Add MSRV check for const rem_euclid

Author: Evan Typanski

clippy_lints/src/manual_rem_euclid.rs

@@ -1,7 +1,7 @@
 use clippy_utils::consts::{constant_full_int, FullInt};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::{meets_msrv, msrvs, path_to_local};
+use clippy_utils::{in_constant, meets_msrv, msrvs, path_to_local};
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, Node, TyKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -51,6 +51,10 @@ impl<'tcx> LateLintPass<'tcx> for ManualRemEuclid {
             return;
         }
 
+        if in_constant(cx, expr.hir_id) && !meets_msrv(self.msrv, msrvs::REM_EUCLID_CONST) {
+            return;
+        }
+
         if let ExprKind::Binary(op1, ..) = expr.kind
             && op1.node == BinOpKind::Rem
             && let Some((const1, expr1)) = check_for_positive_int_constant(cx, expr, false)

clippy_utils/src/msrvs.rs

@@ -13,7 +13,7 @@ macro_rules! msrv_aliases {
 // names may refer to stabilized feature flags or library items
 msrv_aliases! {
     1,53,0 { OR_PATTERNS, MANUAL_BITS }
-    1,52,0 { STR_SPLIT_ONCE }
+    1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
     1,51,0 { BORROW_AS_PTR, UNSIGNED_ABS }
     1,50,0 { BOOL_THEN }
     1,47,0 { TAU }

tests/ui/manual_rem_euclid.fixed

@@ -31,3 +31,8 @@ fn main() {
 pub fn rem_euclid_4(num: i32) -> i32 {
     num.rem_euclid(4)
 }
+
+// Constant version came later, should still lint
+pub const fn const_rem_euclid_4(num: i32) -> i32 {
+    num.rem_euclid(4)
+}

tests/ui/manual_rem_euclid.rs

@@ -31,3 +31,8 @@ fn main() {
 pub fn rem_euclid_4(num: i32) -> i32 {
     ((num % 4) + 4) % 4
 }
+
+// Constant version came later, should still lint
+pub const fn const_rem_euclid_4(num: i32) -> i32 {
+    ((num % 4) + 4) % 4
+}

tests/ui/manual_rem_euclid.stderr

@@ -36,5 +36,11 @@ error: manual `rem_euclid` implementation
 LL |     ((num % 4) + 4) % 4
    |     ^^^^^^^^^^^^^^^^^^^ help: consider using: `num.rem_euclid(4)`
 
-error: aborting due to 6 previous errors
+error: manual `rem_euclid` implementation
+  --> $DIR/manual_rem_euclid.rs:37:5
+   |
+LL |     ((num % 4) + 4) % 4
+   |     ^^^^^^^^^^^^^^^^^^^ help: consider using: `num.rem_euclid(4)`
+
+error: aborting due to 7 previous errors