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Move AssignOps into Operators lint pass

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This commit is contained in:
Jason Newcomb 2022-05-31 21:57:32 -04:00
parent 448b6f45bd
commit 751131b4ac
9 changed files with 261 additions and 243 deletions
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235
clippy_lints/src/assign_ops.rs
View File

@ -1,235 +0,0 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::implements_trait;
use clippy_utils::{binop_traits, sugg};
use clippy_utils::{eq_expr_value, trait_ref_of_method};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::intravisit::{walk_expr, Visitor};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// ### What it does
/// Checks 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
/// While forbidden by the spec, `OpAssign` traits may have
/// implementations that differ from the regular `Op` impl.
///
/// ### Example
/// ```rust
/// let mut a = 5;
/// let b = 0;
/// // ...
///
/// a = a + b;
/// ```
///
/// Use instead:
/// ```rust
/// let mut a = 5;
/// let b = 0;
/// // ...
///
/// a += b;
/// ```
#[clippy::version = "pre 1.29.0"]
pub ASSIGN_OP_PATTERN,
style,
"assigning the result of an operation on a variable to that same variable"
}
declare_clippy_lint! {
/// ### What it does
/// Checks for `a op= a op b` or `a op= b op a` patterns.
///
/// ### Why is this bad?
/// Most likely these are bugs where one meant to write `a
/// op= b`.
///
/// ### Known problems
/// Clippy cannot know for sure if `a op= a op b` should have
/// been `a = a op a op b` or `a = a op b`/`a op= b`. Therefore, it suggests both.
/// If `a op= a op b` is really the correct behavior it should be
/// written as `a = a op a op b` as it's less confusing.
///
/// ### Example
/// ```rust
/// let mut a = 5;
/// let b = 2;
/// // ...
/// a += a + b;
/// ```
#[clippy::version = "pre 1.29.0"]
pub MISREFACTORED_ASSIGN_OP,
suspicious,
"having a variable on both sides of an assign op"
}
declare_lint_pass!(AssignOps => [ASSIGN_OP_PATTERN, MISREFACTORED_ASSIGN_OP]);
impl<'tcx> LateLintPass<'tcx> for AssignOps {
#[allow(clippy::too_many_lines)]
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
match &expr.kind {
hir::ExprKind::AssignOp(op, lhs, rhs) => {
if let hir::ExprKind::Binary(binop, l, r) = &rhs.kind {
if op.node != binop.node {
return;
}
// lhs op= l op r
if eq_expr_value(cx, lhs, l) {
lint_misrefactored_assign_op(cx, expr, *op, rhs, lhs, r);
}
// lhs op= l commutative_op r
if is_commutative(op.node) && eq_expr_value(cx, lhs, r) {
lint_misrefactored_assign_op(cx, expr, *op, rhs, lhs, l);
}
}
},
hir::ExprKind::Assign(assignee, e, _) => {
if let hir::ExprKind::Binary(op, l, r) = &e.kind {
let lint = |assignee: &hir::Expr<'_>, rhs: &hir::Expr<'_>| {
let ty = cx.typeck_results().expr_ty(assignee);
let rty = cx.typeck_results().expr_ty(rhs);
if_chain! {
if let Some((_, lang_item)) = binop_traits(op.node);
if let Ok(trait_id) = cx.tcx.lang_items().require(lang_item);
let parent_fn = cx.tcx.hir().get_parent_item(e.hir_id);
if trait_ref_of_method(cx, parent_fn)
.map_or(true, |t| t.path.res.def_id() != trait_id);
if implements_trait(cx, ty, trait_id, &[rty.into()]);
then {
span_lint_and_then(
cx,
ASSIGN_OP_PATTERN,
expr.span,
"manual implementation of an assign operation",
|diag| {
if let (Some(snip_a), Some(snip_r)) =
(snippet_opt(cx, assignee.span), snippet_opt(cx, rhs.span))
{
diag.span_suggestion(
expr.span,
"replace it with",
format!("{} {}= {}", snip_a, op.node.as_str(), snip_r),
Applicability::MachineApplicable,
);
}
},
);
}
}
};
let mut visitor = ExprVisitor {
assignee,
counter: 0,
cx,
};
walk_expr(&mut visitor, e);
if visitor.counter == 1 {
// a = a op b
if eq_expr_value(cx, assignee, l) {
lint(assignee, r);
}
// a = b commutative_op a
// Limited to primitive type as these ops are know to be commutative
if eq_expr_value(cx, assignee, r) && cx.typeck_results().expr_ty(assignee).is_primitive_ty() {
match op.node {
hir::BinOpKind::Add
| hir::BinOpKind::Mul
| hir::BinOpKind::And
| hir::BinOpKind::Or
| hir::BinOpKind::BitXor
| hir::BinOpKind::BitAnd
| hir::BinOpKind::BitOr => {
lint(assignee, l);
},
_ => {},
}
}
}
}
},
_ => {},
}
}
}
fn lint_misrefactored_assign_op(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
op: hir::BinOp,
rhs: &hir::Expr<'_>,
assignee: &hir::Expr<'_>,
rhs_other: &hir::Expr<'_>,
) {
span_lint_and_then(
cx,
MISREFACTORED_ASSIGN_OP,
expr.span,
"variable appears on both sides of an assignment operation",
|diag| {
if let (Some(snip_a), Some(snip_r)) = (snippet_opt(cx, assignee.span), snippet_opt(cx, rhs_other.span)) {
let a = &sugg::Sugg::hir(cx, assignee, "..");
let r = &sugg::Sugg::hir(cx, rhs, "..");
let long = format!("{} = {}", snip_a, sugg::make_binop(op.node.into(), a, r));
diag.span_suggestion(
expr.span,
&format!(
"did you mean `{} = {} {} {}` or `{}`? Consider replacing it with",
snip_a,
snip_a,
op.node.as_str(),
snip_r,
long
),
format!("{} {}= {}", snip_a, op.node.as_str(), snip_r),
Applicability::MaybeIncorrect,
);
diag.span_suggestion(
expr.span,
"or",
long,
Applicability::MaybeIncorrect, // snippet
);
}
},
);
}
#[must_use]
fn is_commutative(op: hir::BinOpKind) -> bool {
use rustc_hir::BinOpKind::{
Add, And, BitAnd, BitOr, BitXor, Div, Eq, Ge, Gt, Le, Lt, Mul, Ne, Or, Rem, Shl, Shr, Sub,
};
match op {
Add | Mul | And | Or | BitXor | BitAnd | BitOr | Eq | Ne => true,
Sub | Div | Rem | Shl | Shr | Lt | Le | Ge | Gt => false,
}
}
struct ExprVisitor<'a, 'tcx> {
assignee: &'a hir::Expr<'a>,
counter: u8,
cx: &'a LateContext<'tcx>,
}
impl<'a, 'tcx> Visitor<'tcx> for ExprVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
if eq_expr_value(self.cx, self.assignee, expr) {
self.counter += 1;
}
walk_expr(self, expr);
}
}

