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manual-unwrap-or / pr remarks

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This commit is contained in:
Tim Nielens 2020-10-11 22:55:05 +02:00
parent 9c9327980b
commit 6d4eeeabcd
8 changed files with 101 additions and 79 deletions
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9
clippy_lints/src/lib.rs
View file

@ -224,7 +224,6 @@ mod large_const_arrays;
mod large_enum_variant;
mod large_stack_arrays;
mod len_zero;
mod less_concise_than;
mod let_if_seq;
mod let_underscore;
mod lifetimes;
@ -235,6 +234,7 @@ mod main_recursion;
mod manual_async_fn;
mod manual_non_exhaustive;
mod manual_strip;
mod manual_unwrap_or;
mod map_clone;
mod map_err_ignore;
mod map_identity;
@ -610,7 +610,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
&large_stack_arrays::LARGE_STACK_ARRAYS,
&len_zero::LEN_WITHOUT_IS_EMPTY,
&len_zero::LEN_ZERO,
&less_concise_than::LESS_CONCISE_THAN_OPTION_UNWRAP_OR,
&let_if_seq::USELESS_LET_IF_SEQ,
&let_underscore::LET_UNDERSCORE_LOCK,
&let_underscore::LET_UNDERSCORE_MUST_USE,
@ -642,6 +641,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
&manual_async_fn::MANUAL_ASYNC_FN,
&manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE,
&manual_strip::MANUAL_STRIP,
&manual_unwrap_or::MANUAL_UNWRAP_OR,
&map_clone::MAP_CLONE,
&map_err_ignore::MAP_ERR_IGNORE,
&map_identity::MAP_IDENTITY,
@ -1128,7 +1128,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|| box repeat_once::RepeatOnce);
store.register_late_pass(|| box unwrap_in_result::UnwrapInResult);
store.register_late_pass(|| box self_assignment::SelfAssignment);
store.register_late_pass(|| box less_concise_than::LessConciseThan);
store.register_late_pass(|| box manual_unwrap_or::ManualUnwrapOr);
store.register_late_pass(|| box float_equality_without_abs::FloatEqualityWithoutAbs);
store.register_late_pass(|| box async_yields_async::AsyncYieldsAsync);
store.register_late_pass(|| box manual_strip::ManualStrip);
@ -1213,7 +1213,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(&infinite_iter::MAYBE_INFINITE_ITER),
LintId::of(&items_after_statements::ITEMS_AFTER_STATEMENTS),
LintId::of(&large_stack_arrays::LARGE_STACK_ARRAYS),
LintId::of(&less_concise_than::LESS_CONCISE_THAN_OPTION_UNWRAP_OR),
LintId::of(&literal_representation::LARGE_DIGIT_GROUPS),
LintId::of(&literal_representation::UNREADABLE_LITERAL),
LintId::of(&loops::EXPLICIT_INTO_ITER_LOOP),
@ -1371,6 +1370,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(&manual_async_fn::MANUAL_ASYNC_FN),
LintId::of(&manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
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),
@ -1666,6 +1666,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(&loops::MUT_RANGE_BOUND),
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),

