1 use crate::consts::constant_simple;
2 use crate::source::snippet_opt;
3 use rustc_ast::ast::InlineAsmTemplatePiece;
4 use rustc_data_structures::fx::FxHasher;
5 use rustc_hir::def::Res;
6 use rustc_hir::HirIdMap;
8 ArrayLen, BinOpKind, Block, BodyId, Expr, ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, Guard, HirId,
9 InlineAsmOperand, Let, Lifetime, LifetimeName, ParamName, Pat, PatField, PatKind, Path, PathSegment, QPath, Stmt,
10 StmtKind, Ty, TyKind, TypeBinding,
12 use rustc_lexer::{tokenize, TokenKind};
13 use rustc_lint::LateContext;
14 use rustc_middle::ty::TypeckResults;
15 use rustc_span::Symbol;
16 use std::hash::{Hash, Hasher};
18 /// Type used to check whether two ast are the same. This is different from the
19 /// operator `==` on ast types as this operator would compare true equality with
22 /// Note that some expressions kinds are not considered but could be added.
23 pub struct SpanlessEq<'a, 'tcx> {
24 /// Context used to evaluate constant expressions.
25 cx: &'a LateContext<'tcx>,
26 maybe_typeck_results: Option<(&'tcx TypeckResults<'tcx>, &'tcx TypeckResults<'tcx>)>,
27 allow_side_effects: bool,
28 expr_fallback: Option<Box<dyn FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a>>,
31 impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
32 pub fn new(cx: &'a LateContext<'tcx>) -> Self {
35 maybe_typeck_results: cx.maybe_typeck_results().map(|x| (x, x)),
36 allow_side_effects: true,
41 /// Consider expressions containing potential side effects as not equal.
43 pub fn deny_side_effects(self) -> Self {
45 allow_side_effects: false,
51 pub fn expr_fallback(self, expr_fallback: impl FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a) -> Self {
53 expr_fallback: Some(Box::new(expr_fallback)),
58 /// Use this method to wrap comparisons that may involve inter-expression context.
59 /// See `self.locals`.
60 pub fn inter_expr(&mut self) -> HirEqInterExpr<'_, 'a, 'tcx> {
63 locals: HirIdMap::default(),
67 pub fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
68 self.inter_expr().eq_block(left, right)
71 pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
72 self.inter_expr().eq_expr(left, right)
75 pub fn eq_path(&mut self, left: &Path<'_>, right: &Path<'_>) -> bool {
76 self.inter_expr().eq_path(left, right)
79 pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool {
80 self.inter_expr().eq_path_segment(left, right)
83 pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
84 self.inter_expr().eq_path_segments(left, right)
88 pub struct HirEqInterExpr<'a, 'b, 'tcx> {
89 inner: &'a mut SpanlessEq<'b, 'tcx>,
91 // When binding are declared, the binding ID in the left expression is mapped to the one on the
92 // right. For example, when comparing `{ let x = 1; x + 2 }` and `{ let y = 1; y + 2 }`,
93 // these blocks are considered equal since `x` is mapped to `y`.
94 locals: HirIdMap<HirId>,
97 impl HirEqInterExpr<'_, '_, '_> {
98 pub fn eq_stmt(&mut self, left: &Stmt<'_>, right: &Stmt<'_>) -> bool {
99 match (&left.kind, &right.kind) {
100 (&StmtKind::Local(l), &StmtKind::Local(r)) => {
101 // This additional check ensures that the type of the locals are equivalent even if the init
102 // expression or type have some inferred parts.
103 if let Some((typeck_lhs, typeck_rhs)) = self.inner.maybe_typeck_results {
104 let l_ty = typeck_lhs.pat_ty(l.pat);
105 let r_ty = typeck_rhs.pat_ty(r.pat);
111 // eq_pat adds the HirIds to the locals map. We therefor call it last to make sure that
112 // these only get added if the init and type is equal.
113 both(&l.init, &r.init, |l, r| self.eq_expr(l, r))
114 && both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r))
115 && self.eq_pat(l.pat, r.pat)
117 (&StmtKind::Expr(l), &StmtKind::Expr(r)) | (&StmtKind::Semi(l), &StmtKind::Semi(r)) => self.eq_expr(l, r),
122 /// Checks whether two blocks are the same.
123 fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
124 match (left.stmts, left.expr, right.stmts, right.expr) {
125 ([], None, [], None) => {
126 // For empty blocks, check to see if the tokens are equal. This will catch the case where a macro
127 // expanded to nothing, or the cfg attribute was used.