4
clippy_lints/src/lib.register_all.rs
View File

@ -6,8 +6,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
LintId::of(almost_complete_letter_range::ALMOST_COMPLETE_LETTER_RANGE),
LintId::of(approx_const::APPROX_CONSTANT),
LintId::of(assertions_on_constants::ASSERTIONS_ON_CONSTANTS),
LintId::of(assign_ops::ASSIGN_OP_PATTERN),
LintId::of(assign_ops::MISREFACTORED_ASSIGN_OP),
LintId::of(async_yields_async::ASYNC_YIELDS_ASYNC),
LintId::of(attrs::BLANKET_CLIPPY_RESTRICTION_LINTS),
LintId::of(attrs::DEPRECATED_CFG_ATTR),
@ -260,6 +258,8 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
LintId::of(octal_escapes::OCTAL_ESCAPES),
LintId::of(open_options::NONSENSICAL_OPEN_OPTIONS),
LintId::of(operators::ABSURD_EXTREME_COMPARISONS),
LintId::of(operators::ASSIGN_OP_PATTERN),
LintId::of(operators::MISREFACTORED_ASSIGN_OP),
LintId::of(option_env_unwrap::OPTION_ENV_UNWRAP),
LintId::of(overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL),
LintId::of(partialeq_ne_impl::PARTIALEQ_NE_IMPL),