113
clippy_lints/src/manual_unwrap_or.rs
View file

@ -2,12 +2,14 @@ use crate::utils;
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{def, Arm, Expr, ExprKind, PatKind, QPath};
use rustc_lint::LintContext;
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
/// **What it does:**
/// Finds patterns that can be encoded more concisely with `Option::unwrap_or`.
/// Finds patterns that reimplement `Option::unwrap_or`.
///
/// **Why is this bad?**
/// Concise code helps focusing on behavior instead of boilerplate.
@ -16,7 +18,7 @@ declare_clippy_lint! {
///
/// **Example:**
/// ```rust
/// match int_optional {
/// match int_option {
/// Some(v) => v,
/// None => 1,
/// }
@ -24,39 +26,35 @@ declare_clippy_lint! {
///
/// Use instead:
/// ```rust
/// int_optional.unwrap_or(1)
/// int_option.unwrap_or(1)
/// ```
pub LESS_CONCISE_THAN_OPTION_UNWRAP_OR,
pedantic,
"finds patterns that can be encoded more concisely with `Option::unwrap_or`"
pub MANUAL_UNWRAP_OR,
complexity,
"finds patterns that can be encoded more concisely with `Option::unwrap_or(_else)`"
}
declare_lint_pass!(LessConciseThan => [LESS_CONCISE_THAN_OPTION_UNWRAP_OR]);
declare_lint_pass!(ManualUnwrapOr => [MANUAL_UNWRAP_OR]);
impl LateLintPass<'_> for LessConciseThan {
impl LateLintPass<'_> for ManualUnwrapOr {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if utils::in_macro(expr.span) {
return;
}
if lint_option_unwrap_or_case(cx, expr) {
if in_external_macro(cx.sess(), expr.span) {
return;
}
lint_option_unwrap_or_case(cx, expr);
}
}
fn lint_option_unwrap_or_case<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
#[allow(clippy::needless_bool)]
fn applicable_none_arm<'a>(arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
if_chain! {
if arms.len() == 2;
if arms.iter().all(|arm| arm.guard.is_none());
if let Some((idx, none_arm)) = arms.iter().enumerate().find(|(_, arm)|
if_chain! {
if let PatKind::Path(ref qpath) = arm.pat.kind;
if utils::match_qpath(qpath, &utils::paths::OPTION_NONE);
then { true }
else { false }
}
if let PatKind::Path(ref qpath) = arm.pat.kind {
utils::match_qpath(qpath, &utils::paths::OPTION_NONE)
} else {
false
}
);
let some_arm = &arms[1 - idx];
if let PatKind::TupleStruct(ref some_qpath, &[some_binding], _) = some_arm.pat.kind;
@ -65,43 +63,50 @@ fn lint_option_unwrap_or_case<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tc
if let ExprKind::Path(QPath::Resolved(_, body_path)) = some_arm.body.kind;
if let def::Res::Local(body_path_hir_id) = body_path.res;
if body_path_hir_id == binding_hir_id;
then { Some(none_arm) }
else { None }
if !utils::usage::contains_return_break_continue_macro(none_arm.body);
then {
Some(none_arm)
}
else {
None
}
}
}
if_chain! {
if !utils::usage::contains_return_break_continue_macro(expr);
if let ExprKind::Match (match_expr, match_arms, _) = expr.kind;
let ty = cx.typeck_results().expr_ty(match_expr);
if utils::is_type_diagnostic_item(cx, ty, sym!(option_type));
if let Some(none_arm) = applicable_none_arm(match_arms);
if let Some(match_expr_snippet) = utils::snippet_opt(cx, match_expr.span);
if let Some(none_body_snippet) = utils::snippet_opt(cx, none_arm.body.span);
if let Some(indent) = utils::indent_of(cx, expr.span);
then {
let reindented_none_body =
utils::reindent_multiline(none_body_snippet.into(), true, Some(indent));
let eager_eval = utils::eager_or_lazy::is_eagerness_candidate(cx, none_arm.body);
let method = if eager_eval {
"unwrap_or"
} else {
"unwrap_or_else"
};
utils::span_lint_and_sugg(
cx,
LESS_CONCISE_THAN_OPTION_UNWRAP_OR, expr.span,
"this pattern can be more concisely encoded with `Option::unwrap_or`",
"replace with",
format!(
"{}.{}({}{})",
match_expr_snippet,
method,
if eager_eval { ""} else { "|| " },
reindented_none_body
),
Applicability::MachineApplicable,
);
true
} else { false}
if let ExprKind::Match(scrutinee, match_arms, _) = expr.kind;
let ty = cx.typeck_results().expr_ty(scrutinee);
if utils::is_type_diagnostic_item(cx, ty, sym!(option_type));
if let Some(none_arm) = applicable_none_arm(match_arms);
if let Some(scrutinee_snippet) = utils::snippet_opt(cx, scrutinee.span);
if let Some(none_body_snippet) = utils::snippet_opt(cx, none_arm.body.span);
if let Some(indent) = utils::indent_of(cx, expr.span);
then {
let reindented_none_body =
utils::reindent_multiline(none_body_snippet.into(), true, Some(indent));
let eager_eval = utils::eager_or_lazy::is_eagerness_candidate(cx, none_arm.body);
let method = if eager_eval {
"unwrap_or"
} else {
"unwrap_or_else"
};
utils::span_lint_and_sugg(
cx,
MANUAL_UNWRAP_OR, expr.span,
&format!("this pattern reimplements `Option::{}`", &method),
"replace with",
format!(
"{}.{}({}{})",
scrutinee_snippet,
method,
if eager_eval { ""} else { "|| " },
reindented_none_body
),
Applicability::MachineApplicable,
);
true
} else {
false
}
}
}