Disallow bit-shifting in integer_arithmetic lint

With this change, the lint checks all operations that are defined as
being capable of overflow in the Rust Reference.
This commit is contained in:
Michael Sproul 2020-04-13 13:11:19 +10:00
parent e29d550565
commit 23df4a0183
No known key found for this signature in database
GPG key ID: 77B1309D2E54E914
4 changed files with 48 additions and 22 deletions

View file

@ -6,11 +6,17 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::source_map::Span;
declare_clippy_lint! {
/// **What it does:** Checks for plain integer arithmetic.
/// **What it does:** Checks for integer arithmetic operations which could overflow or panic.
///
/// **Why is this bad?** This is only checked against overflow in debug builds.
/// In some applications one wants explicitly checked, wrapping or saturating
/// arithmetic.
/// Specifically, checks for any operators (`+`, `-`, `*`, `<<`, etc) which are capable
/// of overflowing according to the [Rust
/// Reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#overflow),
/// or which can panic (`/`, `%`). No bounds analysis or sophisticated reasoning is
/// attempted.
///
/// **Why is this bad?** Integer overflow will trigger a panic in debug builds or will wrap in
/// release mode. Division by zero will cause a panic in either mode. In some applications one
/// wants explicitly checked, wrapping or saturating arithmetic.
///
/// **Known problems:** None.
///
@ -21,7 +27,7 @@ declare_clippy_lint! {
/// ```
pub INTEGER_ARITHMETIC,
restriction,
"any integer arithmetic statement"
"any integer arithmetic expression which could overflow or panic"
}
declare_clippy_lint! {
@ -71,8 +77,6 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Arithmetic {
| hir::BinOpKind::BitAnd
| hir::BinOpKind::BitOr
| hir::BinOpKind::BitXor
| hir::BinOpKind::Shl
| hir::BinOpKind::Shr
| hir::BinOpKind::Eq
| hir::BinOpKind::Lt
| hir::BinOpKind::Le

View file

@ -846,7 +846,7 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
Lint {
name: "integer_arithmetic",
group: "restriction",
desc: "any integer arithmetic statement",
desc: "any integer arithmetic expression which could overflow or panic",
deprecation: None,
module: "arithmetic",
},

View file

@ -17,6 +17,8 @@ fn main() {
i / 2; // no error, this is part of the expression in the preceding line
i - 2 + 2 - i;
-i;
i >> 1;
i << 1;
// no error, overflows are checked by `overflowing_literals`
-1;
@ -25,18 +27,16 @@ fn main() {
i & 1; // no wrapping
i | 1;
i ^ 1;
i >> 1;
i << 1;
i += 1;
i -= 1;
i *= 2;
i /= 2;
i %= 2;
// no errors
i <<= 3;
i >>= 2;
// no errors
i |= 1;
i &= 1;
i ^= i;
@ -72,8 +72,6 @@ fn main() {
1 + 1
};
}
}
// warn on references as well! (#5328)

View file

@ -31,6 +31,18 @@ error: integer arithmetic detected
LL | -i;
| ^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:20:5
|
LL | i >> 1;
| ^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:21:5
|
LL | i << 1;
| ^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:31:5
|
@ -62,46 +74,58 @@ LL | i %= 2;
| ^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:81:5
--> $DIR/integer_arithmetic.rs:36:5
|
LL | i <<= 3;
| ^^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:37:5
|
LL | i >>= 2;
| ^^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:79:5
|
LL | 3 + &1;
| ^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:82:5
--> $DIR/integer_arithmetic.rs:80:5
|
LL | &3 + 1;
| ^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:83:5
--> $DIR/integer_arithmetic.rs:81:5
|
LL | &3 + &1;
| ^^^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:88:5
--> $DIR/integer_arithmetic.rs:86:5
|
LL | a + x
| ^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:92:5
--> $DIR/integer_arithmetic.rs:90:5
|
LL | x + y
| ^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:96:5
--> $DIR/integer_arithmetic.rs:94:5
|
LL | x + y
| ^^^^^
error: integer arithmetic detected
--> $DIR/integer_arithmetic.rs:100:5
--> $DIR/integer_arithmetic.rs:98:5
|
LL | (&x + &y)
| ^^^^^^^^^
error: aborting due to 17 previous errors
error: aborting due to 21 previous errors