128 let (left, right) = match (
129 snippet_opt(self.inner.cx, left.span),
130 snippet_opt(self.inner.cx, right.span),
132 (Some(left), Some(right)) => (left, right),
135 let mut left_pos = 0;
136 let left = tokenize(&left)
138 let end = left_pos + t.len;
139 let s = &left[left_pos..end];
146 TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
150 let mut right_pos = 0;
151 let right = tokenize(&right)
153 let end = right_pos + t.len;
154 let s = &right[right_pos..end];
161 TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
168 over(left.stmts, right.stmts, |l, r| self.eq_stmt(l, r))
169 && both(&left.expr, &right.expr, |l, r| self.eq_expr(l, r))
174 pub fn eq_array_length(&mut self, left: ArrayLen, right: ArrayLen) -> bool {
175 match (left, right) {
176 (ArrayLen::Infer(..), ArrayLen::Infer(..)) => true,
177 (ArrayLen::Body(l_ct), ArrayLen::Body(r_ct)) => self.eq_body(l_ct.body, r_ct.body),
182 pub fn eq_body(&mut self, left: BodyId, right: BodyId) -> bool {
183 // swap out TypeckResults when hashing a body
184 let old_maybe_typeck_results = self.inner.maybe_typeck_results.replace((
185 self.inner.cx.tcx.typeck_body(left),
186 self.inner.cx.tcx.typeck_body(right),
188 let res = self.eq_expr(
189 &self.inner.cx.tcx.hir().body(left).value,
190 &self.inner.cx.tcx.hir().body(right).value,
192 self.inner.maybe_typeck_results = old_maybe_typeck_results;
196 #[expect(clippy::similar_names)]
197 pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
198 if !self.inner.allow_side_effects && left.span.ctxt() != right.span.ctxt() {
202 if let Some((typeck_lhs, typeck_rhs)) = self.inner.maybe_typeck_results {
203 if let (Some(l), Some(r)) = (
204 constant_simple(self.inner.cx, typeck_lhs, left),
205 constant_simple(self.inner.cx, typeck_rhs, right),
214 reduce_exprkind(self.inner.cx, &left.kind),
215 reduce_exprkind(self.inner.cx, &right.kind),
217 (&ExprKind::AddrOf(lb, l_mut, le), &ExprKind::AddrOf(rb, r_mut, re)) => {
218 lb == rb && l_mut == r_mut && self.eq_expr(le, re)
220 (&ExprKind::Continue(li), &ExprKind::Continue(ri)) => {
221 both(&li.label, &ri.label, |l, r| l.ident.name == r.ident.name)
223 (&ExprKind::Assign(ll, lr, _), &ExprKind::Assign(rl, rr, _)) => {
224 self.inner.allow_side_effects && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
226 (&ExprKind::AssignOp(ref lo, ll, lr), &ExprKind::AssignOp(ref ro, rl, rr)) => {
227 self.inner.allow_side_effects && lo.node == ro.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
229 (&ExprKind::Block(l, _), &ExprKind::Block(r, _)) => self.eq_block(l, r),
230 (&ExprKind::Binary(l_op, ll, lr), &ExprKind::Binary(r_op, rl, rr)) => {
231 l_op.node == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
232 || swap_binop(l_op.node, ll, lr).map_or(false, |(l_op, ll, lr)| {
233 l_op == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
236 (&ExprKind::Break(li, ref le), &ExprKind::Break(ri, ref re)) => {
237 both(&li.label, &ri.label, |l, r| l.ident.name == r.ident.name)
238 && both(le, re, |l, r| self.eq_expr(l, r))
240 (&ExprKind::Box(l), &ExprKind::Box(r)) => self.eq_expr(l, r),
241 (&ExprKind::Call(l_fun, l_args), &ExprKind::Call(r_fun, r_args)) => {
242 self.inner.allow_side_effects && self.eq_expr(l_fun, r_fun) && self.eq_exprs(l_args, r_args)
244 (&ExprKind::Cast(lx, lt), &ExprKind::Cast(rx, rt)) | (&ExprKind::Type(lx, lt), &ExprKind::Type(rx, rt)) => {
245 self.eq_expr(lx, rx) && self.eq_ty(lt, rt)
247 (&ExprKind::Field(l_f_exp, ref l_f_ident), &ExprKind::Field(r_f_exp, ref r_f_ident)) => {
248 l_f_ident.name == r_f_ident.name && self.eq_expr(l_f_exp, r_f_exp)
