42 lines
1.6 KiB
Rust
42 lines
1.6 KiB
Rust
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use rustc::lint::*;
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use rustc_front::hir::*;
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use utils::{span_lint};
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/// **What it does:** This lint finds classic overflow checks.
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///
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/// **Why is this bad?** Most classic C overflow checks will fail in Rust. Users can use functions like `overflowing_*` and `wrapping_*` instead.
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///
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/// **Known problems:** None.
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///
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/// **Example:** `a + b < a`
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declare_lint!(pub OVERFLOW_CHECK_CONDITIONAL, Warn,
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"Using overflow checks which are likely to panic");
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#[derive(Copy, Clone)]
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pub struct OverflowCheckConditional;
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impl LintPass for OverflowCheckConditional {
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fn get_lints(&self) -> LintArray {
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lint_array!(OVERFLOW_CHECK_CONDITIONAL)
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}
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}
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impl LateLintPass for OverflowCheckConditional {
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fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
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if_let_chain! {[
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let Expr_::ExprBinary(ref op, ref first, ref second) = expr.node,
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let BinOp_::BiLt = op.node,
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let Expr_::ExprBinary(ref op2, ref add1, ref add2) = first.node,
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let BinOp_::BiAdd = op2.node,
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let Expr_::ExprPath(_,ref path1) = add1.node,
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let Expr_::ExprPath(_, ref path2) = add2.node,
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let Expr_::ExprPath(_, ref path3) = second.node,
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(&path1.segments[0]).identifier == (&path3.segments[0]).identifier || (&path2.segments[0]).identifier == (&path3.segments[0]).identifier,
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cx.tcx.expr_ty(add1).is_integral(),
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cx.tcx.expr_ty(add2).is_integral()
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], {
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span_lint(cx, OVERFLOW_CHECK_CONDITIONAL, expr.span, "You are trying to use classic C overflow conditons that will fail in Rust.");
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}}
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}
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}
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