Add: option_manual_map lint
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@ -2161,6 +2161,7 @@ Released 2018-09-13
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[`manual_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_filter_map
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[`manual_find_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_find_map
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[`manual_flatten`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_flatten
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[`manual_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_map
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[`manual_memcpy`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_memcpy
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[`manual_non_exhaustive`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_non_exhaustive
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[`manual_ok_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_ok_or
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@ -241,6 +241,7 @@ mod loops;
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mod macro_use;
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mod main_recursion;
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mod manual_async_fn;
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mod manual_map;
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mod manual_non_exhaustive;
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mod manual_ok_or;
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mod manual_strip;
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@ -706,6 +707,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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¯o_use::MACRO_USE_IMPORTS,
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&main_recursion::MAIN_RECURSION,
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&manual_async_fn::MANUAL_ASYNC_FN,
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&manual_map::MANUAL_MAP,
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&manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE,
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&manual_ok_or::MANUAL_OK_OR,
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&manual_strip::MANUAL_STRIP,
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@ -1262,6 +1264,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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store.register_late_pass(|| box case_sensitive_file_extension_comparisons::CaseSensitiveFileExtensionComparisons);
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store.register_late_pass(|| box redundant_slicing::RedundantSlicing);
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store.register_late_pass(|| box from_str_radix_10::FromStrRadix10);
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store.register_late_pass(|| box manual_map::ManualMap);
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store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
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LintId::of(&arithmetic::FLOAT_ARITHMETIC),
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@ -1521,6 +1524,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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LintId::of(&loops::WHILE_LET_ON_ITERATOR),
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LintId::of(&main_recursion::MAIN_RECURSION),
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LintId::of(&manual_async_fn::MANUAL_ASYNC_FN),
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LintId::of(&manual_map::MANUAL_MAP),
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LintId::of(&manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
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LintId::of(&manual_strip::MANUAL_STRIP),
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LintId::of(&manual_unwrap_or::MANUAL_UNWRAP_OR),
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@ -1750,6 +1754,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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LintId::of(&loops::WHILE_LET_ON_ITERATOR),
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LintId::of(&main_recursion::MAIN_RECURSION),
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LintId::of(&manual_async_fn::MANUAL_ASYNC_FN),
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LintId::of(&manual_map::MANUAL_MAP),
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LintId::of(&manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
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LintId::of(&map_clone::MAP_CLONE),
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LintId::of(&matches::INFALLIBLE_DESTRUCTURING_MATCH),
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@ -0,0 +1,262 @@
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use crate::utils::{
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is_type_diagnostic_item, match_def_path, paths, peel_hir_expr_refs, peel_mid_ty_refs_is_mutable,
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snippet_with_applicability, span_lint_and_sugg,
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};
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use rustc_ast::util::parser::PREC_POSTFIX;
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use rustc_errors::Applicability;
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use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, Mutability, Pat, PatKind, Path, QPath};
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use rustc_lint::{LateContext, LateLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::symbol::{sym, Ident};
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declare_clippy_lint! {
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/// **What it does:** Checks for usages of `match` which could be implemented using `map`
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///
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/// **Why is this bad?** Using the `map` method is clearer and more concise.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// ```rust
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/// match Some(0) {
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/// Some(x) => Some(x + 1),
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/// None => None,
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/// };
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/// ```
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/// Use instead:
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/// ```rust
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/// Some(0).map(|x| x + 1);
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/// ```
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pub MANUAL_MAP,
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style,
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"reimplementation of `map`"
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}
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declare_lint_pass!(ManualMap => [MANUAL_MAP]);
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impl LateLintPass<'_> for ManualMap {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
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if in_external_macro(cx.sess(), expr.span) {
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return;
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}
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if let ExprKind::Match(scrutinee, [arm1 @ Arm { guard: None, .. }, arm2 @ Arm { guard: None, .. }], _) =
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expr.kind
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{
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let (scrutinee_ty, ty_ref_count, ty_mutability) =
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peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrutinee));
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if !is_type_diagnostic_item(cx, scrutinee_ty, sym::option_type)
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|| !is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::option_type)
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{
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return;
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}
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let (some_expr, some_pat, pat_ref_count, is_wild_none) =
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match (try_parse_pattern(cx, arm1.pat), try_parse_pattern(cx, arm2.pat)) {
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(Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count }))
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if is_none_expr(cx, arm1.body) =>
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{
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(arm2.body, pattern, ref_count, true)
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},
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(Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count }))
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if is_none_expr(cx, arm1.body) =>
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{
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(arm2.body, pattern, ref_count, false)
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},
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(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild))
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if is_none_expr(cx, arm2.body) =>
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{
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(arm1.body, pattern, ref_count, true)
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},
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(Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None))
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if is_none_expr(cx, arm2.body) =>
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{
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(arm1.body, pattern, ref_count, false)
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},
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_ => return,
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};
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// Top level or patterns aren't allowed in closures.
