
691 | attr: &D, | |
692 | applicability: Applicability, | |
693 | ); | |
694 | ||
695 | /// Suggest to add an item before another. | |
696 | /// | |
697 | /// The item should not be indented (except for inner indentation). | |
698 | /// | |
699 | /// # Example | |
700 | /// | |
701 | /// ```rust,ignore | |
702 | /// diag.suggest_prepend_item(cx, item, | |
703 | /// "fn foo() { | |
704 | /// bar(); | |
705 | /// }"); | |
706 | /// ``` | |
707 | fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability); | |
708 | ||
709 | /// Suggest to completely remove an item. | |
710 | /// | |
711 | /// This will remove an item and all following whitespace until the next non-whitespace | |
712 | /// character. This should work correctly if item is on the same indentation level as the | |
713 | /// following item. | |
714 | /// | |
715 | /// # Example | |
716 | /// | |
717 | /// ```rust,ignore | |
718 | /// diag.suggest_remove_item(cx, item, "remove this") | |
719 | /// ``` | |
720 | fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability); | |
721 | } | |
722 | ||
5e7ed085 | 723 | impl<T: LintContext> DiagnosticExt<T> for rustc_errors::Diagnostic { |
f20569fa XL |
724 | fn suggest_item_with_attr<D: Display + ?Sized>( |
725 | &mut self, | |
726 | cx: &T, | |
727 | item: Span, | |
728 | msg: &str, | |
729 | attr: &D, | |
730 | applicability: Applicability, | |
731 | ) { | |
732 | if let Some(indent) = indentation(cx, item) { | |
733 | let span = item.with_hi(item.lo()); | |
734 | ||
735 | self.span_suggestion(span, msg, format!("{}\n{}", attr, indent), applicability); | |
736 | } | |
737 | } | |
738 | ||
739 | fn suggest_prepend_item(&mut self, cx: &T, item: Span, msg: &str, new_item: &str, applicability: Applicability) { | |
740 | if let Some(indent) = indentation(cx, item) { | |
741 | let span = item.with_hi(item.lo()); | |
742 | ||
743 | let mut first = true; | |
744 | let new_item = new_item | |
745 | .lines() | |
746 | .map(|l| { | |
747 | if first { | |
748 | first = false; | |
749 | format!("{}\n", l) | |
750 | } else { | |
751 | format!("{}{}\n", indent, l) | |
752 | } | |
753 | }) | |
754 | .collect::<String>(); | |
755 | ||
756 | self.span_suggestion(span, msg, format!("{}\n{}", new_item, indent), applicability); | |
757 | } | |
758 | } | |
759 | ||
760 | fn suggest_remove_item(&mut self, cx: &T, item: Span, msg: &str, applicability: Applicability) { | |
761 | let mut remove_span = item; | |
762 | let hi = cx.sess().source_map().next_point(remove_span).hi(); | |
763 | let fmpos = cx.sess().source_map().lookup_byte_offset(hi); | |
764 | ||
765 | if let Some(ref src) = fmpos.sf.src { | |
766 | let non_whitespace_offset = src[fmpos.pos.to_usize()..].find(|c| c != ' ' && c != '\t' && c != '\n'); | |
767 | ||
768 | if let Some(non_whitespace_offset) = non_whitespace_offset { | |
769 | remove_span = remove_span | |
17df50a5 | 770 | .with_hi(remove_span.hi() + BytePos(non_whitespace_offset.try_into().expect("offset too large"))); |
f20569fa XL |
771 | } |
772 | } | |
773 | ||
923072b8 | 774 | self.span_suggestion(remove_span, msg, "", applicability); |
f20569fa XL |
775 | } |
776 | } | |
777 | ||
a2a8927a XL |
778 | /// Suggestion results for handling closure |
779 | /// args dereferencing and borrowing | |
780 | pub struct DerefClosure { | |
781 | /// confidence on the built suggestion | |
782 | pub applicability: Applicability, | |
783 | /// gradually built suggestion | |
784 | pub suggestion: String, | |
785 | } | |
786 | ||
