1 //! A group of attributes that can be attached to Rust code in order
2 //! to generate a clippy lint detecting said code automatically.
4 #![allow(clippy::print_stdout, clippy::use_debug)]
6 use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
7 use rustc::{declare_tool_lint, lint_array};
9 use rustc::hir::{Expr, ExprKind, QPath, TyKind, Pat, PatKind, BindingAnnotation, StmtKind, DeclKind, Stmt};
10 use rustc::hir::intravisit::{NestedVisitorMap, Visitor};
11 use rustc_data_structures::fx::FxHashMap;
12 use syntax::ast::{Attribute, LitKind, DUMMY_NODE_ID};
13 use crate::utils::get_attr;
15 /// **What it does:** Generates clippy code that detects the offending pattern
19 /// // ./tests/ui/my_lint.rs
21 /// // detect the following pattern
24 /// // but ignore everything from here on
25 /// #![clippy::author = "ignore"]
30 /// Running `TESTNAME=ui/my_lint cargo test --test compile-test` will produce
31 /// a `./tests/ui/new_lint.stdout` file with the generated code:
34 /// // ./tests/ui/new_lint.stdout
36 /// if let ExprKind::If(ref cond, ref then, None) = item.node,
37 /// if let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.node,
38 /// if let ExprKind::Path(ref path) = left.node,
39 /// if let ExprKind::Lit(ref lit) = right.node,
40 /// if let LitKind::Int(42, _) = lit.node,
42 /// // report your lint here
46 declare_clippy_lint! {
49 "helper for writing lints"
54 impl LintPass for Pass {
55 fn get_lints(&self) -> LintArray {
56 lint_array!(LINT_AUTHOR)
61 println!("if_chain! {{");
66 println!(" // report your lint here");
71 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
72 fn check_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
73 if !has_attr(&item.attrs) {
77 PrintVisitor::new("item").visit_item(item);
81 fn check_impl_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::ImplItem) {
82 if !has_attr(&item.attrs) {
86 PrintVisitor::new("item").visit_impl_item(item);
90 fn check_trait_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem) {
91 if !has_attr(&item.attrs) {
95 PrintVisitor::new("item").visit_trait_item(item);
99 fn check_variant(&mut self, _cx: &LateContext<'a, 'tcx>, var: &'tcx hir::Variant, generics: &hir::Generics) {
100 if !has_attr(&var.node.attrs) {
104 PrintVisitor::new("var").visit_variant(var, generics, DUMMY_NODE_ID);
108 fn check_struct_field(&mut self, _cx: &LateContext<'a, 'tcx>, field: &'tcx hir::StructField) {
109 if !has_attr(&field.attrs) {
113 PrintVisitor::new("field").visit_struct_field(field);
117 fn check_expr(&mut self, _cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
118 if !has_attr(&expr.attrs) {
122 PrintVisitor::new("expr").visit_expr(expr);
126 fn check_arm(&mut self, _cx: &LateContext<'a, 'tcx>, arm: &'tcx hir::Arm) {
127 if !has_attr(&arm.attrs) {
131 PrintVisitor::new("arm").visit_arm(arm);
135 fn check_stmt(&mut self, _cx: &LateContext<'a, 'tcx>, stmt: &'tcx hir::Stmt) {
136 if !has_attr(stmt.node.attrs()) {
140 PrintVisitor::new("stmt").visit_stmt(stmt);
144 fn check_foreign_item(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::ForeignItem) {
145 if !has_attr(&item.attrs) {
149 PrintVisitor::new("item").visit_foreign_item(item);
155 fn new(s: &'static str) -> Self {
157 ids: FxHashMap::default(),
158 current: s.to_owned(),
162 fn next(&mut self, s: &'static str) -> String {
163 use std::collections::hash_map::Entry::*;
164 match self.ids.entry(s) {
165 // already there: start numbering from `1`
166 Occupied(mut occ) => {
167 let val = occ.get_mut();
169 format!("{}{}", s, *val)
171 // not there: insert and return name as given
