//! lint on blocks unnecessarily using >= with a + 1 or - 1
-use rustc::lint::*;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_lint_pass, declare_tool_lint};
+use rustc_errors::Applicability;
use syntax::ast::*;
-use utils::{span_lint_and_then, snippet_opt};
+use crate::utils::{snippet_opt, span_lint_and_then};
-/// **What it does:** Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
-///
-///
-/// **Why is this bad?** Readability -- better to use `> y` instead of `>= y + 1`.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// x >= y + 1
-/// ```
-///
-/// Could be written:
-///
-/// ```rust
-/// x > y
-/// ```
-declare_lint! {
+declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
+ ///
+ ///
+ /// **Why is this bad?** Readability -- better to use `> y` instead of `>= y + 1`.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let x = 1;
+ /// # let y = 1;
+ /// if x >= y + 1 {}
+ /// ```
+ ///
+ /// Could be written as:
+ ///
+ /// ```rust
+ /// # let x = 1;
+ /// # let y = 1;
+ /// if x > y {}
+ /// ```
pub INT_PLUS_ONE,
- Allow,
+ complexity,
"instead of using x >= y + 1, use x > y"
}
-pub struct IntPlusOne;
-
-impl LintPass for IntPlusOne {
- fn get_lints(&self) -> LintArray {
- lint_array!(INT_PLUS_ONE)
- }
-}
+declare_lint_pass!(IntPlusOne => [INT_PLUS_ONE]);
// cases:
// BinOpKind::Ge
// x + 1 <= y
// x <= y - 1
+#[derive(Copy, Clone)]
enum Side {
LHS,
RHS,
}
impl IntPlusOne {
- #[allow(cast_sign_loss)]
- fn check_lit(&self, lit: &Lit, target_value: i128) -> bool {
+ #[allow(clippy::cast_sign_loss)]
+ fn check_lit(self, lit: &Lit, target_value: i128) -> bool {
if let LitKind::Int(value, ..) = lit.node {
- return value == (target_value as u128)
+ return value == (target_value as u128);
}
false
}
- fn check_binop(&self, cx: &EarlyContext, binop: BinOpKind, lhs: &Expr, rhs: &Expr) -> Option<String> {
+ fn check_binop(self, cx: &EarlyContext<'_>, binop: BinOpKind, lhs: &Expr, rhs: &Expr) -> Option<String> {
match (binop, &lhs.node, &rhs.node) {
// case where `x - 1 >= ...` or `-1 + x >= ...`
(BinOpKind::Ge, &ExprKind::Binary(ref lhskind, ref lhslhs, ref lhsrhs), _) => {
match (lhskind.node, &lhslhs.node, &lhsrhs.node) {
// `-1 + x`
- (BinOpKind::Add, &ExprKind::Lit(ref lit), _) if self.check_lit(lit, -1) => self.generate_recommendation(cx, binop, lhsrhs, rhs, Side::LHS),
+ (BinOpKind::Add, &ExprKind::Lit(ref lit), _) if self.check_lit(lit, -1) => {
+ self.generate_recommendation(cx, binop, lhsrhs, rhs, Side::LHS)
+ },
// `x - 1`
- (BinOpKind::Sub, _, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, lhslhs, rhs, Side::LHS),
- _ => None
+ (BinOpKind::Sub, _, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, lhslhs, rhs, Side::LHS)
+ },
+ _ => None,
}
},
// case where `... >= y + 1` or `... >= 1 + y`
- (BinOpKind::Ge, _, &ExprKind::Binary(ref rhskind, ref rhslhs, ref rhsrhs)) if rhskind.node == BinOpKind::Add => {
+ (BinOpKind::Ge, _, &ExprKind::Binary(ref rhskind, ref rhslhs, ref rhsrhs))
+ if rhskind.node == BinOpKind::Add =>
+ {
match (&rhslhs.node, &rhsrhs.node) {
// `y + 1` and `1 + y`
- (&ExprKind::Lit(ref lit), _) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, rhsrhs, lhs, Side::RHS),
- (_, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, rhslhs, lhs, Side::RHS),
- _ => None
