Rewrite logic of has_nontrivial_oprand.
Check whether operator is overrided with a `struct` operand. The struct here refers to `struct`, `enum`, `union`. Add and fix test for `no_effect` lint.
This commit is contained in:
cocodery
parent
6d40b105ed
commit
89774234be
@ -10,6 +10,7 @@ use rustc_hir::{
|
||||
use rustc_infer::infer::TyCtxtInferExt as _;
|
||||
use rustc_lint::{LateContext, LateLintPass, LintContext};
|
||||
use rustc_middle::lint::in_external_macro;
|
||||
use rustc_middle::ty;
|
||||
use rustc_session::declare_lint_pass;
|
||||
use std::ops::Deref;
|
||||
|
||||
@ -87,8 +88,13 @@ impl<'tcx> LateLintPass<'tcx> for NoEffect {
|
||||
|
||||
fn check_no_effect(cx: &LateContext<'_>, stmt: &Stmt<'_>) -> bool {
|
||||
if let StmtKind::Semi(expr) = stmt.kind {
|
||||
// move `expr.span.from_expansion()` ahead
|
||||
if expr.span.from_expansion() {
|
||||
return false;
|
||||
}
|
||||
let expr = peel_blocks(expr);
|
||||
// assume nontrivial oprand of `Binary` Expr can skip `check_unnecessary_operation`
|
||||
if has_nontrivial_oprand(expr) {
|
||||
if has_nontrivial_oprand(cx, expr) {
|
||||
return true;
|
||||
}
|
||||
if has_no_effect(cx, expr) {
|
||||
@ -157,66 +163,38 @@ fn check_no_effect(cx: &LateContext<'_>, stmt: &Stmt<'_>) -> bool {
|
||||
false
|
||||
}
|
||||
|
||||
fn has_nontrivial_oprand(expr: &Expr<'_>) -> bool {
|
||||
if expr.span.from_expansion() {
|
||||
return false;
|
||||
}
|
||||
return match peel_blocks(expr).kind {
|
||||
ExprKind::Binary(_, lhs, rhs) => !check_nontrivial_operand(lhs, rhs),
|
||||
fn has_nontrivial_oprand(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
|
||||
// It's very hard or impossable to check whether overrided operator have side-effect this lint.
|
||||
// So, this function assume user-defined binary operator is overrided with an side-effect.
|
||||
// The definition of user-defined structure here is `struct`, `enum`, `uniom`,
|
||||
// Althrough this will weaken the ability of this lint, less error lint-fix happen.
|
||||
match expr.kind {
|
||||
ExprKind::Binary(_, lhs, rhs) => {
|
||||
// get type of lhs and rhs
|
||||
let tyck_result = cx.typeck_results();
|
||||
let ty_lhs = tyck_result.expr_ty(lhs).kind();
|
||||
let ty_rhs = tyck_result.expr_ty(rhs).kind();
|
||||
// check whether lhs is a user-defined structure
|
||||
// only need to check lhs in fact
|
||||
let ud_lhs = match ty_lhs {
|
||||
ty::Adt(adt_def, _) => adt_def.is_struct() || adt_def.is_enum() || adt_def.is_union(),
|
||||
_ => false,
|
||||
};
|
||||
}
|
||||
|
||||
fn check_nontrivial_operand(lhs: &Expr<'_>, rhs: &Expr<'_>) -> bool {
|
||||
// It's seem that impossable to check whether operator is overrided through context of this lint,
|
||||
// so, this function assume user-defined binary operator is overrided with an side-effect.
|
||||
// The definition of user-defined structure here is `tuple`, `array`, `struct`,
|
||||
// it looks like a little bit simple, but useful.
|
||||
// Althrough this will weaken the ability of this lint,
|
||||
// less miss lint-fix happen.