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if matches!(some_pat.kind, PatKind::Or(_)) {
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return;
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}
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let some_expr = match get_some_expr(cx, some_expr) {
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Some(expr) => expr,
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None => return,
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};
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// Determine which binding mode to use.
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let explicit_ref = some_pat.contains_explicit_ref_binding();
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let binding_mutability = explicit_ref.or(if ty_ref_count != pat_ref_count {
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Some(ty_mutability)
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} else {
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None
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});
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let as_ref_str = match binding_mutability {
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Some(Mutability::Mut) => ".as_mut()",
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Some(Mutability::Not) => ".as_ref()",
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None => "",
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};
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let mut app = Applicability::MachineApplicable;
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// Remove address-of expressions from the scrutinee. `as_ref` will be called,
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// the type is copyable, or the option is being passed by value.
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let scrutinee = peel_hir_expr_refs(scrutinee).0;
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let scrutinee_str = snippet_with_applicability(cx, scrutinee.span, "_", &mut app);
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let scrutinee_str = if expr.precedence().order() < PREC_POSTFIX {
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// Parens are needed to chain method calls.
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format!("({})", scrutinee_str)
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} else {
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scrutinee_str.into()
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};
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let body_str = if let PatKind::Binding(annotation, _, some_binding, None) = some_pat.kind {
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if let Some(func) = can_pass_as_func(cx, some_binding, some_expr) {
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snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
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} else {
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// `ref` and `ref mut` annotations were handled earlier.
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let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
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"mut "
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} else {
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""
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};
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format!(
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"|{}{}| {}",
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annotation,
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some_binding,
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snippet_with_applicability(cx, some_expr.span, "..", &mut app)
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)
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}
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} else if !is_wild_none && explicit_ref.is_none() {
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// TODO: handle explicit reference annotations.
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format!(
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"|{}| {}",
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snippet_with_applicability(cx, some_pat.span, "..", &mut app),
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snippet_with_applicability(cx, some_expr.span, "..", &mut app)
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)
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} else {
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// Refutable bindings and mixed reference annotations can't be handled by `map`.
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return;
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};
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span_lint_and_sugg(
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cx,
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MANUAL_MAP,
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expr.span,
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"manual implementation of `Option::map`",
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"try this",
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format!("{}{}.map({})", scrutinee_str, as_ref_str, body_str),
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app,
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);
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}
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}
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}
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// Checks whether the expression could be passed as a function, or whether a closure is needed.
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// Returns the function to be passed to `map` if it exists.
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fn can_pass_as_func(cx: &LateContext<'tcx>, binding: Ident, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
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match expr.kind {
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ExprKind::Call(func, [arg])
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if matches!(arg.kind,
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ExprKind::Path(QPath::Resolved(None, Path { segments: [path], ..}))
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if path.ident == binding
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) && cx.typeck_results().expr_adjustments(arg).is_empty() =>
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{
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Some(func)
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},
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_ => None,
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}
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}
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enum OptionPat<'a> {
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Wild,
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None,
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Some {
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// The pattern contained in the `Some` tuple.
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pattern: &'a Pat<'a>,
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// The number of references before the `Some` tuple.
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// e.g. `&&Some(_)` has a ref count of 2.
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ref_count: usize,
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},
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}
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// Try to parse into a recognized `Option` pattern.