787 | /// Build suggestion gradually by handling closure arg specific usages, | |
788 | /// such as explicit deref and borrowing cases. | |
789 | /// Returns `None` if no such use cases have been triggered in closure body | |
790 | /// | |
791 | /// note: this only works on single line immutable closures with exactly one input parameter. | |
792 | pub fn deref_closure_args<'tcx>(cx: &LateContext<'_>, closure: &'tcx hir::Expr<'_>) -> Option<DerefClosure> { | |
064997fb | 793 | if let hir::ExprKind::Closure(&Closure { fn_decl, body, .. }) = closure.kind { |
923072b8 | 794 | let closure_body = cx.tcx.hir().body(body); |
a2a8927a XL |
795 | // is closure arg a type annotated double reference (i.e.: `|x: &&i32| ...`) |
796 | // a type annotation is present if param `kind` is different from `TyKind::Infer` | |
797 | let closure_arg_is_type_annotated_double_ref = if let TyKind::Rptr(_, MutTy { ty, .. }) = fn_decl.inputs[0].kind | |
798 | { | |
799 | matches!(ty.kind, TyKind::Rptr(_, MutTy { .. })) | |
800 | } else { | |
801 | false | |
802 | }; | |
803 | ||
804 | let mut visitor = DerefDelegate { | |
805 | cx, | |
806 | closure_span: closure.span, | |
807 | closure_arg_is_type_annotated_double_ref, | |
808 | next_pos: closure.span.lo(), | |
809 | suggestion_start: String::new(), | |
5e7ed085 | 810 | applicability: Applicability::MachineApplicable, |
a2a8927a XL |
811 | }; |
812 | ||
813 | let fn_def_id = cx.tcx.hir().local_def_id(closure.hir_id); | |
814 | cx.tcx.infer_ctxt().enter(|infcx| { | |
815 | ExprUseVisitor::new(&mut visitor, &infcx, fn_def_id, cx.param_env, cx.typeck_results()) | |
816 | .consume_body(closure_body); | |
817 | }); | |
818 | ||
819 | if !visitor.suggestion_start.is_empty() { | |
820 | return Some(DerefClosure { | |
821 | applicability: visitor.applicability, | |
822 | suggestion: visitor.finish(), | |
823 | }); | |
824 | } | |
825 | } | |
826 | None | |
827 | } | |
828 | ||
829 | /// Visitor struct used for tracking down | |
830 | /// dereferencing and borrowing of closure's args | |
831 | struct DerefDelegate<'a, 'tcx> { | |
832 | /// The late context of the lint | |
833 | cx: &'a LateContext<'tcx>, | |
834 | /// The span of the input closure to adapt | |
835 | closure_span: Span, | |
836 | /// Indicates if the arg of the closure is a type annotated double reference | |
837 | closure_arg_is_type_annotated_double_ref: bool, | |
838 | /// last position of the span to gradually build the suggestion | |
839 | next_pos: BytePos, | |
840 | /// starting part of the gradually built suggestion | |
841 | suggestion_start: String, | |
842 | /// confidence on the built suggestion | |
843 | applicability: Applicability, | |
844 | } | |
845 | ||
5099ac24 | 846 | impl<'tcx> DerefDelegate<'_, 'tcx> { |
a2a8927a XL |
847 | /// build final suggestion: |
848 | /// - create the ending part of suggestion | |
849 | /// - concatenate starting and ending parts | |
850 | /// - potentially remove needless borrowing | |
851 | pub fn finish(&mut self) -> String { | |
852 | let end_span = Span::new(self.next_pos, self.closure_span.hi(), self.closure_span.ctxt(), None); | |
853 | let end_snip = snippet_with_applicability(self.cx, end_span, "..", &mut self.applicability); | |
854 | let sugg = format!("{}{}", self.suggestion_start, end_snip); | |
855 | if self.closure_arg_is_type_annotated_double_ref { | |
856 | sugg.replacen('&', "", 1) | |
857 | } else { | |
858 | sugg | |
859 | } | |
860 | } | |
861 | ||