179 fn print_qpath(&mut self, path: &QPath) {
180 print!(" if match_qpath({}, &[", self.current);
181 print_path(path, &mut true);
186 struct PrintVisitor {
187 /// Fields are the current index that needs to be appended to pattern
189 ids: FxHashMap<&'static str, usize>,
190 /// the name that needs to be destructured
194 impl<'tcx> Visitor<'tcx> for PrintVisitor {
195 fn visit_expr(&mut self, expr: &Expr) {
196 print!(" if let ExprKind::");
197 let current = format!("{}.node", self.current);
199 ExprKind::Box(ref inner) => {
200 let inner_pat = self.next("inner");
201 println!("Box(ref {}) = {};", inner_pat, current);
202 self.current = inner_pat;
203 self.visit_expr(inner);
205 ExprKind::Array(ref elements) => {
206 let elements_pat = self.next("elements");
207 println!("Array(ref {}) = {};", elements_pat, current);
208 println!(" if {}.len() == {};", elements_pat, elements.len());
209 for (i, element) in elements.iter().enumerate() {
210 self.current = format!("{}[{}]", elements_pat, i);
211 self.visit_expr(element);
214 ExprKind::Call(ref func, ref args) => {
215 let func_pat = self.next("func");
216 let args_pat = self.next("args");
217 println!("Call(ref {}, ref {}) = {};", func_pat, args_pat, current);
218 self.current = func_pat;
219 self.visit_expr(func);
220 println!(" if {}.len() == {};", args_pat, args.len());
221 for (i, arg) in args.iter().enumerate() {
222 self.current = format!("{}[{}]", args_pat, i);
223 self.visit_expr(arg);
226 ExprKind::MethodCall(ref _method_name, ref _generics, ref _args) => {
227 println!("MethodCall(ref method_name, ref generics, ref args) = {};", current);
228 println!(" // unimplemented: `ExprKind::MethodCall` is not further destructured at the moment");
230 ExprKind::Tup(ref elements) => {
231 let elements_pat = self.next("elements");
232 println!("Tup(ref {}) = {};", elements_pat, current);
233 println!(" if {}.len() == {};", elements_pat, elements.len());
234 for (i, element) in elements.iter().enumerate() {
235 self.current = format!("{}[{}]", elements_pat, i);
236 self.visit_expr(element);
239 ExprKind::Binary(ref op, ref left, ref right) => {
240 let op_pat = self.next("op");
241 let left_pat = self.next("left");
242 let right_pat = self.next("right");
243 println!("Binary(ref {}, ref {}, ref {}) = {};", op_pat, left_pat, right_pat, current);
244 println!(" if BinOpKind::{:?} == {}.node;", op.node, op_pat);
245 self.current = left_pat;
246 self.visit_expr(left);
247 self.current = right_pat;
248 self.visit_expr(right);
250 ExprKind::Unary(ref op, ref inner) => {
251 let inner_pat = self.next("inner");
252 println!("Unary(UnOp::{:?}, ref {}) = {};", op, inner_pat, current);
253 self.current = inner_pat;
254 self.visit_expr(inner);
256 ExprKind::Lit(ref lit) => {
257 let lit_pat = self.next("lit");
258 println!("Lit(ref {}) = {};", lit_pat, current);
260 LitKind::Bool(val) => println!(" if let LitKind::Bool({:?}) = {}.node;", val, lit_pat),
261 LitKind::Char(c) => println!(" if let LitKind::Char({:?}) = {}.node;", c, lit_pat),
262 LitKind::Byte(b) => println!(" if let LitKind::Byte({}) = {}.node;", b, lit_pat),
263 // FIXME: also check int type
264 LitKind::Int(i, _) => println!(" if let LitKind::Int({}, _) = {}.node;", i, lit_pat),
265 LitKind::Float(..) => println!(" if let LitKind::Float(..) = {}.node;", lit_pat),
266 LitKind::FloatUnsuffixed(_) => {
267 println!(" if let LitKind::FloatUnsuffixed(_) = {}.node;", lit_pat)
269 LitKind::ByteStr(ref vec) => {
270 let vec_pat = self.next("vec");
