use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
+use rustc::{declare_lint, lint_array};
use rustc::hir::def::Def;
-use rustc::hir::{Expr, Expr_, Stmt, StmtSemi, BlockCheckMode, UnsafeSource, BiAnd, BiOr};
-use utils::{in_macro, span_lint, snippet_opt, span_lint_and_sugg};
+use rustc::hir::{BinOpKind, BlockCheckMode, Expr, ExprKind, Stmt, StmtKind, UnsafeSource};
+use crate::utils::{has_drop, in_macro, snippet_opt, span_lint, span_lint_and_sugg};
use std::ops::Deref;
/// **What it does:** Checks for statements which have no effect.
/// ```rust
/// 0;
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub NO_EFFECT,
- Warn,
+ complexity,
"statements with no effect"
}
/// ```rust
/// compute_array()[0];
/// ```
-declare_lint! {
+declare_clippy_lint! {
pub UNNECESSARY_OPERATION,
- Warn,
+ complexity,
"outer expressions with no effect"
}
return false;
}
match expr.node {
- Expr_::ExprLit(..) |
- Expr_::ExprClosure(..) |
- Expr_::ExprPath(..) => true,
- Expr_::ExprIndex(ref a, ref b) |
- Expr_::ExprBinary(_, ref a, ref b) => has_no_effect(cx, a) && has_no_effect(cx, b),
- Expr_::ExprArray(ref v) |
- Expr_::ExprTup(ref v) => v.iter().all(|val| has_no_effect(cx, val)),
- Expr_::ExprRepeat(ref inner, _) |
- Expr_::ExprCast(ref inner, _) |
- Expr_::ExprType(ref inner, _) |
- Expr_::ExprUnary(_, ref inner) |
- Expr_::ExprField(ref inner, _) |
- Expr_::ExprTupField(ref inner, _) |
- Expr_::ExprAddrOf(_, ref inner) |
- Expr_::ExprBox(ref inner) => has_no_effect(cx, inner),
- Expr_::ExprStruct(_, ref fields, ref base) => {
- fields.iter().all(|field| has_no_effect(cx, &field.expr)) &&
- match *base {
- Some(ref base) => has_no_effect(cx, base),
- None => true,
- }
+ ExprKind::Lit(..) | ExprKind::Closure(.., _) => true,
+ ExprKind::Path(..) => !has_drop(cx, expr),
+ ExprKind::Index(ref a, ref b) | ExprKind::Binary(_, ref a, ref b) => {
+ has_no_effect(cx, a) && has_no_effect(cx, b)
},
- Expr_::ExprCall(ref callee, ref args) => {
- if let Expr_::ExprPath(ref qpath) = callee.node {
- let def = cx.tables.qpath_def(qpath, callee.hir_id);
- match def {
- Def::Struct(..) |
- Def::Variant(..) |
- Def::StructCtor(..) |
- Def::VariantCtor(..) => args.iter().all(|arg| has_no_effect(cx, arg)),
- _ => false,
- }
+ ExprKind::Array(ref v) | ExprKind::Tup(ref v) => v.iter().all(|val| has_no_effect(cx, val)),
+ ExprKind::Repeat(ref inner, _) |
+ ExprKind::Cast(ref inner, _) |
+ ExprKind::Type(ref inner, _) |
+ ExprKind::Unary(_, ref inner) |
+ ExprKind::Field(ref inner, _) |
+ ExprKind::AddrOf(_, ref inner) |
+ ExprKind::Box(ref inner) => has_no_effect(cx, inner),
+ ExprKind::Struct(_, ref fields, ref base) => {
+ !has_drop(cx, expr) && fields.iter().all(|field| has_no_effect(cx, &field.expr)) && match *base {
+ Some(ref base) => has_no_effect(cx, base),
+ None => true,
+ }
+ },
+ ExprKind::Call(ref callee, ref args) => if let ExprKind::Path(ref qpath) = callee.node {
+ let def = cx.tables.qpath_def(qpath, callee.hir_id);
+ match def {
+ Def::Struct(..) | Def::Variant(..) | Def::StructCtor(..) | Def::VariantCtor(..) => {
+ !has_drop(cx, expr) && args.iter().all(|arg| has_no_effect(cx, arg))
+ },
+ _ => false,
+ }
+ } else {
+ false
+ },
+ ExprKind::Block(ref block, _) => {
+ block.stmts.is_empty() && if let Some(ref expr) = block.expr {
+ has_no_effect(cx, expr)
} else {
false
}
},
- Expr_::ExprBlock(ref block) => {
- block.stmts.is_empty() &&
- if let Some(ref expr) = block.expr {
- has_no_effect(cx, expr)
- } else {
- false
- }
- },
_ => false,
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt) {
- if let StmtSemi(ref expr, _) = stmt.node {
+ if let StmtKind::Semi(ref expr, _) = stmt.node {
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) {
return None;
}
match expr.node {
- Expr_::ExprIndex(ref a, ref b) => Some(vec![&**a, &**b]),
- Expr_::ExprBinary(ref binop, ref a, ref b) if binop.node != BiAnd && binop.node != BiOr => {
+ 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])
},
- Expr_::ExprArray(ref v) |
- Expr_::ExprTup(ref v) => Some(v.iter().collect()),
- Expr_::ExprRepeat(ref inner, _) |
- Expr_::ExprCast(ref inner, _) |
- Expr_::ExprType(ref inner, _) |
- Expr_::ExprUnary(_, ref inner) |
- Expr_::ExprField(ref inner, _) |
- Expr_::ExprTupField(ref inner, _) |
- Expr_::ExprAddrOf(_, ref inner) |
- Expr_::ExprBox(ref inner) => reduce_expression(cx, inner).or_else(|| Some(vec![inner])),
- Expr_::ExprStruct(_, ref fields, ref base) => {
+ ExprKind::Array(ref v) | ExprKind::Tup(ref v) => Some(v.iter().collect()),
+ ExprKind::Repeat(ref inner, _) |
+ ExprKind::Cast(ref inner, _) |
+ ExprKind::Type(ref inner, _) |
+ ExprKind::Unary(_, ref inner) |
+ ExprKind::Field(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, expr) {
+ None
+ } else {
Some(
fields
.iter()
.collect(),
)
},
- Expr_::ExprCall(ref callee, ref args) => {
- if let Expr_::ExprPath(ref qpath) = callee.node {
- let def = cx.tables.qpath_def(qpath, callee.hir_id);
- match def {
- Def::Struct(..) |
- Def::Variant(..) |
- Def::StructCtor(..) |
- Def::VariantCtor(..) => Some(args.iter().collect()),
- _ => None,
- }
- } else {
- None
+ ExprKind::Call(ref callee, ref args) => if let ExprKind::Path(ref qpath) = callee.node {
+ let def = cx.tables.qpath_def(qpath, callee.hir_id);
+ match def {
+ Def::Struct(..) | Def::Variant(..) | Def::StructCtor(..) | Def::VariantCtor(..)
+ if !has_drop(cx, expr) =>
+ {
+ Some(args.iter().collect())
+ },
+ _ => None,
}
+ } else {
+ None
},
- Expr_::ExprBlock(ref block) => {
+ ExprKind::Block(ref block, _) => {
if block.stmts.is_empty() {
block.expr.as_ref().and_then(|e| {
match block.rules {
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