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Add new lint [needless_braces_on_range_literal]
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‎CHANGELOG.md

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@@ -3596,6 +3596,7 @@ Released 2018-09-13
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[`needless_bool`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_bool
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[`needless_borrow`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
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[`needless_borrowed_reference`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrowed_reference
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[`needless_braces_on_range_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_braces_on_range_literal
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[`needless_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_collect
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[`needless_continue`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue
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[`needless_doctest_main`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_doctest_main

‎clippy_lints/src/lib.register_all.rs

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@@ -241,6 +241,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
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LintId::of(needless_bool::BOOL_COMPARISON),
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LintId::of(needless_bool::NEEDLESS_BOOL),
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LintId::of(needless_borrowed_ref::NEEDLESS_BORROWED_REFERENCE),
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LintId::of(needless_braces_on_range_literal::NEEDLESS_BRACES_ON_RANGE_LITERAL),
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LintId::of(needless_late_init::NEEDLESS_LATE_INIT),
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LintId::of(needless_question_mark::NEEDLESS_QUESTION_MARK),
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LintId::of(needless_update::NEEDLESS_UPDATE),

‎clippy_lints/src/lib.register_lints.rs

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@@ -405,6 +405,7 @@ store.register_lints(&[
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needless_bool::BOOL_COMPARISON,
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needless_bool::NEEDLESS_BOOL,
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needless_borrowed_ref::NEEDLESS_BORROWED_REFERENCE,
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needless_braces_on_range_literal::NEEDLESS_BRACES_ON_RANGE_LITERAL,
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needless_continue::NEEDLESS_CONTINUE,
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needless_for_each::NEEDLESS_FOR_EACH,
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needless_late_init::NEEDLESS_LATE_INIT,

‎clippy_lints/src/lib.register_style.rs

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@@ -90,6 +90,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
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LintId::of(misc_early::REDUNDANT_PATTERN),
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LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK),
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LintId::of(mut_reference::UNNECESSARY_MUT_PASSED),
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LintId::of(needless_braces_on_range_literal::NEEDLESS_BRACES_ON_RANGE_LITERAL),
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LintId::of(needless_late_init::NEEDLESS_LATE_INIT),
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LintId::of(neg_multiply::NEG_MULTIPLY),
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LintId::of(new_without_default::NEW_WITHOUT_DEFAULT),

‎clippy_lints/src/lib.rs

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@@ -312,6 +312,7 @@ mod needless_arbitrary_self_type;
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mod needless_bitwise_bool;
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mod needless_bool;
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mod needless_borrowed_ref;
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mod needless_braces_on_range_literal;
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mod needless_continue;
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mod needless_for_each;
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mod needless_late_init;
@@ -746,6 +747,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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store.register_early_pass(|| Box::new(collapsible_if::CollapsibleIf));
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store.register_early_pass(|| Box::new(items_after_statements::ItemsAfterStatements));
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store.register_early_pass(|| Box::new(precedence::Precedence));
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store.register_early_pass(|| Box::new(needless_braces_on_range_literal::NeedlessBracesOnRangeLiteral));
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store.register_early_pass(|| Box::new(needless_continue::NeedlessContinue));
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store.register_early_pass(|| Box::new(redundant_else::RedundantElse));
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store.register_late_pass(|| Box::new(create_dir::CreateDir));