4
clippy_lints/src/lib.register_lints.rs
View File

@ -42,8 +42,6 @@ store.register_lints(&[
asm_syntax::INLINE_ASM_X86_ATT_SYNTAX,
asm_syntax::INLINE_ASM_X86_INTEL_SYNTAX,
assertions_on_constants::ASSERTIONS_ON_CONSTANTS,
assign_ops::ASSIGN_OP_PATTERN,
assign_ops::MISREFACTORED_ASSIGN_OP,
async_yields_async::ASYNC_YIELDS_ASYNC,
attrs::ALLOW_ATTRIBUTES_WITHOUT_REASON,
attrs::BLANKET_CLIPPY_RESTRICTION_LINTS,
@ -435,8 +433,10 @@ store.register_lints(&[
only_used_in_recursion::ONLY_USED_IN_RECURSION,
open_options::NONSENSICAL_OPEN_OPTIONS,
operators::ABSURD_EXTREME_COMPARISONS,
operators::ASSIGN_OP_PATTERN,
operators::FLOAT_ARITHMETIC,
operators::INTEGER_ARITHMETIC,
operators::MISREFACTORED_ASSIGN_OP,
option_env_unwrap::OPTION_ENV_UNWRAP,
option_if_let_else::OPTION_IF_LET_ELSE,
overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL,

2
clippy_lints/src/lib.register_style.rs
View File

@ -4,7 +4,6 @@
store.register_group(true, "clippy::style", Some("clippy_style"), vec![
LintId::of(assertions_on_constants::ASSERTIONS_ON_CONSTANTS),
LintId::of(assign_ops::ASSIGN_OP_PATTERN),
LintId::of(blacklisted_name::BLACKLISTED_NAME),
LintId::of(blocks_in_if_conditions::BLOCKS_IN_IF_CONDITIONS),
LintId::of(bool_assert_comparison::BOOL_ASSERT_COMPARISON),
@ -98,6 +97,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
LintId::of(non_copy_const::BORROW_INTERIOR_MUTABLE_CONST),
LintId::of(non_copy_const::DECLARE_INTERIOR_MUTABLE_CONST),
LintId::of(non_expressive_names::JUST_UNDERSCORES_AND_DIGITS),
LintId::of(operators::ASSIGN_OP_PATTERN),
LintId::of(ptr::CMP_NULL),
LintId::of(ptr::PTR_ARG),
LintId::of(ptr_eq::PTR_EQ),

2
clippy_lints/src/lib.register_suspicious.rs
View File

@ -4,7 +4,6 @@
store.register_group(true, "clippy::suspicious", Some("clippy_suspicious"), vec![
LintId::of(almost_complete_letter_range::ALMOST_COMPLETE_LETTER_RANGE),
LintId::of(assign_ops::MISREFACTORED_ASSIGN_OP),
LintId::of(attrs::BLANKET_CLIPPY_RESTRICTION_LINTS),
LintId::of(await_holding_invalid::AWAIT_HOLDING_INVALID_TYPE),
LintId::of(await_holding_invalid::AWAIT_HOLDING_LOCK),
@ -29,6 +28,7 @@ store.register_group(true, "clippy::suspicious", Some("clippy_suspicious"), vec!
LintId::of(methods::SUSPICIOUS_MAP),
LintId::of(mut_key::MUTABLE_KEY_TYPE),
LintId::of(octal_escapes::OCTAL_ESCAPES),
LintId::of(operators::MISREFACTORED_ASSIGN_OP),
LintId::of(rc_clone_in_vec_init::RC_CLONE_IN_VEC_INIT),
LintId::of(suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL),
LintId::of(suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),

2
clippy_lints/src/lib.rs
View File

@ -174,7 +174,6 @@ mod as_conversions;
mod as_underscore;
mod asm_syntax;
mod assertions_on_constants;
mod assign_ops;
mod async_yields_async;
mod attrs;
mod await_holding_invalid;
@ -704,7 +703,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(move || Box::new(doc::DocMarkdown::new(doc_valid_idents.clone())));
store.register_late_pass(|| Box::new(neg_multiply::NegMultiply));
store.register_late_pass(|| Box::new(mem_forget::MemForget));
store.register_late_pass(|| Box::new(assign_ops::AssignOps));
store.register_late_pass(|| Box::new(let_if_seq::LetIfSeq));
store.register_late_pass(|| Box::new(mixed_read_write_in_expression::EvalOrderDependence));
store.register_late_pass(|| Box::new(missing_doc::MissingDoc::new()));