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// i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
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fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>) -> Option<OptionPat<'tcx>> {
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fn f(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ref_count: usize) -> Option<OptionPat<'tcx>> {
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match pat.kind {
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PatKind::Wild => Some(OptionPat::Wild),
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PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1),
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PatKind::Path(QPath::Resolved(None, path))
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if path
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.res
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.opt_def_id()
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.map_or(false, |id| match_def_path(cx, id, &paths::OPTION_NONE)) =>
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{
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Some(OptionPat::None)
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},
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PatKind::TupleStruct(QPath::Resolved(None, path), [pattern], _)
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if path
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.res
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.opt_def_id()
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.map_or(false, |id| match_def_path(cx, id, &paths::OPTION_SOME)) =>
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{
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Some(OptionPat::Some { pattern, ref_count })
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},
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_ => None,
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}
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}
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f(cx, pat, 0)
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}
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// Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
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fn get_some_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
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// TODO: Allow more complex expressions.
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match expr.kind {
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ExprKind::Call(
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Expr {
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kind: ExprKind::Path(QPath::Resolved(None, path)),
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..
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},
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[arg],
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) => {
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if match_def_path(cx, path.res.opt_def_id()?, &paths::OPTION_SOME) {
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Some(arg)
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} else {
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None
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}
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},
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ExprKind::Block(
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Block {
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stmts: [],
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expr: Some(expr),
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..
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},
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_,
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) => get_some_expr(cx, expr),
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_ => None,
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}
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}
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// Checks for the `None` value.
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fn is_none_expr(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
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match expr.kind {
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ExprKind::Path(QPath::Resolved(None, path)) => path
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.res
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.opt_def_id()
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.map_or(false, |id| match_def_path(cx, id, &paths::OPTION_NONE)),
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ExprKind::Block(
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Block {
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stmts: [],
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expr: Some(expr),
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..
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},
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_,
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) => is_none_expr(cx, expr),
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_ => false,
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}
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}
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@ -32,7 +32,7 @@ use std::collections::hash_map::Entry;
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use std::hash::BuildHasherDefault;
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use if_chain::if_chain;
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use rustc_ast::ast::{self, Attribute, LitKind};
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use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind, Mutability};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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@ -1672,6 +1672,18 @@ pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>,
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f(expr, 0, count)
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}
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/// Peels off all references on the expression. Returns the underlying expression and the number of
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/// references removed.
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pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
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fn f(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
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match expr.kind {
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ExprKind::AddrOf(BorrowKind::Ref, _, expr) => f(expr, count + 1),
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_ => (expr, count),
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}
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}
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f(expr, 0)
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}
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/// Peels off all references on the type. Returns the underlying type and the number of references
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/// removed.
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pub fn peel_mid_ty_refs(ty: Ty<'_>) -> (Ty<'_>, usize) {
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@ -1685,6 +1697,19 @@ pub fn peel_mid_ty_refs(ty: Ty<'_>) -> (Ty<'_>, usize) {
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peel(ty, 0)
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}
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/// Peels off all references on the type.Returns the underlying type, the number of references
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/// removed, and whether the pointer is ultimately mutable or not.
