use crate::utils::sugg::Sugg;
use crate::utils::{get_enclosing_block, match_qpath, span_lint_and_then, SpanlessEq};
use if_chain::if_chain;
-use rustc::hir::intravisit::{walk_block, walk_expr, walk_stmt, NestedVisitorMap, Visitor};
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, Lint, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
-use syntax::ast::{LitKind, NodeId};
-use syntax_pos::symbol::Symbol;
-
-/// **What it does:** Checks slow zero-filled vector initialization
-///
-/// **Why is this bad?** These structures are non-idiomatic and less efficient than simply using
-/// `vec![0; len]`.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// let mut vec1 = Vec::with_capacity(len);
-/// vec1.resize(len, 0);
-///
-/// let mut vec2 = Vec::with_capacity(len);
-/// vec2.extend(repeat(0).take(len))
-/// ```
+use rustc_hir::intravisit::{walk_block, walk_expr, walk_stmt, NestedVisitorMap, Visitor};
+use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, HirId, PatKind, QPath, Stmt, StmtKind};
+use rustc_lint::{LateContext, LateLintPass, Lint};
+use rustc_middle::hir::map::Map;
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::Symbol;
+
declare_clippy_lint! {
+ /// **What it does:** Checks slow zero-filled vector initialization
+ ///
+ /// **Why is this bad?** These structures are non-idiomatic and less efficient than simply using
+ /// `vec![0; len]`.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # use core::iter::repeat;
+ /// # let len = 4;
+ ///
+ /// // Bad
+ /// let mut vec1 = Vec::with_capacity(len);
+ /// vec1.resize(len, 0);
+ ///
+ /// let mut vec2 = Vec::with_capacity(len);
+ /// vec2.extend(repeat(0).take(len));
+ ///
+ /// // Good
+ /// let mut vec1 = vec![0; len];
+ /// let mut vec2 = vec![0; len];
+ /// ```
pub SLOW_VECTOR_INITIALIZATION,
perf,
"slow vector initialization"
}
-#[derive(Copy, Clone, Default)]
-pub struct Pass;
-
-impl LintPass for Pass {
- fn get_lints(&self) -> LintArray {
- lint_array!(SLOW_VECTOR_INITIALIZATION,)
- }
-
- fn name(&self) -> &'static str {
- "SlowVectorInit"
- }
-}
+declare_lint_pass!(SlowVectorInit => [SLOW_VECTOR_INITIALIZATION]);
/// `VecAllocation` contains data regarding a vector allocated with `with_capacity` and then
/// assigned to a variable. For example, `let mut vec = Vec::with_capacity(0)` or
variable_name: Symbol,
/// Reference to the expression which allocates the vector
- allocation_expr: &'tcx Expr,
+ allocation_expr: &'tcx Expr<'tcx>,
/// Reference to the expression used as argument on `with_capacity` call. This is used
/// to only match slow zero-filling idioms of the same length than vector initialization.
- len_expr: &'tcx Expr,
+ len_expr: &'tcx Expr<'tcx>,
}
/// Type of slow initialization
enum InitializationType<'tcx> {
/// Extend is a slow initialization with the form `vec.extend(repeat(0).take(..))`
- Extend(&'tcx Expr),
+ Extend(&'tcx Expr<'tcx>),
/// Resize is a slow initialization with the form `vec.resize(.., 0)`
- Resize(&'tcx Expr),
+ Resize(&'tcx Expr<'tcx>),
}
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
+impl<'tcx> LateLintPass<'tcx> for SlowVectorInit {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
// Matches initialization on reassignements. For example: `vec = Vec::with_capacity(100)`
if_chain! {
- if let ExprKind::Assign(ref left, ref right) = expr.node;
+ if let ExprKind::Assign(ref left, ref right, _) = expr.kind;
// Extract variable name
- if let ExprKind::Path(QPath::Resolved(_, ref path)) = left.node;
+ if let ExprKind::Path(QPath::Resolved(_, ref path)) = left.kind;
if let Some(variable_name) = path.segments.get(0);
// Extract len argument
len_expr: len_arg,
};
- Self::search_initialization(cx, vi, expr.id);
+ Self::search_initialization(cx, vi, expr.hir_id);
}
}
}
- fn check_stmt(&mut self, cx: &LateContext<'a, 'tcx>, stmt: &'tcx Stmt) {
+ fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) {
// Matches statements which initializes vectors. For example: `let mut vec = Vec::with_capacity(10)`
if_chain! {
- if let StmtKind::Local(ref local) = stmt.node;
- if let PatKind::Binding(BindingAnnotation::Mutable, .., variable_name, None) = local.pat.node;
+ if let StmtKind::Local(ref local) = stmt.kind;
+ if let PatKind::Binding(BindingAnnotation::Mutable, .., variable_name, None) = local.pat.kind;
if let Some(ref init) = local.init;
if let Some(ref len_arg) = Self::is_vec_with_capacity(init);
len_expr: len_arg,
};
- Self::search_initialization(cx, vi, stmt.id);
+ Self::search_initialization(cx, vi, stmt.hir_id);
}
}
}
}
-impl Pass {
+impl SlowVectorInit {
/// Checks if the given expression is `Vec::with_capacity(..)`. It will return the expression
/// of the first argument of `with_capacity` call if it matches or `None` if it does not.
