use crate::utils::{
- has_drop, in_macro, is_copy, match_def_path, match_type, paths, snippet_opt, span_lint_node,
- span_lint_node_and_then, walk_ptrs_ty_depth,
+ has_drop, in_macro_or_desugar, is_copy, match_def_path, match_type, paths, snippet_opt, span_lint_hir,
+ span_lint_hir_and_then, walk_ptrs_ty_depth,
};
use if_chain::if_chain;
use matches::matches;
use rustc::hir::intravisit::FnKind;
-use rustc::hir::{def_id, Body, FnDecl};
+use rustc::hir::{def_id, Body, FnDecl, HirId};
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::mir::{
self, traversal,
visit::{MutatingUseContext, PlaceContext, Visitor},
TerminatorKind,
};
-use rustc::ty;
-use rustc::{declare_tool_lint, lint_array};
+use rustc::ty::{self, Ty};
+use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
use std::convert::TryFrom;
-use syntax::{
- ast::NodeId,
- source_map::{BytePos, Span},
-};
+use syntax::source_map::{BytePos, Span};
macro_rules! unwrap_or_continue {
($x:expr) => {
};
}
-/// **What it does:** Checks for a redudant `clone()` (and its relatives) which clones an owned
-/// value that is going to be dropped without further use.
-///
-/// **Why is this bad?** It is not always possible for the compiler to eliminate useless
-/// allocations and deallocations generated by redundant `clone()`s.
-///
-/// **Known problems:**
-///
-/// * Suggestions made by this lint could require NLL to be enabled.
-/// * False-positive if there is a borrow preventing the value from moving out.
-///
-/// ```rust
-/// let x = String::new();
-///
-/// let y = &x;
-///
-/// foo(x.clone()); // This lint suggests to remove this `clone()`
-/// ```
-///
-/// **Example:**
-/// ```rust
-/// {
-/// let x = Foo::new();
-/// call(x.clone());
-/// call(x.clone()); // this can just pass `x`
-/// }
-///
-/// ["lorem", "ipsum"].join(" ").to_string()
-///
-/// Path::new("/a/b").join("c").to_path_buf()
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for a redudant `clone()` (and its relatives) which clones an owned
+ /// value that is going to be dropped without further use.
+ ///
+ /// **Why is this bad?** It is not always possible for the compiler to eliminate useless
+ /// allocations and deallocations generated by redundant `clone()`s.
+ ///
+ /// **Known problems:**
+ ///
+ /// * Suggestions made by this lint could require NLL to be enabled.
+ /// * False-positive if there is a borrow preventing the value from moving out.
+ ///
+ /// ```rust
+ /// let x = String::new();
+ ///
+ /// let y = &x;
+ ///
+ /// foo(x.clone()); // This lint suggests to remove this `clone()`
+ /// ```
+ ///
+ /// **Example:**
+ /// ```rust
+ /// {
+ /// let x = Foo::new();
+ /// call(x.clone());
+ /// call(x.clone()); // this can just pass `x`
+ /// }
+ ///
+ /// ["lorem", "ipsum"].join(" ").to_string()
+ ///
+ /// Path::new("/a/b").join("c").to_path_buf()
+ /// ```
pub REDUNDANT_CLONE,
nursery,
"`clone()` of an owned value that is going to be dropped immediately"
}
-pub struct RedundantClone;
-
-impl LintPass for RedundantClone {
- fn get_lints(&self) -> LintArray {
- lint_array!(REDUNDANT_CLONE)
- }
-
- fn name(&self) -> &'static str {
- "RedundantClone"
- }
-}
+declare_lint_pass!(RedundantClone => [REDUNDANT_CLONE]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for RedundantClone {
