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Auto merge of rust-lang#10467 - blyxyas:underscore_typed, r=Jarcho
Add `let_with_type_underscore` lint Fixes rust-lang#10463 changelog: [`let_with_type_underscore`]: Add the lint.
2 parents ea4ebed + ca3bf94 commit 5f98734

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-65
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‎CHANGELOG.md

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@@ -4643,6 +4643,7 @@ Released 2018-09-13
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[`let_underscore_must_use`]: https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_must_use
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[`let_underscore_untyped`]: https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped
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[`let_unit_value`]: https://rust-lang.github.io/rust-clippy/master/index.html#let_unit_value
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[`let_with_type_underscore`]: https://rust-lang.github.io/rust-clippy/master/index.html#let_with_type_underscore
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[`linkedlist`]: https://rust-lang.github.io/rust-clippy/master/index.html#linkedlist
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[`logic_bug`]: https://rust-lang.github.io/rust-clippy/master/index.html#logic_bug
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[`lossy_float_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#lossy_float_literal

‎clippy_lints/src/declared_lints.rs

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@@ -227,6 +227,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
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crate::let_underscore::LET_UNDERSCORE_LOCK_INFO,
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crate::let_underscore::LET_UNDERSCORE_MUST_USE_INFO,
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crate::let_underscore::LET_UNDERSCORE_UNTYPED_INFO,
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crate::let_with_type_underscore::LET_WITH_TYPE_UNDERSCORE_INFO,
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crate::lifetimes::EXTRA_UNUSED_LIFETIMES_INFO,
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crate::lifetimes::NEEDLESS_LIFETIMES_INFO,
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crate::literal_representation::DECIMAL_LITERAL_REPRESENTATION_INFO,

‎clippy_lints/src/let_with_type_underscore.rs

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@@ -0,0 +1,45 @@
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use clippy_utils::diagnostics::span_lint_and_help;
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use rustc_hir::*;
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use rustc_lint::{LateContext, LateLintPass};
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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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declare_clippy_lint! {
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/// ### What it does
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/// Detects when a variable is declared with an explicit type of `_`.
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/// ### Why is this bad?
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/// It adds noise, `: _` provides zero clarity or utility.
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/// ### Example
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/// ```rust,ignore
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/// let my_number: _ = 1;
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/// ```
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/// Use instead:
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/// ```rust,ignore
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/// let my_number = 1;
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/// ```
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#[clippy::version = "1.69.0"]
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pub LET_WITH_TYPE_UNDERSCORE,
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complexity,
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"unneeded underscore type (`_`) in a variable declaration"
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}
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declare_lint_pass!(UnderscoreTyped => [LET_WITH_TYPE_UNDERSCORE]);
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27+
impl LateLintPass<'_> for UnderscoreTyped {
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fn check_local<'tcx>(&mut self, cx: &LateContext<'tcx>, local: &'tcx Local<'tcx>) {
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if_chain! {
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if !in_external_macro(cx.tcx.sess, local.span);
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if let Some(ty) = local.ty; // Ensure that it has a type defined
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if let TyKind::Infer = &ty.kind; // that type is '_'
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if local.span.ctxt() == ty.span.ctxt();
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then {
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span_lint_and_help(cx,
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LET_WITH_TYPE_UNDERSCORE,
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local.span,
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"variable declared with type underscore",
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Some(ty.span.with_lo(local.pat.span.hi())),
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"remove the explicit type `_` declaration"
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)
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}
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};
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}
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}

‎clippy_lints/src/lib.rs

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@@ -167,6 +167,7 @@ mod large_stack_arrays;
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mod len_zero;
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mod let_if_seq;
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mod let_underscore;
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mod let_with_type_underscore;
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mod lifetimes;
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mod literal_representation;
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mod loops;
@@ -930,6 +931,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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store.register_late_pass(|_| Box::new(collection_is_never_read::CollectionIsNeverRead));
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store.register_late_pass(|_| Box::new(missing_assert_message::MissingAssertMessage));
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store.register_early_pass(|| Box::new(redundant_async_block::RedundantAsyncBlock));
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store.register_late_pass(|_| Box::new(let_with_type_underscore::UnderscoreTyped));
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// add lints here, do not remove this comment, it's used in `new_lint`
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}
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‎tests/ui/crashes/ice-6179.rs