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pub fn peel_mid_ty_refs_is_mutable(ty: Ty<'_>) -> (Ty<'_>, usize, Mutability) {
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fn f(ty: Ty<'_>, count: usize, mutability: Mutability) -> (Ty<'_>, usize, Mutability) {
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match ty.kind() {
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ty::Ref(_, ty, Mutability::Mut) => f(ty, count + 1, mutability),
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ty::Ref(_, ty, Mutability::Not) => f(ty, count + 1, Mutability::Not),
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_ => (ty, count, mutability),
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}
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}
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f(ty, 0, Mutability::Mut)
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}
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#[macro_export]
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macro_rules! unwrap_cargo_metadata {
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($cx: ident, $lint: ident, $deps: expr) => {{
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@ -0,0 +1,61 @@
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// run-rustfix
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#![warn(clippy::manual_map)]
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#![allow(clippy::no_effect, clippy::map_identity, clippy::unit_arg, clippy::match_ref_pats)]
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fn main() {
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Some(0).map(|_| 2);
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Some(0).map(|x| x + 1);
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Some("").map(|x| x.is_empty());
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Some(0).map(|x| !x);
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#[rustfmt::skip]
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Some(0).map(std::convert::identity);
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Some(&String::new()).map(|x| str::len(x));
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match Some(0) {
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Some(x) if false => Some(x + 1),
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_ => None,
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};
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Some([0, 1]).as_ref().map(|x| x[0]);
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Some(0).map(|x| x * 2);
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Some(String::new()).as_ref().map(|x| x.is_empty());
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Some(String::new()).as_ref().map(|x| x.len());
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Some(0).map(|x| x + x);
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Some(String::new()).as_mut().map(|x| x.push_str(""));
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Some(String::new()).as_ref().map(|x| &**x);
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Some(String::new()).as_ref().map(|x| x.is_empty());
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Some((0, 1, 2)).map(|(x, y, z)| x + y + z);
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Some([1, 2, 3]).map(|[first, ..]| first);
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Some((String::new(), "test")).as_ref().map(|(x, y)| (y, x));
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match Some((String::new(), 0)) {
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Some((ref x, y)) => Some((y, x)),
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None => None,
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};
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match Some(Some(0)) {
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Some(Some(_)) | Some(None) => Some(0),
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None => None,
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};
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match Some(Some((0, 1))) {
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Some(Some((x, 1))) => Some(x),
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_ => None,
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};
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||||
}
|
|
@ -0,0 +1,113 @@
|
|||
// run-rustfix
|
||||
|
||||
#![warn(clippy::manual_map)]
|
||||
#![allow(clippy::no_effect, clippy::map_identity, clippy::unit_arg, clippy::match_ref_pats)]
|
||||
|
||||
fn main() {
|
||||
match Some(0) {
|
||||
Some(_) => Some(2),
|
||||
None::<u32> => None,
|
||||
};
|
||||
|
||||
match Some(0) {
|
||||
Some(x) => Some(x + 1),
|
||||
_ => None,
|
||||
};
|
||||
|
||||
match Some("") {
|
||||
Some(x) => Some(x.is_empty()),
|
||||
None => None,
|
||||
};
|
||||
|
||||
if let Some(x) = Some(0) {
|
||||
Some(!x)
|
||||
} else {
|
||||
None
|
||||
};
|
||||
|
||||
#[rustfmt::skip]
|
||||
match Some(0) {
|
||||
Some(x) => { Some(std::convert::identity(x)) }
|
||||
None => { None }
|
||||
};
|
||||
|
||||
match Some(&String::new()) {
|
||||
Some(x) => Some(str::len(x)),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some(0) {
|
||||
Some(x) if false => Some(x + 1),
|
||||
_ => None,
|
||||
};
|
||||
|
||||
match &Some([0, 1]) {
|
||||
Some(x) => Some(x[0]),
|
||||
&None => None,
|
||||
};
|
||||
|
||||
match &Some(0) {
|
||||
&Some(x) => Some(x * 2),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some(String::new()) {
|
||||
Some(ref x) => Some(x.is_empty()),
