mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-12 22:32:59 +00:00
334 lines
12 KiB
Rust
334 lines
12 KiB
Rust
use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_note};
|
||
use clippy_utils::is_span_if;
|
||
use clippy_utils::source::snippet_opt;
|
||
use if_chain::if_chain;
|
||
use rustc_ast::ast::{BinOpKind, Block, Expr, ExprKind, StmtKind, UnOp};
|
||
use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
|
||
use rustc_middle::lint::in_external_macro;
|
||
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
||
use rustc_span::source_map::Span;
|
||
|
||
declare_clippy_lint! {
|
||
/// ### What it does
|
||
/// Checks for use of the non-existent `=*`, `=!` and `=-`
|
||
/// operators.
|
||
///
|
||
/// ### Why is this bad?
|
||
/// This is either a typo of `*=`, `!=` or `-=` or
|
||
/// confusing.
|
||
///
|
||
/// ### Example
|
||
/// ```rust,ignore
|
||
/// a =- 42; // confusing, should it be `a -= 42` or `a = -42`?
|
||
/// ```
|
||
#[clippy::version = "pre 1.29.0"]
|
||
pub SUSPICIOUS_ASSIGNMENT_FORMATTING,
|
||
suspicious,
|
||
"suspicious formatting of `*=`, `-=` or `!=`"
|
||
}
|
||
|
||
declare_clippy_lint! {
|
||
/// ### What it does
|
||
/// Checks the formatting of a unary operator on the right hand side
|
||
/// of a binary operator. It lints if there is no space between the binary and unary operators,
|
||
/// but there is a space between the unary and its operand.
|
||
///
|
||
/// ### Why is this bad?
|
||
/// This is either a typo in the binary operator or confusing.
|
||
///
|
||
/// ### Example
|
||
/// ```rust
|
||
/// # let foo = true;
|
||
/// # let bar = false;
|
||
/// // &&! looks like a different operator
|
||
/// if foo &&! bar {}
|
||
/// ```
|
||
///
|
||
/// Use instead:
|
||
/// ```rust
|
||
/// # let foo = true;
|
||
/// # let bar = false;
|
||
/// if foo && !bar {}
|
||
/// ```
|
||
#[clippy::version = "1.40.0"]
|
||
pub SUSPICIOUS_UNARY_OP_FORMATTING,
|
||
suspicious,
|
||
"suspicious formatting of unary `-` or `!` on the RHS of a BinOp"
|
||
}
|
||
|
||
declare_clippy_lint! {
|
||
/// ### What it does
|
||
/// Checks for formatting of `else`. It lints if the `else`
|
||
/// is followed immediately by a newline or the `else` seems to be missing.
|
||
///
|
||
/// ### Why is this bad?
|
||
/// This is probably some refactoring remnant, even if the
|
||
/// code is correct, it might look confusing.
|
||
///
|
||
/// ### Example
|
||
/// ```rust,ignore
|
||
/// if foo {
|
||
/// } { // looks like an `else` is missing here
|
||
/// }
|
||
///
|
||
/// if foo {
|
||
/// } if bar { // looks like an `else` is missing here
|
||
/// }
|
||
///
|
||
/// if foo {
|
||
/// } else
|
||
///
|
||
/// { // this is the `else` block of the previous `if`, but should it be?
|
||
/// }
|
||
///
|
||
/// if foo {
|
||
/// } else
|
||
///
|
||
/// if bar { // this is the `else` block of the previous `if`, but should it be?
|
||
/// }
|
||
/// ```
|
||
#[clippy::version = "pre 1.29.0"]
|
||
pub SUSPICIOUS_ELSE_FORMATTING,
|
||
suspicious,
|
||
"suspicious formatting of `else`"
|
||
}
|
||
|
||
declare_clippy_lint! {
|
||
/// ### What it does
|
||
/// Checks for possible missing comma in an array. It lints if
|
||
/// an array element is a binary operator expression and it lies on two lines.
|
||
///
|
||
/// ### Why is this bad?
|
||
/// This could lead to unexpected results.
