Return 0 when main falls off its end

Author: lucic71

cpp2rust/converter/converter.cpp

@@ -429,6 +429,12 @@ void Converter::ConvertFunctionBody(clang::FunctionDecl *decl) {
     return;
   }
   auto compound = clang::dyn_cast<clang::CompoundStmt>(decl->getBody());
+  if (decl->isMain() && compound &&
+      (compound->body_empty() ||
+       !clang::isa<clang::ReturnStmt>(compound->body_back()))) {
+    StrCat("0");
+    return;
+  }
   if (!compound || compound->body_empty()) {
     return;
   }

tests/unit/empty_main.cpp

@@ -1 +1 @@
-int main(int, char **) { return 0; }
+int main(int, char **) {}