Fix test errors

Don't report error when checking synthesized constructor, we will
remove this constructor instead.

Change the location where we create the member initialize constructor
signature to SemanticsDeclAttributesVisitor to avoid the circular
checking problem.

source/slang/slang-check-conversion.cpp

@@ -262,9 +262,8 @@ namespace Slang
 
         // 4. All of its members have to have the same visibility as the struct itself.
         DeclVisibility structVisibility = getDeclVisibility(structDecl);
-        for (auto varDeclRef : getMembersOfType<VarDeclBase>(getASTBuilder(), structDecl, MemberFilterStyle::Instance))
+        for (auto varDecl : structDecl->getMembersOfType<VarDeclBase>())
         {
-            auto varDecl = varDeclRef.getDecl();
             if (getDeclVisibility(varDecl) != structVisibility)
             {
                 return false;
@@ -289,24 +288,25 @@ namespace Slang
         }
 
         // 5. All its members are legacy C-Style structs or arrays of legacy C-style structs
-        for (auto varDeclRef : getMembersOfType<VarDeclBase>(getASTBuilder(), structDecl, MemberFilterStyle::Instance))
+        for (auto varDecl : structDecl->getMembersOfType<VarDeclBase>())
         {
-            auto varDecl = varDeclRef.getDecl();
-
             // if the member is an array, check if the element is legacy C-style rule.
             if (auto arrayType = as<ArrayExpressionType>(varDecl->getType()))
             {
                 auto* elementType = arrayType->getElementType();
-                ArrayExpressionType* nextType = nullptr;
-                while(nextType = as<ArrayExpressionType>(elementType))
+                for (;;)
                 {
+                    ArrayExpressionType* nextType = as<ArrayExpressionType>(elementType);
+                    if(!nextType)
+                        break;
+
                     elementType = nextType->getElementType();
                 }
-                if(auto structDecl = _getStructDecl(elementType))
+                if(auto elemStructDecl = _getStructDecl(elementType))
                 {
-                    if (!_cStyleStructBasicCheck(structDecl))
+                    if (!_cStyleStructBasicCheck(elemStructDecl))
                     {
-                        getShared()->cacheCStyleStruct(structDecl, false);
+                        getShared()->cacheCStyleStruct(elemStructDecl, false);
                         return false;
                     }
                 }
@@ -391,6 +391,11 @@ namespace Slang
 
         bool isCStyle = isCStyleStruct(structDecl);
 
+        if (structDecl->m_synthesizedCtorMap.getCount() == 0)
+        {
+            return false;
+        }
+
         List<Expr*> coercedArgs;
         auto ctorInvokeExpr = _createCtorInvokeExpr(toType, fromInitializerListExpr->loc, fromInitializerListExpr->args);