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Move map_identity into the methods module

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This commit is contained in:
xFrednet 2021-06-08 00:14:43 +02:00
parent 9e54ce865c
commit 5336f88403
4 changed files with 67 additions and 81 deletions
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8
clippy_lints/src/lib.rs
View File

@ -254,7 +254,6 @@ mod manual_strip;
mod manual_unwrap_or;
mod map_clone;
mod map_err_ignore;
mod map_identity;
mod map_unit_fn;
mod match_on_vec_items;
mod matches;
@ -705,7 +704,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
manual_unwrap_or::MANUAL_UNWRAP_OR,
map_clone::MAP_CLONE,
map_err_ignore::MAP_ERR_IGNORE,
map_identity::MAP_IDENTITY,
map_unit_fn::OPTION_MAP_UNIT_FN,
map_unit_fn::RESULT_MAP_UNIT_FN,
match_on_vec_items::MATCH_ON_VEC_ITEMS,
@ -765,6 +763,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
methods::MANUAL_STR_REPEAT,
methods::MAP_COLLECT_RESULT_UNIT,
methods::MAP_FLATTEN,
methods::MAP_IDENTITY,
methods::MAP_UNWRAP_OR,
methods::NEW_RET_NO_SELF,
methods::OK_EXPECT,
@ -1260,7 +1259,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(manual_strip::MANUAL_STRIP),
LintId::of(manual_unwrap_or::MANUAL_UNWRAP_OR),
LintId::of(map_clone::MAP_CLONE),
LintId::of(map_identity::MAP_IDENTITY),
LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN),
LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
@ -1301,6 +1299,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(methods::MANUAL_SATURATING_ARITHMETIC),
LintId::of(methods::MANUAL_STR_REPEAT),
LintId::of(methods::MAP_COLLECT_RESULT_UNIT),
LintId::of(methods::MAP_IDENTITY),
LintId::of(methods::NEW_RET_NO_SELF),
LintId::of(methods::OK_EXPECT),
LintId::of(methods::OPTION_AS_REF_DEREF),
@ -1586,7 +1585,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(loops::WHILE_LET_LOOP),
LintId::of(manual_strip::MANUAL_STRIP),
LintId::of(manual_unwrap_or::MANUAL_UNWRAP_OR),
LintId::of(map_identity::MAP_IDENTITY),
LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN),
LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
LintId::of(matches::MATCH_AS_REF),
@ -1601,6 +1599,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(methods::ITER_COUNT),
LintId::of(methods::MANUAL_FILTER_MAP),
LintId::of(methods::MANUAL_FIND_MAP),
LintId::of(methods::MAP_IDENTITY),
LintId::of(methods::OPTION_AS_REF_DEREF),
LintId::of(methods::OPTION_FILTER_MAP),
LintId::of(methods::SEARCH_IS_SOME),
@ -2039,7 +2038,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
single_char_binding_names_threshold,
});
store.register_late_pass(|| box macro_use::MacroUseImports::default());
store.register_late_pass(|| box map_identity::MapIdentity);
store.register_late_pass(|| box pattern_type_mismatch::PatternTypeMismatch);
store.register_late_pass(|| box stable_sort_primitive::StableSortPrimitive);
store.register_late_pass(|| box repeat_once::RepeatOnce);

