[`absurd_extreme_comparisons`]: https://github.com/Manishearth/rust-clippy/wiki#absurd_extreme_comparisons
[`almost_swapped`]: https://github.com/Manishearth/rust-clippy/wiki#almost_swapped
[`approx_constant`]: https://github.com/Manishearth/rust-clippy/wiki#approx_constant
+[`assign_op_pattern`]: https://github.com/Manishearth/rust-clippy/wiki#assign_op_pattern
+[`assign_ops`]: https://github.com/Manishearth/rust-clippy/wiki#assign_ops
[`bad_bit_mask`]: https://github.com/Manishearth/rust-clippy/wiki#bad_bit_mask
[`blacklisted_name`]: https://github.com/Manishearth/rust-clippy/wiki#blacklisted_name
[`block_in_if_condition_expr`]: https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_expr
## Lints
-There are 147 lints included in this crate:
+There are 149 lints included in this crate:
name | default | meaning
---------------------------------------------------------------------------------------------------------------------|---------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
[absurd_extreme_comparisons](https://github.com/Manishearth/rust-clippy/wiki#absurd_extreme_comparisons) | warn | a comparison involving a maximum or minimum value involves a case that is always true or always false
[almost_swapped](https://github.com/Manishearth/rust-clippy/wiki#almost_swapped) | warn | `foo = bar; bar = foo` sequence
[approx_constant](https://github.com/Manishearth/rust-clippy/wiki#approx_constant) | warn | the approximate of a known float constant (in `std::f64::consts` or `std::f32::consts`) is found; suggests to use the constant
+[assign_op_pattern](https://github.com/Manishearth/rust-clippy/wiki#assign_op_pattern) | warn | assigning the result of an operation on a variable to that same variable
+[assign_ops](https://github.com/Manishearth/rust-clippy/wiki#assign_ops) | allow | Any assignment operation
[bad_bit_mask](https://github.com/Manishearth/rust-clippy/wiki#bad_bit_mask) | warn | expressions of the form `_ & mask == select` that will only ever return `true` or `false` (because in the example `select` containing bits that `mask` doesn't have)
[blacklisted_name](https://github.com/Manishearth/rust-clippy/wiki#blacklisted_name) | warn | usage of a blacklisted/placeholder name
[block_in_if_condition_expr](https://github.com/Manishearth/rust-clippy/wiki#block_in_if_condition_expr) | warn | braces can be eliminated in conditions that are expressions, e.g `if { true } ...`
--- /dev/null
+use rustc::hir;
+use rustc::lint::*;
+use utils::{span_lint_and_then, span_lint, snippet_opt, SpanlessEq, get_trait_def_id, implements_trait};
+
+/// **What it does:** This lint checks for `+=` operations and similar
+///
+/// **Why is this bad?** Projects with many developers from languages without those operations
+/// may find them unreadable and not worth their weight
+///
+/// **Known problems:** None
+///
+/// **Example:**
+/// ```
+/// a += 1;
+/// ```
+declare_restriction_lint! {
+ pub ASSIGN_OPS,
+ "Any assignment operation"
+}
+
+/// **What it does:** Check for `a = a op b` or `a = b commutative_op a` patterns
+///
+/// **Why is this bad?** These can be written as the shorter `a op= b`
+///
+/// **Known problems:** Hopefully none.
+///
+/// **Example:**
+///
+/// ```
+/// let mut a = 5;
+/// ...
+/// a = a + b;
+/// ```
+declare_lint! {
+ pub ASSIGN_OP_PATTERN,
+ Warn,
+ "assigning the result of an operation on a variable to that same variable"
+}
+
+#[derive(Copy, Clone, Default)]
+pub struct AssignOps;
+
+impl LintPass for AssignOps {
+ fn get_lints(&self) -> LintArray {
+ lint_array!(ASSIGN_OPS, ASSIGN_OP_PATTERN)
+ }
+}
+
+impl LateLintPass for AssignOps {
+ fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) {
+ match expr.node {
+ hir::ExprAssignOp(op, ref lhs, ref rhs) => {
+ if let (Some(l), Some(r)) = (snippet_opt(cx, lhs.span), snippet_opt(cx, rhs.span)) {
+ span_lint_and_then(cx,
+ ASSIGN_OPS,
+ expr.span,
+ "assign operation detected",
+ |db| {
+ match rhs.node {
+ hir::ExprBinary(op2, _, _) if op2 != op => {
+ db.span_suggestion(expr.span,
+ "replace it with",
+ format!("{} = {} {} ({})", l, l, op.node.as_str(), r));
+ },
+ _ => {
+ db.span_suggestion(expr.span,
+ "replace it with",
+ format!("{} = {} {} {}", l, l, op.node.as_str(), r));
+ }
+ }
+ });
+ } else {
+ span_lint(cx,
+ ASSIGN_OPS,
+ expr.span,
+ "assign operation detected");
+ }
+ },
+ hir::ExprAssign(ref assignee, ref e) => {
+ if let hir::ExprBinary(op, ref l, ref r) = e.node {
+ let lint = |assignee: &hir::Expr, rhs: &hir::Expr| {
+ let ty = cx.tcx.expr_ty(assignee);
+ if ty.walk_shallow().next().is_some() {
+ return; // implements_trait does not work with generics
+ }
+ let rty = cx.tcx.expr_ty(rhs);
+ if rty.walk_shallow().next().is_some() {
+ return; // implements_trait does not work with generics
