Add repeat_n if MSRV is at least 1.83

Author: rspencer01

clippy_config/src/msrvs.rs

@@ -17,7 +17,7 @@ macro_rules! msrv_aliases {
 
 // names may refer to stabilized feature flags or library items
 msrv_aliases! {
-    1,83,0 { CONST_EXTERN_FN, CONST_FLOAT_BITS_CONV, CONST_FLOAT_CLASSIFY }
+    1,83,0 { CONST_EXTERN_FN, CONST_FLOAT_BITS_CONV, CONST_FLOAT_CLASSIFY, REPEAT_N }
     1,82,0 { IS_NONE_OR }
     1,81,0 { LINT_REASONS_STABILIZATION }
     1,80,0 { BOX_INTO_ITER}

clippy_lints/src/methods/map_with_unused_argument_over_ranges.rs

@@ -78,14 +78,24 @@ pub(super) fn check(
     {
         let method_to_use_name;
         let new_span;
+        let use_take;
 
         if eager_or_lazy::switch_to_eager_eval(cx, body_expr) {
-            method_to_use_name = "repeat";
-            let body_snippet = snippet_with_applicability(cx, body_expr.span, "..", &mut applicability);
-            new_span = (arg.span, body_snippet.to_string());
+            if msrv.meets(msrvs::REPEAT_N) {
+                method_to_use_name = "repeat_n";
+                let body_snippet = snippet_with_applicability(cx, body_expr.span, "..", &mut applicability);
+                new_span = (arg.span, format!("{body_snippet}, {count}"));
+                use_take = false;
+            } else {
+                method_to_use_name = "repeat";
+                let body_snippet = snippet_with_applicability(cx, body_expr.span, "..", &mut applicability);
+                new_span = (arg.span, body_snippet.to_string());
+                use_take = true;
+            }
         } else if msrv.meets(msrvs::REPEAT_WITH) {
             method_to_use_name = "repeat_with";
             new_span = (param.span, String::new());
+            use_take = true;
         } else {
             return;
         }
@@ -97,14 +107,25 @@ pub(super) fn check(
             "map of a closure that does not depend on its parameter over a range",
             |diag| {
                 diag.multipart_suggestion(
-                    format!("remove the explicit range and use `{method_to_use_name}` and `take`"),
+                    if use_take {
+                        format!("remove the explicit range and use `{method_to_use_name}` and `take`")
+                    } else {
+                        format!("remove the explicit range and use `{method_to_use_name}`")
+                    },
                     vec![
                         (
                             receiver.span.to(method_call_span),
                             format!("std::iter::{method_to_use_name}"),
                         ),
                         new_span,
-                        (ex.span.shrink_to_hi(), format!(".take({count})")),
+                        (
+                            ex.span.shrink_to_hi(),
+                            if use_take {
+                                format!(".take({count})")
+                            } else {
+                                String::new()
+                            },
+                        ),
                     ],
                     applicability,
                 );

tests/ui/map_with_unused_argument_over_ranges.fixed

@@ -27,7 +27,7 @@ fn main() {
     std::iter::repeat_with(|| do_something()).take(11);
     std::iter::repeat_with(|| do_something()).take(7);
     std::iter::repeat_with(|| do_something()).take(8);
-    std::iter::repeat(3).take(10);
+    std::iter::repeat_n(3, 10);
     std::iter::repeat_with(|| {
         let x = 3;
         x + 2
@@ -66,3 +66,8 @@ fn msrv_1_27() {
 fn msrv_1_28() {
     std::iter::repeat_with(|| do_something()).take(10);
 }
+
+#[clippy::msrv = "1.82"]
+fn msrv_1_82() {
+    std::iter::repeat(3).take(10);
+}

tests/ui/map_with_unused_argument_over_ranges.rs

@@ -66,3 +66,8 @@ fn msrv_1_27() {
 fn msrv_1_28() {
     (0..10).map(|_| do_something());
 }
+
+#[clippy::msrv = "1.82"]
+fn msrv_1_82() {
+    (0..10).map(|_| 3);
+}

tests/ui/map_with_unused_argument_over_ranges.stderr

@@ -66,10 +66,10 @@ error: map of a closure that does not depend on its parameter over a range
 LL |     (0..10).map(|_| 3);
    |     ^^^^^^^^^^^^^^^^^^
    |
-help: remove the explicit range and use `repeat` and `take`
+help: remove the explicit range and use `repeat_n`
    |
-LL |     std::iter::repeat(3).take(10);
-   |     ~~~~~~~~~~~~~~~~~ ~ +++++++++
+LL |     std::iter::repeat_n(3, 10);
+   |     ~~~~~~~~~~~~~~~~~~~ ~~~~~
 
 error: map of a closure that does not depend on its parameter over a range
   --> tests/ui/map_with_unused_argument_over_ranges.rs:31:5
@@ -208,5 +208,16 @@ LL -     (0..10).map(|_| do_something());
 LL +     std::iter::repeat_with(|| do_something()).take(10);
    |
 
-error: aborting due to 17 previous errors
+error: map of a closure that does not depend on its parameter over a range
+  --> tests/ui/map_with_unused_argument_over_ranges.rs:72:5
+   |
+LL |     (0..10).map(|_| 3);
+   |     ^^^^^^^^^^^^^^^^^^
+   |
+help: remove the explicit range and use `repeat` and `take`
+   |
+LL |     std::iter::repeat(3).take(10);
+   |     ~~~~~~~~~~~~~~~~~ ~ +++++++++
+
+error: aborting due to 18 previous errors