Replace dynamic_cast with parser::cast_node for consistency (#405)

parser/prism/Translator.cc

@@ -257,7 +257,7 @@ unique_ptr<parser::Node> Translator::translate(pm_node_t *node) {
             // parameters. So we need to extract the args vector from the Args node, and insert the locals at the end of
             // it.
             auto sorbetArgsNode = translate(up_cast(paramsNode->parameters));
-            auto argsNode = dynamic_cast<parser::Args *>(sorbetArgsNode.get());
+            auto argsNode = parser::cast_node<parser::Args>(sorbetArgsNode.get());
             auto sorbetShadowArgs = translateMulti(paramsNode->locals);
             // Sorbet's legacy parser inserts locals (Shadowargs) at the end of the the block's Args node
             argsNode->args.insert(argsNode->args.end(), std::make_move_iterator(sorbetShadowArgs.begin()),
@@ -301,7 +301,7 @@ unique_ptr<parser::Node> Translator::translate(pm_node_t *node) {
             // Handle `~[Integer]`, like `~42`
             // Unlike `-[Integer]`, Prism treats `~[Integer]` as a method call
             // But Sorbet's legacy parser treats both `~[Integer]` and `-[Integer]` as integer literals
-            if (name == "~" && dynamic_cast<parser::Integer *>(receiver.get())) {
+            if (name == "~" && parser::cast_node<parser::Integer>(receiver.get())) {
                 std::string valueString(reinterpret_cast<const char *>(callNode->base.location.start),
                                         callNode->base.location.end - callNode->base.location.start);
 
@@ -525,11 +525,11 @@ unique_ptr<parser::Node> Translator::translate(pm_node_t *node) {
                 // If that's the case, we need to check if the body contains an ensure or rescue clause, and if so,
                 // we need to elevate that node to the top level of the method definition, without the Kwbegin node to
                 // match the behavior of Sorbet's legacy parser.
-                auto kwbeginNode = dynamic_cast<parser::Kwbegin *>(body.get());
+                auto kwbeginNode = parser::cast_node<parser::Kwbegin>(body.get());
 
                 if (kwbeginNode != nullptr && kwbeginNode->stmts[0] != nullptr &&
-                    (dynamic_cast<parser::Rescue *>(kwbeginNode->stmts[0].get()) != nullptr ||
-                     dynamic_cast<parser::Ensure *>(kwbeginNode->stmts[0].get()) != nullptr)) {
+                    (parser::cast_node<parser::Rescue>(kwbeginNode->stmts[0].get()) ||
+                     parser::cast_node<parser::Ensure>(kwbeginNode->stmts[0].get()))) {
                     if (kwbeginNode->stmts.size() == 1) {
                         body = move(kwbeginNode->stmts[0]);
                     } else {
@@ -1770,7 +1770,7 @@ unique_ptr<parser::Node> Translator::translateCallWithBlock(pm_node_t *prismBloc
         body = translate(prismLambdaNode->body);
     }
 
-    if (dynamic_cast<parser::NumParams *>(parametersNode.get())) {
+    if (parser::cast_node<parser::NumParams>(parametersNode.get())) {
         return make_unique<parser::NumBlock>(sendNode->loc, move(sendNode), move(parametersNode), move(body));
     } else {
         return make_unique<parser::Block>(sendNode->loc, move(sendNode), move(parametersNode), move(body));