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Teach SpanlessEq binding IDs

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This commit is contained in:
Cameron Steffen 2021-02-17 09:34:35 -06:00
parent e2753f9a7b
commit 4ac14f9e63
4 changed files with 102 additions and 50 deletions
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134
clippy_lints/src/utils/hir_utils.rs
View File

@ -1,10 +1,12 @@
use crate::consts::{constant_context, constant_simple};
use crate::utils::differing_macro_contexts;
use rustc_ast::ast::InlineAsmTemplatePiece;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_hir::def::Res;
use rustc_hir::{
BinOpKind, Block, BlockCheckMode, BodyId, BorrowKind, CaptureBy, Expr, ExprKind, Field, FieldPat, FnRetTy,
GenericArg, GenericArgs, Guard, InlineAsmOperand, Lifetime, LifetimeName, ParamName, Pat, PatKind, Path,
GenericArg, GenericArgs, Guard, HirId, InlineAsmOperand, Lifetime, LifetimeName, ParamName, Pat, PatKind, Path,
PathSegment, QPath, Stmt, StmtKind, Ty, TyKind, TypeBinding,
};
use rustc_lint::LateContext;
@ -52,8 +54,47 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
}
}
/// Checks whether two statements are the same.
pub fn eq_stmt(&mut self, left: &Stmt<'_>, right: &Stmt<'_>) -> bool {
/// Use this method to wrap comparisons that may involve inter-expression context.
/// See `self.locals`.
fn inter_expr(&mut self) -> HirEqInterExpr<'_, 'a, 'tcx> {
HirEqInterExpr {
inner: self,
locals: FxHashMap::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_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 fn eq_ty_kind(&mut self, left: &TyKind<'_>, right: &TyKind<'_>) -> bool {
self.inter_expr().eq_ty_kind(left, right)
}
}
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`.
locals: FxHashMap<HirId, HirId>,
}
impl HirEqInterExpr<'_, '_, '_> {
fn eq_stmt(&mut self, left: &Stmt<'_>, right: &Stmt<'_>) -> bool {
match (&left.kind, &right.kind) {
(&StmtKind::Local(ref l), &StmtKind::Local(ref r)) => {
self.eq_pat(&l.pat, &r.pat)
@ -68,21 +109,21 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
}
/// Checks whether two blocks are the same.
pub fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
fn eq_block(&mut self, left: &Block<'_>, right: &Block<'_>) -> bool {
over(&left.stmts, &right.stmts, |l, r| self.eq_stmt(l, r))
&& both(&left.expr, &right.expr, |l, r| self.eq_expr(l, r))
}
#[allow(clippy::similar_names)]
pub fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
if !self.allow_side_effects && differing_macro_contexts(left.span, right.span) {
fn eq_expr(&mut self, left: &Expr<'_>, right: &Expr<'_>) -> bool {
if !self.inner.allow_side_effects && differing_macro_contexts(left.span, right.span) {
return false;
}
if let Some(typeck_results) = self.maybe_typeck_results {
if let Some(typeck_results) = self.inner.maybe_typeck_results {
if let (Some(l), Some(r)) = (
constant_simple(self.cx, typeck_results, left),
constant_simple(self.cx, typeck_results, right),
constant_simple(self.inner.cx, typeck_results, left),
constant_simple(self.inner.cx, typeck_results, right),
) {
if l == r {
return true;
@ -98,10 +139,10 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
both(&li.label, &ri.label, |l, r| l.ident.name == r.ident.name)
},
(&ExprKind::Assign(ref ll, ref lr, _), &ExprKind::Assign(ref rl, ref rr, _)) => {
self.allow_side_effects && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
self.inner.allow_side_effects && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
},
(&ExprKind::AssignOp(ref lo, ref ll, ref lr), &ExprKind::AssignOp(ref ro, ref rl, ref rr)) => {
self.allow_side_effects && lo.node == ro.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
self.inner.allow_side_effects && lo.node == ro.node && self.eq_expr(ll, rl) && self.eq_expr(lr, rr)
},
(&ExprKind::Block(ref l, _), &ExprKind::Block(ref r, _)) => self.eq_block(l, r),
(&ExprKind::Binary(l_op, ref ll, ref lr), &ExprKind::Binary(r_op, ref rl, ref rr)) => {
@ -116,7 +157,7 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
},
(&ExprKind::Box(ref l), &ExprKind::Box(ref r)) => self.eq_expr(l, r),
(&ExprKind::Call(l_fun, l_args), &ExprKind::Call(r_fun, r_args)) => {
self.allow_side_effects && self.eq_expr(l_fun, r_fun) && self.eq_exprs(l_args, r_args)
self.inner.allow_side_effects && self.eq_expr(l_fun, r_fun) && self.eq_exprs(l_args, r_args)
},
(&ExprKind::Cast(ref lx, ref lt), &ExprKind::Cast(ref rx, ref rt))
| (&ExprKind::Type(ref lx, ref lt), &ExprKind::Type(ref rx, ref rt)) => {
@ -139,19 +180,19 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
ls == rs
&& self.eq_expr(le, re)
&& over(la, ra, |l, r| {
self.eq_expr(&l.body, &r.body)
self.eq_pat(&l.pat, &r.pat)
&& both(&l.guard, &r.guard, |l, r| self.eq_guard(l, r))
&& self.eq_pat(&l.pat, &r.pat)
&& self.eq_expr(&l.body, &r.body)
})
},
(&ExprKind::MethodCall(l_path, _, l_args, _), &ExprKind::MethodCall(r_path, _, r_args, _)) => {
