//! lint on if branches that could be swapped so no `!` operation is necessary
//! on the condition
-use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass, in_external_macro, LintContext};
-use rustc::{declare_tool_lint, lint_array};
-use syntax::ast::*;
+use rustc_ast::ast::{BinOpKind, Expr, ExprKind, UnOp};
+use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
-use crate::utils::span_help_and_lint;
+use crate::utils::span_lint_and_help;
-/// **What it does:** Checks for usage of `!` or `!=` in an if condition with an
-/// else branch.
-///
-/// **Why is this bad?** Negations reduce the readability of statements.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// if !v.is_empty() {
-/// a()
-/// } else {
-/// b()
-/// }
-/// ```
-///
-/// Could be written:
-///
-/// ```rust
-/// if v.is_empty() {
-/// b()
-/// } else {
-/// a()
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `!` or `!=` in an if condition with an
+ /// else branch.
+ ///
+ /// **Why is this bad?** Negations reduce the readability of statements.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let v: Vec<usize> = vec![];
+ /// # fn a() {}
+ /// # fn b() {}
+ /// if !v.is_empty() {
+ /// a()
+ /// } else {
+ /// b()
+ /// }
+ /// ```
+ ///
+ /// Could be written:
+ ///
+ /// ```rust
+ /// # let v: Vec<usize> = vec![];
+ /// # fn a() {}
+ /// # fn b() {}
+ /// if v.is_empty() {
+ /// b()
+ /// } else {
+ /// a()
+ /// }
+ /// ```
pub IF_NOT_ELSE,
pedantic,
"`if` branches that could be swapped so no negation operation is necessary on the condition"
}
-pub struct IfNotElse;
-
-impl LintPass for IfNotElse {
- fn get_lints(&self) -> LintArray {
- lint_array!(IF_NOT_ELSE)
- }
-}
+declare_lint_pass!(IfNotElse => [IF_NOT_ELSE]);
impl EarlyLintPass for IfNotElse {
fn check_expr(&mut self, cx: &EarlyContext<'_>, item: &Expr) {
if in_external_macro(cx.sess(), item.span) {
return;
}
- if let ExprKind::If(ref cond, _, Some(ref els)) = item.node {
- if let ExprKind::Block(..) = els.node {
- match cond.node {
+ if let ExprKind::If(ref cond, _, Some(ref els)) = item.kind {
+ if let ExprKind::Block(..) = els.kind {
+ match cond.kind {
ExprKind::Unary(UnOp::Not, _) => {
- span_help_and_lint(
+ span_lint_and_help(
cx,
IF_NOT_ELSE,
item.span,
- "Unnecessary boolean `not` operation",
- "remove the `!` and swap the blocks of the if/else",
+ "unnecessary boolean `not` operation",
+ None,
+ "remove the `!` and swap the blocks of the `if`/`else`",
);
},
ExprKind::Binary(ref kind, _, _) if kind.node == BinOpKind::Ne => {
- span_help_and_lint(
+ span_lint_and_help(
cx,
IF_NOT_ELSE,
item.span,
- "Unnecessary `!=` operation",
- "change to `==` and swap the blocks of the if/else",
+ "unnecessary `!=` operation",
+ None,
+ "change to `==` and swap the blocks of the `if`/`else`",
);
},
_ => (),