+ }
+ macro_rules! ops {
+ ($op:expr, $cx:expr, $ty:expr, $rty:expr, $($trait_name:ident:$full_trait_name:ident),+) => {
+ match $op {
+ $(hir::$full_trait_name => {
+ let [krate, module] = ::utils::paths::OPS_MODULE;
+ let path = [krate, module, concat!(stringify!($trait_name), "Assign")];
+ let trait_id = if let Some(trait_id) = get_trait_def_id($cx, &path) {
+ trait_id
+ } else {
+ return; // useless if the trait doesn't exist
+ };
+ implements_trait($cx, $ty, trait_id, vec![$rty])
+ },)*
+ _ => false,
+ }
+ }
+ }
+ if ops!(op.node, cx, ty, rty, Add:BiAdd,
+ Sub:BiSub,
+ Mul:BiMul,
+ Div:BiDiv,
+ Rem:BiRem,
+ And:BiAnd,
+ Or:BiOr,
+ BitAnd:BiBitAnd,
+ BitOr:BiBitOr,
+ BitXor:BiBitXor,
+ Shr:BiShr,
+ Shl:BiShl
+ ) {
+ if let (Some(snip_a), Some(snip_r)) = (snippet_opt(cx, assignee.span), snippet_opt(cx, rhs.span)) {
+ span_lint_and_then(cx,
+ ASSIGN_OP_PATTERN,
+ expr.span,
+ "manual implementation of an assign operation",
+ |db| {
+ db.span_suggestion(expr.span,
+ "replace it with",
+ format!("{} {}= {}", snip_a, op.node.as_str(), snip_r));
+ });
+ } else {
+ span_lint(cx,
+ ASSIGN_OP_PATTERN,
+ expr.span,
+ "manual implementation of an assign operation");
+ }
+ }
+ };
+ // a = a op b
+ if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, l) {
+ lint(assignee, r);
+ }
+ // a = b commutative_op a
+ if SpanlessEq::new(cx).ignore_fn().eq_expr(assignee, r) {
+ match op.node {
+ hir::BiAdd | hir::BiMul |
+ hir::BiAnd | hir::BiOr |
+ hir::BiBitXor | hir::BiBitAnd | hir::BiBitOr => {
+ lint(assignee, l);
+ },
+ _ => {},
+ }
+ }
+ }
+ },
+ _ => {},
+ }
+ }
+}
#![feature(question_mark)]
#![feature(stmt_expr_attributes)]
#![allow(indexing_slicing, shadow_reuse, unknown_lints)]
-#![allow(float_arithmetic, integer_arithmetic)]
extern crate rustc_driver;
extern crate getopts;
pub mod approx_const;
pub mod arithmetic;
pub mod array_indexing;
+pub mod assign_ops;
pub mod attrs;
pub mod bit_mask;
pub mod blacklisted_name;
reg.register_late_lint_pass(box unsafe_removed_from_name::UnsafeNameRemoval);
reg.register_late_lint_pass(box mem_forget::MemForget);
reg.register_late_lint_pass(box arithmetic::Arithmetic::default());
+ reg.register_late_lint_pass(box assign_ops::AssignOps);
reg.register_lint_group("clippy_restrictions", vec![
arithmetic::FLOAT_ARITHMETIC,
arithmetic::INTEGER_ARITHMETIC,
+ assign_ops::ASSIGN_OPS,
]);
reg.register_lint_group("clippy_pedantic", vec![
reg.register_lint_group("clippy", vec![
approx_const::APPROX_CONSTANT,
array_indexing::OUT_OF_BOUNDS_INDEXING,
+ assign_ops::ASSIGN_OP_PATTERN,
attrs::DEPRECATED_SEMVER,
attrs::INLINE_ALWAYS,
bit_mask::BAD_BIT_MASK,
pub const MEM_FORGET: [&'static str; 3] = ["core", "mem", "forget"];
pub const MUTEX: [&'static str; 4] = ["std", "sync", "mutex", "Mutex"];
pub const OPEN_OPTIONS: [&'static str; 3] = ["std", "fs", "OpenOptions"];
+pub const OPS_MODULE: [&'static str; 2] = ["core", "ops"];
pub const OPTION: [&'static str; 3] = ["core", "option", "Option"];
pub const RANGE: [&'static str; 3] = ["core", "ops", "Range"];
pub const RANGE_FROM: [&'static str; 3] = ["core", "ops", "RangeFrom"];
--- /dev/null
+#![feature(plugin)]
+#![plugin(clippy)]
+
+#[deny(assign_ops)]
+#[allow(unused_assignments)]
+fn main() {
+ let mut i = 1i32;
+ i += 2; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i + 2
+ i -= 6; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i - 6
+ i *= 5; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i * 5
+ i /= 32; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i / 32
+ i %= 42; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i % 42
+ i >>= i; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i >> i
+ i <<= 9 + 6 - 7; //~ ERROR assign operation detected
+ //~^ HELP replace it with
+ //~| SUGGESTION i = i << (9 + 6 - 7)
+}
+
+#[allow(dead_code, unused_assignments)]
+#[deny(assign_op_pattern)]
+fn bla() {
+ let mut a = 5;
+ a = a + 1; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a += 1
+ a = 1 + a; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a += 1
+ a = a - 1; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a -= 1
+ a = a * 99; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a *= 99
+ a = 42 * a; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a *= 42
+ a = a / 2; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a /= 2
+ a = a % 5; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a %= 5
+ a = a & 1; //~ ERROR manual implementation of an assign operation
+ //~^ HELP replace it with
+ //~| SUGGESTION a &= 1
+ a = 1 - a;
+ a = 5 / a;
+ a = 42 % a;
+ a = 6 << a;
+ let mut s = String::new();
+ s = s + "bla";
+}
// the add is only caught for String
let mut x = 1;
- x = x + 1;
+ x = x + 1; //~ WARN assign_op_pattern
assert_eq!(2, x);
}
projects / rust.git / commitdiff