|
||||
_ => None,
|
||||
};
|
||||
|
||||
match &&Some(String::new()) {
|
||||
Some(x) => Some(x.len()),
|
||||
_ => None,
|
||||
};
|
||||
|
||||
match &&Some(0) {
|
||||
&&Some(x) => Some(x + x),
|
||||
&&_ => None,
|
||||
};
|
||||
|
||||
match &mut Some(String::new()) {
|
||||
Some(x) => Some(x.push_str("")),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match &mut Some(String::new()) {
|
||||
Some(ref x) => Some(&**x),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match &mut &Some(String::new()) {
|
||||
Some(x) => Some(x.is_empty()),
|
||||
&mut _ => None,
|
||||
};
|
||||
|
||||
match Some((0, 1, 2)) {
|
||||
Some((x, y, z)) => Some(x + y + z),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some([1, 2, 3]) {
|
||||
Some([first, ..]) => Some(first),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match &Some((String::new(), "test")) {
|
||||
Some((x, y)) => Some((y, x)),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some((String::new(), 0)) {
|
||||
Some((ref x, y)) => Some((y, x)),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some(Some(0)) {
|
||||
Some(Some(_)) | Some(None) => Some(0),
|
||||
None => None,
|
||||
};
|
||||
|
||||
match Some(Some((0, 1))) {
|
||||
Some(Some((x, 1))) => Some(x),
|
||||
_ => None,
|
||||
};
|
||||
}
|
|
@ -0,0 +1,158 @@
|
|||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:7:5
|
||||
|
|
||||
LL | / match Some(0) {
|
||||
LL | | Some(_) => Some(2),
|
||||
LL | | None::<u32> => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(|_| 2)`
|
||||
|
|
||||
= note: `-D clippy::manual-map` implied by `-D warnings`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:12:5
|
||||
|
|
||||
LL | / match Some(0) {
|
||||
LL | | Some(x) => Some(x + 1),
|
||||
LL | | _ => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(|x| x + 1)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:17:5
|
||||
|
|
||||
LL | / match Some("") {
|
||||
LL | | Some(x) => Some(x.is_empty()),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some("").map(|x| x.is_empty())`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:22:5
|
||||
|
|
||||
LL | / if let Some(x) = Some(0) {
|
||||
LL | | Some(!x)
|
||||
LL | | } else {
|
||||
LL | | None
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(|x| !x)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:29:5
|
||||
|
|
||||
LL | / match Some(0) {
|
||||
LL | | Some(x) => { Some(std::convert::identity(x)) }
|
||||
LL | | None => { None }
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(std::convert::identity)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:34:5
|
||||
|
|
||||
LL | / match Some(&String::new()) {
|
||||
LL | | Some(x) => Some(str::len(x)),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(&String::new()).map(|x| str::len(x))`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:44:5
|
||||
|
|
||||
LL | / match &Some([0, 1]) {
|
||||
LL | | Some(x) => Some(x[0]),
|
||||
LL | | &None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some([0, 1]).as_ref().map(|x| x[0])`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:49:5
|
||||
|
|
||||
LL | / match &Some(0) {
|
||||
LL | | &Some(x) => Some(x * 2),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(|x| x * 2)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:54:5
|
||||
|
|
||||
LL | / match Some(String::new()) {
|
||||
LL | | Some(ref x) => Some(x.is_empty()),
|
||||
LL | | _ => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.is_empty())`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:59:5
|
||||
|
|
||||
LL | / match &&Some(String::new()) {
|
||||
LL | | Some(x) => Some(x.len()),
|
||||
LL | | _ => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.len())`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:64:5
|
||||
|
|
||||
LL | / match &&Some(0) {
|
||||
LL | | &&Some(x) => Some(x + x),
|
||||
LL | | &&_ => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(0).map(|x| x + x)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:69:5
|
||||
|
|
||||
LL | / match &mut Some(String::new()) {
|
||||
LL | | Some(x) => Some(x.push_str("")),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(String::new()).as_mut().map(|x| x.push_str(""))`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:74:5
|
||||
|
|
||||
LL | / match &mut Some(String::new()) {
|
||||
LL | | Some(ref x) => Some(&**x),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| &**x)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:79:5
|
||||
|
|
||||
LL | / match &mut &Some(String::new()) {
|
||||
LL | | Some(x) => Some(x.is_empty()),
|
||||
LL | | &mut _ => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.is_empty())`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:84:5
|
||||
|
|
||||
LL | / match Some((0, 1, 2)) {
|
||||
LL | | Some((x, y, z)) => Some(x + y + z),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some((0, 1, 2)).map(|(x, y, z)| x + y + z)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:89:5
|
||||
|
|
||||
LL | / match Some([1, 2, 3]) {
|
||||
LL | | Some([first, ..]) => Some(first),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some([1, 2, 3]).map(|[first, ..]| first)`
|
||||
|
||||
error: manual implementation of `Option::map`
|
||||
--> $DIR/manual_map_option.rs:94:5
|
||||
|
|
||||
LL | / match &Some((String::new(), "test")) {
|
||||
LL | | Some((x, y)) => Some((y, x)),
|
||||
LL | | None => None,
|
||||
LL | | };
|
||||
| |_____^ help: try this: `Some((String::new(), "test")).as_ref().map(|(x, y)| (y, x))`
|
||||
|
||||
error: aborting due to 17 previous errors
|
||||
|
Loading…
Reference in New Issue