|
||||
|
||||
// a closure to check whether expr belongs to user-defined structure
|
||||
let closure = |expr: &Expr<'_>| -> bool {
|
||||
match &expr.kind {
|
||||
// check whether expr is a user-defined sturcture
|
||||
ExprKind::Tup(..) | ExprKind::Array(..) | ExprKind::Struct(..) => true,
|
||||
// resolve expr's path
|
||||
ExprKind::Path(rustc_hir::QPath::Resolved(
|
||||
_,
|
||||
rustc_hir::Path {
|
||||
span: _,
|
||||
res,
|
||||
segments: _,
|
||||
},
|
||||
)) => {
|
||||
match res {
|
||||
Res::Def(defkind, _) => match defkind {
|
||||
// user-defined
|
||||
DefKind::Struct | DefKind::Ctor(_, _) => true,
|
||||
_ => false,
|
||||
},
|
||||
let ud_rhs = match ty_rhs {
|
||||
ty::Adt(adt_def, _) => adt_def.is_struct() || adt_def.is_enum() || adt_def.is_union(),
|
||||
_ => false,
|
||||
};
|
||||
false
|
||||
|
||||
// reference: rust/compiler/rustc_middle/src/ty/typeck_results.rs: `is_method_call`.
|
||||
// use this function to check whether operator is overrided in `ExprKind::Binary`.
|
||||
(ud_lhs || ud_rhs) && tyck_result.is_method_call(expr)
|
||||
},
|
||||
_ => false,
|
||||
}
|
||||
};
|
||||
|
||||
let lhs_ud = closure(lhs);
|
||||
let rhs_ud = closure(rhs);
|
||||
// one of lhs or rhs is user-defined structure
|
||||
if lhs_ud || rhs_ud {
|
||||
return false;
|
||||
}
|
||||
true
|
||||
}
|
||||
|
||||
fn has_no_effect(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
|
||||
if expr.span.from_expansion() {
|
||||
return false;
|
||||
}
|
||||
match peel_blocks(expr).kind {
|
||||
match expr.kind {
|
||||
ExprKind::Lit(..) | ExprKind::Closure { .. } => true,
|
||||
ExprKind::Path(..) => !has_drop(cx, cx.typeck_results().expr_ty(expr)),
|
||||
ExprKind::Index(a, b, _) | ExprKind::Binary(_, a, b) => has_no_effect(cx, a) && has_no_effect(cx, b),
|
||||
|
||||
@ -9,6 +9,22 @@
|
||||
clippy::useless_vec
|
||||
)]
|
||||
|
||||
use std::fmt::Display;
|
||||
use std::ops::Shl;
|
||||
|
||||
struct Cout;
|
||||
|
||||
impl<T> Shl<T> for Cout
|
||||
where
|
||||
T: Display,
|
||||
{
|
||||
type Output = Self;
|
||||
fn shl(self, rhs: T) -> Self::Output {
|
||||
println!("{}", rhs);
|
||||
self
|
||||
}
|
||||
}
|
||||
|
||||
struct Unit;
|
||||
struct Tuple(i32);
|
||||
struct Struct {
|
||||
@ -174,4 +190,11 @@ fn main() {
|
||||
GreetStruct1("world");
|
||||
GreetStruct2()("world");
|
||||
GreetStruct3 {}("world");
|
||||
|
||||
fn n() -> i32 {
|
||||
42
|
||||
}
|
||||
|
||||
Cout << 142;
|
||||
Cout << n();
|
||||
}
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:98:5
|
||||
--> $DIR/no_effect.rs:114:5
|
||||
|
|
||||
LL | 0;
|
||||
| ^^
|
||||
@ -8,151 +8,151 @@ LL | 0;
|
||||
= help: to override `-D warnings` add `#[allow(clippy::no_effect)]`
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:101:5
|
||||
--> $DIR/no_effect.rs:117:5
|
||||
|
|
||||
LL | s2;
|
||||
| ^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:103:5
|
||||
--> $DIR/no_effect.rs:119:5
|
||||
|
|
||||
LL | Unit;
|
||||
| ^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:105:5
|
||||
--> $DIR/no_effect.rs:121:5
|
||||
|
|
||||
LL | Tuple(0);
|
||||
| ^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:107:5
|
||||
--> $DIR/no_effect.rs:123:5
|
||||
|
|
||||
LL | Struct { field: 0 };
|
||||
| ^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:109:5
|
||||
--> $DIR/no_effect.rs:125:5
|
||||
|
|
||||
LL | Struct { ..s };
|
||||
| ^^^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:111:5
|
||||
--> $DIR/no_effect.rs:127:5
|
||||
|
|
||||
LL | Union { a: 0 };
|
||||
| ^^^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:113:5
