cgen: fix cast interface value in match expr (#23068)

vlib/v/gen/c/cgen.v

@@ -5302,6 +5302,12 @@ fn (mut g Gen) cast_expr(node ast.CastExpr) {
 			g.expr_with_opt(node.expr, expr_type, sym.info.parent_type)
 		} else {
 			g.write('(${cast_label}(')
+			if node.expr is ast.Ident {
+				if !node.typ.is_ptr() && node.expr_type.is_ptr() && node.expr.obj is ast.Var
+					&& node.expr.obj.smartcasts.len > 0 {
+					g.write('*'.repeat(node.expr_type.nr_muls()))
+				}
+			}
 			if sym.kind == .alias && g.table.final_sym(node.typ).kind == .string {
 				ptr_cnt := node.typ.nr_muls() - expr_type.nr_muls()
 				if ptr_cnt > 0 {

vlib/v/tests/casts/cast_interface_value_in_match_test.v

@@ -0,0 +1,24 @@
+interface Number2 {}
+
+fn t(v Number2) {
+	match v {
+		int, i32, isize, i64 {
+			x := isize(v)
+			println(x)
+			assert x == 42
+		}
+		else {}
+	}
+	match v {
+		int {
+			x := isize(v)
+			println(x)
+			assert x == 42
+		}
+		else {}
+	}
+}
+
+fn test_cast_interface_value_in_match() {
+	t(int(42))
+}