250 (&ExprKind::Index(la, li), &ExprKind::Index(ra, ri)) => self.eq_expr(la, ra) && self.eq_expr(li, ri),
251 (&ExprKind::If(lc, lt, ref le), &ExprKind::If(rc, rt, ref re)) => {
252 self.eq_expr(lc, rc) && self.eq_expr(lt, rt) && both(le, re, |l, r| self.eq_expr(l, r))
254 (&ExprKind::Let(l), &ExprKind::Let(r)) => {
255 self.eq_pat(l.pat, r.pat) && both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r)) && self.eq_expr(l.init, r.init)
257 (&ExprKind::Lit(ref l), &ExprKind::Lit(ref r)) => l.node == r.node,
258 (&ExprKind::Loop(lb, ref ll, ref lls, _), &ExprKind::Loop(rb, ref rl, ref rls, _)) => {
259 lls == rls && self.eq_block(lb, rb) && both(ll, rl, |l, r| l.ident.name == r.ident.name)
261 (&ExprKind::Match(le, la, ref ls), &ExprKind::Match(re, ra, ref rs)) => {
263 && self.eq_expr(le, re)
264 && over(la, ra, |l, r| {
265 self.eq_pat(l.pat, r.pat)
266 && both(&l.guard, &r.guard, |l, r| self.eq_guard(l, r))
267 && self.eq_expr(l.body, r.body)
270 (&ExprKind::MethodCall(l_path, l_args, _), &ExprKind::MethodCall(r_path, r_args, _)) => {
271 self.inner.allow_side_effects && self.eq_path_segment(l_path, r_path) && self.eq_exprs(l_args, r_args)
273 (&ExprKind::Repeat(le, ll), &ExprKind::Repeat(re, rl)) => {
274 self.eq_expr(le, re) && self.eq_array_length(ll, rl)
276 (&ExprKind::Ret(ref l), &ExprKind::Ret(ref r)) => both(l, r, |l, r| self.eq_expr(l, r)),
277 (&ExprKind::Path(ref l), &ExprKind::Path(ref r)) => self.eq_qpath(l, r),
278 (&ExprKind::Struct(l_path, lf, ref lo), &ExprKind::Struct(r_path, rf, ref ro)) => {
279 self.eq_qpath(l_path, r_path)
280 && both(lo, ro, |l, r| self.eq_expr(l, r))
281 && over(lf, rf, |l, r| self.eq_expr_field(l, r))
283 (&ExprKind::Tup(l_tup), &ExprKind::Tup(r_tup)) => self.eq_exprs(l_tup, r_tup),
284 (&ExprKind::Unary(l_op, le), &ExprKind::Unary(r_op, re)) => l_op == r_op && self.eq_expr(le, re),
285 (&ExprKind::Array(l), &ExprKind::Array(r)) => self.eq_exprs(l, r),
286 (&ExprKind::DropTemps(le), &ExprKind::DropTemps(re)) => self.eq_expr(le, re),
289 is_eq || self.inner.expr_fallback.as_mut().map_or(false, |f| f(left, right))
292 fn eq_exprs(&mut self, left: &[Expr<'_>], right: &[Expr<'_>]) -> bool {
293 over(left, right, |l, r| self.eq_expr(l, r))
296 fn eq_expr_field(&mut self, left: &ExprField<'_>, right: &ExprField<'_>) -> bool {
297 left.ident.name == right.ident.name && self.eq_expr(left.expr, right.expr)
300 fn eq_guard(&mut self, left: &Guard<'_>, right: &Guard<'_>) -> bool {
301 match (left, right) {
302 (Guard::If(l), Guard::If(r)) => self.eq_expr(l, r),
303 (Guard::IfLet(l), Guard::IfLet(r)) => {
304 self.eq_pat(l.pat, r.pat) && both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r)) && self.eq_expr(l.init, r.init)
310 fn eq_generic_arg(&mut self, left: &GenericArg<'_>, right: &GenericArg<'_>) -> bool {
311 match (left, right) {
312 (GenericArg::Const(l), GenericArg::Const(r)) => self.eq_body(l.value.body, r.value.body),
313 (GenericArg::Lifetime(l_lt), GenericArg::Lifetime(r_lt)) => Self::eq_lifetime(l_lt, r_lt),
314 (GenericArg::Type(l_ty), GenericArg::Type(r_ty)) => self.eq_ty(l_ty, r_ty),
315 (GenericArg::Infer(l_inf), GenericArg::Infer(r_inf)) => self.eq_ty(&l_inf.to_ty(), &r_inf.to_ty()),
320 fn eq_lifetime(left: &Lifetime, right: &Lifetime) -> bool {
321 left.name == right.name
324 fn eq_pat_field(&mut self, left: &PatField<'_>, right: &PatField<'_>) -> bool {
325 let (PatField { ident: li, pat: lp, .. }, PatField { ident: ri, pat: rp, .. }) = (&left, &right);
326 li.name == ri.name && self.eq_pat(lp, rp)
329 /// Checks whether two patterns are the same.