+ #[allow(clippy::too_many_lines)]
fn check_fn(
&mut self,
cx: &LateContext<'a, 'tcx>,
_: &'tcx FnDecl,
body: &'tcx Body,
_: Span,
- _: NodeId,
+ _: HirId,
) {
let def_id = cx.tcx.hir().body_owner_def_id(body.id());
let mir = cx.tcx.optimized_mir(def_id);
for (bb, bbdata) in mir.basic_blocks().iter_enumerated() {
let terminator = bbdata.terminator();
- if in_macro(terminator.source_info.span) {
+ if in_macro_or_desugar(terminator.source_info.span) {
continue;
}
let (fn_def_id, arg, arg_ty, _) = unwrap_or_continue!(is_call_with_ref_arg(cx, mir, &terminator.kind));
- let from_borrow = match_def_path(cx.tcx, fn_def_id, &paths::CLONE_TRAIT_METHOD)
- || match_def_path(cx.tcx, fn_def_id, &paths::TO_OWNED_METHOD)
- || (match_def_path(cx.tcx, fn_def_id, &paths::TO_STRING_METHOD)
- && match_type(cx, arg_ty, &paths::STRING));
+ let from_borrow = match_def_path(cx, fn_def_id, &paths::CLONE_TRAIT_METHOD)
+ || match_def_path(cx, fn_def_id, &paths::TO_OWNED_METHOD)
+ || (match_def_path(cx, fn_def_id, &paths::TO_STRING_METHOD) && match_type(cx, arg_ty, &paths::STRING));
let from_deref = !from_borrow
- && (match_def_path(cx.tcx, fn_def_id, &paths::PATH_TO_PATH_BUF)
- || match_def_path(cx.tcx, fn_def_id, &paths::OS_STR_TO_OS_STRING));
+ && (match_def_path(cx, fn_def_id, &paths::PATH_TO_PATH_BUF)
+ || match_def_path(cx, fn_def_id, &paths::OS_STR_TO_OS_STRING));
if !from_borrow && !from_deref {
continue;
let pred_arg = if_chain! {
if let Some((pred_fn_def_id, pred_arg, pred_arg_ty, Some(res))) =
is_call_with_ref_arg(cx, mir, &pred_terminator.kind);
- if *res == mir::Place::Local(cloned);
- if match_def_path(cx.tcx, pred_fn_def_id, &paths::DEREF_TRAIT_METHOD);
+ if res.base == mir::PlaceBase::Local(cloned);
+ if match_def_path(cx, pred_fn_def_id, &paths::DEREF_TRAIT_METHOD);
if match_type(cx, pred_arg_ty, &paths::PATH_BUF)
|| match_type(cx, pred_arg_ty, &paths::OS_STRING);
then {
span.lo() + BytePos(u32::try_from(dot).unwrap())
);
- span_lint_node_and_then(cx, REDUNDANT_CLONE, node, sugg_span, "redundant clone", |db| {
+ span_lint_hir_and_then(cx, REDUNDANT_CLONE, node, sugg_span, "redundant clone", |db| {
db.span_suggestion(
sugg_span,
"remove this",
);
});
} else {
- span_lint_node(cx, REDUNDANT_CLONE, node, span, "redundant clone");
+ span_lint_hir(cx, REDUNDANT_CLONE, node, span, "redundant clone");
}
}
}
/// If `kind` is `y = func(x: &T)` where `T: !Copy`, returns `(DefId of func, x, T, y)`.
fn is_call_with_ref_arg<'tcx>(
cx: &LateContext<'_, 'tcx>,
- mir: &'tcx mir::Mir<'tcx>,
+ mir: &'tcx mir::Body<'tcx>,
kind: &'tcx mir::TerminatorKind<'tcx>,
-) -> Option<(def_id::DefId, mir::Local, ty::Ty<'tcx>, Option<&'tcx mir::Place<'tcx>>)> {
+) -> Option<(def_id::DefId, mir::Local, Ty<'tcx>, Option<&'tcx mir::Place<'tcx>>)> {
if_chain! {
if let TerminatorKind::Call { func, args, destination, .. } = kind;
if args.len() == 1;
- if let mir::Operand::Move(mir::Place::Local(local)) = &args[0];
+ if let mir::Operand::Move(mir::Place { base: mir::PlaceBase::Local(local), .. }) = &args[0];
if let ty::FnDef(def_id, _) = func.ty(&*mir, cx.tcx).sty;
if let (inner_ty, 1) = walk_ptrs_ty_depth(args[0].ty(&*mir, cx.tcx));
if !is_copy(cx, inner_ty);
/// ``Some((from, [`true` if `from` cannot be moved out]))``.