- fn is_vec_with_capacity(expr: &Expr) -> Option<&Expr> {
+ fn is_vec_with_capacity<'tcx>(expr: &Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
if_chain! {
- if let ExprKind::Call(ref func, ref args) = expr.node;
- if let ExprKind::Path(ref path) = func.node;
+ if let ExprKind::Call(ref func, ref args) = expr.kind;
+ if let ExprKind::Path(ref path) = func.kind;
if match_qpath(path, &["Vec", "with_capacity"]);
if args.len() == 1;
}
/// Search initialization for the given vector
- fn search_initialization<'tcx>(cx: &LateContext<'_, 'tcx>, vec_alloc: VecAllocation<'tcx>, parent_node: NodeId) {
+ fn search_initialization<'tcx>(cx: &LateContext<'tcx>, vec_alloc: VecAllocation<'tcx>, parent_node: HirId) {
let enclosing_body = get_enclosing_block(cx, parent_node);
if enclosing_body.is_none() {
}
fn lint_initialization<'tcx>(
- cx: &LateContext<'_, 'tcx>,
+ cx: &LateContext<'tcx>,
initialization: &InitializationType<'tcx>,
vec_alloc: &VecAllocation<'_>,
) {
}
fn emit_lint<'tcx>(
- cx: &LateContext<'_, 'tcx>,
- slow_fill: &Expr,
+ cx: &LateContext<'tcx>,
+ slow_fill: &Expr<'_>,
vec_alloc: &VecAllocation<'_>,
msg: &str,
lint: &'static Lint,
) {
let len_expr = Sugg::hir(cx, vec_alloc.len_expr, "len");
- span_lint_and_then(cx, lint, slow_fill.span, msg, |db| {
- db.span_suggestion(
+ span_lint_and_then(cx, lint, slow_fill.span, msg, |diag| {
+ diag.span_suggestion(
vec_alloc.allocation_expr.span,
"consider replace allocation with",
format!("vec![0; {}]", len_expr),
/// `VectorInitializationVisitor` searches for unsafe or slow vector initializations for the given
/// vector.
-struct VectorInitializationVisitor<'a, 'tcx: 'a> {
- cx: &'a LateContext<'a, 'tcx>,
+struct VectorInitializationVisitor<'a, 'tcx> {
+ cx: &'a LateContext<'tcx>,
- /// Contains the information
+ /// Contains the information.
vec_alloc: VecAllocation<'tcx>,
- /// Contains, if found, the slow initialization expression
+ /// Contains the slow initialization expression, if one was found.
slow_expression: Option<InitializationType<'tcx>>,
- /// true if the initialization of the vector has been found on the visited block
+ /// `true` if the initialization of the vector has been found on the visited block.
