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-rw-r--r--src/tools/clippy/clippy_utils/src/hir_utils.rs1031
1 files changed, 1031 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_utils/src/hir_utils.rs b/src/tools/clippy/clippy_utils/src/hir_utils.rs
new file mode 100644
index 000000000..1834e2a2d
--- /dev/null
+++ b/src/tools/clippy/clippy_utils/src/hir_utils.rs
@@ -0,0 +1,1031 @@
+use crate::consts::constant_simple;
+use crate::macros::macro_backtrace;
+use crate::source::snippet_opt;
+use rustc_ast::ast::InlineAsmTemplatePiece;
+use rustc_data_structures::fx::FxHasher;
+use rustc_hir::def::Res;
+use rustc_hir::HirIdMap;
+use rustc_hir::{
+ ArrayLen, BinOpKind, Block, BodyId, Closure, Expr, ExprField, ExprKind, FnRetTy, GenericArg, GenericArgs, Guard,
+ HirId, InlineAsmOperand, Let, Lifetime, LifetimeName, ParamName, Pat, PatField, PatKind, Path, PathSegment, QPath,
+ Stmt, StmtKind, Ty, TyKind, TypeBinding,
+};
+use rustc_lexer::{tokenize, TokenKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::TypeckResults;
+use rustc_span::{sym, Symbol};
+use std::hash::{Hash, Hasher};
+
+/// Callback that is called when two expressions are not equal in the sense of `SpanlessEq`, but
+/// other conditions would make them equal.
+type SpanlessEqCallback<'a> = dyn FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a;
+
+/// Type used to check whether two ast are the same. This is different from the
+/// operator `==` on ast types as this operator would compare true equality with
+/// ID and span.
+///
+/// Note that some expressions kinds are not considered but could be added.
+pub struct SpanlessEq<'a, 'tcx> {
+ /// Context used to evaluate constant expressions.
+ cx: &'a LateContext<'tcx>,
+ maybe_typeck_results: Option<(&'tcx TypeckResults<'tcx>, &'tcx TypeckResults<'tcx>)>,
+ allow_side_effects: bool,
+ expr_fallback: Option<Box<SpanlessEqCallback<'a>>>,
+}
+
+impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
+ pub fn new(cx: &'a LateContext<'tcx>) -> Self {
+ Self {
+ cx,
+ maybe_typeck_results: cx.maybe_typeck_results().map(|x| (x, x)),
+ allow_side_effects: true,
+ expr_fallback: None,
+ }
+ }
+
+ /// Consider expressions containing potential side effects as not equal.
+ #[must_use]
+ pub fn deny_side_effects(self) -> Self {
+ Self {
+ allow_side_effects: false,
+ ..self
+ }
+ }
+
+ #[must_use]
+ pub fn expr_fallback(self, expr_fallback: impl FnMut(&Expr<'_>, &Expr<'_>) -> bool + 'a) -> Self {
+ Self {
+ expr_fallback: Some(Box::new(expr_fallback)),
+ ..self
+ }
+ }
+
+ /// Use this method to wrap comparisons that may involve inter-expression context.
+ /// See `self.locals`.
+ pub fn inter_expr(&mut self) -> HirEqInterExpr<'_, 'a, 'tcx> {
+ HirEqInterExpr {
+ inner: self,
+ locals: HirIdMap::default(),
+ }
+ }
+
+ pub fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
+ self.inter_expr().eq_block(left, right)
+ }
+
+ pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
+ self.inter_expr().eq_expr(left, right)
+ }
+
+ pub fn eq_path(&mut self, left: &Path<'_>, right: &Path<'_>) -> bool {
+ self.inter_expr().eq_path(left, right)
+ }
+
+ pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool {
+ self.inter_expr().eq_path_segment(left, right)
+ }
+
+ pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
+ self.inter_expr().eq_path_segments(left, right)
+ }
+}
+
+pub struct HirEqInterExpr<'a, 'b, 'tcx> {
+ inner: &'a mut SpanlessEq<'b, 'tcx>,
+
+ // When binding are declared, the binding ID in the left expression is mapped to the one on the
+ // right. For example, when comparing `{ let x = 1; x + 2 }` and `{ let y = 1; y + 2 }`,
+ // these blocks are considered equal since `x` is mapped to `y`.
+ pub locals: HirIdMap<HirId>,
+}
+
+impl HirEqInterExpr<'_, '_, '_> {
+ pub fn eq_stmt(&mut self, left: &Stmt<'_>, right: &Stmt<'_>) -> bool {
+ match (&left.kind, &right.kind) {
+ (&StmtKind::Local(l), &StmtKind::Local(r)) => {
+ // This additional check ensures that the type of the locals are equivalent even if the init
+ // expression or type have some inferred parts.
+ if let Some((typeck_lhs, typeck_rhs)) = self.inner.maybe_typeck_results {
+ let l_ty = typeck_lhs.pat_ty(l.pat);
+ let r_ty = typeck_rhs.pat_ty(r.pat);
+ if l_ty != r_ty {
+ return false;
+ }
+ }
+
+ // eq_pat adds the HirIds to the locals map. We therefor call it last to make sure that
+ // these only get added if the init and type is equal.
+ both(&l.init, &r.init, |l, r| self.eq_expr(l, r))
+ && both(&l.ty, &r.ty, |l, r| self.eq_ty(l, r))
+ && both(&l.els, &r.els, |l, r| self.eq_block(l, r))
+ && self.eq_pat(l.pat, r.pat)
+ },
+ (&StmtKind::Expr(l), &StmtKind::Expr(r)) | (&StmtKind::Semi(l), &StmtKind::Semi(r)) => self.eq_expr(l, r),
+ _ => false,
+ }
+ }
+
+ /// Checks whether two blocks are the same.
+ fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
+ match (left.stmts, left.expr, right.stmts, right.expr) {
+ ([], None, [], None) => {
+ // For empty blocks, check to see if the tokens are equal. This will catch the case where a macro
+ // expanded to nothing, or the cfg attribute was used.
+ let (left, right) = match (
+ snippet_opt(self.inner.cx, left.span),
+ snippet_opt(self.inner.cx, right.span),
+ ) {
+ (Some(left), Some(right)) => (left, right),
+ _ => return true,
+ };
+ let mut left_pos = 0;
+ let left = tokenize(&left)
+ .map(|t| {
+ let end = left_pos + t.len as usize;
+ let s = &left[left_pos..end];
+ left_pos = end;
+ (t, s)
+ })
+ .filter(|(t, _)| {
+ !matches!(
+ t.kind,
+ TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
+ )
+ })
+ .map(|(_, s)| s);
+ let mut right_pos = 0;
+ let right = tokenize(&right)
+ .map(|t| {
+ let end = right_pos + t.len as usize;
+ let s = &right[right_pos..end];
+ right_pos = end;
+ (t, s)
+ })
+ .filter(|(t, _)| {
+ !matches!(
+ t.kind,
+ TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
+ )
+ })
+ .map(|(_, s)| s);
+ left.eq(right)
+ },
+ _ => {
+ over(left.stmts, right.stmts, |l, r| self.eq_stmt(l, r))
+ && both(&left.expr, &right.expr, |l, r| self.eq_expr(l, r))
+ },
+ }
+ }
+
+ fn should_ignore(&mut self, expr: &Expr<'_>) -> bool {
+ macro_backtrace(expr.span).last().map_or(false, |macro_call| {
+ matches!(
+ &self.inner.cx.tcx.get_diagnostic_name(macro_call.def_id),
+ Some(sym::todo_macro | sym::unimplemented_macro)
+ )
+ })
+ }
+
+ pub fn eq_array_length(&mut self, left: ArrayLen, right: ArrayLen) -> bool {
+ match (left, right) {
+ (ArrayLen::Infer(..), ArrayLen::Infer(..)) => true,
+ (ArrayLen::Body(l_ct), ArrayLen::Body(r_ct)) => self.eq_body(l_ct.body, r_ct.body),
+ (_, _) => false,
+ }
+ }
+
+ pub fn eq_body(&mut self, left: BodyId, right: BodyId) -> bool {
+ // swap out TypeckResults when hashing a body
+ let old_maybe_typeck_results = self.inner.maybe_typeck_results.replace((
+ self.inner.cx.tcx.typeck_body(left),
+ self.inner.cx.tcx.typeck_body(right),
+ ));
+ let res = self.eq_expr(
+ &self.inner.cx.tcx.hir().body(left).value,
+ &self.inner.cx.tcx.hir().body(right).value,
+ );
+ self.inner.maybe_typeck_results = old_maybe_typeck_results;
+ res
+ }
+
+ #[expect(clippy::similar_names)]
+ pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
+ if !self.inner.allow_side_effects && left.span.ctxt() != right.span.ctxt() {
+ return false;
+ }
+
+ if let Some((typeck_lhs, typeck_rhs)) = self.inner.maybe_typeck_results {
+ if let (Some(l), Some(r)) = (
+ constant_simple(self.inner.cx, typeck_lhs, left),
+ constant_simple(self.inner.cx, typeck_rhs, right),
+ ) {
+ if l == r {
+ return true;
+ }
+ }
+ }
+
+ let is_eq = match (
+ reduce_exprkind(self.inner.cx, &left.kind),
+ reduce_exprkind(self.inner.cx, &right.kind),
+ ) {
+ (&ExprKind::AddrOf(lb, l_mut, le), &ExprKind::AddrOf(rb, r_mut, re)) => {
+ lb == rb && l_mut == r_mut && self.eq_expr(le, re)
+ },
+ (&ExprKind::Continue(li), &ExprKind::Continue(ri)) => {
+ both(&li.label, &ri.label, |l, r| l.ident.name == r.ident.name)
+ },
+ (&ExprKind::Assign(ll, lr, _), &ExprKind::Assign(rl, rr, _)) => {
+ self.inner.allow_side_effects && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
+ },
+ (&ExprKind::AssignOp(ref lo, ll, lr), &ExprKind::AssignOp(ref ro, rl, rr)) => {
+ self.inner.allow_side_effects && lo.node == ro.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
+ },
+ (&ExprKind::Block(l, _), &ExprKind::Block(r, _)) => self.eq_block(l, r),
+ (&ExprKind::Binary(l_op, ll, lr), &ExprKind::Binary(r_op, rl, rr)) => {
+ l_op.node == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
+ || swap_binop(l_op.node, ll, lr).map_or(false, |(l_op, ll, lr)| {
+ l_op == r_op.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
+ })
+ },
+ (&ExprKind::Break(li, ref le), &ExprKind::Break(ri, ref re)) => {
+ both(&li.label, &ri.label, |l, r| l.ident.name == r.ident.name)
+ && both(le, re, |l, r| self.eq_expr(l, r))
+ },
+ (&ExprKind::Box(l), &ExprKind::Box(r)) => self.eq_expr(l, r),
