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Fix FP in same_item_push

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Don't emit a lint when the pushed item doesn't have Clone trait
This commit is contained in:
Takayuki Nakata 2020-09-01 22:39:09 +09:00
parent 001c1c51d2
commit aa7ffa5257
2 changed files with 49 additions and 35 deletions
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78
clippy_lints/src/loops.rs
View file

@ -1140,43 +1140,51 @@ fn detect_same_item_push<'tcx>(
walk_expr(&mut same_item_push_visitor, body);
if same_item_push_visitor.should_lint {
if let Some((vec, pushed_item)) = same_item_push_visitor.vec_push {
// Make sure that the push does not involve possibly mutating values
if let PatKind::Wild = pat.kind {
let vec_str = snippet_with_macro_callsite(cx, vec.span, "");
let item_str = snippet_with_macro_callsite(cx, pushed_item.span, "");
if let ExprKind::Path(ref qpath) = pushed_item.kind {
if_chain! {
if let Res::Local(hir_id) = qpath_res(cx, qpath, pushed_item.hir_id);
let node = cx.tcx.hir().get(hir_id);
if let Node::Binding(pat) = node;
if let PatKind::Binding(bind_ann, ..) = pat.kind;
if !matches!(bind_ann, BindingAnnotation::RefMut | BindingAnnotation::Mutable);
then {
span_lint_and_help(
cx,
SAME_ITEM_PUSH,
vec.span,
"it looks like the same item is being pushed into this Vec",
None,
&format!(
"try using vec![{};SIZE] or {}.resize(NEW_SIZE, {})",
item_str, vec_str, item_str
),
)
let ty = cx.typeck_results().expr_ty(pushed_item);
if cx
.tcx
.lang_items()
.clone_trait()
.map_or(false, |id| implements_trait(cx, ty, id, &[]))
{
// Make sure that the push does not involve possibly mutating values
if let PatKind::Wild = pat.kind {
let vec_str = snippet_with_macro_callsite(cx, vec.span, "");
let item_str = snippet_with_macro_callsite(cx, pushed_item.span, "");
if let ExprKind::Path(ref qpath) = pushed_item.kind {
if_chain! {
if let Res::Local(hir_id) = qpath_res(cx, qpath, pushed_item.hir_id);
let node = cx.tcx.hir().get(hir_id);
if let Node::Binding(pat) = node;
if let PatKind::Binding(bind_ann, ..) = pat.kind;
if !matches!(bind_ann, BindingAnnotation::RefMut | BindingAnnotation::Mutable);
then {
span_lint_and_help(
cx,
SAME_ITEM_PUSH,
vec.span,
"it looks like the same item is being pushed into this Vec",
None,
&format!(
"try using vec![{};SIZE] or {}.resize(NEW_SIZE, {})",
item_str, vec_str, item_str
),
)
}
}
} else if mutated_variables(pushed_item, cx).map_or(false, |mutvars| mutvars.is_empty()) {
span_lint_and_help(
cx,
SAME_ITEM_PUSH,
vec.span,
"it looks like the same item is being pushed into this Vec",
None,
&format!(
"try using vec![{};SIZE] or {}.resize(NEW_SIZE, {})",
item_str, vec_str, item_str
),
)
}
} else if mutated_variables(pushed_item, cx).map_or(false, |mutvars| mutvars.is_empty()) {
span_lint_and_help(
cx,
SAME_ITEM_PUSH,
vec.span,
"it looks like the same item is being pushed into this Vec",
None,
&format!(
"try using vec![{};SIZE] or {}.resize(NEW_SIZE, {})",
item_str, vec_str, item_str
),
)
}
}
}

6
tests/ui/same_item_push.rs
View file

@ -94,4 +94,10 @@ fn main() {
vec13.push(item);
item += 10;
}
// Fix #5979
let mut vec14: Vec<std::fs::File> = Vec::new();
for _ in 0..10 {
vec14.push(std::fs::File::open("foobar").unwrap());
}
}