improve the no_effect lint

This commit is contained in:
Oliver Schneider 2016-02-11 13:50:41 +01:00
parent 1013026f18
commit eed9ec15fb
14 changed files with 67 additions and 15 deletions

View file

@ -1,6 +1,6 @@
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::middle::def::Def;
use rustc_front::hir::{Expr, ExprCall, ExprLit, ExprPath, ExprStruct};
use rustc_front::hir::{Expr, Expr_};
use rustc_front::hir::{Stmt, StmtSemi};
use utils::in_macro;
@ -24,16 +24,33 @@ fn has_no_effect(cx: &LateContext, expr: &Expr) -> bool {
return false;
}
match expr.node {
ExprLit(..) |
ExprPath(..) => true,
ExprStruct(_, ref fields, ref base) => {
Expr_::ExprLit(..) |
Expr_::ExprClosure(..) |
Expr_::ExprRange(None, None) |
Expr_::ExprPath(..) => true,
Expr_::ExprIndex(ref a, ref b) |
Expr_::ExprRange(Some(ref a), Some(ref b)) |
Expr_::ExprBinary(_, ref a, ref b) => has_no_effect(cx, a) && has_no_effect(cx, b),
Expr_::ExprVec(ref v) |
Expr_::ExprTup(ref v) => v.iter().all(|val| has_no_effect(cx, val)),
Expr_::ExprRange(Some(ref inner), None) |
Expr_::ExprRange(None, Some(ref inner)) |
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,
}
}
ExprCall(ref callee, ref args) => {
Expr_::ExprCall(ref callee, ref args) => {
let def = cx.tcx.def_map.borrow().get(&callee.id).map(|d| d.full_def());
match def {
Some(Def::Struct(..)) |

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@ -2,7 +2,7 @@
#![plugin(clippy)]
#![deny(absurd_extreme_comparisons)]
#![allow(unused, eq_op)]
#![allow(unused, eq_op, no_effect)]
fn main() {
const Z: u32 = 0;

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@ -2,6 +2,7 @@
#![plugin(clippy)]
#![deny(out_of_bounds_indexing)]
#![allow(no_effect)]
fn main() {
let x = [1,2,3,4];

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@ -5,7 +5,7 @@ const THREE_BITS : i64 = 7;
const EVEN_MORE_REDIRECTION : i64 = THREE_BITS;
#[deny(bad_bit_mask)]
#[allow(ineffective_bit_mask, identity_op)]
#[allow(ineffective_bit_mask, identity_op, no_effect)]
fn main() {
let x = 5;
@ -45,7 +45,7 @@ fn main() {
}
#[deny(ineffective_bit_mask)]
#[allow(bad_bit_mask)]
#[allow(bad_bit_mask, no_effect)]
fn ineffective() {
let x = 5;

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@ -2,6 +2,7 @@
#![plugin(clippy)]
#[deny(cast_precision_loss, cast_possible_truncation, cast_sign_loss, cast_possible_wrap)]
#[allow(no_effect)]
fn main() {
// Test cast_precision_loss
1i32 as f32; //~ERROR casting i32 to f32 causes a loss of precision (i32 is 32 bits wide, but f32's mantissa is only 23 bits wide)

View file

@ -2,7 +2,7 @@
#![plugin(clippy)]
#[deny(cmp_nan)]
#[allow(float_cmp)]
#[allow(float_cmp, no_effect)]
fn main() {
let x = 5f32;
x == std::f32::NAN; //~ERROR doomed comparison with NAN

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@ -1,7 +1,7 @@
#![feature(plugin)]
#![plugin(clippy)]
#![allow(dead_code)]
#![allow(dead_code, no_effect)]
#![allow(let_and_return)]
#![allow(needless_return)]
#![allow(unused_variables)]

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@ -3,6 +3,7 @@
#[deny(eq_op)]
#[allow(identity_op)]
#[allow(no_effect)]
fn main() {
// simple values and comparisons
1 == 1; //~ERROR equal expressions

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@ -1,6 +1,6 @@
#![feature(plugin)]
#![plugin(clippy)]
#![allow(unknown_lints, unused)]
#![allow(unknown_lints, unused, no_effect)]
#![deny(redundant_closure)]
fn main() {

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@ -2,7 +2,7 @@
#![plugin(clippy)]
#![deny(float_cmp)]
#![allow(unused)]
#![allow(unused, no_effect)]
use std::ops::Add;

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@ -5,7 +5,7 @@ const ONE : i64 = 1;
const NEG_ONE : i64 = -1;
const ZERO : i64 = 0;
#[allow(eq_op)]
#[allow(eq_op, no_effect)]
#[deny(identity_op)]
fn main() {
let x = 0;

View file

@ -1,6 +1,7 @@
#![feature(plugin)]
#![plugin(clippy)]
#![deny(modulo_one)]
#![allow(no_effect)]
fn main() {
10 % 1; //~ERROR any number modulo 1 will be 0

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@ -1,7 +1,7 @@
#![feature(plugin)]
#![plugin(clippy)]
#![allow(unused)]
#![allow(unused, no_effect)]
//#![plugin(regex_macros)]
//extern crate regex;

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@ -1,4 +1,4 @@
#![feature(plugin)]
#![feature(plugin, box_syntax)]
#![plugin(clippy)]
#![deny(no_effect)]
@ -20,14 +20,32 @@ fn get_struct() -> Struct { Struct { field: 0 } }
fn main() {
let s = get_struct();
let s2 = get_struct();
0; //~ERROR statement with no effect
s2; //~ERROR statement with no effect
Unit; //~ERROR statement with no effect
Tuple(0); //~ERROR statement with no effect
Struct { field: 0 }; //~ERROR statement with no effect
Struct { ..s }; //~ERROR statement with no effect
Enum::Tuple(0); //~ERROR statement with no effect
Enum::Struct { field: 0 }; //~ERROR statement with no effect
5 + 6; //~ERROR statement with no effect
*&42; //~ERROR statement with no effect
&6; //~ERROR statement with no effect
(5, 6, 7); //~ERROR statement with no effect
box 42; //~ERROR statement with no effect
..; //~ERROR statement with no effect
5..; //~ERROR statement with no effect
..5; //~ERROR statement with no effect
5..6; //~ERROR statement with no effect
[42, 55]; //~ERROR statement with no effect
[42, 55][1]; //~ERROR statement with no effect
(42, 55).1; //~ERROR statement with no effect
[42; 55]; //~ERROR statement with no effect
[42; 55][13]; //~ERROR statement with no effect
let mut x = 0;
|| x += 5; //~ERROR statement with no effect
// Do not warn
get_number();
@ -36,4 +54,17 @@ fn main() {
Struct { ..get_struct() };
Enum::Tuple(get_number());
Enum::Struct { field: get_number() };
5 + get_number();
*&get_number();
&get_number();
(5, 6, get_number());
box get_number();
get_number()..;
..get_number();
5..get_number();
[42, get_number()];
[42, 55][get_number() as usize];
(42, get_number()).1;
[get_number(); 55];
[42; 55][get_number() as usize];
}