271 println!(" if let LitKind::ByteStr(ref {}) = {}.node;", vec_pat, lit_pat);
272 println!(" if let [{:?}] = **{};", vec, vec_pat);
274 LitKind::Str(ref text, _) => {
275 let str_pat = self.next("s");
276 println!(" if let LitKind::Str(ref {}) = {}.node;", str_pat, lit_pat);
277 println!(" if {}.as_str() == {:?}", str_pat, &*text.as_str())
281 ExprKind::Cast(ref expr, ref ty) => {
282 let cast_pat = self.next("expr");
283 let cast_ty = self.next("cast_ty");
284 let qp_label = self.next("qp");
286 println!("Cast(ref {}, ref {}) = {};", cast_pat, cast_ty, current);
287 if let TyKind::Path(ref qp) = ty.node {
288 println!(" if let TyKind::Path(ref {}) = {}.node;", qp_label, cast_ty);
289 self.current = qp_label;
290 self.print_qpath(qp);
292 self.current = cast_pat;
293 self.visit_expr(expr);
295 ExprKind::Type(ref expr, ref _ty) => {
296 let cast_pat = self.next("expr");
297 println!("Type(ref {}, _) = {};", cast_pat, current);
298 self.current = cast_pat;
299 self.visit_expr(expr);
301 ExprKind::If(ref cond, ref then, ref opt_else) => {
302 let cond_pat = self.next("cond");
303 let then_pat = self.next("then");
304 if let Some(ref else_) = *opt_else {
305 let else_pat = self.next("else_");
306 println!("If(ref {}, ref {}, Some(ref {})) = {};", cond_pat, then_pat, else_pat, current);
307 self.current = else_pat;
308 self.visit_expr(else_);
310 println!("If(ref {}, ref {}, None) = {};", cond_pat, then_pat, current);
312 self.current = cond_pat;
313 self.visit_expr(cond);
314 self.current = then_pat;
315 self.visit_expr(then);
317 ExprKind::While(ref cond, ref body, _) => {
318 let cond_pat = self.next("cond");
319 let body_pat = self.next("body");
320 let label_pat = self.next("label");
321 println!("While(ref {}, ref {}, ref {}) = {};", cond_pat, body_pat, label_pat, current);
322 self.current = cond_pat;
323 self.visit_expr(cond);
324 self.current = body_pat;
325 self.visit_block(body);
327 ExprKind::Loop(ref body, _, desugaring) => {
328 let body_pat = self.next("body");
329 let des = loop_desugaring_name(desugaring);
330 let label_pat = self.next("label");
331 println!("Loop(ref {}, ref {}, {}) = {};", body_pat, label_pat, des, current);
332 self.current = body_pat;
333 self.visit_block(body);
335 ExprKind::Match(ref expr, ref arms, desugaring) => {
336 let des = desugaring_name(desugaring);
337 let expr_pat = self.next("expr");
338 let arms_pat = self.next("arms");
339 println!("Match(ref {}, ref {}, {}) = {};", expr_pat, arms_pat, des, current);
340 self.current = expr_pat;
341 self.visit_expr(expr);
342 println!(" if {}.len() == {};", arms_pat, arms.len());
343 for (i, arm) in arms.iter().enumerate() {
344 self.current = format!("{}[{}].body", arms_pat, i);
345 self.visit_expr(&arm.body);
346 if let Some(ref guard) = arm.guard {
347 let guard_pat = self.next("guard");
348 println!(" if let Some(ref {}) = {}[{}].guard;", guard_pat, arms_pat, i);
350 hir::Guard::If(ref if_expr) => {
351 let if_expr_pat = self.next("expr");
352 println!(" if let Guard::If(ref {}) = {};", if_expr_pat, guard_pat);
353 self.current = if_expr_pat;
354 self.visit_expr(if_expr);
358 println!(" if {}[{}].pats.len() == {};", arms_pat, i, arm.pats.len());
359 for (j, pat) in arm.pats.iter().enumerate() {
360 self.current = format!("{}[{}].pats[{}]", arms_pat, i, j);
365 ExprKind::Closure(ref _capture_clause, ref _func, _, _, _) => {
366 println!("Closure(ref capture_clause, ref func, _, _, _) = {};", current);
367 println!(" // unimplemented: `ExprKind::Closure` is not further destructured at the moment");
369 ExprKind::Yield(ref sub) => {