self.allow_side_effects && self.eq_path_segment(l_path, r_path) && self.eq_exprs(l_args, r_args)
self.inner.allow_side_effects && self.eq_path_segment(l_path, r_path) && self.eq_exprs(l_args, r_args)
},
(&ExprKind::Repeat(ref le, ref ll_id), &ExprKind::Repeat(ref re, ref rl_id)) => {
let mut celcx = constant_context(self.cx, self.cx.tcx.typeck_body(ll_id.body));
let ll = celcx.expr(&self.cx.tcx.hir().body(ll_id.body).value);
let mut celcx = constant_context(self.cx, self.cx.tcx.typeck_body(rl_id.body));
let rl = celcx.expr(&self.cx.tcx.hir().body(rl_id.body).value);
let mut celcx = constant_context(self.inner.cx, self.inner.cx.tcx.typeck_body(ll_id.body));
let ll = celcx.expr(&self.inner.cx.tcx.hir().body(ll_id.body).value);
let mut celcx = constant_context(self.inner.cx, self.inner.cx.tcx.typeck_body(rl_id.body));
let rl = celcx.expr(&self.inner.cx.tcx.hir().body(rl_id.body).value);
self.eq_expr(le, re) && ll == rl
},
@ -168,7 +209,7 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
(&ExprKind::DropTemps(ref le), &ExprKind::DropTemps(ref re)) => self.eq_expr(le, re),
_ => false,
};
is_eq || self.expr_fallback.as_ref().map_or(false, |f| f(left, right))
is_eq || self.inner.expr_fallback.as_ref().map_or(false, |f| f(left, right))
}
fn eq_exprs(&mut self, left: &[Expr<'_>], right: &[Expr<'_>]) -> bool {
@ -199,13 +240,13 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
left.name == right.name
}
pub fn eq_fieldpat(&mut self, left: &FieldPat<'_>, right: &FieldPat<'_>) -> bool {
fn eq_fieldpat(&mut self, left: &FieldPat<'_>, right: &FieldPat<'_>) -> bool {
let (FieldPat { ident: li, pat: lp, .. }, FieldPat { ident: ri, pat: rp, .. }) = (&left, &right);
li.name == ri.name && self.eq_pat(lp, rp)
}
/// Checks whether two patterns are the same.
pub fn eq_pat(&mut self, left: &Pat<'_>, right: &Pat<'_>) -> bool {
fn eq_pat(&mut self, left: &Pat<'_>, right: &Pat<'_>) -> bool {
match (&left.kind, &right.kind) {
(&PatKind::Box(ref l), &PatKind::Box(ref r)) => self.eq_pat(l, r),
(&PatKind::Struct(ref lp, ref la, ..), &PatKind::Struct(ref rp, ref ra, ..)) => {
@ -214,8 +255,12 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
(&PatKind::TupleStruct(ref lp, ref la, ls), &PatKind::TupleStruct(ref rp, ref ra, rs)) => {
self.eq_qpath(lp, rp) && over(la, ra, |l, r| self.eq_pat(l, r)) && ls == rs
},
(&PatKind::Binding(ref lb, .., ref li, ref lp), &PatKind::Binding(ref rb, .., ref ri, ref rp)) => {
lb == rb && li.name == ri.name && both(lp, rp, |l, r| self.eq_pat(l, r))
(&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(ref l), &PatKind::Lit(ref r)) => self.eq_expr(l, r),
@ -251,8 +296,11 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
}
fn eq_path(&mut self, left: &Path<'_>, right: &Path<'_>) -> bool {
left.is_global() == right.is_global()
&& over(&left.segments, &right.segments, |l, r| self.eq_path_segment(l, r))
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 {
@ -279,28 +327,19 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
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 {
fn eq_ty(&mut self, left: &Ty<'_>, right: &Ty<'_>) -> bool {
self.eq_ty_kind(&left.kind, &right.kind)
}
#[allow(clippy::similar_names)]
pub fn eq_ty_kind(&mut self, left: &TyKind<'_>, right: &TyKind<'_>) -> bool {
fn eq_ty_kind(&mut self, left: &TyKind<'_>, right: &TyKind<'_>) -> bool {
match (left, right) {
(&TyKind::Slice(ref l_vec), &TyKind::Slice(ref r_vec)) => self.eq_ty(l_vec, r_vec),
(&TyKind::Array(ref lt, ref ll_id), &TyKind::Array(ref rt, ref rl_id)) => {
let old_maybe_typeck_results = self.maybe_typeck_results;
let mut celcx = constant_context(self.cx, self.cx.tcx.typeck_body(ll_id.body));
self.maybe_typeck_results = Some(self.cx.tcx.typeck_body(ll_id.body));
let ll = celcx.expr(&self.cx.tcx.hir().body(ll_id.body).value);
let mut celcx = constant_context(self.cx, self.cx.tcx.typeck_body(rl_id.body));
self.maybe_typeck_results = Some(self.cx.tcx.typeck_body(rl_id.body));
let rl = celcx.expr(&self.cx.tcx.hir().body(rl_id.body).value);
let eq_ty = self.eq_ty(lt, rt);
self.maybe_typeck_results = old_maybe_typeck_results;
eq_ty && ll == rl
let cx = self.inner.cx;
let eval_const =
|body| constant_context(cx, cx.tcx.typeck_body(body)).expr(&cx.tcx.hir().body(body).value);
self.eq_ty(lt, rt) && eval_const(ll_id.body) == eval_const(rl_id.body)
},
(&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)
@ -667,10 +706,15 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
// self.maybe_typeck_results.unwrap().qpath_res(p, id).hash(&mut self.s);
}
pub fn hash_path(&mut self, p: &Path<'_>) {
p.is_global().hash(&mut self.s);
for p in p.segments {
self.hash_name(p.ident.name);
pub fn hash_path(&mut self, path: &Path<'_>) {
match path.res {
// constant hash since equality is dependant on inter-expression context
Res::Local(_) => 1_usize.hash(&mut self.s),
_ => {
for seg in path.segments {
self.hash_name(seg.ident.name);
}
},
}
}

