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move useless_asref to its own module

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This commit is contained in:
Takayuki Maeda 2021-03-06 18:59:35 +09:00
parent caaba8270c
commit 78e572c627
2 changed files with 50 additions and 40 deletions
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45
clippy_lints/src/methods/mod.rs
View file

@ -42,6 +42,7 @@ mod uninit_assumed_init;
mod unnecessary_filter_map;
mod unnecessary_lazy_eval;
mod unwrap_used;
mod useless_asref;
mod wrong_self_convention;
mod zst_offset;
@ -65,11 +66,11 @@ use rustc_typeck::hir_ty_to_ty;
use crate::utils::eager_or_lazy::is_lazyness_candidate;
use crate::utils::usage::mutated_variables;
use crate::utils::{
contains_return, contains_ty, get_parent_expr, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of,
contains_return, contains_ty, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of,
is_type_diagnostic_item, iter_input_pats, last_path_segment, match_def_path, match_qpath, match_trait_method,
match_type, meets_msrv, method_calls, method_chain_args, path_to_local_id, paths, remove_blocks, return_ty,
single_segment_path, snippet, snippet_with_applicability, snippet_with_macro_callsite, span_lint,
span_lint_and_help, span_lint_and_sugg, strip_pat_refs, walk_ptrs_ty_depth, SpanlessEq,
span_lint_and_help, span_lint_and_sugg, strip_pat_refs, SpanlessEq,
};
declare_clippy_lint! {
@ -1733,8 +1734,8 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
["step_by", ..] => iterator_step_by_zero::check(cx, expr, arg_lists[0]),
["next", "skip"] => iter_skip_next::check(cx, expr, arg_lists[1]),
["collect", "cloned"] => iter_cloned_collect::check(cx, expr, arg_lists[1]),
["as_ref"] => lint_asref(cx, expr, "as_ref", arg_lists[0]),
["as_mut"] => lint_asref(cx, expr, "as_mut", arg_lists[0]),
["as_ref"] => useless_asref::check(cx, expr, "as_ref", arg_lists[0]),
["as_mut"] => useless_asref::check(cx, expr, "as_mut", arg_lists[0]),
["fold", ..] => lint_unnecessary_fold(cx, expr, arg_lists[0], method_spans[0]),
["filter_map", ..] => {
unnecessary_filter_map::check(cx, expr, arg_lists[0]);
@ -2751,42 +2752,6 @@ fn get_hint_if_single_char_arg(
}
}
/// Checks for the `USELESS_ASREF` lint.
fn lint_asref(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, as_ref_args: &[hir::Expr<'_>]) {
// when we get here, we've already checked that the call name is "as_ref" or "as_mut"
// check if the call is to the actual `AsRef` or `AsMut` trait
if match_trait_method(cx, expr, &paths::ASREF_TRAIT) || match_trait_method(cx, expr, &paths::ASMUT_TRAIT) {
// check if the type after `as_ref` or `as_mut` is the same as before
let recvr = &as_ref_args[0];
let rcv_ty = cx.typeck_results().expr_ty(recvr);
let res_ty = cx.typeck_results().expr_ty(expr);
let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty);
let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty);
if base_rcv_ty == base_res_ty && rcv_depth >= res_depth {
// allow the `as_ref` or `as_mut` if it is followed by another method call
if_chain! {
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::MethodCall(_, ref span, _, _) = parent.kind;
if span != &expr.span;
then {
return;
}
}
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
USELESS_ASREF,
expr.span,
&format!("this call to `{}` does nothing", call_name),
"try this",
snippet_with_applicability(cx, recvr.span, "..", &mut applicability).to_string(),
applicability,
);
}
}
}
const FN_HEADER: hir::FnHeader = hir::FnHeader {
unsafety: hir::Unsafety::Normal,
constness: hir::Constness::NotConst,

45
clippy_lints/src/methods/useless_asref.rs Normal file
View file

@ -0,0 +1,45 @@
use crate::utils::{
get_parent_expr, match_trait_method, paths, snippet_with_applicability, span_lint_and_sugg, walk_ptrs_ty_depth,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::USELESS_ASREF;
/// Checks for the `USELESS_ASREF` lint.
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, as_ref_args: &[hir::Expr<'_>]) {
// when we get here, we've already checked that the call name is "as_ref" or "as_mut"
// check if the call is to the actual `AsRef` or `AsMut` trait
if match_trait_method(cx, expr, &paths::ASREF_TRAIT) || match_trait_method(cx, expr, &paths::ASMUT_TRAIT) {
// check if the type after `as_ref` or `as_mut` is the same as before
let recvr = &as_ref_args[0];
let rcv_ty = cx.typeck_results().expr_ty(recvr);
let res_ty = cx.typeck_results().expr_ty(expr);
let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty);
let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty);
if base_rcv_ty == base_res_ty && rcv_depth >= res_depth {
// allow the `as_ref` or `as_mut` if it is followed by another method call
if_chain! {
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::MethodCall(_, ref span, _, _) = parent.kind;
if span != &expr.span;
then {
return;
}
}
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
USELESS_ASREF,
expr.span,
&format!("this call to `{}` does nothing", call_name),
"try this",
snippet_with_applicability(cx, recvr.span, "..", &mut applicability).to_string(),
applicability,
);
}
}
}