+ (&ExprKind::Call(l_fun, l_args), &ExprKind::Call(r_fun, r_args)) => {
+ self.inner.allow_side_effects && self.eq_expr(l_fun, r_fun) && self.eq_exprs(l_args, r_args)
+ },
+ (&ExprKind::Cast(lx, lt), &ExprKind::Cast(rx, rt)) | (&ExprKind::Type(lx, lt), &ExprKind::Type(rx, rt)) => {
+ self.eq_expr(lx, rx) && self.eq_ty(lt, rt)
+ },
+ (&ExprKind::Field(l_f_exp, ref l_f_ident), &ExprKind::Field(r_f_exp, ref r_f_ident)) => {
+ l_f_ident.name == r_f_ident.name && self.eq_expr(l_f_exp, r_f_exp)
+ },
+ (&ExprKind::Index(la, li), &ExprKind::Index(ra, ri)) => self.eq_expr(la, ra) && self.eq_expr(li, ri),
+ (&ExprKind::If(lc, lt, ref le), &ExprKind::If(rc, rt, ref re)) => {
+ self.eq_expr(lc, rc) && self.eq_expr(lt, rt) && both(le, re, |l, r| self.eq_expr(l, r))
+ },
+ (&ExprKind::Let(l), &ExprKind::Let(r)) => {
+ 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)
+ },
+ (&ExprKind::Lit(ref l), &ExprKind::Lit(ref r)) => l.node == r.node,
+ (&ExprKind::Loop(lb, ref ll, ref lls, _), &ExprKind::Loop(rb, ref rl, ref rls, _)) => {
+ lls == rls && self.eq_block(lb, rb) && both(ll, rl, |l, r| l.ident.name == r.ident.name)
+ },
+ (&ExprKind::Match(le, la, ref ls), &ExprKind::Match(re, ra, ref rs)) => {
+ ls == rs
+ && self.eq_expr(le, re)
+ && over(la, ra, |l, r| {
+ self.eq_pat(l.pat, r.pat)
+ && both(&l.guard, &r.guard, |l, r| self.eq_guard(l, r))
+ && self.eq_expr(l.body, r.body)
+ })
+ },
+ (&ExprKind::MethodCall(l_path, l_args, _), &ExprKind::MethodCall(r_path, r_args, _)) => {
+ self.inner.allow_side_effects && self.eq_path_segment(l_path, r_path) && self.eq_exprs(l_args, r_args)
+ },
+ (&ExprKind::Repeat(le, ll), &ExprKind::Repeat(re, rl)) => {
+ self.eq_expr(le, re) && self.eq_array_length(ll, rl)
+ },
+ (&ExprKind::Ret(ref l), &ExprKind::Ret(ref r)) => both(l, r, |l, r| self.eq_expr(l, r)),
+ (&ExprKind::Path(ref l), &ExprKind::Path(ref r)) => self.eq_qpath(l, r),
+ (&ExprKind::Struct(l_path, lf, ref lo), &ExprKind::Struct(r_path, rf, ref ro)) => {
+ self.eq_qpath(l_path, r_path)
+ && both(lo, ro, |l, r| self.eq_expr(l, r))
+ && over(lf, rf, |l, r| self.eq_expr_field(l, r))
+ },
+ (&ExprKind::Tup(l_tup), &ExprKind::Tup(r_tup)) => self.eq_exprs(l_tup, r_tup),
+ (&ExprKind::Unary(l_op, le), &ExprKind::Unary(r_op, re)) => l_op == r_op && self.eq_expr(le, re),
+ (&ExprKind::Array(l), &ExprKind::Array(r)) => self.eq_exprs(l, r),
+ (&ExprKind::DropTemps(le), &ExprKind::DropTemps(re)) => self.eq_expr(le, re),
+ _ => false,
+ };
+ (is_eq && (!self.should_ignore(left) || !self.should_ignore(right)))
+ || self.inner.expr_fallback.as_mut().map_or(false, |f| f(left, right))
+ }
+
+ fn eq_exprs(&mut self, left: &[Expr<'_>], right: &[Expr<'_>]) -> bool {
+ over(left, right, |l, r| self.eq_expr(l, r))
+ }
+
+ fn eq_expr_field(&mut self, left: &ExprField<'_>, right: &ExprField<'_>) -> bool {
+ left.ident.name == right.ident.name && self.eq_expr(left.expr, right.expr)
+ }
+
+ fn eq_guard(&mut self, left: &Guard<'_>, right: &Guard<'_>) -> bool {
+ match (left, right) {
+ (Guard::If(l), Guard::If(r)) => self.eq_expr(l, r),
+ (Guard::IfLet(l), Guard::IfLet(r)) => {
+ 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)
+ },
+ _ => false,
+ }
+ }
+
+ fn eq_generic_arg(&mut self, left: &GenericArg<'_>, right: &GenericArg<'_>) -> bool {
+ match (left, right) {
+ (GenericArg::Const(l), GenericArg::Const(r)) => self.eq_body(l.value.body, r.value.body),
+ (GenericArg::Lifetime(l_lt), GenericArg::Lifetime(r_lt)) => Self::eq_lifetime(l_lt, r_lt),
+ (GenericArg::Type(l_ty), GenericArg::Type(r_ty)) => self.eq_ty(l_ty, r_ty),
+ (GenericArg::Infer(l_inf), GenericArg::Infer(r_inf)) => self.eq_ty(&l_inf.to_ty(), &r_inf.to_ty()),
+ _ => false,
+ }
+ }
+
+ fn eq_lifetime(left: &Lifetime, right: &Lifetime) -> bool {
+ left.name == right.name
+ }
+
+ fn eq_pat_field(&mut self, left: &PatField<'_>, right: &PatField<'_>) -> bool {
+ let (PatField { ident: li, pat: lp, .. }, PatField { ident: ri, pat: rp, .. }) = (&left, &right);
+ li.name == ri.name && self.eq_pat(lp, rp)
+ }
+
+ /// Checks whether two patterns are the same.