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//! The ICE is mainly caused by using `hir_ty_to_ty`. See the discussion in the PR for details.
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#![warn(clippy::use_self)]
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#![allow(dead_code)]
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#![allow(dead_code, clippy::let_with_type_underscore)]
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struct Foo;
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‎tests/ui/default_numeric_fallback_f64.fixed

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clippy::unnecessary_operation,
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clippy::branches_sharing_code,
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clippy::match_single_binding,
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clippy::let_unit_value
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clippy::let_unit_value,
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clippy::let_with_type_underscore
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)]
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#[macro_use]

‎tests/ui/default_numeric_fallback_f64.rs

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clippy::unnecessary_operation,
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clippy::branches_sharing_code,
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clippy::match_single_binding,
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clippy::let_unit_value
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clippy::let_unit_value,
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clippy::let_with_type_underscore
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)]
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#[macro_use]

‎tests/ui/default_numeric_fallback_f64.stderr

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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:21:17
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--> $DIR/default_numeric_fallback_f64.rs:22:17
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|
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LL | let x = 0.12;
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| ^^^^ help: consider adding suffix: `0.12_f64`
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|
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= note: `-D clippy::default-numeric-fallback` implied by `-D warnings`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:22:18
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--> $DIR/default_numeric_fallback_f64.rs:23:18
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|
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LL | let x = [1., 2., 3.];
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| ^^ help: consider adding suffix: `1.0_f64`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:22:22
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--> $DIR/default_numeric_fallback_f64.rs:23:22
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|
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LL | let x = [1., 2., 3.];
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| ^^ help: consider adding suffix: `2.0_f64`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:22:26
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--> $DIR/default_numeric_fallback_f64.rs:23:26
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LL | let x = [1., 2., 3.];
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| ^^ help: consider adding suffix: `3.0_f64`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:23:28
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--> $DIR/default_numeric_fallback_f64.rs:24:28
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|
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LL | let x = if true { (1., 2.) } else { (3., 4.) };
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| ^^ help: consider adding suffix: `1.0_f64`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:23:32
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--> $DIR/default_numeric_fallback_f64.rs:24:32
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|
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LL | let x = if true { (1., 2.) } else { (3., 4.) };
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| ^^ help: consider adding suffix: `2.0_f64`
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error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:23:46
40+
--> $DIR/default_numeric_fallback_f64.rs:24:46
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|
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LL | let x = if true { (1., 2.) } else { (3., 4.) };
4343
| ^^ help: consider adding suffix: `3.0_f64`
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4545
error: default numeric fallback might occur
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--> $DIR/default_numeric_fallback_f64.rs:23:50
46+
--> $DIR/default_numeric_fallback_f64.rs:24:50
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|
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LL | let x = if true { (1., 2.) } else { (3., 4.) };
4949
| ^^ help: consider adding suffix: `4.0_f64`
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error: default numeric fallback might occur
52-
--> $DIR/default_numeric_fallback_f64.rs:24:23
52+
--> $DIR/default_numeric_fallback_f64.rs:25:23
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|
5454
LL | let x = match 1. {
5555
| ^^ help: consider adding suffix: `1.0_f64`
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5757
error: default numeric fallback might occur
58-
--> $DIR/default_numeric_fallback_f64.rs:25:18
58+
--> $DIR/default_numeric_fallback_f64.rs:26:18
5959
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6060
LL | _ => 1.,
6161
| ^^ help: consider adding suffix: `1.0_f64`
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6363
error: default numeric fallback might occur
64-
--> $DIR/default_numeric_fallback_f64.rs:44:21
64+
--> $DIR/default_numeric_fallback_f64.rs:45:21
6565
|
6666
LL | let y = 1.;
6767
| ^^ help: consider adding suffix: `1.0_f64`
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error: default numeric fallback might occur
70-
--> $DIR/default_numeric_fallback_f64.rs:52:21
70+
--> $DIR/default_numeric_fallback_f64.rs:53:21
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|
7272
LL | let y = 1.;
7373
| ^^ help: consider adding suffix: `1.0_f64`
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7575
error: default numeric fallback might occur
76-
--> $DIR/default_numeric_fallback_f64.rs:58:21
76+
--> $DIR/default_numeric_fallback_f64.rs:59:21
7777
|
7878
LL | let y = 1.;
7979
| ^^ help: consider adding suffix: `1.0_f64`
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error: default numeric fallback might occur
82-
--> $DIR/default_numeric_fallback_f64.rs:66:21
82+
--> $DIR/default_numeric_fallback_f64.rs:67:21
8383
|
8484
LL | let y = 1.;
8585
| ^^ help: consider adding suffix: `1.0_f64`
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8787
error: default numeric fallback might occur
88-
--> $DIR/default_numeric_fallback_f64.rs:78:9
88+
--> $DIR/default_numeric_fallback_f64.rs:79:9
8989
|
9090
LL | 1.
9191
| ^^ help: consider adding suffix: `1.0_f64`
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9393
error: default numeric fallback might occur
94-
--> $DIR/default_numeric_fallback_f64.rs:84:27
94+
--> $DIR/default_numeric_fallback_f64.rs:85:27
9595
|
9696
LL | let f = || -> _ { 1. };
9797
| ^^ help: consider adding suffix: `1.0_f64`
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9999
error: default numeric fallback might occur
100-
--> $DIR/default_numeric_fallback_f64.rs:88:29
100+
--> $DIR/default_numeric_fallback_f64.rs:89:29
101101
|
102102
LL | let f = || -> f64 { 1. };
103103
| ^^ help: consider adding suffix: `1.0_f64`
104104