330 fn eq_pat(&mut self, left: &Pat<'_>, right: &Pat<'_>) -> bool {
331 match (&left.kind, &right.kind) {
332 (&PatKind::Box(l), &PatKind::Box(r)) => self.eq_pat(l, r),
333 (&PatKind::Struct(ref lp, la, ..), &PatKind::Struct(ref rp, ra, ..)) => {
334 self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat_field(l, r))
336 (&PatKind::TupleStruct(ref lp, la, ls), &PatKind::TupleStruct(ref rp, ra, rs)) => {
337 self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat(l, r)) && ls == rs
339 (&PatKind::Binding(lb, li, _, ref lp), &PatKind::Binding(rb, ri, _, ref rp)) => {
340 let eq = lb == rb && both(lp, rp, |l, r| self.eq_pat(l, r));
342 self.locals.insert(li, ri);
346 (&PatKind::Path(ref l), &PatKind::Path(ref r)) => self.eq_qpath(l, r),
347 (&PatKind::Lit(l), &PatKind::Lit(r)) => self.eq_expr(l, r),
348 (&PatKind::Tuple(l, ls), &PatKind::Tuple(r, rs)) => ls == rs && over(l, r, |l, r| self.eq_pat(l, r)),
349 (&PatKind::Range(ref ls, ref le, li), &PatKind::Range(ref rs, ref re, ri)) => {
350 both(ls, rs, |a, b| self.eq_expr(a, b)) && both(le, re, |a, b| self.eq_expr(a, b)) && (li == ri)
352 (&PatKind::Ref(le, ref lm), &PatKind::Ref(re, ref rm)) => lm == rm && self.eq_pat(le, re),
353 (&PatKind::Slice(ls, ref li, le), &PatKind::Slice(rs, ref ri, re)) => {
354 over(ls, rs, |l, r| self.eq_pat(l, r))
355 && over(le, re, |l, r| self.eq_pat(l, r))
356 && both(li, ri, |l, r| self.eq_pat(l, r))
358 (&PatKind::Wild, &PatKind::Wild) => true,
363 #[expect(clippy::similar_names)]
364 fn eq_qpath(&mut self, left: &QPath<'_>, right: &QPath<'_>) -> bool {
365 match (left, right) {
366 (&QPath::Resolved(ref lty, lpath), &QPath::Resolved(ref rty, rpath)) => {
367 both(lty, rty, |l, r| self.eq_ty(l, r)) && self.eq_path(lpath, rpath)
369 (&QPath::TypeRelative(lty, lseg), &QPath::TypeRelative(rty, rseg)) => {
370 self.eq_ty(lty, rty) && self.eq_path_segment(lseg, rseg)
372 (&QPath::LangItem(llang_item, ..), &QPath::LangItem(rlang_item, ..)) => llang_item == rlang_item,
377 pub fn eq_path(&mut self, left: &Path<'_>, right: &Path<'_>) -> bool {
378 match (left.res, right.res) {
379 (Res::Local(l), Res::Local(r)) => l == r || self.locals.get(&l) == Some(&r),
380 (Res::Local(_), _) | (_, Res::Local(_)) => false,
381 _ => over(left.segments, right.segments, |l, r| self.eq_path_segment(l, r)),
385 fn eq_path_parameters(&mut self, left: &GenericArgs<'_>, right: &GenericArgs<'_>) -> bool {
386 if !(left.parenthesized || right.parenthesized) {
387 over(left.args, right.args, |l, r| self.eq_generic_arg(l, r)) // FIXME(flip1995): may not work
388 && over(left.bindings, right.bindings, |l, r| self.eq_type_binding(l, r))
389 } else if left.parenthesized && right.parenthesized {
390 over(left.inputs(), right.inputs(), |l, r| self.eq_ty(l, r))
391 && both(&Some(&left.bindings[0].ty()), &Some(&right.bindings[0].ty()), |l, r| {
399 pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
400 left.len() == right.len() && left.iter().zip(right).all(|(l, r)| self.eq_path_segment(l, r))
403 pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool {
404 // The == of idents doesn't work with different contexts,
405 // we have to be explicit about hygiene
406 left.ident.name == right.ident.name && both(&left.args, &right.args, |l, r| self.eq_path_parameters(l, r))
409 pub fn eq_ty(&mut self, left: &Ty<'_>, right: &Ty<'_>) -> bool {
410 match (&left.kind, &right.kind) {
411 (&TyKind::Slice(l_vec), &TyKind::Slice(r_vec)) => self.eq_ty(l_vec, r_vec),
412 (&TyKind::Array(lt, ll), &TyKind::Array(rt, rl)) => self.eq_ty(lt, rt) && self.eq_array_length(ll, rl),
413 (&TyKind::Ptr(ref l_mut), &TyKind::Ptr(ref r_mut)) => {
414 l_mut.mutbl == r_mut.mutbl && self.eq_ty(l_mut.ty, r_mut.ty)
416 (&TyKind::Rptr(_, ref l_rmut), &TyKind::Rptr(_, ref r_rmut)) => {
417 l_rmut.mutbl == r_rmut.mutbl && self.eq_ty(l_rmut.ty, r_rmut.ty)
419 (&TyKind::Path(ref l), &TyKind::Path(ref r)) => self.eq_qpath(l, r),
420 (&TyKind::Tup(l), &TyKind::Tup(r)) => over(l, r, |l, r| self.eq_ty(l, r)),
421 (&TyKind::Infer, &TyKind::Infer) => true,
426 fn eq_type_binding(&mut self, left: &TypeBinding<'_>, right: &TypeBinding<'_>) -> bool {
427 left.ident.name == right.ident.name && self.eq_ty(left.ty(), right.ty())
431 /// Some simple reductions like `{ return }` => `return`
432 fn reduce_exprkind<'hir>(cx: &LateContext<'_>, kind: &'hir ExprKind<'hir>) -> &'hir ExprKind<'hir> {
433 if let ExprKind::Block(block, _) = kind {
434 match (block.stmts, block.expr) {
435 // From an `if let` expression without an `else` block. The arm for the implicit wild pattern is an empty
436 // block with an empty span.
437 ([], None) if block.span.is_empty() => &ExprKind::Tup(&[]),
439 ([], None) => match snippet_opt(cx, block.span) {
440 // Don't reduce if there are any tokens contained in the braces
447 TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
450 .ne([TokenKind::OpenBrace, TokenKind::CloseBrace].iter().copied()) =>
454 _ => &ExprKind::Tup(&[]),
456 ([], Some(expr)) => match expr.kind {
457 // `{ return .. }` => `return ..`
458 ExprKind::Ret(..) => &expr.kind,
461 ([stmt], None) => match stmt.kind {
462 StmtKind::Expr(expr) | StmtKind::Semi(expr) => match expr.kind {
463 // `{ return ..; }` => `return ..`
464 ExprKind::Ret(..) => &expr.kind,
480 ) -> Option<(BinOpKind, &'a Expr<'a>, &'a Expr<'a>)> {
482 BinOpKind::Add | BinOpKind::Eq | BinOpKind::Ne | BinOpKind::BitAnd | BinOpKind::BitXor | BinOpKind::BitOr => {
483 Some((binop, rhs, lhs))
485 BinOpKind::Lt => Some((BinOpKind::Gt, rhs, lhs)),
486 BinOpKind::Le => Some((BinOpKind::Ge, rhs, lhs)),
487 BinOpKind::Ge => Some((BinOpKind::Le, rhs, lhs)),
488 BinOpKind::Gt => Some((BinOpKind::Lt, rhs, lhs)),
489 BinOpKind::Mul // Not always commutative, e.g. with matrices. See issue #5698
496 | BinOpKind::Or => None,
500 /// Checks if the two `Option`s are both `None` or some equal values as per
502 pub fn both<X>(l: &Option<X>, r: &Option<X>, mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
504 .map_or_else(|| r.is_none(), |x| r.as_ref().map_or(false, |y| eq_fn(x, y)))
507 /// Checks if two slices are equal as per `eq_fn`.