+ (&ExprKind::Lit(ref lit), _) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, rhsrhs, lhs, Side::RHS)
+ },
+ (_, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, rhslhs, lhs, Side::RHS)
+ },
+ _ => None,
}
- },
+ }
// case where `x + 1 <= ...` or `1 + x <= ...`
- (BinOpKind::Le, &ExprKind::Binary(ref lhskind, ref lhslhs, ref lhsrhs), _) if lhskind.node == BinOpKind::Add => {
+ (BinOpKind::Le, &ExprKind::Binary(ref lhskind, ref lhslhs, ref lhsrhs), _)
+ if lhskind.node == BinOpKind::Add =>
+ {
match (&lhslhs.node, &lhsrhs.node) {
// `1 + x` and `x + 1`
- (&ExprKind::Lit(ref lit), _) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, lhsrhs, rhs, Side::LHS),
- (_, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, lhslhs, rhs, Side::LHS),
- _ => None
+ (&ExprKind::Lit(ref lit), _) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, lhsrhs, rhs, Side::LHS)
+ },
+ (_, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, lhslhs, rhs, Side::LHS)
+ },
+ _ => None,
}
- },
+ }
// case where `... >= y - 1` or `... >= -1 + y`
(BinOpKind::Le, _, &ExprKind::Binary(ref rhskind, ref rhslhs, ref rhsrhs)) => {
match (rhskind.node, &rhslhs.node, &rhsrhs.node) {
// `-1 + y`
- (BinOpKind::Add, &ExprKind::Lit(ref lit), _) if self.check_lit(lit, -1) => self.generate_recommendation(cx, binop, rhsrhs, lhs, Side::RHS),
+ (BinOpKind::Add, &ExprKind::Lit(ref lit), _) if self.check_lit(lit, -1) => {
+ self.generate_recommendation(cx, binop, rhsrhs, lhs, Side::RHS)
+ },
// `y - 1`
- (BinOpKind::Sub, _, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => self.generate_recommendation(cx, binop, rhslhs, lhs, Side::RHS),
- _ => None
+ (BinOpKind::Sub, _, &ExprKind::Lit(ref lit)) if self.check_lit(lit, 1) => {
+ self.generate_recommendation(cx, binop, rhslhs, lhs, Side::RHS)
+ },
+ _ => None,
}
},
- _ => None
+ _ => None,
}
}
- fn generate_recommendation(&self, cx: &EarlyContext, binop: BinOpKind, node: &Expr, other_side: &Expr, side: Side) -> Option<String> {
+ fn generate_recommendation(
+ self,
+ cx: &EarlyContext<'_>,
+ binop: BinOpKind,
+ node: &Expr,
+ other_side: &Expr,
+ side: Side,
+ ) -> Option<String> {
let binop_string = match binop {
BinOpKind::Ge => ">",
BinOpKind::Le => "<",
- _ => return None
+ _ => return None,
};
if let Some(snippet) = snippet_opt(cx, node.span) {
if let Some(other_side_snippet) = snippet_opt(cx, other_side.span) {
None
}
- fn emit_warning(&self, cx: &EarlyContext, block: &Expr, recommendation: String) {
- span_lint_and_then(cx,
- INT_PLUS_ONE,
- block.span,
- "Unnecessary `>= y + 1` or `x - 1 >=`",
- |db| {
- db.span_suggestion(block.span, "change `>= y + 1` to `> y` as shown", recommendation);
- });
+ fn emit_warning(self, cx: &EarlyContext<'_>, block: &Expr, recommendation: String) {
+ span_lint_and_then(
+ cx,
+ INT_PLUS_ONE,
+ block.span,
+ "Unnecessary `>= y + 1` or `x - 1 >=`",
+ |db| {
+ db.span_suggestion(
+ block.span,
+ "change it to",
+ recommendation,
+ Applicability::MachineApplicable, // snippet
+ );
+ },
+ );
}
}
impl EarlyLintPass for IntPlusOne {
- fn check_expr(&mut self, cx: &EarlyContext, item: &Expr) {
+ fn check_expr(&mut self, cx: &EarlyContext<'_>, item: &Expr) {
if let ExprKind::Binary(ref kind, ref lhs, ref rhs) = item.node {
if let Some(ref rec) = self.check_binop(cx, kind.node, lhs, rhs) {
self.emit_warning(cx, item, rec.clone());
projects / rust.git / blobdiff