fn find_stmt_assigns_to<'a, 'tcx: 'a>(
cx: &LateContext<'_, 'tcx>,
- mir: &mir::Mir<'tcx>,
+ mir: &mir::Body<'tcx>,
to: mir::Local,
by_ref: bool,
stmts: impl DoubleEndedIterator<Item = &'a mir::Statement<'tcx>>,
stmts
.rev()
.find_map(|stmt| {
- if let mir::StatementKind::Assign(mir::Place::Local(local), v) = &stmt.kind {
+ if let mir::StatementKind::Assign(
+ mir::Place {
+ base: mir::PlaceBase::Local(local),
+ ..
+ },
+ v,
+ ) = &stmt.kind
+ {
if *local == to {
return Some(v);
}
/// Also reports whether given `place` cannot be moved out.
fn base_local_and_movability<'tcx>(
cx: &LateContext<'_, 'tcx>,
- mir: &mir::Mir<'tcx>,
- mut place: &mir::Place<'tcx>,
+ mir: &mir::Body<'tcx>,
+ place: &mir::Place<'tcx>,
) -> Option<(mir::Local, CannotMoveOut)> {
- use rustc::mir::Place::*;
+ use rustc::mir::Place;
+ use rustc::mir::PlaceBase;
+ use rustc::mir::PlaceRef;
+ use rustc::mir::Projection;
// Dereference. You cannot move things out from a borrowed value.
let mut deref = false;
// Accessing a field of an ADT that has `Drop`. Moving the field out will cause E0509.
let mut field = false;
- loop {
- match place {
- Local(local) => return Some((*local, deref || field)),
- Projection(proj) => {
- place = &proj.base;
- deref = deref || matches!(proj.elem, mir::ProjectionElem::Deref);
- if !field && matches!(proj.elem, mir::ProjectionElem::Field(..)) {
- field = has_drop(cx, place.ty(&mir.local_decls, cx.tcx).to_ty(cx.tcx));
- }
- },
- _ => return None,
+ let PlaceRef {
+ base: place_base,
+ mut projection,
+ } = place.as_place_ref();
+ if let PlaceBase::Local(local) = place_base {
+ while let Some(box Projection { base, elem }) = projection {
+ projection = base;
+ deref = matches!(elem, mir::ProjectionElem::Deref);
+ field = !field
+ && matches!(elem, mir::ProjectionElem::Field(..))
+ && has_drop(cx, Place::ty_from(place_base, projection, &mir.local_decls, cx.tcx).ty);
}
+
+ Some((*local, deref || field))
+ } else {
+ None
}
}
fn visit_basic_block_data(&mut self, block: mir::BasicBlock, data: &mir::BasicBlockData<'tcx>) {
let statements = &data.statements;
for (statement_index, statement) in statements.iter().enumerate() {
- self.visit_statement(block, statement, mir::Location { block, statement_index });
+ self.visit_statement(statement, mir::Location { block, statement_index });
// Once flagged, skip remaining statements
if self.used_other_than_drop {
}
self.visit_terminator(
- block,
data.terminator(),
mir::Location {
block,
);
}
- fn visit_local(&mut self, local: &mir::Local, ctx: PlaceContext<'tcx>, _: mir::Location) {
+ fn visit_local(&mut self, local: &mir::Local, ctx: PlaceContext, _: mir::Location) {
match ctx {
PlaceContext::MutatingUse(MutatingUseContext::Drop) | PlaceContext::NonUse(_) => return,
_ => {},
projects / rust.git / blobdiff