76
clippy_lints/src/map_identity.rs
View File

@ -1,76 +0,0 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{is_expr_identity_function, is_trait_method};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
declare_clippy_lint! {
/// **What it does:** Checks for instances of `map(f)` where `f` is the identity function.
///
/// **Why is this bad?** It can be written more concisely without the call to `map`.
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```rust
/// let x = [1, 2, 3];
/// let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect();
/// ```
/// Use instead:
/// ```rust
/// let x = [1, 2, 3];
/// let y: Vec<_> = x.iter().map(|x| 2*x).collect();
/// ```
pub MAP_IDENTITY,
complexity,
"using iterator.map(|x| x)"
}
declare_lint_pass!(MapIdentity => [MAP_IDENTITY]);
impl<'tcx> LateLintPass<'tcx> for MapIdentity {
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
if expr.span.from_expansion() {
return;
}
if_chain! {
if let Some([caller, func]) = get_map_argument(cx, expr);
if is_expr_identity_function(cx, func);
then {
span_lint_and_sugg(
cx,
MAP_IDENTITY,
expr.span.trim_start(caller.span).unwrap(),
"unnecessary map of the identity function",
"remove the call to `map`",
String::new(),
Applicability::MachineApplicable
)
}
}
}
}
/// Returns the arguments passed into map() if the expression is a method call to
/// map(). Otherwise, returns None.
fn get_map_argument<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<&'a [Expr<'a>]> {
if_chain! {
if let ExprKind::MethodCall(method, _, args, _) = expr.kind;
if args.len() == 2 && method.ident.name == sym::map;
let caller_ty = cx.typeck_results().expr_ty(&args[0]);
if is_trait_method(cx, expr, sym::Iterator)
|| is_type_diagnostic_item(cx, caller_ty, sym::result_type)
|| is_type_diagnostic_item(cx, caller_ty, sym::option_type);
then {
Some(args)
} else {
None
}
}
}

38
clippy_lints/src/methods/map_identity.rs Normal file
View File

@ -0,0 +1,38 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{is_expr_identity_function, is_trait_method};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::{source_map::Span, sym};
use super::MAP_IDENTITY;
pub(super) fn check(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
caller: &hir::Expr<'_>,
map_arg: &hir::Expr<'_>,
_map_span: Span,
) {
let caller_ty = cx.typeck_results().expr_ty(caller);
if_chain! {
if is_trait_method(cx, expr, sym::Iterator)
|| is_type_diagnostic_item(cx, caller_ty, sym::result_type)
|| is_type_diagnostic_item(cx, caller_ty, sym::option_type);
if is_expr_identity_function(cx, map_arg);
if let Some(sugg_span) = expr.span.trim_start(caller.span);
then {
span_lint_and_sugg(
cx,
MAP_IDENTITY,
sugg_span,
"unnecessary map of the identity function",
"remove the call to `map`",
String::new(),
Applicability::MachineApplicable,
)
}
}
}

26
clippy_lints/src/methods/mod.rs
View File

@ -35,6 +35,7 @@ mod manual_saturating_arithmetic;
mod manual_str_repeat;
mod map_collect_result_unit;
mod map_flatten;
mod map_identity;
mod map_unwrap_or;
mod ok_expect;
mod option_as_ref_deref;
@ -1561,6 +1562,29 @@ declare_clippy_lint! {
"call to `filter_map` where `flatten` is sufficient"
}
declare_clippy_lint! {
/// **What it does:** Checks for instances of `map(f)` where `f` is the identity function.
///
/// **Why is this bad?** It can be written more concisely without the call to `map`.
///
/// **Known problems:** None.
///
/// **Example:**
///
/// ```rust
/// let x = [1, 2, 3];
/// let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect();
/// ```
/// Use instead:
/// ```rust
/// let x = [1, 2, 3];
/// let y: Vec<_> = x.iter().map(|x| 2*x).collect();
/// ```
pub MAP_IDENTITY,
complexity,
"using iterator.map(|x| x)"
}
declare_clippy_lint! {
/// **What it does:** Checks for the use of `.bytes().nth()`.
///
@ -1728,6 +1752,7 @@ impl_lint_pass!(Methods => [
FILTER_NEXT,
SKIP_WHILE_NEXT,
FILTER_MAP_IDENTITY,
MAP_IDENTITY,
MANUAL_FILTER_MAP,
MANUAL_FIND_MAP,
OPTION_FILTER_MAP,
@ -2058,6 +2083,7 @@ fn check_methods<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, msrv: Optio
_ => {},
}
}
map_identity::check(cx, expr, recv, m_arg, span);
},
("map_or", [def, map]) => option_map_or_none::check(cx, expr, recv, def, map),
("next", []) => {