370 let sub_pat = self.next("sub");
371 println!("Yield(ref sub) = {};", current);
372 self.current = sub_pat;
373 self.visit_expr(sub);
375 ExprKind::Block(ref block, _) => {
376 let block_pat = self.next("block");
377 println!("Block(ref {}) = {};", block_pat, current);
378 self.current = block_pat;
379 self.visit_block(block);
381 ExprKind::Assign(ref target, ref value) => {
382 let target_pat = self.next("target");
383 let value_pat = self.next("value");
384 println!("Assign(ref {}, ref {}) = {};", target_pat, value_pat, current);
385 self.current = target_pat;
386 self.visit_expr(target);
387 self.current = value_pat;
388 self.visit_expr(value);
390 ExprKind::AssignOp(ref op, ref target, ref value) => {
391 let op_pat = self.next("op");
392 let target_pat = self.next("target");
393 let value_pat = self.next("value");
394 println!("AssignOp(ref {}, ref {}, ref {}) = {};", op_pat, target_pat, value_pat, current);
395 println!(" if BinOpKind::{:?} == {}.node;", op.node, op_pat);
396 self.current = target_pat;
397 self.visit_expr(target);
398 self.current = value_pat;
399 self.visit_expr(value);
401 ExprKind::Field(ref object, ref field_ident) => {
402 let obj_pat = self.next("object");
403 let field_name_pat = self.next("field_name");
404 println!("Field(ref {}, ref {}) = {};", obj_pat, field_name_pat, current);
405 println!(" if {}.node.as_str() == {:?}", field_name_pat, field_ident.as_str());
406 self.current = obj_pat;
407 self.visit_expr(object);
409 ExprKind::Index(ref object, ref index) => {
410 let object_pat = self.next("object");
411 let index_pat = self.next("index");
412 println!("Index(ref {}, ref {}) = {};", object_pat, index_pat, current);
413 self.current = object_pat;
414 self.visit_expr(object);
415 self.current = index_pat;
416 self.visit_expr(index);
418 ExprKind::Path(ref path) => {
419 let path_pat = self.next("path");
420 println!("Path(ref {}) = {};", path_pat, current);
421 self.current = path_pat;
422 self.print_qpath(path);
424 ExprKind::AddrOf(mutability, ref inner) => {
425 let inner_pat = self.next("inner");
426 println!("AddrOf({:?}, ref {}) = {};", mutability, inner_pat, current);
427 self.current = inner_pat;
428 self.visit_expr(inner);
430 ExprKind::Break(ref _destination, ref opt_value) => {
431 let destination_pat = self.next("destination");
432 if let Some(ref value) = *opt_value {
433 let value_pat = self.next("value");
434 println!("Break(ref {}, Some(ref {})) = {};", destination_pat, value_pat, current);
435 self.current = value_pat;
436 self.visit_expr(value);
438 println!("Break(ref {}, None) = {};", destination_pat, current);
440 // FIXME: implement label printing
442 ExprKind::Continue(ref _destination) => {
443 let destination_pat = self.next("destination");
444 println!("Again(ref {}) = {};", destination_pat, current);
445 // FIXME: implement label printing
447 ExprKind::Ret(ref opt_value) => if let Some(ref value) = *opt_value {
448 let value_pat = self.next("value");
449 println!("Ret(Some(ref {})) = {};", value_pat, current);
450 self.current = value_pat;
451 self.visit_expr(value);
453 println!("Ret(None) = {};", current);
455 ExprKind::InlineAsm(_, ref _input, ref _output) => {
456 println!("InlineAsm(_, ref input, ref output) = {};", current);
457 println!(" // unimplemented: `ExprKind::InlineAsm` is not further destructured at the moment");
459 ExprKind::Struct(ref path, ref fields, ref opt_base) => {
460 let path_pat = self.next("path");
461 let fields_pat = self.next("fields");
462 if let Some(ref base) = *opt_base {
463 let base_pat = self.next("base");