105105
error: default numeric fallback might occur
106-
--> $DIR/default_numeric_fallback_f64.rs:102:21
106+
--> $DIR/default_numeric_fallback_f64.rs:103:21
107107
|
108108
LL | generic_arg(1.);
109109
| ^^ help: consider adding suffix: `1.0_f64`
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111111
error: default numeric fallback might occur
112-
--> $DIR/default_numeric_fallback_f64.rs:105:32
112+
--> $DIR/default_numeric_fallback_f64.rs:106:32
113113
|
114114
LL | let x: _ = generic_arg(1.);
115115
| ^^ help: consider adding suffix: `1.0_f64`
116116

117117
error: default numeric fallback might occur
118-
--> $DIR/default_numeric_fallback_f64.rs:123:28
118+
--> $DIR/default_numeric_fallback_f64.rs:124:28
119119
|
120120
LL | GenericStruct { x: 1. };
121121
| ^^ help: consider adding suffix: `1.0_f64`
122122

123123
error: default numeric fallback might occur
124-
--> $DIR/default_numeric_fallback_f64.rs:126:36
124+
--> $DIR/default_numeric_fallback_f64.rs:127:36
125125
|
126126
LL | let _ = GenericStruct { x: 1. };
127127
| ^^ help: consider adding suffix: `1.0_f64`
128128

129129
error: default numeric fallback might occur
130-
--> $DIR/default_numeric_fallback_f64.rs:144:24
130+
--> $DIR/default_numeric_fallback_f64.rs:145:24
131131
|
132132
LL | GenericEnum::X(1.);
133133
| ^^ help: consider adding suffix: `1.0_f64`
134134

135135
error: default numeric fallback might occur
136-
--> $DIR/default_numeric_fallback_f64.rs:164:23
136+
--> $DIR/default_numeric_fallback_f64.rs:165:23
137137
|
138138
LL | s.generic_arg(1.);
139139
| ^^ help: consider adding suffix: `1.0_f64`
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141141
error: default numeric fallback might occur
142-
--> $DIR/default_numeric_fallback_f64.rs:171:21
142+
--> $DIR/default_numeric_fallback_f64.rs:172:21
143143
|
144144
LL | let x = 22.;
145145
| ^^^ help: consider adding suffix: `22.0_f64`

‎tests/ui/default_numeric_fallback_i32.fixed

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@@ -9,7 +9,8 @@
99
clippy::no_effect,
1010
clippy::unnecessary_operation,
1111
clippy::branches_sharing_code,
12-
clippy::let_unit_value
12+
clippy::let_unit_value,
13+
clippy::let_with_type_underscore
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)]
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#[macro_use]

‎tests/ui/default_numeric_fallback_i32.rs

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@@ -9,7 +9,8 @@
99
clippy::no_effect,
1010
clippy::unnecessary_operation,
1111
clippy::branches_sharing_code,
12-
clippy::let_unit_value
12+
clippy::let_unit_value,
13+
clippy::let_with_type_underscore
1314
)]
1415

1516
#[macro_use]

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