+ fn eq_pat(&mut self, left: &Pat<'_>, right: &Pat<'_>) -> bool {
+ match (&left.kind, &right.kind) {
+ (&PatKind::Box(l), &PatKind::Box(r)) => self.eq_pat(l, r),
+ (&PatKind::Struct(ref lp, la, ..), &PatKind::Struct(ref rp, ra, ..)) => {
+ self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat_field(l, r))
+ },
+ (&PatKind::TupleStruct(ref lp, la, ls), &PatKind::TupleStruct(ref rp, ra, rs)) => {
+ self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat(l, r)) && ls == rs
+ },
+ (&PatKind::Binding(lb, li, _, ref lp), &PatKind::Binding(rb, ri, _, ref rp)) => {
+ let eq = lb == rb && both(lp, rp, |l, r| self.eq_pat(l, r));
+ if eq {
+ self.locals.insert(li, ri);
+ }
+ eq
+ },
+ (&PatKind::Path(ref l), &PatKind::Path(ref r)) => self.eq_qpath(l, r),
+ (&PatKind::Lit(l), &PatKind::Lit(r)) => self.eq_expr(l, r),
+ (&PatKind::Tuple(l, ls), &PatKind::Tuple(r, rs)) => ls == rs && over(l, r, |l, r| self.eq_pat(l, r)),
+ (&PatKind::Range(ref ls, ref le, li), &PatKind::Range(ref rs, ref re, ri)) => {
+ both(ls, rs, |a, b| self.eq_expr(a, b)) && both(le, re, |a, b| self.eq_expr(a, b)) && (li == ri)
+ },
+ (&PatKind::Ref(le, ref lm), &PatKind::Ref(re, ref rm)) => lm == rm && self.eq_pat(le, re),
+ (&PatKind::Slice(ls, ref li, le), &PatKind::Slice(rs, ref ri, re)) => {
+ over(ls, rs, |l, r| self.eq_pat(l, r))
+ && over(le, re, |l, r| self.eq_pat(l, r))
+ && both(li, ri, |l, r| self.eq_pat(l, r))
+ },
+ (&PatKind::Wild, &PatKind::Wild) => true,
+ _ => false,
+ }
+ }
+
+ #[expect(clippy::similar_names)]
+ fn eq_qpath(&mut self, left: &QPath<'_>, right: &QPath<'_>) -> bool {
+ match (left, right) {
+ (&QPath::Resolved(ref lty, lpath), &QPath::Resolved(ref rty, rpath)) => {
+ both(lty, rty, |l, r| self.eq_ty(l, r)) && self.eq_path(lpath, rpath)
+ },
+ (&QPath::TypeRelative(lty, lseg), &QPath::TypeRelative(rty, rseg)) => {
+ self.eq_ty(lty, rty) && self.eq_path_segment(lseg, rseg)
+ },
+ (&QPath::LangItem(llang_item, ..), &QPath::LangItem(rlang_item, ..)) => llang_item == rlang_item,
+ _ => false,
+ }
+ }
+
+ pub fn eq_path(&mut self, left: &Path<'_>, right: &Path<'_>) -> bool {
+ match (left.res, right.res) {
+ (Res::Local(l), Res::Local(r)) => l == r || self.locals.get(&l) == Some(&r),
+ (Res::Local(_), _) | (_, Res::Local(_)) => false,
+ _ => over(left.segments, right.segments, |l, r| self.eq_path_segment(l, r)),
+ }
+ }
+
+ fn eq_path_parameters(&mut self, left: &GenericArgs<'_>, right: &GenericArgs<'_>) -> bool {
+ if !(left.parenthesized || right.parenthesized) {
+ over(left.args, right.args, |l, r| self.eq_generic_arg(l, r)) // FIXME(flip1995): may not work
+ && over(left.bindings, right.bindings, |l, r| self.eq_type_binding(l, r))
+ } else if left.parenthesized && right.parenthesized {
+ over(left.inputs(), right.inputs(), |l, r| self.eq_ty(l, r))
+ && both(&Some(&left.bindings[0].ty()), &Some(&right.bindings[0].ty()), |l, r| {
+ self.eq_ty(l, r)
+ })
+ } else {
+ false
+ }
+ }
+
+ pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegment<'_>]) -> bool {
+ left.len() == right.len() && left.iter().zip(right).all(|(l, r)| self.eq_path_segment(l, r))
+ }
+
+ pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool {
+ // The == of idents doesn't work with different contexts,
+ // we have to be explicit about hygiene
+ left.ident.name == right.ident.name && both(&left.args, &right.args, |l, r| self.eq_path_parameters(l, r))
+ }
+
+ pub fn eq_ty(&mut self, left: &Ty<'_>, right: &Ty<'_>) -> bool {
+ match (&left.kind, &right.kind) {
+ (&TyKind::Slice(l_vec), &TyKind::Slice(r_vec)) => self.eq_ty(l_vec, r_vec),
+ (&TyKind::Array(lt, ll), &TyKind::Array(rt, rl)) => self.eq_ty(lt, rt) && self.eq_array_length(ll, rl),
+ (&TyKind::Ptr(ref l_mut), &TyKind::Ptr(ref r_mut)) => {
+ l_mut.mutbl == r_mut.mutbl && self.eq_ty(l_mut.ty, r_mut.ty)
+ },
+ (&TyKind::Rptr(_, ref l_rmut), &TyKind::Rptr(_, ref r_rmut)) => {
+ l_rmut.mutbl == r_rmut.mutbl && self.eq_ty(l_rmut.ty, r_rmut.ty)
+ },
+ (&TyKind::Path(ref l), &TyKind::Path(ref r)) => self.eq_qpath(l, r),
+ (&TyKind::Tup(l), &TyKind::Tup(r)) => over(l, r, |l, r| self.eq_ty(l, r)),
+ (&TyKind::Infer, &TyKind::Infer) => true,
+ _ => false,
+ }
+ }
+
+ fn eq_type_binding(&mut self, left: &TypeBinding<'_>, right: &TypeBinding<'_>) -> bool {
+ left.ident.name == right.ident.name && self.eq_ty(left.ty(), right.ty())
+ }
+}
+
+/// Some simple reductions like `{ return }` => `return`
+fn reduce_exprkind<'hir>(cx: &LateContext<'_>, kind: &'hir ExprKind<'hir>) -> &'hir ExprKind<'hir> {
+ if let ExprKind::Block(block, _) = kind {
+ match (block.stmts, block.expr) {
+ // From an `if let` expression without an `else` block. The arm for the implicit wild pattern is an empty
+ // block with an empty span.
