use rustc::lint::*;
use rustc::hir::*;
use utils::span_lint;
declare_lint! {
pub OVERFLOW_CHECK_CONDITIONAL,
Warn,
"overflow checks inspired by C 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 {
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] == &path3.segments[0] || &path2.segments[0] == &path3.segments[0],
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 conditions 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 conditions 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] == &path3.segments[0] || &path2.segments[0] == &path3.segments[0],
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 conditions 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 conditions that will fail in Rust.");
}
}
}}
}
}