8
tests/ui/collapsible_match.rs
View File

@ -232,6 +232,14 @@ fn negative_cases(res_opt: Result<Option<u32>, String>, res_res: Result<Result<u
};
}
}
let _: &dyn std::any::Any = match &Some(Some(1)) {
Some(e) => match e {
Some(e) => e,
e => e,
},
// else branch looks the same but the binding is different
e => e,
};
}
fn make<T>() -> T {

6
tests/ui/if_same_then_else2.rs
View File

@ -12,7 +12,7 @@ fn if_same_then_else2() -> Result<&'static str, ()> {
if true {
for _ in &[42] {
let foo: &Option<_> = &Some::<u8>(42);
if true {
if foo.is_some() {
break;
} else {
continue;
@ -21,8 +21,8 @@ fn if_same_then_else2() -> Result<&'static str, ()> {
} else {
//~ ERROR same body as `if` block
for _ in &[42] {
let foo: &Option<_> = &Some::<u8>(42);
if true {
let bar: &Option<_> = &Some::<u8>(42);
if bar.is_some() {
break;
} else {
continue;

4
tests/ui/if_same_then_else2.stderr
View File

@ -5,7 +5,7 @@ LL | } else {
| ____________^
LL | | //~ ERROR same body as `if` block
LL | | for _ in &[42] {
LL | | let foo: &Option<_> = &Some::<u8>(42);
LL | | let bar: &Option<_> = &Some::<u8>(42);
... |
LL | | }
LL | | }
@ -19,7 +19,7 @@ LL | if true {
| _____________^
LL | | for _ in &[42] {
LL | | let foo: &Option<_> = &Some::<u8>(42);
LL | | if true {
LL | | if foo.is_some() {
... |
LL | | }
LL | | } else {