862 | /// indicates whether the function from `parent_expr` takes its args by double reference | |
863 | fn func_takes_arg_by_double_ref(&self, parent_expr: &'tcx hir::Expr<'_>, cmt_hir_id: HirId) -> bool { | |
064997fb | 864 | let ty = match parent_expr.kind { |
5099ac24 | 865 | ExprKind::MethodCall(_, call_args, _) => { |
064997fb FG |
866 | if let Some(sig) = self |
867 | .cx | |
868 | .typeck_results() | |
869 | .type_dependent_def_id(parent_expr.hir_id) | |
870 | .map(|did| self.cx.tcx.fn_sig(did).skip_binder()) | |
871 | { | |
872 | call_args | |
873 | .iter() | |
874 | .position(|arg| arg.hir_id == cmt_hir_id) | |
875 | .map(|i| sig.inputs()[i]) | |
a2a8927a XL |
876 | } else { |
877 | return false; | |
878 | } | |
879 | }, | |
880 | ExprKind::Call(func, call_args) => { | |
064997fb FG |
881 | if let Some(sig) = expr_sig(self.cx, func) { |
882 | call_args | |
883 | .iter() | |
884 | .position(|arg| arg.hir_id == cmt_hir_id) | |
885 | .and_then(|i| sig.input(i)) | |
886 | .map(ty::Binder::skip_binder) | |
887 | } else { | |
888 | return false; | |
889 | } | |
a2a8927a XL |
890 | }, |
891 | _ => return false, | |
892 | }; | |
893 | ||
064997fb | 894 | ty.map_or(false, |ty| matches!(ty.kind(), ty::Ref(_, inner, _) if inner.is_ref())) |
a2a8927a XL |
895 | } |
896 | } | |
897 | ||
898 | impl<'tcx> Delegate<'tcx> for DerefDelegate<'_, 'tcx> { | |
899 | fn consume(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId) {} | |
900 | ||
a2a8927a XL |
901 | fn borrow(&mut self, cmt: &PlaceWithHirId<'tcx>, _: HirId, _: ty::BorrowKind) { |
902 | if let PlaceBase::Local(id) = cmt.place.base { | |
903 | let map = self.cx.tcx.hir(); | |
904 | let span = map.span(cmt.hir_id); | |
905 | let start_span = Span::new(self.next_pos, span.lo(), span.ctxt(), None); | |
906 | let mut start_snip = snippet_with_applicability(self.cx, start_span, "..", &mut self.applicability); | |
907 | ||
908 | // identifier referring to the variable currently triggered (i.e.: `fp`) | |
909 | let ident_str = map.name(id).to_string(); | |
910 | // full identifier that includes projection (i.e.: `fp.field`) | |
911 | let ident_str_with_proj = snippet(self.cx, span, "..").to_string(); | |
912 | ||
913 | if cmt.place.projections.is_empty() { | |
914 | // handle item without any projection, that needs an explicit borrowing | |
915 | // i.e.: suggest `&x` instead of `x` | |
04454e1e | 916 | let _ = write!(self.suggestion_start, "{}&{}", start_snip, ident_str); |
a2a8927a XL |
917 | } else { |
918 | // cases where a parent `Call` or `MethodCall` is using the item | |
919 | // i.e.: suggest `.contains(&x)` for `.find(|x| [1, 2, 3].contains(x)).is_none()` | |
920 | // | |
921 | // Note about method calls: | |
922 | // - compiler automatically dereference references if the target type is a reference (works also for | |
923 | // function call) | |
924 | // - `self` arguments in the case of `x.is_something()` are also automatically (de)referenced, and | |
925 | // no projection should be suggested | |
926 | if let Some(parent_expr) = get_parent_expr_for_hir(self.cx, cmt.hir_id) { | |
927 | match &parent_expr.kind { | |
928 | // given expression is the self argument and will be handled completely by the compiler | |
929 | // i.e.: `|x| x.is_something()` | |
5099ac24 | 930 | ExprKind::MethodCall(_, [self_expr, ..], _) if self_expr.hir_id == cmt.hir_id => { |
04454e1e | 931 | let _ = write!(self.suggestion_start, "{}{}", start_snip, ident_str_with_proj); |
a2a8927a XL |
932 | self.next_pos = span.hi(); |
933 | return; | |
