Fix implicit and explicit casts between u8/c_char

Author: lucic71

cpp2rust/converter/models/converter_refcount.cpp

@@ -1241,8 +1241,13 @@ bool ConverterRefCount::VisitExplicitCastExpr(clang::ExplicitCastExpr *expr) {
                expr->getType()->isPointerType()) {
       Convert(expr->getSubExpr());
       PushConversionKind push(*this, ConversionKind::Unboxed);
-      StrCat(std::format(".cast::<{}>().expect(\"ub:wrong type\")",
-                         ConvertPointeeType(expr->getType())));
+      if (expr->getType()->getPointeeType()->isCharType()) {
+        StrCat(std::format(".reinterpret_cast::<{}>()",
+                           ConvertPointeeType(expr->getType())));
+      } else {
+        StrCat(std::format(".cast::<{}>().expect(\"ub:wrong type\")",
+                           ConvertPointeeType(expr->getType())));
+      }
       return false;
     } else if (expr->getType()->isVoidPointerType() &&
                expr->getSubExpr()->getType()->isPointerType()) {
@@ -1253,9 +1258,18 @@ bool ConverterRefCount::VisitExplicitCastExpr(clang::ExplicitCastExpr *expr) {
     } else if (expr->getSubExpr()->getType()->isPointerType() &&
                !expr->getSubExpr()->isNullPointerConstant(
                    ctx_, clang::Expr::NPC_ValueDependentIsNull)) {
-      StrCat(std::format("({}.to_strong().as_pointer() as {})",
-                         ToString(expr->getSubExpr()),
-                         ToString(expr->getType())));
+      auto src_type = ToString(expr->getSubExpr()->getType());
+      auto tgt_type = ToString(expr->getType());
+      if (src_type == tgt_type) {
+        StrCat(std::format("({}.to_strong().as_pointer() as {})",
+                           ToString(expr->getSubExpr()), tgt_type));
+      } else {
+        PushConversionKind push(*this, ConversionKind::Unboxed);
+        StrCat(std::format(
+            "({}.to_strong().as_pointer() as {}).reinterpret_cast::<{}>()",
+            ToString(expr->getSubExpr()), src_type,
+            ConvertPointeeType(expr->getType())));
+      }
       return false;
     }
     return Converter::VisitExplicitCastExpr(expr);