+ ([], None) if block.span.is_empty() => &ExprKind::Tup(&[]),
+ // `{}` => `()`
+ ([], None) => match snippet_opt(cx, block.span) {
+ // Don't reduce if there are any tokens contained in the braces
+ Some(snip)
+ if tokenize(&snip)
+ .map(|t| t.kind)
+ .filter(|t| {
+ !matches!(
+ t,
+ TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
+ )
+ })
+ .ne([TokenKind::OpenBrace, TokenKind::CloseBrace].iter().copied()) =>
+ {
+ kind
+ },
+ _ => &ExprKind::Tup(&[]),
+ },
+ ([], Some(expr)) => match expr.kind {
+ // `{ return .. }` => `return ..`
+ ExprKind::Ret(..) => &expr.kind,
+ _ => kind,
+ },
+ ([stmt], None) => match stmt.kind {
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => match expr.kind {
+ // `{ return ..; }` => `return ..`
+ ExprKind::Ret(..) => &expr.kind,
+ _ => kind,
+ },
+ _ => kind,
+ },
+ _ => kind,
+ }
+ } else {
+ kind
+ }
+}
+
+fn swap_binop<'a>(
+ binop: BinOpKind,
+ lhs: &'a Expr<'a>,
+ rhs: &'a Expr<'a>,
+) -> Option<(BinOpKind, &'a Expr<'a>, &'a Expr<'a>)> {
+ match binop {
+ BinOpKind::Add | BinOpKind::Eq | BinOpKind::Ne | BinOpKind::BitAnd | BinOpKind::BitXor | BinOpKind::BitOr => {
+ Some((binop, rhs, lhs))
+ },
+ BinOpKind::Lt => Some((BinOpKind::Gt, rhs, lhs)),
+ BinOpKind::Le => Some((BinOpKind::Ge, rhs, lhs)),
+ BinOpKind::Ge => Some((BinOpKind::Le, rhs, lhs)),
+ BinOpKind::Gt => Some((BinOpKind::Lt, rhs, lhs)),
+ BinOpKind::Mul // Not always commutative, e.g. with matrices. See issue #5698
+ | BinOpKind::Shl
+ | BinOpKind::Shr
+ | BinOpKind::Rem
+ | BinOpKind::Sub
+ | BinOpKind::Div
+ | BinOpKind::And
+ | BinOpKind::Or => None,
+ }
+}
+
+/// Checks if the two `Option`s are both `None` or some equal values as per
+/// `eq_fn`.
+pub fn both<X>(l: &Option<X>, r: &Option<X>, mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
+ l.as_ref()
+ .map_or_else(|| r.is_none(), |x| r.as_ref().map_or(false, |y| eq_fn(x, y)))
+}
+
+/// Checks if two slices are equal as per `eq_fn`.
+pub fn over<X>(left: &[X], right: &[X], mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
+ left.len() == right.len() && left.iter().zip(right).all(|(x, y)| eq_fn(x, y))
+}
+
+/// Counts how many elements of the slices are equal as per `eq_fn`.
+pub fn count_eq<X: Sized>(
+ left: &mut dyn Iterator<Item = X>,
+ right: &mut dyn Iterator<Item = X>,
+ mut eq_fn: impl FnMut(&X, &X) -> bool,
+) -> usize {
+ left.zip(right).take_while(|(l, r)| eq_fn(l, r)).count()
+}
+
+/// Checks if two expressions evaluate to the same value, and don't contain any side effects.
+pub fn eq_expr_value(cx: &LateContext<'_>, left: &Expr<'_>, right: &Expr<'_>) -> bool {
+ SpanlessEq::new(cx).deny_side_effects().eq_expr(left, right)
+}
+
+/// Type used to hash an ast element. This is different from the `Hash` trait
+/// on ast types as this
+/// trait would consider IDs and spans.
+///
+/// All expressions kind are hashed, but some might have a weaker hash.
+pub struct SpanlessHash<'a, 'tcx> {
+ /// Context used to evaluate constant expressions.