|
||
///
|
||
/// ### Example
|
||
/// ```rust,ignore
|
||
/// let a = &[
|
||
/// -1, -2, -3 // <= no comma here
|
||
/// -4, -5, -6
|
||
/// ];
|
||
/// ```
|
||
#[clippy::version = "pre 1.29.0"]
|
||
pub POSSIBLE_MISSING_COMMA,
|
||
correctness,
|
||
"possible missing comma in array"
|
||
}
|
||
|
||
declare_lint_pass!(Formatting => [
|
||
SUSPICIOUS_ASSIGNMENT_FORMATTING,
|
||
SUSPICIOUS_UNARY_OP_FORMATTING,
|
||
SUSPICIOUS_ELSE_FORMATTING,
|
||
POSSIBLE_MISSING_COMMA
|
||
]);
|
||
|
||
impl EarlyLintPass for Formatting {
|
||
fn check_block(&mut self, cx: &EarlyContext<'_>, block: &Block) {
|
||
for w in block.stmts.windows(2) {
|
||
if let (StmtKind::Expr(first), StmtKind::Expr(second) | StmtKind::Semi(second)) = (&w[0].kind, &w[1].kind) {
|
||
check_missing_else(cx, first, second);
|
||
}
|
||
}
|
||
}
|
||
|
||
fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
|
||
check_assign(cx, expr);
|
||
check_unop(cx, expr);
|
||
check_else(cx, expr);
|
||
check_array(cx, expr);
|
||
}
|
||
}
|
||
|
||
/// Implementation of the `SUSPICIOUS_ASSIGNMENT_FORMATTING` lint.
|
||
fn check_assign(cx: &EarlyContext<'_>, expr: &Expr) {
|
||
if let ExprKind::Assign(ref lhs, ref rhs, _) = expr.kind {
|
||
if !lhs.span.from_expansion() && !rhs.span.from_expansion() {
|
||
let eq_span = lhs.span.between(rhs.span);
|
||
if let ExprKind::Unary(op, ref sub_rhs) = rhs.kind {
|
||
if let Some(eq_snippet) = snippet_opt(cx, eq_span) {
|
||
let op = UnOp::to_string(op);
|
||
let eqop_span = lhs.span.between(sub_rhs.span);
|
||
if eq_snippet.ends_with('=') {
|
||
span_lint_and_note(
|
||
cx,
|
||
SUSPICIOUS_ASSIGNMENT_FORMATTING,
|
||
eqop_span,
|
||
&format!(
|
||
"this looks like you are trying to use `.. {op}= ..`, but you \
|
||
really are doing `.. = ({op} ..)`"
|
||
),
|
||
None,
|
||
&format!("to remove this lint, use either `{op}=` or `= {op}`"),
|
||
);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Implementation of the `SUSPICIOUS_UNARY_OP_FORMATTING` lint.
|
||
fn check_unop(cx: &EarlyContext<'_>, expr: &Expr) {
|
||
if_chain! {
|
||
if let ExprKind::Binary(ref binop, ref lhs, ref rhs) = expr.kind;
|
||
if !lhs.span.from_expansion() && !rhs.span.from_expansion();
|
||
// span between BinOp LHS and RHS
|
||
let binop_span = lhs.span.between(rhs.span);
|
||
// if RHS is an UnOp
|
||
if let ExprKind::Unary(op, ref un_rhs) = rhs.kind;
|
||
// from UnOp operator to UnOp operand
|
||
let unop_operand_span = rhs.span.until(un_rhs.span);
|
||
if let Some(binop_snippet) = snippet_opt(cx, binop_span);
|
||
if let Some(unop_operand_snippet) = snippet_opt(cx, unop_operand_span);
|
||
let binop_str = BinOpKind::to_string(&binop.node);
|
||
// no space after BinOp operator and space after UnOp operator
|
||
if binop_snippet.ends_with(binop_str) && unop_operand_snippet.ends_with(' ');
|
||
then {
|
||
let unop_str = UnOp::to_string(op);
|
||
let eqop_span = lhs.span.between(un_rhs.span);
|
||
span_lint_and_help(
|
||
cx,
|
||
SUSPICIOUS_UNARY_OP_FORMATTING,
|
||
eqop_span,
|
||
&format!(
|
||
"by not having a space between `{binop_str}` and `{unop_str}` it looks like \
|
||
`{binop_str}{unop_str}` is a single operator"
|
||
),
|
||
None,
|
||
&format!(
|
||
"put a space between `{binop_str}` and `{unop_str}` and remove the space after `{unop_str}`"
|
||
),
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Implementation of the `SUSPICIOUS_ELSE_FORMATTING` lint for weird `else`.
