user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix needless_pass_by_value

Browse source 
This also accidentally improved the spans of the suggestions
This commit is contained in:
flip1995 2019-10-04 15:00:01 +02:00
parent b46f5b4a98
commit c420b07191
No known key found for this signature in database
GPG key ID: 693086869D506637
3 changed files with 15 additions and 109 deletions
Download patch file Download diff file Expand all files Collapse all files

84
clippy_lints/src/needless_pass_by_value.rs
View file

@ -134,7 +134,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NeedlessPassByValue {
spans_need_deref,
..
} = {
let mut ctx = MovedVariablesCtxt::new(cx);
let mut ctx = MovedVariablesCtxt::default();
let region_scope_tree = &cx.tcx.region_scope_tree(fn_def_id);
euv::ExprUseVisitor::new(
&mut ctx,
@ -324,98 +324,28 @@ fn requires_exact_signature(attrs: &[Attribute]) -> bool {
})
}
struct MovedVariablesCtxt<'a, 'tcx> {
cx: &'a LateContext<'a, 'tcx>,
#[derive(Default)]
struct MovedVariablesCtxt {
moved_vars: FxHashSet<HirId>,
/// Spans which need to be prefixed with `*` for dereferencing the
/// suggested additional reference.
spans_need_deref: FxHashMap<HirId, FxHashSet<Span>>,
}
impl<'a, 'tcx> MovedVariablesCtxt<'a, 'tcx> {
fn new(cx: &'a LateContext<'a, 'tcx>) -> Self {
Self {
cx,
moved_vars: FxHashSet::default(),
spans_need_deref: FxHashMap::default(),
}
}
fn move_common(&mut self, _consume_id: HirId, _span: Span, cmt: &mc::cmt_<'tcx>) {
impl MovedVariablesCtxt {
fn move_common(&mut self, cmt: &mc::cmt_<'_>) {
let cmt = unwrap_downcast_or_interior(cmt);
if let mc::Categorization::Local(vid) = cmt.cat {
self.moved_vars.insert(vid);
}
}
fn non_moving_pat(&mut self, matched_pat: &Pat, cmt: &mc::cmt_<'tcx>) {
let cmt = unwrap_downcast_or_interior(cmt);
if let mc::Categorization::Local(vid) = cmt.cat {
let mut id = matched_pat.hir_id;
loop {
let parent = self.cx.tcx.hir().get_parent_node(id);
if id == parent {
// no parent
return;
}
id = parent;
if let Some(node) = self.cx.tcx.hir().find(id) {
match node {
Node::Expr(e) => {
// `match` and `if let`
if let ExprKind::Match(ref c, ..) = e.kind {
self.spans_need_deref
.entry(vid)
.or_insert_with(FxHashSet::default)
.insert(c.span);
}
},
Node::Stmt(s) => {
// `let <pat> = x;`
if_chain! {
if let StmtKind::Local(ref local) = s.kind;
then {
self.spans_need_deref
.entry(vid)
.or_insert_with(FxHashSet::default)
.insert(local.init
.as_ref()
.map(|e| e.span)
.expect("`let` stmt without init aren't caught by match_pat"));
}
}
},
_ => {},
}
}
}
}
}
}
impl<'a, 'tcx> euv::Delegate<'tcx> for MovedVariablesCtxt<'a, 'tcx> {
impl<'tcx> euv::Delegate<'tcx> for MovedVariablesCtxt {
fn consume(&mut self, cmt: &mc::cmt_<'tcx>, mode: euv::ConsumeMode) {
if let euv::ConsumeMode::Move = mode {
self.move_common(cmt.hir_id, cmt.span, cmt);
}
}
fn matched_pat(&mut self, matched_pat: &Pat, cmt: &mc::cmt_<'tcx>, mode: euv::MatchMode) {
if let euv::MatchMode::MovingMatch = mode {
self.move_common(matched_pat.hir_id, matched_pat.span, cmt);
} else {
self.non_moving_pat(matched_pat, cmt);
}
}
fn consume_pat(&mut self, consume_pat: &Pat, cmt: &mc::cmt_<'tcx>, mode: euv::ConsumeMode) {
if let euv::ConsumeMode::Move(_) = mode {
self.move_common(consume_pat.hir_id, consume_pat.span, cmt);
self.move_common(cmt);
}
}