508 pub fn over<X>(left: &[X], right: &[X], mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
509 left.len() == right.len() && left.iter().zip(right).all(|(x, y)| eq_fn(x, y))
512 /// Counts how many elements of the slices are equal as per `eq_fn`.
513 pub fn count_eq<X: Sized>(
514 left: &mut dyn Iterator<Item = X>,
515 right: &mut dyn Iterator<Item = X>,
516 mut eq_fn: impl FnMut(&X, &X) -> bool,
518 left.zip(right).take_while(|(l, r)| eq_fn(l, r)).count()
521 /// Checks if two expressions evaluate to the same value, and don't contain any side effects.
522 pub fn eq_expr_value(cx: &LateContext<'_>, left: &Expr<'_>, right: &Expr<'_>) -> bool {
523 SpanlessEq::new(cx).deny_side_effects().eq_expr(left, right)
526 /// Type used to hash an ast element. This is different from the `Hash` trait
527 /// on ast types as this
528 /// trait would consider IDs and spans.
530 /// All expressions kind are hashed, but some might have a weaker hash.
531 pub struct SpanlessHash<'a, 'tcx> {
532 /// Context used to evaluate constant expressions.
533 cx: &'a LateContext<'tcx>,
534 maybe_typeck_results: Option<&'tcx TypeckResults<'tcx>>,
538 impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
539 pub fn new(cx: &'a LateContext<'tcx>) -> Self {
542 maybe_typeck_results: cx.maybe_typeck_results(),
543 s: FxHasher::default(),
547 pub fn finish(self) -> u64 {
551 pub fn hash_block(&mut self, b: &Block<'_>) {
556 if let Some(e) = b.expr {
560 std::mem::discriminant(&b.rules).hash(&mut self.s);
563 #[expect(clippy::too_many_lines)]
564 pub fn hash_expr(&mut self, e: &Expr<'_>) {
565 let simple_const = self
566 .maybe_typeck_results
567 .and_then(|typeck_results| constant_simple(self.cx, typeck_results, e));
569 // const hashing may result in the same hash as some unrelated node, so add a sort of
570 // discriminant depending on which path we're choosing next
571 simple_const.hash(&mut self.s);
572 if simple_const.is_some() {
576 std::mem::discriminant(&e.kind).hash(&mut self.s);
579 ExprKind::AddrOf(kind, m, e) => {
580 std::mem::discriminant(&kind).hash(&mut self.s);
584 ExprKind::Continue(i) => {
585 if let Some(i) = i.label {
586 self.hash_name(i.ident.name);
589 ExprKind::Assign(l, r, _) => {
593 ExprKind::AssignOp(ref o, l, r) => {
594 std::mem::discriminant(&o.node).hash(&mut self.s);
598 ExprKind::Block(b, _) => {
601 ExprKind::Binary(op, l, r) => {
602 std::mem::discriminant(&op.node).hash(&mut self.s);
606 ExprKind::Break(i, ref j) => {
607 if let Some(i) = i.label {
608 self.hash_name(i.ident.name);
610 if let Some(j) = *j {
614 ExprKind::Box(e) | ExprKind::DropTemps(e) | ExprKind::Yield(e, _) => {
617 ExprKind::Call(fun, args) => {
619 self.hash_exprs(args);
621 ExprKind::Cast(e, ty) | ExprKind::Type(e, ty) => {
625 ExprKind::Closure(cap, _, eid, _, _) => {
626 std::mem::discriminant(&cap).hash(&mut self.s);
627 // closures inherit TypeckResults
628 self.hash_expr(&self.cx.tcx.hir().body(eid).value);
630 ExprKind::Field(e, ref f) => {
632 self.hash_name(f.name);
634 ExprKind::Index(a, i) => {
638 ExprKind::InlineAsm(asm) => {
639 for piece in asm.template {
641 InlineAsmTemplatePiece::String(s) => s.hash(&mut self.s),
642 InlineAsmTemplatePiece::Placeholder {
647 operand_idx.hash(&mut self.s);
648 modifier.hash(&mut self.s);
652 asm.options.hash(&mut self.s);
653 for (op, _op_sp) in asm.operands {
655 InlineAsmOperand::In { reg, expr } => {
656 reg.hash(&mut self.s);
657 self.hash_expr(expr);
659 InlineAsmOperand::Out { reg, late, expr } => {
660 reg.hash(&mut self.s);