+ cx: &'a LateContext<'tcx>,
+ maybe_typeck_results: Option<&'tcx TypeckResults<'tcx>>,
+ s: FxHasher,
+}
+
+impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
+ pub fn new(cx: &'a LateContext<'tcx>) -> Self {
+ Self {
+ cx,
+ maybe_typeck_results: cx.maybe_typeck_results(),
+ s: FxHasher::default(),
+ }
+ }
+
+ pub fn finish(self) -> u64 {
+ self.s.finish()
+ }
+
+ pub fn hash_block(&mut self, b: &Block<'_>) {
+ for s in b.stmts {
+ self.hash_stmt(s);
+ }
+
+ if let Some(e) = b.expr {
+ self.hash_expr(e);
+ }
+
+ std::mem::discriminant(&b.rules).hash(&mut self.s);
+ }
+
+ #[expect(clippy::too_many_lines)]
+ pub fn hash_expr(&mut self, e: &Expr<'_>) {
+ let simple_const = self
+ .maybe_typeck_results
+ .and_then(|typeck_results| constant_simple(self.cx, typeck_results, e));
+
+ // const hashing may result in the same hash as some unrelated node, so add a sort of
+ // discriminant depending on which path we're choosing next
+ simple_const.hash(&mut self.s);
+ if simple_const.is_some() {
+ return;
+ }
+
+ std::mem::discriminant(&e.kind).hash(&mut self.s);
+
+ match e.kind {
+ ExprKind::AddrOf(kind, m, e) => {
+ std::mem::discriminant(&kind).hash(&mut self.s);
+ m.hash(&mut self.s);
+ self.hash_expr(e);
+ },
+ ExprKind::Continue(i) => {
+ if let Some(i) = i.label {
+ self.hash_name(i.ident.name);
+ }
+ },
+ ExprKind::Assign(l, r, _) => {
+ self.hash_expr(l);
+ self.hash_expr(r);
+ },
+ ExprKind::AssignOp(ref o, l, r) => {
+ std::mem::discriminant(&o.node).hash(&mut self.s);
+ self.hash_expr(l);
+ self.hash_expr(r);
+ },
+ ExprKind::Block(b, _) => {
+ self.hash_block(b);
+ },
+ ExprKind::Binary(op, l, r) => {
+ std::mem::discriminant(&op.node).hash(&mut self.s);
+ self.hash_expr(l);
+ self.hash_expr(r);
+ },
+ ExprKind::Break(i, ref j) => {
+ if let Some(i) = i.label {
+ self.hash_name(i.ident.name);
+ }
+ if let Some(j) = *j {
+ self.hash_expr(j);
+ }
+ },
+ ExprKind::Box(e) | ExprKind::DropTemps(e) | ExprKind::Yield(e, _) => {
+ self.hash_expr(e);
+ },
+ ExprKind::Call(fun, args) => {
+ self.hash_expr(fun);
+ self.hash_exprs(args);
+ },
+ ExprKind::Cast(e, ty) | ExprKind::Type(e, ty) => {
+ self.hash_expr(e);
+ self.hash_ty(ty);
+ },
+ ExprKind::Closure(&Closure {
+ capture_clause, body, ..
+ }) => {
+ std::mem::discriminant(&capture_clause).hash(&mut self.s);
+ // closures inherit TypeckResults
+ self.hash_expr(&self.cx.tcx.hir().body(body).value);
+ },
+ ExprKind::Field(e, ref f) => {
+ self.hash_expr(e);
+ self.hash_name(f.name);
+ },
+ ExprKind::Index(a, i) => {
+ self.hash_expr(a);
+ self.hash_expr(i);
+ },
+ ExprKind::InlineAsm(asm) => {
+ for piece in asm.template {
+ match piece {
+ InlineAsmTemplatePiece::String(s) => s.hash(&mut self.s),
+ InlineAsmTemplatePiece::Placeholder {
+ operand_idx,
+ modifier,
+ span: _,
+ } => {
+ operand_idx.hash(&mut self.s);
+ modifier.hash(&mut self.s);
+ },
+ }
+ }
+ asm.options.hash(&mut self.s);
+ for (op, _op_sp) in asm.operands {
+ match op {
+ InlineAsmOperand::In { reg, expr } => {
+ reg.hash(&mut self.s);
+ self.hash_expr(expr);
+ },
+ InlineAsmOperand::Out { reg, late, expr } => {
+ reg.hash(&mut self.s);
+ late.hash(&mut self.s);
+ if let Some(expr) = expr {
+ self.hash_expr(expr);
+ }
+ },
+ InlineAsmOperand::InOut { reg, late, expr } => {
+ reg.hash(&mut self.s);
+ late.hash(&mut self.s);
+ self.hash_expr(expr);
+ },
+ InlineAsmOperand::SplitInOut {
+ reg,
+ late,
+ in_expr,
+ out_expr,
+ } => {
+ reg.hash(&mut self.s);
+ late.hash(&mut self.s);
+ self.hash_expr(in_expr);
+ if let Some(out_expr) = out_expr {
+ self.hash_expr(out_expr);
+ }
+ },
+ InlineAsmOperand::Const { anon_const } | InlineAsmOperand::SymFn { anon_const } => {
+ self.hash_body(anon_const.body);
+ },
+ InlineAsmOperand::SymStatic { path, def_id: _ } => self.hash_qpath(path),
+ }
+ }
+ },
+ ExprKind::Let(Let { pat, init, ty, .. }) => {