934 | }, | |
935 | // item is used in a call | |
936 | // i.e.: `Call`: `|x| please(x)` or `MethodCall`: `|x| [1, 2, 3].contains(x)` | |
5099ac24 | 937 | ExprKind::Call(_, [call_args @ ..]) | ExprKind::MethodCall(_, [_, call_args @ ..], _) => { |
a2a8927a XL |
938 | let expr = self.cx.tcx.hir().expect_expr(cmt.hir_id); |
939 | let arg_ty_kind = self.cx.typeck_results().expr_ty(expr).kind(); | |
940 | ||
941 | if matches!(arg_ty_kind, ty::Ref(_, _, Mutability::Not)) { | |
942 | // suggest ampersand if call function is taking args by double reference | |
943 | let takes_arg_by_double_ref = | |
944 | self.func_takes_arg_by_double_ref(parent_expr, cmt.hir_id); | |
945 | ||
946 | // compiler will automatically dereference field or index projection, so no need | |
947 | // to suggest ampersand, but full identifier that includes projection is required | |
948 | let has_field_or_index_projection = | |
949 | cmt.place.projections.iter().any(|proj| { | |
950 | matches!(proj.kind, ProjectionKind::Field(..) | ProjectionKind::Index) | |
951 | }); | |
952 | ||
953 | // no need to bind again if the function doesn't take arg by double ref | |
954 | // and if the item is already a double ref | |
955 | let ident_sugg = if !call_args.is_empty() | |
956 | && !takes_arg_by_double_ref | |
957 | && (self.closure_arg_is_type_annotated_double_ref || has_field_or_index_projection) | |
958 | { | |
959 | let ident = if has_field_or_index_projection { | |
960 | ident_str_with_proj | |
961 | } else { | |
962 | ident_str | |
963 | }; | |
964 | format!("{}{}", start_snip, ident) | |
965 | } else { | |
966 | format!("{}&{}", start_snip, ident_str) | |
967 | }; | |
968 | self.suggestion_start.push_str(&ident_sugg); | |
969 | self.next_pos = span.hi(); | |
970 | return; | |
971 | } | |
972 | ||
973 | self.applicability = Applicability::Unspecified; | |
974 | }, | |
975 | _ => (), | |
976 | } | |
977 | } | |
978 | ||
979 | let mut replacement_str = ident_str; | |
980 | let mut projections_handled = false; | |
981 | cmt.place.projections.iter().enumerate().for_each(|(i, proj)| { | |
982 | match proj.kind { | |
983 | // Field projection like `|v| v.foo` | |
984 | // no adjustment needed here, as field projections are handled by the compiler | |
985 | ProjectionKind::Field(..) => match cmt.place.ty_before_projection(i).kind() { | |
986 | ty::Adt(..) | ty::Tuple(_) => { | |
987 | replacement_str = ident_str_with_proj.clone(); | |
988 | projections_handled = true; | |
989 | }, | |
990 | _ => (), | |
991 | }, | |
992 | // Index projection like `|x| foo[x]` | |
993 | // the index is dropped so we can't get it to build the suggestion, | |
994 | // so the span is set-up again to get more code, using `span.hi()` (i.e.: `foo[x]`) | |
995 | // instead of `span.lo()` (i.e.: `foo`) | |
996 | ProjectionKind::Index => { | |
997 | let start_span = Span::new(self.next_pos, span.hi(), span.ctxt(), None); | |
998 | start_snip = snippet_with_applicability(self.cx, start_span, "..", &mut self.applicability); | |
999 | replacement_str.clear(); | |
1000 | projections_handled = true; | |
1001 | }, | |
1002 | // note: unable to trigger `Subslice` kind in tests | |
1003 | ProjectionKind::Subslice => (), | |
1004 | ProjectionKind::Deref => { | |
1005 | // Explicit derefs are typically handled later on, but | |
1006 | // some items do not need explicit deref, such as array accesses, | |
1007 | // so we mark them as already processed | |
1008 | // i.e.: don't suggest `*sub[1..4].len()` for `|sub| sub[1..4].len() == 3` | |
