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relax needless_range_loop so that it reports only direct indexing

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This commit is contained in:
Andriy S. from cobalt 2017-10-08 18:34:31 +03:00
parent a54baad4fa
commit 52bd7bb662
1 changed files with 16 additions and 4 deletions
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20
clippy_lints/src/loops.rs
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@ -925,14 +925,16 @@ fn check_for_loop_range<'a, 'tcx>(
cx: cx,
var: canonical_id,
indexed: HashMap::new(),
indexed_directly: HashMap::new(),
referenced: HashSet::new(),
nonindex: false,
};
walk_expr(&mut visitor, body);
// linting condition: we only indexed one variable
if visitor.indexed.len() == 1 {
let (indexed, indexed_extent) = visitor.indexed.into_iter().next().expect(
// linting condition: we only indexed one variable, and indexed it directly
// (`indexed_directly` is subset of `indexed`)
if visitor.indexed.len() == 1 && visitor.indexed_directly.len() == 1 {
let (indexed, indexed_extent) = visitor.indexed_directly.into_iter().next().expect(
"already checked that we have exactly 1 element",
);
@ -1481,6 +1483,9 @@ struct VarVisitor<'a, 'tcx: 'a> {
var: ast::NodeId,
/// indexed variables, the extend is `None` for global
indexed: HashMap<Name, Option<region::Scope>>,
/// subset of `indexed` of vars that are indexed directly: `v[i]`
/// this will not contain cases like `v[calc_index(i)]` or `v[(i + 4) % N]`
indexed_directly: HashMap<Name, Option<region::Scope>>,
/// Any names that are used outside an index operation.
/// Used to detect things like `&mut vec` used together with `vec[i]`
referenced: HashSet<Name>,
@ -1499,7 +1504,8 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
let QPath::Resolved(None, ref seqvar) = *seqpath,
seqvar.segments.len() == 1,
], {
let index_used = same_var(self.cx, idx, self.var) || {
let index_used_directly = same_var(self.cx, idx, self.var);
let index_used = index_used_directly || {
let mut used_visitor = LocalUsedVisitor {
cx: self.cx,
local: self.var,
@ -1519,10 +1525,16 @@ impl<'a, 'tcx> Visitor<'tcx> for VarVisitor<'a, 'tcx> {
let parent_def_id = self.cx.tcx.hir.local_def_id(parent_id);
let extent = self.cx.tcx.region_scope_tree(parent_def_id).var_scope(hir_id.local_id);
self.indexed.insert(seqvar.segments[0].name, Some(extent));
if index_used_directly {
self.indexed_directly.insert(seqvar.segments[0].name, Some(extent));
}
return; // no need to walk further *on the variable*
}
Def::Static(..) | Def::Const(..) => {
self.indexed.insert(seqvar.segments[0].name, None);
if index_used_directly {
self.indexed_directly.insert(seqvar.segments[0].name, None);
}
return; // no need to walk further *on the variable*
}
_ => (),