+ self.hash_expr(init);
+ if let Some(ty) = ty {
+ self.hash_ty(ty);
+ }
+ self.hash_pat(pat);
+ },
+ ExprKind::Err => {},
+ ExprKind::Lit(ref l) => {
+ l.node.hash(&mut self.s);
+ },
+ ExprKind::Loop(b, ref i, ..) => {
+ self.hash_block(b);
+ if let Some(i) = *i {
+ self.hash_name(i.ident.name);
+ }
+ },
+ ExprKind::If(cond, then, ref else_opt) => {
+ self.hash_expr(cond);
+ self.hash_expr(then);
+ if let Some(e) = *else_opt {
+ self.hash_expr(e);
+ }
+ },
+ ExprKind::Match(e, arms, ref s) => {
+ self.hash_expr(e);
+
+ for arm in arms {
+ self.hash_pat(arm.pat);
+ if let Some(ref e) = arm.guard {
+ self.hash_guard(e);
+ }
+ self.hash_expr(arm.body);
+ }
+
+ s.hash(&mut self.s);
+ },
+ ExprKind::MethodCall(path, args, ref _fn_span) => {
+ self.hash_name(path.ident.name);
+ self.hash_exprs(args);
+ },
+ ExprKind::ConstBlock(ref l_id) => {
+ self.hash_body(l_id.body);
+ },
+ ExprKind::Repeat(e, len) => {
+ self.hash_expr(e);
+ self.hash_array_length(len);
+ },
+ ExprKind::Ret(ref e) => {
+ if let Some(e) = *e {
+ self.hash_expr(e);
+ }
+ },
+ ExprKind::Path(ref qpath) => {
+ self.hash_qpath(qpath);
+ },
+ ExprKind::Struct(path, fields, ref expr) => {
+ self.hash_qpath(path);
+
+ for f in fields {
+ self.hash_name(f.ident.name);
+ self.hash_expr(f.expr);
+ }
+
+ if let Some(e) = *expr {
+ self.hash_expr(e);
+ }
+ },
+ ExprKind::Tup(tup) => {
+ self.hash_exprs(tup);
+ },
+ ExprKind::Array(v) => {
+ self.hash_exprs(v);
+ },
+ ExprKind::Unary(lop, le) => {
+ std::mem::discriminant(&lop).hash(&mut self.s);
+ self.hash_expr(le);
+ },
+ }
+ }
+
+ pub fn hash_exprs(&mut self, e: &[Expr<'_>]) {
+ for e in e {
+ self.hash_expr(e);
+ }
+ }
+
+ pub fn hash_name(&mut self, n: Symbol) {
+ n.hash(&mut self.s);
+ }
+
+ pub fn hash_qpath(&mut self, p: &QPath<'_>) {
+ match *p {
+ QPath::Resolved(_, path) => {
+ self.hash_path(path);
+ },
+ QPath::TypeRelative(_, path) => {
+ self.hash_name(path.ident.name);
+ },
+ QPath::LangItem(lang_item, ..) => {
+ std::mem::discriminant(&lang_item).hash(&mut self.s);
+ },
+ }
+ // self.maybe_typeck_results.unwrap().qpath_res(p, id).hash(&mut self.s);
+ }
+
+ pub fn hash_pat(&mut self, pat: &Pat<'_>) {
+ std::mem::discriminant(&pat.kind).hash(&mut self.s);
+ match pat.kind {
+ PatKind::Binding(ann, _, _, pat) => {
+ std::mem::discriminant(&ann).hash(&mut self.s);
+ if let Some(pat) = pat {
+ self.hash_pat(pat);
+ }
+ },
+ PatKind::Box(pat) => self.hash_pat(pat),
+ PatKind::Lit(expr) => self.hash_expr(expr),
+ PatKind::Or(pats) => {
+ for pat in pats {
+ self.hash_pat(pat);
+ }
+ },
+ PatKind::Path(ref qpath) => self.hash_qpath(qpath),
+ PatKind::Range(s, e, i) => {
+ if let Some(s) = s {
+ self.hash_expr(s);
+ }
+ if let Some(e) = e {
+ self.hash_expr(e);
+ }
+ std::mem::discriminant(&i).hash(&mut self.s);
+ },
+ PatKind::Ref(pat, mu) => {
+ self.hash_pat(pat);
+ std::mem::discriminant(&mu).hash(&mut self.s);
+ },
+ PatKind::Slice(l, m, r) => {
+ for pat in l {
+ self.hash_pat(pat);
+ }
+ if let Some(pat) = m {
+ self.hash_pat(pat);
+ }
+ for pat in r {
+ self.hash_pat(pat);
+ }
+ },
+ PatKind::Struct(ref qpath, fields, e) => {
+ self.hash_qpath(qpath);
+ for f in fields {
+ self.hash_name(f.ident.name);
+ self.hash_pat(f.pat);
+ }
+ e.hash(&mut self.s);
+ },
+ PatKind::Tuple(pats, e) => {
+ for pat in pats {
+ self.hash_pat(pat);
+ }
+ e.hash(&mut self.s);
+ },
+ PatKind::TupleStruct(ref qpath, pats, e) => {
+ self.hash_qpath(qpath);
+ for pat in pats {
+ self.hash_pat(pat);
+ }
+ e.hash(&mut self.s);
+ },
+ PatKind::Wild => {},
+ }
+ }
+
+ pub fn hash_path(&mut self, path: &Path<'_>) {
+ match path.res {
+ // constant hash since equality is dependant on inter-expression context
+ // e.g. The expressions `if let Some(x) = foo() {}` and `if let Some(y) = foo() {}` are considered equal
+ // even though the binding names are different and they have different `HirId`s.
