use crate::utils::{has_drop, snippet_opt, span_lint, span_lint_and_sugg};
-use rustc::hir::def::{DefKind, Res};
-use rustc::hir::{BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::{BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
use std::ops::Deref;
declare_clippy_lint! {
"outer expressions with no effect"
}
-fn has_no_effect(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
+fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
if expr.span.from_expansion() {
return false;
}
- match expr.node {
- ExprKind::Lit(..) | ExprKind::Closure(.., _) => true,
- ExprKind::Path(..) => !has_drop(cx, cx.tables.expr_ty(expr)),
+ match expr.kind {
+ ExprKind::Lit(..) | ExprKind::Closure(..) => true,
+ ExprKind::Path(..) => !has_drop(cx, cx.typeck_results().expr_ty(expr)),
ExprKind::Index(ref a, ref b) | ExprKind::Binary(_, ref a, ref b) => {
has_no_effect(cx, a) && has_no_effect(cx, b)
},
| ExprKind::Type(ref inner, _)
| ExprKind::Unary(_, ref inner)
| ExprKind::Field(ref inner, _)
- | ExprKind::AddrOf(_, ref inner)
+ | ExprKind::AddrOf(_, _, ref inner)
| ExprKind::Box(ref inner) => has_no_effect(cx, inner),
ExprKind::Struct(_, ref fields, ref base) => {
- !has_drop(cx, cx.tables.expr_ty(expr))
+ !has_drop(cx, cx.typeck_results().expr_ty(expr))
&& fields.iter().all(|field| has_no_effect(cx, &field.expr))
&& base.as_ref().map_or(true, |base| has_no_effect(cx, base))
},
ExprKind::Call(ref callee, ref args) => {
- if let ExprKind::Path(ref qpath) = callee.node {
- let res = cx.tables.qpath_res(qpath, callee.hir_id);
+ if let ExprKind::Path(ref qpath) = callee.kind {
+ let res = cx.qpath_res(qpath, callee.hir_id);
match res {
- Res::Def(DefKind::Struct, ..) | Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _) => {
- !has_drop(cx, cx.tables.expr_ty(expr)) && args.iter().all(|arg| has_no_effect(cx, arg))
+ Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..) => {
+ !has_drop(cx, cx.typeck_results().expr_ty(expr))
+ && args.iter().all(|arg| has_no_effect(cx, arg))
},
_ => false,
}
declare_lint_pass!(NoEffect => [NO_EFFECT, UNNECESSARY_OPERATION]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NoEffect {
- fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt) {
- if let StmtKind::Semi(ref expr) = stmt.node {
+impl<'tcx> LateLintPass<'tcx> for NoEffect {
+ fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
+ if let StmtKind::Semi(ref expr) = stmt.kind {
if has_no_effect(cx, expr) {
span_lint(cx, NO_EFFECT, stmt.span, "statement with no effect");
} else if let Some(reduced) = reduce_expression(cx, expr) {
}
}
-fn reduce_expression<'a>(cx: &LateContext<'_, '_>, expr: &'a Expr) -> Option<Vec<&'a Expr>> {
+fn reduce_expression<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<Vec<&'a Expr<'a>>> {
if expr.span.from_expansion() {
return None;
}
- match expr.node {
+ match expr.kind {
ExprKind::Index(ref a, ref b) => Some(vec![&**a, &**b]),
ExprKind::Binary(ref binop, ref a, ref b) if binop.node != BinOpKind::And && binop.node != BinOpKind::Or => {
Some(vec![&**a, &**b])
| ExprKind::Type(ref inner, _)
| ExprKind::Unary(_, ref inner)
| ExprKind::Field(ref inner, _)
- | ExprKind::AddrOf(_, ref inner)
+ | ExprKind::AddrOf(_, _, ref inner)
| ExprKind::Box(ref inner) => reduce_expression(cx, inner).or_else(|| Some(vec![inner])),
ExprKind::Struct(_, ref fields, ref base) => {
- if has_drop(cx, cx.tables.expr_ty(expr)) {
+ if has_drop(cx, cx.typeck_results().expr_ty(expr)) {
None
} else {
Some(fields.iter().map(|f| &f.expr).chain(base).map(Deref::deref).collect())
}
},
ExprKind::Call(ref callee, ref args) => {
- if let ExprKind::Path(ref qpath) = callee.node {
- let res = cx.tables.qpath_res(qpath, callee.hir_id);
+ if let ExprKind::Path(ref qpath) = callee.kind {
+ let res = cx.qpath_res(qpath, callee.hir_id);
match res {
- Res::Def(DefKind::Struct, ..) | Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(..), _)
- if !has_drop(cx, cx.tables.expr_ty(expr)) =>
+ Res::Def(DefKind::Struct | DefKind::Variant | DefKind::Ctor(..), ..)
+ if !has_drop(cx, cx.typeck_results().expr_ty(expr)) =>
{
Some(args.iter().collect())
},