|
||
fn check_else(cx: &EarlyContext<'_>, expr: &Expr) {
|
||
if_chain! {
|
||
if let ExprKind::If(_, then, Some(else_)) = &expr.kind;
|
||
if is_block(else_) || is_if(else_);
|
||
if !then.span.from_expansion() && !else_.span.from_expansion();
|
||
if !in_external_macro(cx.sess(), expr.span);
|
||
|
||
// workaround for rust-lang/rust#43081
|
||
if expr.span.lo().0 != 0 && expr.span.hi().0 != 0;
|
||
|
||
// this will be a span from the closing ‘}’ of the “then” block (excluding) to
|
||
// the “if” of the “else if” block (excluding)
|
||
let else_span = then.span.between(else_.span);
|
||
|
||
// the snippet should look like " else \n " with maybe comments anywhere
|
||
// it’s bad when there is a ‘\n’ after the “else”
|
||
if let Some(else_snippet) = snippet_opt(cx, else_span);
|
||
if let Some((pre_else, post_else)) = else_snippet.split_once("else");
|
||
if let Some((_, post_else_post_eol)) = post_else.split_once('\n');
|
||
|
||
then {
|
||
// Allow allman style braces `} \n else \n {`
|
||
if_chain! {
|
||
if is_block(else_);
|
||
if let Some((_, pre_else_post_eol)) = pre_else.split_once('\n');
|
||
// Exactly one eol before and after the else
|
||
if !pre_else_post_eol.contains('\n');
|
||
if !post_else_post_eol.contains('\n');
|
||
then {
|
||
return;
|
||
}
|
||
}
|
||
|
||
let else_desc = if is_if(else_) { "if" } else { "{..}" };
|
||
span_lint_and_note(
|
||
cx,
|
||
SUSPICIOUS_ELSE_FORMATTING,
|
||
else_span,
|
||
&format!("this is an `else {else_desc}` but the formatting might hide it"),
|
||
None,
|
||
&format!(
|
||
"to remove this lint, remove the `else` or remove the new line between \
|
||
`else` and `{else_desc}`",
|
||
),
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
#[must_use]
|
||
fn has_unary_equivalent(bin_op: BinOpKind) -> bool {
|
||
// &, *, -
|
||
bin_op == BinOpKind::And || bin_op == BinOpKind::Mul || bin_op == BinOpKind::Sub
|
||
}
|
||
|
||
fn indentation(cx: &EarlyContext<'_>, span: Span) -> usize {
|
||
cx.sess().source_map().lookup_char_pos(span.lo()).col.0
|
||
}
|
||
|
||
/// Implementation of the `POSSIBLE_MISSING_COMMA` lint for array
|
||
fn check_array(cx: &EarlyContext<'_>, expr: &Expr) {
|
||
if let ExprKind::Array(ref array) = expr.kind {
|
||
for element in array {
|
||
if_chain! {
|
||
if let ExprKind::Binary(ref op, ref lhs, _) = element.kind;
|
||
if has_unary_equivalent(op.node) && lhs.span.ctxt() == op.span.ctxt();
|
||
let space_span = lhs.span.between(op.span);
|
||
if let Some(space_snippet) = snippet_opt(cx, space_span);
|
||
let lint_span = lhs.span.with_lo(lhs.span.hi());
|
||
if space_snippet.contains('\n');
|
||
if indentation(cx, op.span) <= indentation(cx, lhs.span);
|
||
then {
|
||
span_lint_and_note(
|
||
cx,
|
||
POSSIBLE_MISSING_COMMA,
|
||
lint_span,
|
||
"possibly missing a comma here",
|
||
None,
|
||
"to remove this lint, add a comma or write the expr in a single line",
|
||
);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
fn check_missing_else(cx: &EarlyContext<'_>, first: &Expr, second: &Expr) {
|
||
if_chain! {
|
||
if !first.span.from_expansion() && !second.span.from_expansion();
|
||
if matches!(first.kind, ExprKind::If(..));
|
||
if is_block(second) || is_if(second);
|
||
|
||
// Proc-macros can give weird spans. Make sure this is actually an `if`.
|
||
if is_span_if(cx, first.span);
|
||
|
||
// If there is a line break between the two expressions, don't lint.
|
||
// If there is a non-whitespace character, this span came from a proc-macro.
|
||
let else_span = first.span.between(second.span);
|
||
if let Some(else_snippet) = snippet_opt(cx, else_span);
|
||
if !else_snippet.chars().any(|c| c == '\n' || !c.is_whitespace());
|
||
then {
|
||
let (looks_like, next_thing) = if is_if(second) {
|
||
("an `else if`", "the second `if`")
|
||
} else {
|
||
("an `else {..}`", "the next block")
|
||
};
|
||
|
||
span_lint_and_note(
|
||
cx,
|
||
SUSPICIOUS_ELSE_FORMATTING,
|
||
else_span,
|
||
&format!("this looks like {looks_like} but the `else` is missing"),
|
||
None,
|
||
&format!(
|
||
"to remove this lint, add the missing `else` or add a new line before {next_thing}",
|
||
),
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
fn is_block(expr: &Expr) -> bool {
|
||
matches!(expr.kind, ExprKind::Block(..))
|
||
}
|
||
|
||
/// Check if the expression is an `if` or `if let`
|
||
fn is_if(expr: &Expr) -> bool {
|
||
matches!(expr.kind, ExprKind::If(..))
|
||
}
|