661 late.hash(&mut self.s);
662 if let Some(expr) = expr {
663 self.hash_expr(expr);
666 InlineAsmOperand::InOut { reg, late, expr } => {
667 reg.hash(&mut self.s);
668 late.hash(&mut self.s);
669 self.hash_expr(expr);
671 InlineAsmOperand::SplitInOut {
677 reg.hash(&mut self.s);
678 late.hash(&mut self.s);
679 self.hash_expr(in_expr);
680 if let Some(out_expr) = out_expr {
681 self.hash_expr(out_expr);
684 InlineAsmOperand::Const { anon_const } | InlineAsmOperand::SymFn { anon_const } => {
685 self.hash_body(anon_const.body);
687 InlineAsmOperand::SymStatic { path, def_id: _ } => self.hash_qpath(path),
691 ExprKind::Let(Let { pat, init, ty, .. }) => {
692 self.hash_expr(init);
693 if let Some(ty) = ty {
699 ExprKind::Lit(ref l) => {
700 l.node.hash(&mut self.s);
702 ExprKind::Loop(b, ref i, ..) => {
704 if let Some(i) = *i {
705 self.hash_name(i.ident.name);
708 ExprKind::If(cond, then, ref else_opt) => {
709 self.hash_expr(cond);
710 self.hash_expr(then);
711 if let Some(e) = *else_opt {
715 ExprKind::Match(e, arms, ref s) => {
719 self.hash_pat(arm.pat);
720 if let Some(ref e) = arm.guard {
723 self.hash_expr(arm.body);
728 ExprKind::MethodCall(path, args, ref _fn_span) => {
729 self.hash_name(path.ident.name);
730 self.hash_exprs(args);
732 ExprKind::ConstBlock(ref l_id) => {
733 self.hash_body(l_id.body);
735 ExprKind::Repeat(e, len) => {
737 self.hash_array_length(len);
739 ExprKind::Ret(ref e) => {
740 if let Some(e) = *e {
744 ExprKind::Path(ref qpath) => {
745 self.hash_qpath(qpath);
747 ExprKind::Struct(path, fields, ref expr) => {
748 self.hash_qpath(path);
751 self.hash_name(f.ident.name);
752 self.hash_expr(f.expr);
755 if let Some(e) = *expr {
759 ExprKind::Tup(tup) => {
760 self.hash_exprs(tup);
762 ExprKind::Array(v) => {
765 ExprKind::Unary(lop, le) => {
766 std::mem::discriminant(&lop).hash(&mut self.s);
772 pub fn hash_exprs(&mut self, e: &[Expr<'_>]) {
778 pub fn hash_name(&mut self, n: Symbol) {
782 pub fn hash_qpath(&mut self, p: &QPath<'_>) {
784 QPath::Resolved(_, path) => {
785 self.hash_path(path);
787 QPath::TypeRelative(_, path) => {
788 self.hash_name(path.ident.name);
790 QPath::LangItem(lang_item, ..) => {
791 std::mem::discriminant(&lang_item).hash(&mut self.s);
794 // self.maybe_typeck_results.unwrap().qpath_res(p, id).hash(&mut self.s);
797 pub fn hash_pat(&mut self, pat: &Pat<'_>) {
798 std::mem::discriminant(&pat.kind).hash(&mut self.s);
800 PatKind::Binding(ann, _, _, pat) => {
801 std::mem::discriminant(&ann).hash(&mut self.s);
802 if let Some(pat) = pat {
806 PatKind::Box(pat) => self.hash_pat(pat),
807 PatKind::Lit(expr) => self.hash_expr(expr),
808 PatKind::Or(pats) => {
813 PatKind::Path(ref qpath) => self.hash_qpath(qpath),
814 PatKind::Range(s, e, i) => {
821 std::mem::discriminant(&i).hash(&mut self.s);
823 PatKind::Ref(pat, mu) => {
825 std::mem::discriminant(&mu).hash(&mut self.s);
827 PatKind::Slice(l, m, r) => {
831 if let Some(pat) = m {
838 PatKind::Struct(ref qpath, fields, e) => {
839 self.hash_qpath(qpath);
841 self.hash_name(f.ident.name);
842 self.hash_pat(f.pat);
846 PatKind::Tuple(pats, e) => {
852 PatKind::TupleStruct(ref qpath, pats, e) => {
853 self.hash_qpath(qpath);
863 pub fn hash_path(&mut self, path: &Path<'_>) {
865 // constant hash since equality is dependant on inter-expression context
866 // e.g. The expressions `if let Some(x) = foo() {}` and `if let Some(y) = foo() {}` are considered equal
867 // even though the binding names are different and they have different `HirId`s.