101
clippy_lints/src/operators/assign_op_pattern.rs Normal file
View File

@ -0,0 +1,101 @@
use clippy_utils::binop_traits;
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::implements_trait;
use clippy_utils::{eq_expr_value, trait_ref_of_method};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::intravisit::{walk_expr, Visitor};
use rustc_lint::LateContext;
use super::ASSIGN_OP_PATTERN;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
assignee: &'tcx hir::Expr<'_>,
e: &'tcx hir::Expr<'_>,
) {
if let hir::ExprKind::Binary(op, l, r) = &e.kind {
let lint = |assignee: &hir::Expr<'_>, rhs: &hir::Expr<'_>| {
let ty = cx.typeck_results().expr_ty(assignee);
let rty = cx.typeck_results().expr_ty(rhs);
if_chain! {
if let Some((_, lang_item)) = binop_traits(op.node);
if let Ok(trait_id) = cx.tcx.lang_items().require(lang_item);
let parent_fn = cx.tcx.hir().get_parent_item(e.hir_id);
if trait_ref_of_method(cx, parent_fn)
.map_or(true, |t| t.path.res.def_id() != trait_id);
if implements_trait(cx, ty, trait_id, &[rty.into()]);
then {
span_lint_and_then(
cx,
ASSIGN_OP_PATTERN,
expr.span,
"manual implementation of an assign operation",
|diag| {
if let (Some(snip_a), Some(snip_r)) =
(snippet_opt(cx, assignee.span), snippet_opt(cx, rhs.span))
{
diag.span_suggestion(
expr.span,
"replace it with",
format!("{} {}= {}", snip_a, op.node.as_str(), snip_r),
Applicability::MachineApplicable,
);
}
},
);
}
}
};
let mut visitor = ExprVisitor {
assignee,
counter: 0,
cx,
};
walk_expr(&mut visitor, e);
if visitor.counter == 1 {
// a = a op b
if eq_expr_value(cx, assignee, l) {
lint(assignee, r);
}
// a = b commutative_op a
// Limited to primitive type as these ops are know to be commutative
if eq_expr_value(cx, assignee, r) && cx.typeck_results().expr_ty(assignee).is_primitive_ty() {
match op.node {
hir::BinOpKind::Add
| hir::BinOpKind::Mul
| hir::BinOpKind::And
| hir::BinOpKind::Or
| hir::BinOpKind::BitXor
| hir::BinOpKind::BitAnd
| hir::BinOpKind::BitOr => {
lint(assignee, l);
},
_ => {},
}
}
}
}
}
struct ExprVisitor<'a, 'tcx> {
assignee: &'a hir::Expr<'a>,
counter: u8,
cx: &'a LateContext<'tcx>,
}
impl<'a, 'tcx> Visitor<'tcx> for ExprVisitor<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
if eq_expr_value(self.cx, self.assignee, expr) {
self.counter += 1;
}
walk_expr(self, expr);
}
}

