Check MSRV for bool to int from impl

clippy_lints/src/casts/cast_lossless.rs

@@ -1,16 +1,24 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::in_constant;
 use clippy_utils::source::snippet_opt;
 use clippy_utils::ty::is_isize_or_usize;
+use clippy_utils::{in_constant, meets_msrv, msrvs};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, FloatTy, Ty};
+use rustc_semver::RustcVersion;
 
 use super::{utils, CAST_LOSSLESS};
 
-pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_op: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {
-    if !should_lint(cx, expr, cast_from, cast_to) {
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    cast_op: &Expr<'_>,
+    cast_from: Ty<'_>,
+    cast_to: Ty<'_>,
+    msrv: &Option<RustcVersion>,
+) {
+    if !should_lint(cx, expr, cast_from, cast_to, msrv) {
         return;
     }
 
@@ -46,7 +54,13 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_op: &Expr<'_>, c
     );
 }
 
-fn should_lint(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) -> bool {
+fn should_lint(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    cast_from: Ty<'_>,
+    cast_to: Ty<'_>,
+    msrv: &Option<RustcVersion>,
+) -> bool {
     // Do not suggest using From in consts/statics until it is valid to do so (see #2267).
     if in_constant(cx, expr.hir_id) {
         return false;
@@ -72,7 +86,7 @@ fn should_lint(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to
             };
             from_nbits < to_nbits
         },
-        (false, true) if matches!(cast_from.kind(), ty::Bool) => true,
+        (false, true) if matches!(cast_from.kind(), ty::Bool) && meets_msrv(msrv.as_ref(), &msrvs::FROM_BOOL) => true,
         (_, _) => {
             matches!(cast_from.kind(), ty::Float(FloatTy::F32)) && matches!(cast_to.kind(), ty::Float(FloatTy::F64))
         },

clippy_lints/src/casts/mod.rs

@@ -435,7 +435,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
                     cast_sign_loss::check(cx, expr, cast_expr, cast_from, cast_to);
                 }
 
-                cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to);
+                cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to, &self.msrv);
             }
         }
 

clippy_utils/src/msrvs.rs

@@ -28,6 +28,7 @@ msrv_aliases! {
     1,35,0 { OPTION_COPIED, RANGE_CONTAINS }
     1,34,0 { TRY_FROM }
     1,30,0 { ITERATOR_FIND_MAP }
+    1,28,0 { FROM_BOOL }
     1,17,0 { FIELD_INIT_SHORTHAND, STATIC_IN_CONST }
     1,16,0 { STR_REPEAT }
 }

tests/ui/min_rust_version_attr.rs

@@ -137,6 +137,11 @@ fn unnest_or_patterns() {
     if let TS(0, x) | TS(1, x) = TS(0, 0) {}
 }
 
+#[warn(clippy::cast_lossless)]
+fn int_from_bool() -> u8 {
+    true as u8
+}
+
 fn main() {
     filter_map_next();
     checked_conversion();
@@ -153,6 +158,7 @@ fn main() {
     map_unwrap_or();
     missing_const_for_fn();
     unnest_or_patterns();
+    int_from_bool();
 }
 
 mod meets_msrv {

tests/ui/min_rust_version_attr.stderr

@@ -1,12 +1,12 @@
 error: stripping a prefix manually
-  --> $DIR/min_rust_version_attr.rs:165:24
+  --> $DIR/min_rust_version_attr.rs:171:24
    |
 LL |             assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
    |                        ^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::manual-strip` implied by `-D warnings`
 note: the prefix was tested here
-  --> $DIR/min_rust_version_attr.rs:164:9
+  --> $DIR/min_rust_version_attr.rs:170:9
    |
 LL |         if s.starts_with("hello, ") {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -17,13 +17,13 @@ LL ~             assert_eq!(<stripped>.to_uppercase(), "WORLD!");
    |
 
 error: stripping a prefix manually
-  --> $DIR/min_rust_version_attr.rs:177:24
+  --> $DIR/min_rust_version_attr.rs:183:24
    |
 LL |             assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
    |                        ^^^^^^^^^^^^^^^^^^^^
    |
 note: the prefix was tested here
-  --> $DIR/min_rust_version_attr.rs:176:9
+  --> $DIR/min_rust_version_attr.rs:182:9
    |
 LL |         if s.starts_with("hello, ") {
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^