fix constructor errors

Signed-off-by: Nitish <snapdgnn@proton.me>

backends/p4fmt/CMakeLists.txt

@@ -9,6 +9,7 @@ set(REFCHECK_SRCS
     refcheck.cpp
     options.cpp
     p4fmt.cpp
+    attach.cpp
 )
 
 # p4fmt

backends/p4fmt/attach.cpp

@@ -37,8 +37,8 @@ void Attach::attachCommentsToNode(const IR::Node *node) {
     }
 }
 
-Attach::Attach(){};
-Attach::~Attach(){};
+Attach::Attach() = default;
+Attach::~Attach() = default;
 
 template <typename T>
 bool Attach::preorderImpl(const T *node) {

backends/p4fmt/attach.h

@@ -9,11 +9,7 @@ namespace P4 {
 class Attach : public Inspector {
  public:
     Attach();
-    Attach(const Attach &) = default;
-    Attach(Attach &&) = delete;
-    Attach &operator=(const Attach &) = delete;
-    Attach &operator=(Attach &&) = delete;
-    ~Attach() override;
+    ~Attach();
 
     template <typename T>
     bool preorderImpl(const T *node);

backends/p4fmt/p4fmt.cpp

@@ -23,8 +23,12 @@ std::stringstream getFormattedOutput(std::filesystem::path inputFile) {
         return formattedOutput;
     }
 
-    PassManager passes({P4::Attach(), P4::ToP4(&formattedOutput, false)});
-    program = program->apply(passes);
+    auto top4 = P4::ToP4(&formattedOutput, false);
+    auto attach = P4::Attach();
+    // attach comments to nodes
+    program->apply(attach);
+    // Print the program before running front end passes.
+    program->apply(top4);
 
     if (::errorCount() > 0) {
         ::error("Failed to format p4 program.");