465 "Struct(ref {}, ref {}, Some(ref {})) = {};",
471 self.current = base_pat;
472 self.visit_expr(base);
474 println!("Struct(ref {}, ref {}, None) = {};", path_pat, fields_pat, current);
476 self.current = path_pat;
477 self.print_qpath(path);
478 println!(" if {}.len() == {};", fields_pat, fields.len());
479 println!(" // unimplemented: field checks");
481 // FIXME: compute length (needs type info)
482 ExprKind::Repeat(ref value, _) => {
483 let value_pat = self.next("value");
484 println!("Repeat(ref {}, _) = {};", value_pat, current);
485 println!("// unimplemented: repeat count check");
486 self.current = value_pat;
487 self.visit_expr(value);
492 fn visit_pat(&mut self, pat: &Pat) {
493 print!(" if let PatKind::");
494 let current = format!("{}.node", self.current);
496 PatKind::Wild => println!("Wild = {};", current),
497 PatKind::Binding(anno, _, ident, ref sub) => {
498 let anno_pat = match anno {
499 BindingAnnotation::Unannotated => "BindingAnnotation::Unannotated",
500 BindingAnnotation::Mutable => "BindingAnnotation::Mutable",
501 BindingAnnotation::Ref => "BindingAnnotation::Ref",
502 BindingAnnotation::RefMut => "BindingAnnotation::RefMut",
504 let name_pat = self.next("name");
505 if let Some(ref sub) = *sub {
506 let sub_pat = self.next("sub");
507 println!("Binding({}, _, {}, Some(ref {})) = {};", anno_pat, name_pat, sub_pat, current);
508 self.current = sub_pat;
511 println!("Binding({}, _, {}, None) = {};", anno_pat, name_pat, current);
513 println!(" if {}.node.as_str() == \"{}\";", name_pat, ident.as_str());
515 PatKind::Struct(ref path, ref fields, ignore) => {
516 let path_pat = self.next("path");
517 let fields_pat = self.next("fields");
518 println!("Struct(ref {}, ref {}, {}) = {};", path_pat, fields_pat, ignore, current);
519 self.current = path_pat;
520 self.print_qpath(path);
521 println!(" if {}.len() == {};", fields_pat, fields.len());
522 println!(" // unimplemented: field checks");
524 PatKind::TupleStruct(ref path, ref fields, skip_pos) => {
525 let path_pat = self.next("path");
526 let fields_pat = self.next("fields");
527 println!("TupleStruct(ref {}, ref {}, {:?}) = {};", path_pat, fields_pat, skip_pos, current);
528 self.current = path_pat;
529 self.print_qpath(path);
530 println!(" if {}.len() == {};", fields_pat, fields.len());
531 println!(" // unimplemented: field checks");
533 PatKind::Path(ref path) => {
534 let path_pat = self.next("path");
535 println!("Path(ref {}) = {};", path_pat, current);
536 self.current = path_pat;
537 self.print_qpath(path);
539 PatKind::Tuple(ref fields, skip_pos) => {
540 let fields_pat = self.next("fields");
541 println!("Tuple(ref {}, {:?}) = {};", fields_pat, skip_pos, current);
542 println!(" if {}.len() == {};", fields_pat, fields.len());
543 println!(" // unimplemented: field checks");
545 PatKind::Box(ref pat) => {
546 let pat_pat = self.next("pat");
547 println!("Box(ref {}) = {};", pat_pat, current);
548 self.current = pat_pat;
551 PatKind::Ref(ref pat, muta) => {
552 let pat_pat = self.next("pat");
553 println!("Ref(ref {}, Mutability::{:?}) = {};", pat_pat, muta, current);
554 self.current = pat_pat;
557 PatKind::Lit(ref lit_expr) => {
558 let lit_expr_pat = self.next("lit_expr");
559 println!("Lit(ref {}) = {}", lit_expr_pat, current);
560 self.current = lit_expr_pat;
561 self.visit_expr(lit_expr);
563 PatKind::Range(ref start, ref end, end_kind) => {
564 let start_pat = self.next("start");
565 let end_pat = self.next("end");
566 println!("Range(ref {}, ref {}, RangeEnd::{:?}) = {};", start_pat, end_pat, end_kind, current);