initialization_found: bool,
}
impl<'a, 'tcx> VectorInitializationVisitor<'a, 'tcx> {
/// Checks if the given expression is extending a vector with `repeat(0).take(..)`
- fn search_slow_extend_filling(&mut self, expr: &'tcx Expr) {
+ fn search_slow_extend_filling(&mut self, expr: &'tcx Expr<'_>) {
if_chain! {
if self.initialization_found;
- if let ExprKind::MethodCall(ref path, _, ref args) = expr.node;
- if let ExprKind::Path(ref qpath_subj) = args[0].node;
- if match_qpath(&qpath_subj, &[&self.vec_alloc.variable_name.to_string()]);
- if path.ident.name == "extend";
+ if let ExprKind::MethodCall(ref path, _, ref args, _) = expr.kind;
+ if let ExprKind::Path(ref qpath_subj) = args[0].kind;
+ if match_qpath(&qpath_subj, &[&*self.vec_alloc.variable_name.as_str()]);
+ if path.ident.name == sym!(extend);
if let Some(ref extend_arg) = args.get(1);
if self.is_repeat_take(extend_arg);
}
/// Checks if the given expression is resizing a vector with 0
- fn search_slow_resize_filling(&mut self, expr: &'tcx Expr) {
+ fn search_slow_resize_filling(&mut self, expr: &'tcx Expr<'_>) {
if_chain! {
if self.initialization_found;
- if let ExprKind::MethodCall(ref path, _, ref args) = expr.node;
- if let ExprKind::Path(ref qpath_subj) = args[0].node;
- if match_qpath(&qpath_subj, &[&self.vec_alloc.variable_name.to_string()]);
- if path.ident.name == "resize";
+ if let ExprKind::MethodCall(ref path, _, ref args, _) = expr.kind;
+ if let ExprKind::Path(ref qpath_subj) = args[0].kind;
+ if match_qpath(&qpath_subj, &[&*self.vec_alloc.variable_name.as_str()]);
+ if path.ident.name == sym!(resize);
if let (Some(ref len_arg), Some(fill_arg)) = (args.get(1), args.get(2));
// Check that is filled with 0
- if let ExprKind::Lit(ref lit) = fill_arg.node;
+ if let ExprKind::Lit(ref lit) = fill_arg.kind;
if let LitKind::Int(0, _) = lit.node;
// Check that len expression is equals to `with_capacity` expression
}
/// Returns `true` if give expression is `repeat(0).take(...)`
- fn is_repeat_take(&self, expr: &Expr) -> bool {
+ fn is_repeat_take(&self, expr: &Expr<'_>) -> bool {
if_chain! {
- if let ExprKind::MethodCall(ref take_path, _, ref take_args) = expr.node;
- if take_path.ident.name == "take";
+ if let ExprKind::MethodCall(ref take_path, _, ref take_args, _) = expr.kind;
+ if take_path.ident.name == sym!(take);
// Check that take is applied to `repeat(0)`
if let Some(ref repeat_expr) = take_args.get(0);
- if self.is_repeat_zero(repeat_expr);
+ if Self::is_repeat_zero(repeat_expr);
// Check that len expression is equals to `with_capacity` expression
if let Some(ref len_arg) = take_args.get(1);
}
/// Returns `true` if given expression is `repeat(0)`
- fn is_repeat_zero(&self, expr: &Expr) -> bool {
+ fn is_repeat_zero(expr: &Expr<'_>) -> bool {
if_chain! {
- if let ExprKind::Call(ref fn_expr, ref repeat_args) = expr.node;
- if let ExprKind::Path(ref qpath_repeat) = fn_expr.node;
+ if let ExprKind::Call(ref fn_expr, ref repeat_args) = expr.kind;
+ if let ExprKind::Path(ref qpath_repeat) = fn_expr.kind;
if match_qpath(&qpath_repeat, &["repeat"]);
if let Some(ref repeat_arg) = repeat_args.get(0);
- if let ExprKind::Lit(ref lit) = repeat_arg.node;
+ if let ExprKind::Lit(ref lit) = repeat_arg.kind;
if let LitKind::Int(0, _) = lit.node;
then {
}
impl<'a, 'tcx> Visitor<'tcx> for VectorInitializationVisitor<'a, 'tcx> {
- fn visit_stmt(&mut self, stmt: &'tcx Stmt) {
+ type Map = Map<'tcx>;
+
+ fn visit_stmt(&mut self, stmt: &'tcx Stmt<'_>) {
if self.initialization_found {
- match stmt.node {
+ match stmt.kind {
StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => {
self.search_slow_extend_filling(expr);
self.search_slow_resize_filling(expr);
}
}
- fn visit_block(&mut self, block: &'tcx Block) {
+ fn visit_block(&mut self, block: &'tcx Block<'_>) {
if self.initialization_found {
if let Some(ref s) = block.stmts.get(0) {
self.visit_stmt(s)
}
}
- fn visit_expr(&mut self, expr: &'tcx Expr) {
+ fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
// Skip all the expressions previous to the vector initialization
- if self.vec_alloc.allocation_expr.id == expr.id {
+ if self.vec_alloc.allocation_expr.hir_id == expr.hir_id {
self.initialization_found = true;
}
walk_expr(self, expr);
}
- fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
+ fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
}
}