use if_chain::if_chain;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use rustc_ast::ast::RangeLimits;
use rustc_errors::Applicability;
-use syntax::ast::RangeLimits;
-use syntax::source_map::Spanned;
+use rustc_hir::{BinOpKind, Expr, ExprKind, QPath};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::source_map::Spanned;
use crate::utils::sugg::Sugg;
-use crate::utils::{get_trait_def_id, higher, implements_trait, SpanlessEq};
-use crate::utils::{is_integer_literal, paths, snippet, snippet_opt, span_lint, span_lint_and_then};
-
-declare_clippy_lint! {
- /// **What it does:** Checks for calling `.step_by(0)` on iterators,
- /// which never terminates.
- ///
- /// **Why is this bad?** This very much looks like an oversight, since with
- /// `loop { .. }` there is an obvious better way to endlessly loop.
- ///
- /// **Known problems:** None.
- ///
- /// **Example:**
- /// ```ignore
- /// for x in (5..5).step_by(0) {
- /// ..
- /// }
- /// ```
- pub ITERATOR_STEP_BY_ZERO,
- correctness,
- "using `Iterator::step_by(0)`, which produces an infinite iterator"
-}
+use crate::utils::{higher, SpanlessEq};
+use crate::utils::{is_integer_const, snippet, snippet_opt, span_lint, span_lint_and_then};
declare_clippy_lint! {
/// **What it does:** Checks for zipping a collection with the range of
///
/// **Example:**
/// ```rust
- /// x.iter().zip(0..x.len())
+ /// # let x = vec![1];
+ /// x.iter().zip(0..x.len());
+ /// ```
+ /// Could be written as
+ /// ```rust
+ /// # let x = vec![1];
+ /// x.iter().enumerate();
/// ```
pub RANGE_ZIP_WITH_LEN,
complexity,
/// and ends with a closing one.
/// I.e., `let _ = (f()+1)..(f()+1)` results in `let _ = ((f()+1)..=f())`.
///
+ /// Also in many cases, inclusive ranges are still slower to run than
+ /// exclusive ranges, because they essentially add an extra branch that
+ /// LLVM may fail to hoist out of the loop.
+ ///
/// **Example:**
- /// ```rust
+ /// ```rust,ignore
/// for x..(y+1) { .. }
/// ```
+ /// Could be written as
+ /// ```rust,ignore
+ /// for x..=y { .. }
+ /// ```
pub RANGE_PLUS_ONE,
- complexity,
+ pedantic,
"`x..(y+1)` reads better as `x..=y`"
}
/// **Known problems:** None.
///
/// **Example:**
- /// ```rust
+ /// ```rust,ignore
/// for x..=(y-1) { .. }
/// ```
+ /// Could be written as
+ /// ```rust,ignore
+ /// for x..y { .. }
+ /// ```
pub RANGE_MINUS_ONE,
complexity,
"`x..=(y-1)` reads better as `x..y`"
}
-#[derive(Copy, Clone)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(
- ITERATOR_STEP_BY_ZERO,
- RANGE_ZIP_WITH_LEN,
- RANGE_PLUS_ONE,
- RANGE_MINUS_ONE
- )
- }
-
- fn name(&self) -> &'static str {
- "Ranges"
- }
-}
+declare_lint_pass!(Ranges => [
+ RANGE_ZIP_WITH_LEN,
+ RANGE_PLUS_ONE,
+ RANGE_MINUS_ONE
+]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
- if let ExprKind::MethodCall(ref path, _, ref args) = expr.node {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Ranges {
+ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+ if let ExprKind::MethodCall(ref path, _, ref args) = expr.kind {
let name = path.ident.as_str();
-
- // Range with step_by(0).
- if name == "step_by" && args.len() == 2 && has_step_by(cx, &args[0]) {
- use crate::consts::{constant, Constant};
- if let Some((Constant::Int(0), _)) = constant(cx, cx.tables, &args[1]) {
- span_lint(
- cx,
- ITERATOR_STEP_BY_ZERO,
- expr.span,
- "Iterator::step_by(0) will panic at runtime",
- );
- }
- } else if name == "zip" && args.len() == 2 {
- let iter = &args[0].node;
+ if name == "zip" && args.len() == 2 {
+ let iter = &args[0].kind;
let zip_arg = &args[1];
if_chain! {
// `.iter()` call
if let ExprKind::MethodCall(ref iter_path, _, ref iter_args ) = *iter;
- if iter_path.ident.name == "iter";
+ if iter_path.ident.name == sym!(iter);
// range expression in `.zip()` call: `0..x.len()`
if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::range(cx, zip_arg);
- if is_integer_literal(start, 0);
+ if is_integer_const(cx, start, 0);
// `.len()` call
- if let ExprKind::MethodCall(ref len_path, _, ref len_args) = end.node;
- if len_path.ident.name == "len" && len_args.len() == 1;
+ if let ExprKind::MethodCall(ref len_path, _, ref len_args) = end.kind;
+ if len_path.ident.name == sym!(len) && len_args.len() == 1;
// `.iter()` and `.len()` called on same `Path`
- if let ExprKind::Path(QPath::Resolved(_, ref iter_path)) = iter_args[0].node;
- if let ExprKind::Path(QPath::Resolved(_, ref len_path)) = len_args[0].node;
+ if let ExprKind::Path(QPath::Resolved(_, ref iter_path)) = iter_args[0].kind;
+ if let ExprKind::Path(QPath::Resolved(_, ref len_path)) = len_args[0].kind;
