move char_lit_as_u8 into the if

allows reusing `cast_from_expr` and `cast_to`

Author: ada4a

clippy_lints/src/casts/char_lit_as_u8.rs

@@ -4,18 +4,17 @@ use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, UintTy};
+use rustc_middle::ty::{self, Ty, UintTy};
 
 use super::CHAR_LIT_AS_U8;
 
-pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
-    if let ExprKind::Cast(e, _) = &expr.kind
-        && let ExprKind::Lit(l) = &e.kind
+pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from_expr: &Expr<'_>, cast_to: Ty<'_>) {
+    if let ExprKind::Lit(l) = &cast_from_expr.kind
         && let LitKind::Char(c) = l.node
-        && ty::Uint(UintTy::U8) == *cx.typeck_results().expr_ty(expr).kind()
+        && ty::Uint(UintTy::U8) == *cast_to.kind()
     {
         let mut applicability = Applicability::MachineApplicable;
-        let snippet = snippet_with_applicability(cx, e.span, "'x'", &mut applicability);
+        let snippet = snippet_with_applicability(cx, cast_from_expr.span, "'x'", &mut applicability);
 
         span_lint_and_then(
             cx,

clippy_lints/src/casts/mod.rs

@@ -871,6 +871,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             if !expr.span.from_expansion() && unnecessary_cast::check(cx, expr, cast_from_expr, cast_from, cast_to) {
                 return;
             }
+            char_lit_as_u8::check(cx, expr, cast_from_expr, cast_to);
             cast_slice_from_raw_parts::check(cx, expr, cast_from_expr, cast_to, self.msrv);
             ptr_cast_constness::check(cx, expr, cast_from_expr, cast_from, cast_to, self.msrv);
             as_ptr_cast_mut::check(cx, expr, cast_from_expr, cast_to);
@@ -911,7 +912,6 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
             borrow_as_ptr::check_implicit_cast(cx, expr);
         }
         cast_ptr_alignment::check(cx, expr);
-        char_lit_as_u8::check(cx, expr);
         ptr_as_ptr::check(cx, expr, self.msrv);
         cast_slice_different_sizes::check(cx, expr, self.msrv);
         ptr_cast_constness::check_null_ptr_cast_method(cx, expr);