Handle implicit autoderef coming from rules

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -3700,8 +3700,11 @@ std::string Converter::ConvertPlaceholder(clang::Expr *expr, clang::Expr *arg,
 
   if (ph_ctx.needs_object_receiver()) {
     Buffer buf(*this);
-    PushExplicitAutoref autoref(*this, ph_ctx.access ==
-                                           TranslationRule::Access::kWrite);
+    PushExplicitAutoref autoref(
+        *this,
+        ph_ctx.needs_autoref
+            ? std::optional(ph_ctx.access == TranslationRule::Access::kWrite)
+            : std::nullopt);
     ConvertDeref(arg);
     return std::move(buf).str();
   }
@@ -3776,6 +3779,7 @@ std::string Converter::ConvertIRFragment(
           .maps_to_rust_ptr = Mapper::MapsToPointer(arg->getType()),
           .declared_in_rule_as_rust_ptr =
               Mapper::ParamIsPointer(GetCalleeOrExpr(expr), arg_idx),
+          .needs_autoref = ph->needs_autoref,
       };
       result += ConvertPlaceholder(expr, arg, ph_ctx);
     } else if (auto *mc =

cpp2rust/converter/converter.h

@@ -185,6 +185,7 @@ class Converter : public clang::RecursiveASTVisitor<Converter> {
     bool is_cpp_ptr;
     bool maps_to_rust_ptr;
     bool declared_in_rule_as_rust_ptr;
+    bool needs_autoref;
 
     bool needs_materialization() const {
       return materialize_ctx && materialize_idx >= 0 &&

cpp2rust/converter/translation_rule.cpp

@@ -45,7 +45,11 @@ Access ParseAccessJSON(llvm::StringRef value) {
 PlaceholderFragment
 ParsePlaceholderFragmentJSON(const llvm::json::Object &obj) {
   auto access = obj.getString("access");
-  return {(unsigned)*obj.getInteger("arg"), ParseAccessJSON(*access)};
+  return {
+      (unsigned)*obj.getInteger("arg"),
+      ParseAccessJSON(*access),
+      obj.getBoolean("needs_autoref").value_or(false),
+  };
 }
 
 std::vector<BodyFragment> ParseBodyFragmentsJSON(const llvm::json::Array &arr);

cpp2rust/converter/translation_rule.h

@@ -26,6 +26,7 @@ enum class Access { kRead, kWrite, kMove };
 struct PlaceholderFragment {
   unsigned n; // "a0", "a1", ...
   Access access;
+  bool needs_autoref = false;
 
   void dump() const;
 };