if SpanlessEq::new(cx).eq_path_segments(&iter_path.segments, &len_path.segments);
then {
span_lint(cx,
RANGE_ZIP_WITH_LEN,
expr.span,
- &format!("It is more idiomatic to use {}.iter().enumerate()",
+ &format!("It is more idiomatic to use `{}.iter().enumerate()`",
snippet(cx, iter_args[0].span, "_")));
}
}
}
}
- // exclusive range plus one: `x..(y+1)`
- if_chain! {
- if let Some(higher::Range {
- start,
- end: Some(end),
- limits: RangeLimits::HalfOpen
- }) = higher::range(cx, expr);
- if let Some(y) = y_plus_one(end);
- then {
- span_lint_and_then(
- cx,
- RANGE_PLUS_ONE,
- expr.span,
- "an inclusive range would be more readable",
- |db| {
- let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
- let end = Sugg::hir(cx, y, "y");
- if let Some(is_wrapped) = &snippet_opt(cx, expr.span) {
- if is_wrapped.starts_with('(') && is_wrapped.ends_with(')') {
- db.span_suggestion(
- expr.span,
- "use",
- format!("({}..={})", start, end),
- Applicability::MaybeIncorrect,
- );
- } else {
- db.span_suggestion(
- expr.span,
- "use",
- format!("{}..={}", start, end),
- Applicability::MachineApplicable, // snippet
- );
- }
- }
- },
- );
- }
- }
+ check_exclusive_range_plus_one(cx, expr);
+ check_inclusive_range_minus_one(cx, expr);
+ }
+}
- // inclusive range minus one: `x..=(y-1)`
- if_chain! {
- if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::range(cx, expr);
- if let Some(y) = y_minus_one(end);
- then {
- span_lint_and_then(
- cx,
- RANGE_MINUS_ONE,
- expr.span,
- "an exclusive range would be more readable",
- |db| {
- let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
- let end = Sugg::hir(cx, y, "y");
- db.span_suggestion(
- expr.span,
- "use",
- format!("{}..{}", start, end),
- Applicability::MachineApplicable, // snippet
- );
- },
- );
- }
+// exclusive range plus one: `x..(y+1)`
+fn check_exclusive_range_plus_one(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
+ if_chain! {
+ if let Some(higher::Range {
+ start,
+ end: Some(end),
+ limits: RangeLimits::HalfOpen
+ }) = higher::range(cx, expr);
+ if let Some(y) = y_plus_one(cx, end);
+ then {
+ let span = if expr.span.from_expansion() {
+ expr.span
+ .ctxt()
+ .outer_expn_data()
+ .call_site
+ } else {
+ expr.span
+ };
+ span_lint_and_then(
+ cx,
+ RANGE_PLUS_ONE,
+ span,
+ "an inclusive range would be more readable",
+ |db| {
+ let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
+ let end = Sugg::hir(cx, y, "y");
+ if let Some(is_wrapped) = &snippet_opt(cx, span) {
+ if is_wrapped.starts_with('(') && is_wrapped.ends_with(')') {
+ db.span_suggestion(
+ span,
+ "use",
+ format!("({}..={})", start, end),
+ Applicability::MaybeIncorrect,
+ );
+ } else {
+ db.span_suggestion(
+ span,
+ "use",
+ format!("{}..={}", start, end),
+ Applicability::MachineApplicable, // snippet
+ );
+ }
+ }
+ },
+ );
}
}
}
-fn has_step_by(cx: &LateContext<'_, '_>, expr: &Expr) -> bool {
- // No need for `walk_ptrs_ty` here because `step_by` moves `self`, so it
- // can't be called on a borrowed range.
- let ty = cx.tables.expr_ty_adjusted(expr);
-
- get_trait_def_id(cx, &paths::ITERATOR).map_or(false, |iterator_trait| implements_trait(cx, ty, iterator_trait, &[]))
+// inclusive range minus one: `x..=(y-1)`
+fn check_inclusive_range_minus_one(cx: &LateContext<'_, '_>, expr: &Expr<'_>) {
+ if_chain! {
+ if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::range(cx, expr);
+ if let Some(y) = y_minus_one(cx, end);
+ then {
+ span_lint_and_then(
+ cx,
+ RANGE_MINUS_ONE,
+ expr.span,
+ "an exclusive range would be more readable",
+ |db| {
+ let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
+ let end = Sugg::hir(cx, y, "y");
+ db.span_suggestion(
+ expr.span,
+ "use",
+ format!("{}..{}", start, end),
+ Applicability::MachineApplicable, // snippet
+ );
+ },
+ );
+ }
+ }
}
-fn y_plus_one(expr: &Expr) -> Option<&Expr> {
- match expr.node {
+fn y_plus_one<'t>(cx: &LateContext<'_, '_>, expr: &'t Expr<'_>) -> Option<&'t Expr<'t>> {
+ match expr.kind {
ExprKind::Binary(
Spanned {
node: BinOpKind::Add, ..
ref lhs,
ref rhs,
) => {
- if is_integer_literal(lhs, 1) {
+ if is_integer_const(cx, lhs, 1) {
Some(rhs)
- } else if is_integer_literal(rhs, 1) {
+ } else if is_integer_const(cx, rhs, 1) {
Some(lhs)
} else {
None
}
}
-fn y_minus_one(expr: &Expr) -> Option<&Expr> {
- match expr.node {
+fn y_minus_one<'t>(cx: &LateContext<'_, '_>, expr: &'t Expr<'_>) -> Option<&'t Expr<'t>> {
+ match expr.kind {
ExprKind::Binary(
Spanned {
node: BinOpKind::Sub, ..
},
ref lhs,
ref rhs,
- ) if is_integer_literal(rhs, 1) => Some(lhs),
+ ) if is_integer_const(cx, rhs, 1) => Some(lhs),
_ => None,
}
}
projects / rust.git / blobdiff