567 self.current = start_pat;
568 self.visit_expr(start);
569 self.current = end_pat;
570 self.visit_expr(end);
572 PatKind::Slice(ref start, ref middle, ref end) => {
573 let start_pat = self.next("start");
574 let end_pat = self.next("end");
575 if let Some(ref middle) = middle {
576 let middle_pat = self.next("middle");
577 println!("Slice(ref {}, Some(ref {}), ref {}) = {};", start_pat, middle_pat, end_pat, current);
578 self.current = middle_pat;
579 self.visit_pat(middle);
581 println!("Slice(ref {}, None, ref {}) = {};", start_pat, end_pat, current);
583 println!(" if {}.len() == {};", start_pat, start.len());
584 for (i, pat) in start.iter().enumerate() {
585 self.current = format!("{}[{}]", start_pat, i);
588 println!(" if {}.len() == {};", end_pat, end.len());
589 for (i, pat) in end.iter().enumerate() {
590 self.current = format!("{}[{}]", end_pat, i);
597 fn visit_stmt(&mut self, s: &Stmt) {
598 print!(" if let StmtKind::");
599 let current = format!("{}.node", self.current);
601 // Could be an item or a local (let) binding:
602 StmtKind::Decl(ref decl, _) => {
603 let decl_pat = self.next("decl");
604 println!("Decl(ref {}, _) = {}", decl_pat, current);
605 print!(" if let DeclKind::");
606 let current = format!("{}.node", decl_pat);
608 // A local (let) binding:
609 DeclKind::Local(ref local) => {
610 let local_pat = self.next("local");
611 println!("Local(ref {}) = {};", local_pat, current);
612 if let Some(ref init) = local.init {
613 let init_pat = self.next("init");
614 println!(" if let Some(ref {}) = {}.init", init_pat, local_pat);
615 self.current = init_pat;
616 self.visit_expr(init);
618 self.current = format!("{}.pat", local_pat);
619 self.visit_pat(&local.pat);
622 DeclKind::Item(_) => {
623 println!("Item(item_id) = {};", current);
628 // Expr without trailing semi-colon (must have unit type):
629 StmtKind::Expr(ref e, _) => {
630 let e_pat = self.next("e");
631 println!("Expr(ref {}, _) = {}", e_pat, current);
632 self.current = e_pat;
636 // Expr with trailing semi-colon (may have any type):
637 StmtKind::Semi(ref e, _) => {
638 let e_pat = self.next("e");
639 println!("Semi(ref {}, _) = {}", e_pat, current);
640 self.current = e_pat;
646 fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
647 NestedVisitorMap::None
651 fn has_attr(attrs: &[Attribute]) -> bool {
652 get_attr(attrs, "author").count() > 0
655 fn desugaring_name(des: hir::MatchSource) -> String {
657 hir::MatchSource::ForLoopDesugar => "MatchSource::ForLoopDesugar".to_string(),
658 hir::MatchSource::TryDesugar => "MatchSource::TryDesugar".to_string(),
659 hir::MatchSource::WhileLetDesugar => "MatchSource::WhileLetDesugar".to_string(),
660 hir::MatchSource::Normal => "MatchSource::Normal".to_string(),
661 hir::MatchSource::IfLetDesugar { contains_else_clause } => format!("MatchSource::IfLetDesugar {{ contains_else_clause: {} }}", contains_else_clause),
665 fn loop_desugaring_name(des: hir::LoopSource) -> &'static str {
667 hir::LoopSource::ForLoop => "LoopSource::ForLoop",
668 hir::LoopSource::Loop => "LoopSource::Loop",
669 hir::LoopSource::WhileLet => "LoopSource::WhileLet",
673 fn print_path(path: &QPath, first: &mut bool) {
675 QPath::Resolved(_, ref path) => for segment in &path.segments {
681 print!("{:?}", segment.ident.as_str());
683 QPath::TypeRelative(ref ty, ref segment) => match ty.node {
684 hir::TyKind::Path(ref inner_path) => {
685 print_path(inner_path, first);
691 print!("{:?}", segment.ident.as_str());
693 ref other => print!("/* unimplemented: {:?}*/", other),