-use rustc::lint::*;
+use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
+use rustc::declare_lint_pass;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc_errors::Applicability;
+use rustc_session::declare_tool_lint;
use syntax::ast::*;
-use syntax::codemap::Spanned;
-use utils::{span_lint, snippet};
+use syntax::source_map::Spanned;
-/// **What it does:** Checks for operations where precedence may be unclear
-/// and suggests to add parentheses. Currently it catches the following:
-/// * mixed usage of arithmetic and bit shifting/combining operators without parentheses
-/// * a "negative" numeric literal (which is really a unary `-` followed by a numeric literal)
-/// followed by a method call
-///
-/// **Why is this bad?** Not everyone knows the precedence of those operators by
-/// heart, so expressions like these may trip others trying to reason about the
-/// code.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// * `1 << 2 + 3` equals 32, while `(1 << 2) + 3` equals 7
-/// * `-1i32.abs()` equals -1, while `(-1i32).abs()` equals 1
-declare_lint! {
+declare_clippy_lint! {
+ /// **What it does:** Checks for operations where precedence may be unclear
+ /// and suggests to add parentheses. Currently it catches the following:
+ /// * mixed usage of arithmetic and bit shifting/combining operators without
+ /// parentheses
+ /// * a "negative" numeric literal (which is really a unary `-` followed by a
+ /// numeric literal)
+ /// followed by a method call
+ ///
+ /// **Why is this bad?** Not everyone knows the precedence of those operators by
+ /// heart, so expressions like these may trip others trying to reason about the
+ /// code.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// * `1 << 2 + 3` equals 32, while `(1 << 2) + 3` equals 7
+ /// * `-1i32.abs()` equals -1, while `(-1i32).abs()` equals 1
pub PRECEDENCE,
- Warn,
+ complexity,
"operations where precedence may be unclear"
}
-#[derive(Copy,Clone)]
-pub struct Precedence;
-
-impl LintPass for Precedence {
- fn get_lints(&self) -> LintArray {
- lint_array!(PRECEDENCE)
- }
-}
+declare_lint_pass!(Precedence => [PRECEDENCE]);
impl EarlyLintPass for Precedence {
- fn check_expr(&mut self, cx: &EarlyContext, expr: &Expr) {
- if let ExprKind::Binary(Spanned { node: op, .. }, ref left, ref right) = expr.node {
+ fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+ if expr.span.from_expansion() {
+ return;
+ }
+
+ if let ExprKind::Binary(Spanned { node: op, .. }, ref left, ref right) = expr.kind {
+ let span_sugg = |expr: &Expr, sugg, appl| {
+ span_lint_and_sugg(
+ cx,
+ PRECEDENCE,
+ expr.span,
+ "operator precedence can trip the unwary",
+ "consider parenthesizing your expression",
+ sugg,
+ appl,
+ );
+ };
+
if !is_bit_op(op) {
return;
}
+ let mut applicability = Applicability::MachineApplicable;
match (is_arith_expr(left), is_arith_expr(right)) {
(true, true) => {
- span_lint(cx,
- PRECEDENCE,
- expr.span,
- &format!("operator precedence can trip the unwary. Consider parenthesizing your \
- expression:`({}) {} ({})`",
- snippet(cx, left.span, ".."),
- op.to_string(),
- snippet(cx, right.span, "..")));
+ let sugg = format!(
+ "({}) {} ({})",
+ snippet_with_applicability(cx, left.span, "..", &mut applicability),
+ op.to_string(),
+ snippet_with_applicability(cx, right.span, "..", &mut applicability)
+ );
+ span_sugg(expr, sugg, applicability);
},
(true, false) => {
- span_lint(cx,
- PRECEDENCE,
- expr.span,
- &format!("operator precedence can trip the unwary. Consider parenthesizing your \
- expression:`({}) {} {}`",
- snippet(cx, left.span, ".."),
- op.to_string(),
- snippet(cx, right.span, "..")));
+ let sugg = format!(
+ "({}) {} {}",
+ snippet_with_applicability(cx, left.span, "..", &mut applicability),
+ op.to_string(),
+ snippet_with_applicability(cx, right.span, "..", &mut applicability)
+ );
+ span_sugg(expr, sugg, applicability);
},
(false, true) => {
- span_lint(cx,
- PRECEDENCE,
- expr.span,
- &format!("operator precedence can trip the unwary. Consider parenthesizing your \
- expression:`{} {} ({})`",
- snippet(cx, left.span, ".."),
- op.to_string(),
- snippet(cx, right.span, "..")));
+ let sugg = format!(
+ "{} {} ({})",
+ snippet_with_applicability(cx, left.span, "..", &mut applicability),
+ op.to_string(),
+ snippet_with_applicability(cx, right.span, "..", &mut applicability)
+ );
+ span_sugg(expr, sugg, applicability);
},
- _ => (),
+ (false, false) => (),
}
}
- if let ExprKind::Unary(UnOp::Neg, ref rhs) = expr.node {
- if let ExprKind::MethodCall(_, _, ref args) = rhs.node {
+ if let ExprKind::Unary(UnOp::Neg, ref rhs) = expr.kind {
+ if let ExprKind::MethodCall(_, ref args) = rhs.kind {
if let Some(slf) = args.first() {
- if let ExprKind::Lit(ref lit) = slf.node {
- match lit.node {
- LitKind::Int(..) |
- LitKind::Float(..) |
- LitKind::FloatUnsuffixed(..) => {
- span_lint(cx,
- PRECEDENCE,
- expr.span,
- &format!("unary minus has lower precedence than method call. Consider \
- adding parentheses to clarify your intent: -({})",
- snippet(cx, rhs.span, "..")));
+ if let ExprKind::Lit(ref lit) = slf.kind {
+ match lit.kind {
+ LitKind::Int(..) | LitKind::Float(..) => {
+ let mut applicability = Applicability::MachineApplicable;
+ span_lint_and_sugg(
+ cx,
+ PRECEDENCE,
+ expr.span,
+ "unary minus has lower precedence than method call",
+ "consider adding parentheses to clarify your intent",
+ format!(
+ "-({})",
+ snippet_with_applicability(cx, rhs.span, "..", &mut applicability)
+ ),
+ applicability,
+ );
},
_ => (),
}
}
fn is_arith_expr(expr: &Expr) -> bool {
- match expr.node {
+ match expr.kind {
ExprKind::Binary(Spanned { node: op, .. }, _, _) => is_arith_op(op),
_ => false,
}
}
+#[must_use]
fn is_bit_op(op: BinOpKind) -> bool {
use syntax::ast::BinOpKind::*;
match op {
}
}
+#[must_use]
fn is_arith_op(op: BinOpKind) -> bool {
use syntax::ast::BinOpKind::*;
match op {
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