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Merge pull request #741 from martiansideofthemoon/blastoise

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Linting classical overflow checks
This commit is contained in:
llogiq 2016-03-08 09:50:00 +01:00
commit 08b7931b6b
4 changed files with 139 additions and 1 deletions
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3
src/lib.rs
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@ -79,6 +79,7 @@ pub mod needless_features;
pub mod needless_update;
pub mod no_effect;
pub mod open_options;
pub mod overflow_check_conditional;
pub mod panic;
pub mod precedence;
pub mod print;
@ -173,6 +174,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
reg.register_early_lint_pass(box formatting::Formatting);
reg.register_late_lint_pass(box swap::Swap);
reg.register_early_lint_pass(box if_not_else::IfNotElse);
reg.register_late_lint_pass(box overflow_check_conditional::OverflowCheckConditional);
reg.register_lint_group("clippy_pedantic", vec![
enum_glob_use::ENUM_GLOB_USE,
@ -283,6 +285,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
needless_update::NEEDLESS_UPDATE,
no_effect::NO_EFFECT,
open_options::NONSENSICAL_OPEN_OPTIONS,
overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL,
panic::PANIC_PARAMS,
precedence::PRECEDENCE,
ptr_arg::PTR_ARG,

73
src/overflow_check_conditional.rs Normal file
View file

@ -0,0 +1,73 @@
#![allow(cyclomatic_complexity)]
use rustc::lint::*;
use rustc_front::hir::*;
use utils::{span_lint};
/// **What it does:** This lint finds classic underflow / overflow checks.
///
/// **Why is this bad?** Most classic C underflow / overflow checks will fail in Rust. Users can use functions like `overflowing_*` and `wrapping_*` instead.
///
/// **Known problems:** None.
///
/// **Example:** `a + b < a`
declare_lint!(pub OVERFLOW_CHECK_CONDITIONAL, Warn,
"Using overflow checks which are likely to panic");
#[derive(Copy, Clone)]
pub struct OverflowCheckConditional;
impl LintPass for OverflowCheckConditional {
fn get_lints(&self) -> LintArray {
lint_array!(OVERFLOW_CHECK_CONDITIONAL)
}
}
impl LateLintPass for OverflowCheckConditional {
// a + b < a, a > a + b, a < a - b, a - b > a
fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
if_let_chain! {[
let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node,
let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = first.node,
let Expr_::ExprPath(_,ref path1) = ident1.node,
let Expr_::ExprPath(_, ref path2) = ident2.node,
let Expr_::ExprPath(_, ref path3) = second.node,
(&path1.segments[0]).identifier == (&path3.segments[0]).identifier || (&path2.segments[0]).identifier == (&path3.segments[0]).identifier,
cx.tcx.expr_ty(ident1).is_integral(),
cx.tcx.expr_ty(ident2).is_integral()
], {
if let BinOp_::BiLt = op.node {
if let BinOp_::BiAdd = op2.node {
span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span, "You are trying to use classic C overflow conditons that will fail in Rust.");
}
}
if let BinOp_::BiGt = op.node {
if let BinOp_::BiSub = op2.node {
span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span, "You are trying to use classic C underflow conditons that will fail in Rust.");
}
}
}}
if_let_chain! {[
let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node,
let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = second.node,
let Expr_::ExprPath(_,ref path1) = ident1.node,
let Expr_::ExprPath(_, ref path2) = ident2.node,
let Expr_::ExprPath(_, ref path3) = first.node,
(&path1.segments[0]).identifier == (&path3.segments[0]).identifier || (&path2.segments[0]).identifier == (&path3.segments[0]).identifier,
cx.tcx.expr_ty(ident1).is_integral(),
cx.tcx.expr_ty(ident2).is_integral()
], {
if let BinOp_::BiGt = op.node {
if let BinOp_::BiAdd = op2.node {
span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span, "You are trying to use classic C overflow conditons that will fail in Rust.");
}
}
if let BinOp_::BiLt = op.node {
if let BinOp_::BiSub = op2.node {
span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span, "You are trying to use classic C underflow conditons that will fail in Rust.");
}
}
}}
}
}