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cmp_owned refactor

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This commit is contained in:
Josh Mcguigan 2018-10-12 04:48:54 -07:00
parent c9718fa589
commit 352863065c
1 changed files with 14 additions and 31 deletions
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45
clippy_lints/src/misc.rs
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@ -21,7 +21,7 @@ use crate::utils::{get_item_name, get_parent_expr, implements_trait, in_constant
iter_input_pats, last_path_segment, match_qpath, match_trait_method, paths, snippet, span_lint,
span_lint_and_then, walk_ptrs_ty, SpanlessEq};
use crate::utils::sugg::Sugg;
use crate::syntax::ast::{LitKind, CRATE_NODE_ID};
use crate::syntax::ast::LitKind;
use crate::consts::{constant, Constant};
use crate::rustc_errors::Applicability;
@ -540,18 +540,10 @@ fn check_to_owned(cx: &LateContext<'_, '_>, expr: &Expr, other: &Expr) {
_ => false,
};
let (lint_span, try_hint) = if deref_arg_impl_partial_eq_other {
// suggest deref on the left
(expr.span, format!("*{}", snip))
} else if other_gets_derefed {
// suggest dropping the to_owned on the left and the deref on the right
let other_snippet = snippet(cx, other.span, "..").into_owned();
let other_without_deref = other_snippet.replacen('*', "", 1);
(expr.span.to(other.span), format!("{} == {}", snip.to_string(), other_without_deref))
let lint_span = if other_gets_derefed {
expr.span.to(other.span)
} else {
// suggest dropping the to_owned on the left
(expr.span, snip.to_string())
expr.span
};
span_lint_and_then(
@ -560,29 +552,20 @@ fn check_to_owned(cx: &LateContext<'_, '_>, expr: &Expr, other: &Expr) {
lint_span,
"this creates an owned instance just for comparison",
|db| {
// this is as good as our recursion check can get, we can't prove that the
// current function is
// called by
// PartialEq::eq, but we can at least ensure that this code is not part of it
let parent_fn = cx.tcx.hir.get_parent(expr.id);
let parent_impl = cx.tcx.hir.get_parent(parent_fn);
if parent_impl != CRATE_NODE_ID {
if let Node::Item(item) = cx.tcx.hir.get(parent_impl) {
if let ItemKind::Impl(.., Some(ref trait_ref), _, _) = item.node {
if trait_ref.path.def.def_id() == partial_eq_trait_id {
// we are implementing PartialEq, don't suggest not doing `to_owned`, otherwise
// we go into
// recursion
db.span_label(lint_span, "try implementing the comparison without allocating");
return;
}
}
}
}
// this also catches PartialEq implementations that call to_owned
if other_gets_derefed {
db.span_label(lint_span, "try implementing the comparison without allocating");
return;
}
let try_hint = if deref_arg_impl_partial_eq_other {
// suggest deref on the left
format!("*{}", snip)
} else {
// suggest dropping the to_owned on the left
snip.to_string()
};
db.span_suggestion_with_applicability(
lint_span,
"try",