|
||||
--> $DIR/no_effect.rs:129:5
|
||||
|
|
||||
LL | Enum::Tuple(0);
|
||||
| ^^^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:115:5
|
||||
--> $DIR/no_effect.rs:131:5
|
||||
|
|
||||
LL | Enum::Struct { field: 0 };
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:117:5
|
||||
--> $DIR/no_effect.rs:133:5
|
||||
|
|
||||
LL | 5 + 6;
|
||||
| ^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:119:5
|
||||
--> $DIR/no_effect.rs:135:5
|
||||
|
|
||||
LL | *&42;
|
||||
| ^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:121:5
|
||||
--> $DIR/no_effect.rs:137:5
|
||||
|
|
||||
LL | &6;
|
||||
| ^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:123:5
|
||||
--> $DIR/no_effect.rs:139:5
|
||||
|
|
||||
LL | (5, 6, 7);
|
||||
| ^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:125:5
|
||||
--> $DIR/no_effect.rs:141:5
|
||||
|
|
||||
LL | ..;
|
||||
| ^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:127:5
|
||||
--> $DIR/no_effect.rs:143:5
|
||||
|
|
||||
LL | 5..;
|
||||
| ^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:129:5
|
||||
--> $DIR/no_effect.rs:145:5
|
||||
|
|
||||
LL | ..5;
|
||||
| ^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:131:5
|
||||
--> $DIR/no_effect.rs:147:5
|
||||
|
|
||||
LL | 5..6;
|
||||
| ^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:133:5
|
||||
--> $DIR/no_effect.rs:149:5
|
||||
|
|
||||
LL | 5..=6;
|
||||
| ^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:135:5
|
||||
--> $DIR/no_effect.rs:151:5
|
||||
|
|
||||
LL | [42, 55];
|
||||
| ^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:137:5
|
||||
--> $DIR/no_effect.rs:153:5
|
||||
|
|
||||
LL | [42, 55][1];
|
||||
| ^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:139:5
|
||||
--> $DIR/no_effect.rs:155:5
|
||||
|
|
||||
LL | (42, 55).1;
|
||||
| ^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:141:5
|
||||
--> $DIR/no_effect.rs:157:5
|
||||
|
|
||||
LL | [42; 55];
|
||||
| ^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:143:5
|
||||
--> $DIR/no_effect.rs:159:5
|
||||
|
|
||||
LL | [42; 55][13];
|
||||
| ^^^^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:146:5
|
||||
--> $DIR/no_effect.rs:162:5
|
||||
|
|
||||
LL | || x += 5;
|
||||
| ^^^^^^^^^^
|
||||
|
||||
error: statement with no effect
|
||||
--> $DIR/no_effect.rs:149:5
|
||||
--> $DIR/no_effect.rs:165:5
|
||||
|
|
||||
LL | FooString { s: s };
|
||||
| ^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error: binding to `_` prefixed variable with no side-effect
|
||||
--> $DIR/no_effect.rs:151:5
|
||||
--> $DIR/no_effect.rs:167:5
|
||||
|
|
||||
LL | let _unused = 1;
|
||||
| ^^^^^^^^^^^^^^^^
|
||||
@ -161,19 +161,19 @@ LL | let _unused = 1;
|
||||
= help: to override `-D warnings` add `#[allow(clippy::no_effect_underscore_binding)]`
|
||||
|
||||
error: binding to `_` prefixed variable with no side-effect
|
||||
--> $DIR/no_effect.rs:154:5
|
||||
--> $DIR/no_effect.rs:170:5
|
||||
|
|
||||
LL | let _penguin = || println!("Some helpful closure");
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error: binding to `_` prefixed variable with no side-effect
|
||||
--> $DIR/no_effect.rs:156:5
|
||||
--> $DIR/no_effect.rs:172:5
|
||||
|
|
||||
LL | let _duck = Struct { field: 0 };
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
error: binding to `_` prefixed variable with no side-effect
|
||||
--> $DIR/no_effect.rs:158:5
|
||||
--> $DIR/no_effect.rs:174:5
|
||||
|
|
||||
LL | let _cat = [2, 4, 6, 8][2];
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user