84
clippy_lints/src/operators/misrefactored_assign_op.rs Normal file
View File

@ -0,0 +1,84 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::eq_expr_value;
use clippy_utils::source::snippet_opt;
use clippy_utils::sugg;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::MISREFACTORED_ASSIGN_OP;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
op: hir::BinOpKind,
lhs: &'tcx hir::Expr<'_>,
rhs: &'tcx hir::Expr<'_>,
) {
if let hir::ExprKind::Binary(binop, l, r) = &rhs.kind {
if op != binop.node {
return;
}
// lhs op= l op r
if eq_expr_value(cx, lhs, l) {
lint_misrefactored_assign_op(cx, expr, op, rhs, lhs, r);
}
// lhs op= l commutative_op r
if is_commutative(op) && eq_expr_value(cx, lhs, r) {
lint_misrefactored_assign_op(cx, expr, op, rhs, lhs, l);
}
}
}
fn lint_misrefactored_assign_op(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
op: hir::BinOpKind,
rhs: &hir::Expr<'_>,
assignee: &hir::Expr<'_>,
rhs_other: &hir::Expr<'_>,
) {
span_lint_and_then(
cx,
MISREFACTORED_ASSIGN_OP,
expr.span,
"variable appears on both sides of an assignment operation",
|diag| {
if let (Some(snip_a), Some(snip_r)) = (snippet_opt(cx, assignee.span), snippet_opt(cx, rhs_other.span)) {
let a = &sugg::Sugg::hir(cx, assignee, "..");
let r = &sugg::Sugg::hir(cx, rhs, "..");
let long = format!("{} = {}", snip_a, sugg::make_binop(op.into(), a, r));
diag.span_suggestion(
expr.span,
&format!(
"did you mean `{} = {} {} {}` or `{}`? Consider replacing it with",
snip_a,
snip_a,
op.as_str(),
snip_r,
long
),
format!("{} {}= {}", snip_a, op.as_str(), snip_r),
Applicability::MaybeIncorrect,
);
diag.span_suggestion(
expr.span,
"or",
long,
Applicability::MaybeIncorrect, // snippet
);
}
},
);
}
#[must_use]
fn is_commutative(op: hir::BinOpKind) -> bool {
use rustc_hir::BinOpKind::{
Add, And, BitAnd, BitOr, BitXor, Div, Eq, Ge, Gt, Le, Lt, Mul, Ne, Or, Rem, Shl, Shr, Sub,
};
match op {
Add | Mul | And | Or | BitXor | BitAnd | BitOr | Eq | Ne => true,
Sub | Div | Rem | Shl | Shr | Lt | Le | Ge | Gt => false,
}
}

70
clippy_lints/src/operators/mod.rs
View File

@ -3,6 +3,8 @@ use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
mod absurd_extreme_comparisons;
mod assign_op_pattern;
mod misrefactored_assign_op;
mod numeric_arithmetic;
declare_clippy_lint! {
@ -82,6 +84,68 @@ declare_clippy_lint! {
"any floating-point arithmetic statement"
}
declare_clippy_lint! {
/// ### What it does
/// Checks 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
/// While forbidden by the spec, `OpAssign` traits may have
/// implementations that differ from the regular `Op` impl.
///
/// ### Example
/// ```rust
/// let mut a = 5;
/// let b = 0;
/// // ...
///
/// a = a + b;
/// ```
///
/// Use instead:
/// ```rust
/// let mut a = 5;
/// let b = 0;
/// // ...
///
/// a += b;
/// ```
#[clippy::version = "pre 1.29.0"]
pub ASSIGN_OP_PATTERN,
style,
"assigning the result of an operation on a variable to that same variable"
}
declare_clippy_lint! {
/// ### What it does
/// Checks for `a op= a op b` or `a op= b op a` patterns.
///
/// ### Why is this bad?
/// Most likely these are bugs where one meant to write `a
/// op= b`.
///
/// ### Known problems
/// Clippy cannot know for sure if `a op= a op b` should have
/// been `a = a op a op b` or `a = a op b`/`a op= b`. Therefore, it suggests both.
/// If `a op= a op b` is really the correct behavior it should be
/// written as `a = a op a op b` as it's less confusing.
///
/// ### Example
/// ```rust
/// let mut a = 5;
/// let b = 2;
/// // ...
/// a += a + b;
/// ```
#[clippy::version = "pre 1.29.0"]
pub MISREFACTORED_ASSIGN_OP,
suspicious,
"having a variable on both sides of an assign op"
}
#[derive(Default)]
pub struct Operators {
arithmetic_context: numeric_arithmetic::Context,
@ -90,6 +154,8 @@ impl_lint_pass!(Operators => [
ABSURD_EXTREME_COMPARISONS,
INTEGER_ARITHMETIC,
FLOAT_ARITHMETIC,
ASSIGN_OP_PATTERN,
MISREFACTORED_ASSIGN_OP,
]);
impl<'tcx> LateLintPass<'tcx> for Operators {
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
@ -102,6 +168,10 @@ impl<'tcx> LateLintPass<'tcx> for Operators {
},
ExprKind::AssignOp(op, lhs, rhs) => {
self.arithmetic_context.check_binary(cx, e, op.node, lhs, rhs);
misrefactored_assign_op::check(cx, e, op.node, lhs, rhs);
},
ExprKind::Assign(lhs, rhs, _) => {
assign_op_pattern::check(cx, e, lhs, rhs);
},
ExprKind::Unary(op, arg) => {
if op == UnOp::Neg {