1009 | if let ty::Ref(_, inner, _) = cmt.place.ty_before_projection(i).kind() { | |
1010 | if matches!(inner.kind(), ty::Ref(_, innermost, _) if innermost.is_array()) { | |
1011 | projections_handled = true; | |
1012 | } | |
1013 | } | |
1014 | }, | |
1015 | } | |
1016 | }); | |
1017 | ||
1018 | // handle `ProjectionKind::Deref` by removing one explicit deref | |
1019 | // if no special case was detected (i.e.: suggest `*x` instead of `**x`) | |
1020 | if !projections_handled { | |
1021 | let last_deref = cmt | |
1022 | .place | |
1023 | .projections | |
1024 | .iter() | |
1025 | .rposition(|proj| proj.kind == ProjectionKind::Deref); | |
1026 | ||
1027 | if let Some(pos) = last_deref { | |
1028 | let mut projections = cmt.place.projections.clone(); | |
1029 | projections.truncate(pos); | |
1030 | ||
1031 | for item in projections { | |
1032 | if item.kind == ProjectionKind::Deref { | |
1033 | replacement_str = format!("*{}", replacement_str); | |
1034 | } | |
1035 | } | |
1036 | } | |
1037 | } | |
1038 | ||
04454e1e | 1039 | let _ = write!(self.suggestion_start, "{}{}", start_snip, replacement_str); |
a2a8927a XL |
1040 | } |
1041 | self.next_pos = span.hi(); | |
1042 | } | |
1043 | } | |
1044 | ||
1045 | fn mutate(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId) {} | |
1046 | ||
923072b8 | 1047 | fn fake_read(&mut self, _: &rustc_typeck::expr_use_visitor::PlaceWithHirId<'tcx>, _: FakeReadCause, _: HirId) {} |
a2a8927a XL |
1048 | } |
1049 | ||
f20569fa XL |
1050 | #[cfg(test)] |
1051 | mod test { | |
1052 | use super::Sugg; | |
cdc7bbd5 XL |
1053 | |
1054 | use rustc_ast::util::parser::AssocOp; | |
f20569fa XL |
1055 | use std::borrow::Cow; |
1056 | ||
1057 | const SUGGESTION: Sugg<'static> = Sugg::NonParen(Cow::Borrowed("function_call()")); | |
1058 | ||
1059 | #[test] | |
1060 | fn make_return_transform_sugg_into_a_return_call() { | |
1061 | assert_eq!("return function_call()", SUGGESTION.make_return().to_string()); | |
1062 | } | |
1063 | ||
1064 | #[test] | |
1065 | fn blockify_transforms_sugg_into_a_block() { | |
1066 | assert_eq!("{ function_call() }", SUGGESTION.blockify().to_string()); | |
1067 | } | |
cdc7bbd5 XL |
1068 | |
1069 | #[test] | |
1070 | fn binop_maybe_par() { | |
a2a8927a | 1071 | let sugg = Sugg::BinOp(AssocOp::Add, "1".into(), "1".into()); |
cdc7bbd5 XL |
1072 | assert_eq!("(1 + 1)", sugg.maybe_par().to_string()); |
1073 | ||
a2a8927a | 1074 | let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into(), "(1 + 1)".into()); |
cdc7bbd5 XL |
1075 | assert_eq!("((1 + 1) + (1 + 1))", sugg.maybe_par().to_string()); |
1076 | } | |
a2a8927a XL |
1077 | #[test] |
1078 | fn not_op() { | |
1079 | use AssocOp::{Add, Equal, Greater, GreaterEqual, LAnd, LOr, Less, LessEqual, NotEqual}; | |
1080 | ||
1081 | fn test_not(op: AssocOp, correct: &str) { | |
1082 | let sugg = Sugg::BinOp(op, "x".into(), "y".into()); | |
1083 | assert_eq!((!sugg).to_string(), correct); | |
1084 | } | |
1085 | ||
1086 | // Invert the comparison operator. | |
1087 | test_not(Equal, "x != y"); | |
1088 | test_not(NotEqual, "x == y"); | |
1089 | test_not(Less, "x >= y"); | |
1090 | test_not(LessEqual, "x > y"); | |
1091 | test_not(Greater, "x <= y"); | |
1092 | test_not(GreaterEqual, "x < y"); | |
1093 | ||
1094 | // Other operators are inverted like !(..). | |
1095 | test_not(Add, "!(x + y)"); | |
1096 | test_not(LAnd, "!(x && y)"); | |
1097 | test_not(LOr, "!(x || y)"); | |
1098 | } | |
f20569fa | 1099 | } |