‎clippy_lints/src/needless_braces_on_range_literal.rs

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//! Checks for braces on literals in range statements
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//!
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//! For example, the lint would catch
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//!
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//! ```rust
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//! for i in (0)..10 {
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//! println!("{i}");
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//! }
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//! ```
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//!
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//! And suggest this:
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//!
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//! ```rust
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//! for i in 0..10 {
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//! println!("{i}");
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//! }
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//! ```
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//!
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//! This lint is **warn** by default.
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use clippy_utils::{diagnostics::span_lint_and_then, source::snippet_opt};
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use rustc_ast::ast::{Expr, ExprKind};
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use rustc_errors::Applicability;
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use rustc_lint::{EarlyContext, EarlyLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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declare_clippy_lint! {
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/// ### What it does
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/// The lint checks for braces on literals in range statements that are
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/// superflous.
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///
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/// ### Why is this bad?
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/// Having superflous braces makes the code less legible as the impose an
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/// overhead when reading.
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#[clippy::version = "1.63.0"]
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pub NEEDLESS_BRACES_ON_RANGE_LITERAL,
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style,
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"needless braces on range literal can be removed"
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}
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declare_lint_pass!(NeedlessBracesOnRangeLiteral => [NEEDLESS_BRACES_ON_RANGE_LITERAL]);
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fn check_for_braces(cx: &EarlyContext<'_>, e: &Expr) {
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if_chain! {
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if let ExprKind::Paren(ref start_statement) = &e.kind;
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if let ExprKind::Lit(ref literal) = start_statement.kind;
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then {
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span_lint_and_then(cx, NEEDLESS_BRACES_ON_RANGE_LITERAL, e.span,
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"needless braces on range literal can be removed",
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|diag| {
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if let Some(suggestion) = snippet_opt(cx, literal.span) {
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diag.span_suggestion(e.span, "try", suggestion, Applicability::MachineApplicable);
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}
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});
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}
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}
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}
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impl EarlyLintPass for NeedlessBracesOnRangeLiteral {
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fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
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if let ExprKind::Range(Some(start), Some(end), _) = &e.kind {
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check_for_braces(cx, start);
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check_for_braces(cx, end);
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}
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}
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}

‎tests/ui/almost_complete_letter_range.fixed

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#![feature(stmt_expr_attributes)]
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#![warn(clippy::almost_complete_letter_range)]
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#![allow(ellipsis_inclusive_range_patterns)]
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#![allow(clippy::needless_braces_on_range_literal)]
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macro_rules! a {
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() => {

‎tests/ui/almost_complete_letter_range.rs

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#![feature(stmt_expr_attributes)]
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#![warn(clippy::almost_complete_letter_range)]
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#![allow(ellipsis_inclusive_range_patterns)]
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#![allow(clippy::needless_braces_on_range_literal)]
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macro_rules! a {
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() => {

‎tests/ui/almost_complete_letter_range.stderr

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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:19:17
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--> $DIR/almost_complete_letter_range.rs:20:17
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|
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LL | let _ = ('a') ..'z';
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| ^^^^^^--^^^
@@ -9,87 +9,87 @@ LL | let _ = ('a') ..'z';
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= note: `-D clippy::almost-complete-letter-range` implied by `-D warnings`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:20:17
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--> $DIR/almost_complete_letter_range.rs:21:17
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|
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LL | let _ = 'A' .. ('Z');
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| ^^^^--^^^^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:26:13
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--> $DIR/almost_complete_letter_range.rs:27:13
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|
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LL | let _ = (b'a')..(b'z');
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| ^^^^^^--^^^^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:27:13
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--> $DIR/almost_complete_letter_range.rs:28:13
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LL | let _ = b'A'..b'Z';
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| ^^^^--^^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:32:13
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--> $DIR/almost_complete_letter_range.rs:33:13
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|
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LL | let _ = a!()..'z';
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| ^^^^--^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:35:9
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--> $DIR/almost_complete_letter_range.rs:36:9
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|
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LL | b'a'..b'z' if true => 1,
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| ^^^^--^^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:36:9
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--> $DIR/almost_complete_letter_range.rs:37:9
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|
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LL | b'A'..b'Z' if true => 2,
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| ^^^^--^^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:43:9
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--> $DIR/almost_complete_letter_range.rs:44:9
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|
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LL | 'a'..'z' if true => 1,
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| ^^^--^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:44:9
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--> $DIR/almost_complete_letter_range.rs:45:9
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|
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LL | 'A'..'Z' if true => 2,
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| ^^^--^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:54:9
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--> $DIR/almost_complete_letter_range.rs:55:9
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|
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LL | 'a'..'z' => 1,
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| ^^^--^^^
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| |
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| help: use an inclusive range: `...`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:61:13
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--> $DIR/almost_complete_letter_range.rs:62:13
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|
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LL | let _ = 'a'..'z';
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| ^^^--^^^
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| |
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| help: use an inclusive range: `..=`
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error: almost complete ascii letter range
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--> $DIR/almost_complete_letter_range.rs:63:9
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--> $DIR/almost_complete_letter_range.rs:64:9
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|
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LL | 'a'..'z' => 1,
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| ^^^--^^^

‎tests/ui/needless_braces_on_range_literal.fixed

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// run-rustfix
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// edition:2018
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#![warn(clippy::needless_braces_on_range_literal)]
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#![allow(clippy::almost_complete_letter_range)]
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fn main() {
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let _ = 'a'..='z';
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}

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