868 Res::Local(_) => 1_usize.hash(&mut self.s),
870 for seg in path.segments {
871 self.hash_name(seg.ident.name);
872 self.hash_generic_args(seg.args().args);
878 pub fn hash_stmt(&mut self, b: &Stmt<'_>) {
879 std::mem::discriminant(&b.kind).hash(&mut self.s);
882 StmtKind::Local(local) => {
883 self.hash_pat(local.pat);
884 if let Some(init) = local.init {
885 self.hash_expr(init);
888 StmtKind::Item(..) => {},
889 StmtKind::Expr(expr) | StmtKind::Semi(expr) => {
890 self.hash_expr(expr);
895 pub fn hash_guard(&mut self, g: &Guard<'_>) {
897 Guard::If(expr) | Guard::IfLet(Let { init: expr, .. }) => {
898 self.hash_expr(expr);
903 pub fn hash_lifetime(&mut self, lifetime: Lifetime) {
904 std::mem::discriminant(&lifetime.name).hash(&mut self.s);
905 if let LifetimeName::Param(param_id, ref name) = lifetime.name {
906 std::mem::discriminant(name).hash(&mut self.s);
907 param_id.hash(&mut self.s);
909 ParamName::Plain(ref ident) => {
910 ident.name.hash(&mut self.s);
912 ParamName::Fresh | ParamName::Error => {},
917 pub fn hash_ty(&mut self, ty: &Ty<'_>) {
918 std::mem::discriminant(&ty.kind).hash(&mut self.s);
919 self.hash_tykind(&ty.kind);
922 pub fn hash_tykind(&mut self, ty: &TyKind<'_>) {
924 TyKind::Slice(ty) => {
927 &TyKind::Array(ty, len) => {
929 self.hash_array_length(len);
931 TyKind::Ptr(ref mut_ty) => {
932 self.hash_ty(mut_ty.ty);
933 mut_ty.mutbl.hash(&mut self.s);
935 TyKind::Rptr(lifetime, ref mut_ty) => {
936 self.hash_lifetime(*lifetime);
937 self.hash_ty(mut_ty.ty);
938 mut_ty.mutbl.hash(&mut self.s);
940 TyKind::BareFn(bfn) => {
941 bfn.unsafety.hash(&mut self.s);
942 bfn.abi.hash(&mut self.s);
943 for arg in bfn.decl.inputs {
946 std::mem::discriminant(&bfn.decl.output).hash(&mut self.s);
947 match bfn.decl.output {
948 FnRetTy::DefaultReturn(_) => {},
949 FnRetTy::Return(ty) => {
953 bfn.decl.c_variadic.hash(&mut self.s);
955 TyKind::Tup(ty_list) => {
960 TyKind::Path(ref qpath) => self.hash_qpath(qpath),
961 TyKind::OpaqueDef(_, arg_list) => {
962 self.hash_generic_args(arg_list);
964 TyKind::TraitObject(_, lifetime, _) => {
965 self.hash_lifetime(*lifetime);
967 TyKind::Typeof(anon_const) => {
968 self.hash_body(anon_const.body);
970 TyKind::Err | TyKind::Infer | TyKind::Never => {},
974 pub fn hash_array_length(&mut self, length: ArrayLen) {
976 ArrayLen::Infer(..) => {},
977 ArrayLen::Body(anon_const) => self.hash_body(anon_const.body),
981 pub fn hash_body(&mut self, body_id: BodyId) {
982 // swap out TypeckResults when hashing a body
983 let old_maybe_typeck_results = self.maybe_typeck_results.replace(self.cx.tcx.typeck_body(body_id));
984 self.hash_expr(&self.cx.tcx.hir().body(body_id).value);
985 self.maybe_typeck_results = old_maybe_typeck_results;
988 fn hash_generic_args(&mut self, arg_list: &[GenericArg<'_>]) {
989 for arg in arg_list {
991 GenericArg::Lifetime(l) => self.hash_lifetime(l),
992 GenericArg::Type(ref ty) => self.hash_ty(ty),
993 GenericArg::Const(ref ca) => self.hash_body(ca.value.body),
994 GenericArg::Infer(ref inf) => self.hash_ty(&inf.to_ty()),