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use rustc::lint::*;
use rustc::hir::*;
use utils::span_lint;
declare_clippy_lint! {
pub OVERFLOW_CHECK_CONDITIONAL,
complexity,
"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<'a, 'tcx> LateLintPass<'a, 'tcx> for OverflowCheckConditional {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if_chain! {
if let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node;
if let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = first.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path1)) = ident1.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path2)) = ident2.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path3)) = second.node;
if path1.segments[0] == path3.segments[0] || path2.segments[0] == path3.segments[0];
if cx.tables.expr_ty(ident1).is_integral();
if cx.tables.expr_ty(ident2).is_integral();
then {
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_chain! {
if let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node;
if let Expr_::ExprBinary(ref op2, ref ident1, ref ident2) = second.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path1)) = ident1.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path2)) = ident2.node;
if let Expr_::ExprPath(QPath::Resolved(_, ref path3)) = first.node;
if path1.segments[0] == path3.segments[0] || path2.segments[0] == path3.segments[0];
if cx.tables.expr_ty(ident1).is_integral();
if cx.tables.expr_ty(ident2).is_integral();
then {
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.");
}
}
}
}
}
}