-use crate::utils::sugg::Sugg;
-use crate::utils::{get_enclosing_block, match_qpath, span_lint_and_then, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::sugg::Sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{get_enclosing_block, is_expr_path_def_path, path_to_local, path_to_local_id, paths, 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_lint_pass, declare_tool_lint};
+use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
-use syntax::ast::LitKind;
-use syntax_pos::symbol::Symbol;
+use rustc_hir::intravisit::{walk_block, walk_expr, walk_stmt, Visitor};
+use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, HirId, PatKind, QPath, Stmt, StmtKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::sym;
declare_clippy_lint! {
- /// **What it does:** Checks slow zero-filled vector initialization
+ /// ### What it does
+ /// Checks slow zero-filled vector initialization
///
- /// **Why is this bad?** These structures are non-idiomatic and less efficient than simply using
+ /// ### Why is this bad?
+ /// These structures are non-idiomatic and less efficient than simply using
/// `vec![0; len]`.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### 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))
+ /// vec2.extend(repeat(0).take(len));
+ ///
+ /// // Good
+ /// let mut vec1 = vec![0; len];
+ /// let mut vec2 = vec![0; len];
/// ```
+ #[clippy::version = "1.32.0"]
pub SLOW_VECTOR_INITIALIZATION,
perf,
"slow vector initialization"
/// assigned to a variable. For example, `let mut vec = Vec::with_capacity(0)` or
/// `vec = Vec::with_capacity(0)`
struct VecAllocation<'tcx> {
- /// Symbol of the local variable name
- variable_name: Symbol,
+ /// HirId of the variable
+ local_id: HirId,
/// 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 SlowVectorInit {
- 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.kind;
+ if let ExprKind::Assign(left, right, _) = expr.kind;
- // Extract variable name
- if let ExprKind::Path(QPath::Resolved(_, ref path)) = left.kind;
- if let Some(variable_name) = path.segments.get(0);
+ // Extract variable
+ if let Some(local_id) = path_to_local(left);
// Extract len argument
- if let Some(ref len_arg) = Self::is_vec_with_capacity(right);
+ if let Some(len_arg) = Self::is_vec_with_capacity(cx, right);
then {
let vi = VecAllocation {
- variable_name: variable_name.ident.name,
+ local_id,
allocation_expr: right,
len_expr: len_arg,
};
}
}
- 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.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);
+ if let StmtKind::Local(local) = stmt.kind;
+ if let PatKind::Binding(BindingAnnotation::Mutable, local_id, _, None) = local.pat.kind;
+ if let Some(init) = local.init;
+ if let Some(len_arg) = Self::is_vec_with_capacity(cx, init);
then {
let vi = VecAllocation {
- variable_name: variable_name.name,
+ local_id,
allocation_expr: init,
len_expr: len_arg,
};
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>(cx: &LateContext<'_>, expr: &Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
if_chain! {
- 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;
-
+ if let ExprKind::Call(func, [arg]) = expr.kind;
+ if let ExprKind::Path(QPath::TypeRelative(ty, name)) = func.kind;
+ if name.ident.as_str() == "with_capacity";
+ if is_type_diagnostic_item(cx, cx.typeck_results().node_type(ty.hir_id), sym::Vec);
then {
- return Some(&args[0]);
+ Some(arg)
+ } else {
+ None
}
}
-
- None
}
/// Search initialization for the given vector
- fn search_initialization<'tcx>(cx: &LateContext<'_, 'tcx>, vec_alloc: VecAllocation<'tcx>, parent_node: HirId) {
+ 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<'_>,
) {
match initialization {
- InitializationType::Extend(e) | InitializationType::Resize(e) => Self::emit_lint(
- cx,
- e,
- vec_alloc,
- "slow zero-filling initialization",
- SLOW_VECTOR_INITIALIZATION,
- ),
+ InitializationType::Extend(e) | InitializationType::Resize(e) => {
+ Self::emit_lint(cx, e, vec_alloc, "slow zero-filling initialization");
+ },
};
}
- fn emit_lint<'tcx>(
- cx: &LateContext<'_, 'tcx>,
- slow_fill: &Expr,
- vec_alloc: &VecAllocation<'_>,
- msg: &str,
- lint: &'static Lint,
- ) {
+ fn emit_lint<'tcx>(cx: &LateContext<'tcx>, slow_fill: &Expr<'_>, vec_alloc: &VecAllocation<'_>, msg: &str) {
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, SLOW_VECTOR_INITIALIZATION, 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> {
- cx: &'a LateContext<'a, 'tcx>,
+ cx: &'a LateContext<'tcx>,
/// Contains the information.
vec_alloc: VecAllocation<'tcx>,
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.kind;
- if let ExprKind::Path(ref qpath_subj) = args[0].kind;
- if match_qpath(&qpath_subj, &[&*self.vec_alloc.variable_name.as_str()]);
+ if let ExprKind::MethodCall(path, [self_arg, extend_arg], _) = expr.kind;
+ if path_to_local_id(self_arg, self.vec_alloc.local_id);
if path.ident.name == sym!(extend);
- if let Some(ref extend_arg) = args.get(1);
if self.is_repeat_take(extend_arg);
then {
}
/// 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.kind;
- if let ExprKind::Path(ref qpath_subj) = args[0].kind;
- if match_qpath(&qpath_subj, &[&*self.vec_alloc.variable_name.as_str()]);
+ if let ExprKind::MethodCall(path, [self_arg, len_arg, fill_arg], _) = expr.kind;
+ if path_to_local_id(self_arg, self.vec_alloc.local_id);
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.kind;
}
/// 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.kind;
+ if let ExprKind::MethodCall(take_path, 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 let Some(repeat_expr) = take_args.get(0);
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);
+ if let Some(len_arg) = take_args.get(1);
if SpanlessEq::new(self.cx).eq_expr(len_arg, self.vec_alloc.len_expr);
then {
}
/// Returns `true` if given expression is `repeat(0)`
- fn is_repeat_zero(&self, expr: &Expr) -> bool {
+ fn is_repeat_zero(&self, expr: &Expr<'_>) -> bool {
if_chain! {
- 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::Call(fn_expr, [repeat_arg]) = expr.kind;
+ if is_expr_path_def_path(self.cx, fn_expr, &paths::ITER_REPEAT);
if let ExprKind::Lit(ref lit) = repeat_arg.kind;
if let LitKind::Int(0, _) = lit.node;
then {
- return true
+ true
+ } else {
+ false
}
}
-
- false
}
}
impl<'a, 'tcx> Visitor<'tcx> for VectorInitializationVisitor<'a, 'tcx> {
- fn visit_stmt(&mut self, stmt: &'tcx Stmt) {
+ fn visit_stmt(&mut self, stmt: &'tcx Stmt<'_>) {
if self.initialization_found {
match stmt.kind {
- StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => {
+ StmtKind::Expr(expr) | StmtKind::Semi(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)
+ if let Some(s) = block.stmts.get(0) {
+ self.visit_stmt(s);
}
self.initialization_found = false;
}
}
- 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.hir_id == expr.hir_id {
self.initialization_found = true;
walk_expr(self, expr);
}
-
- fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
- NestedVisitorMap::None
- }
}
projects / rust.git / blobdiff