+ Res::Local(_) => 1_usize.hash(&mut self.s),
+ _ => {
+ for seg in path.segments {
+ self.hash_name(seg.ident.name);
+ self.hash_generic_args(seg.args().args);
+ }
+ },
+ }
+ }
+
+ pub fn hash_stmt(&mut self, b: &Stmt<'_>) {
+ std::mem::discriminant(&b.kind).hash(&mut self.s);
+
+ match &b.kind {
+ StmtKind::Local(local) => {
+ self.hash_pat(local.pat);
+ if let Some(init) = local.init {
+ self.hash_expr(init);
+ }
+ if let Some(els) = local.els {
+ self.hash_block(els);
+ }
+ },
+ StmtKind::Item(..) => {},
+ StmtKind::Expr(expr) | StmtKind::Semi(expr) => {
+ self.hash_expr(expr);
+ },
+ }
+ }
+
+ pub fn hash_guard(&mut self, g: &Guard<'_>) {
+ match g {
+ Guard::If(expr) | Guard::IfLet(Let { init: expr, .. }) => {
+ self.hash_expr(expr);
+ },
+ }
+ }
+
+ pub fn hash_lifetime(&mut self, lifetime: Lifetime) {
+ std::mem::discriminant(&lifetime.name).hash(&mut self.s);
+ if let LifetimeName::Param(param_id, ref name) = lifetime.name {
+ std::mem::discriminant(name).hash(&mut self.s);
+ param_id.hash(&mut self.s);
+ match name {
+ ParamName::Plain(ref ident) => {
+ ident.name.hash(&mut self.s);
+ },
+ ParamName::Fresh | ParamName::Error => {},
+ }
+ }
+ }
+
+ pub fn hash_ty(&mut self, ty: &Ty<'_>) {
+ std::mem::discriminant(&ty.kind).hash(&mut self.s);
+ self.hash_tykind(&ty.kind);
+ }
+
+ pub fn hash_tykind(&mut self, ty: &TyKind<'_>) {
+ match ty {
+ TyKind::Slice(ty) => {
+ self.hash_ty(ty);
+ },
+ &TyKind::Array(ty, len) => {
+ self.hash_ty(ty);
+ self.hash_array_length(len);
+ },
+ TyKind::Ptr(ref mut_ty) => {
+ self.hash_ty(mut_ty.ty);
+ mut_ty.mutbl.hash(&mut self.s);
+ },
+ TyKind::Rptr(lifetime, ref mut_ty) => {
+ self.hash_lifetime(*lifetime);
+ self.hash_ty(mut_ty.ty);
+ mut_ty.mutbl.hash(&mut self.s);
+ },
+ TyKind::BareFn(bfn) => {
+ bfn.unsafety.hash(&mut self.s);
+ bfn.abi.hash(&mut self.s);
+ for arg in bfn.decl.inputs {
+ self.hash_ty(arg);
+ }
+ std::mem::discriminant(&bfn.decl.output).hash(&mut self.s);
+ match bfn.decl.output {
+ FnRetTy::DefaultReturn(_) => {},
+ FnRetTy::Return(ty) => {
+ self.hash_ty(ty);
+ },
+ }
+ bfn.decl.c_variadic.hash(&mut self.s);
+ },
+ TyKind::Tup(ty_list) => {
+ for ty in *ty_list {
+ self.hash_ty(ty);
+ }
+ },
+ TyKind::Path(ref qpath) => self.hash_qpath(qpath),
+ TyKind::OpaqueDef(_, arg_list) => {
+ self.hash_generic_args(arg_list);
+ },
+ TyKind::TraitObject(_, lifetime, _) => {
+ self.hash_lifetime(*lifetime);
+ },
+ TyKind::Typeof(anon_const) => {
+ self.hash_body(anon_const.body);
+ },
+ TyKind::Err | TyKind::Infer | TyKind::Never => {},
+ }
+ }
+
+ pub fn hash_array_length(&mut self, length: ArrayLen) {
+ match length {
+ ArrayLen::Infer(..) => {},
+ ArrayLen::Body(anon_const) => self.hash_body(anon_const.body),
+ }
+ }
+
+ pub fn hash_body(&mut self, body_id: BodyId) {
+ // swap out TypeckResults when hashing a body
+ let old_maybe_typeck_results = self.maybe_typeck_results.replace(self.cx.tcx.typeck_body(body_id));
+ self.hash_expr(&self.cx.tcx.hir().body(body_id).value);
+ self.maybe_typeck_results = old_maybe_typeck_results;
+ }
+
+ fn hash_generic_args(&mut self, arg_list: &[GenericArg<'_>]) {
+ for arg in arg_list {
+ match *arg {
+ GenericArg::Lifetime(l) => self.hash_lifetime(l),
+ GenericArg::Type(ref ty) => self.hash_ty(ty),
+ GenericArg::Const(ref ca) => self.hash_body(ca.value.body),
+ GenericArg::Infer(ref inf) => self.hash_ty(&inf.to_ty()),
+ }
+ }
+ }
+}
+
+pub fn hash_stmt(cx: &LateContext<'_>, s: &Stmt<'_>) -> u64 {
+ let mut h = SpanlessHash::new(cx);
+ h.hash_stmt(s);
+ h.finish()
+}
+
+pub fn hash_expr(cx: &LateContext<'_>, e: &Expr<'_>) -> u64 {
+ let mut h = SpanlessHash::new(cx);
+ h.hash_expr(e);
+ h.finish()
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-26 18:31:35 +0000