Make `` literals frozen

Author: andrykonchin

spec/truffle/parsing/fixtures/strings/backtick_literal.yaml

@@ -23,11 +23,11 @@ ast: |
           notRuby2KeywordsHashProfile = false
       children:
           arguments = [
-              StringLiteralNode
+              FrozenStringLiteralNode
                   attributes:
-                      encoding = UTF-8
+                      definition = expression
                       flags = 0
-                      tstring = echo 1
+                      frozenString = echo 1
           ]
           receiver =
               SelfNode

spec/truffle/parsing/fixtures/strings/encoding_of_backtick_literal/when_non_ascii_characters_only.yaml renamed to spec/truffle/parsing/fixtures/strings/encoding_of_backtick_literal/when_non_ascii_characters.yaml

@@ -1,5 +1,5 @@
 subject: "String"
-description: "backtick literal / encoding / when there are non-ASCII characters"
+description: "backtick literal / encoding / when there are ASCII and non-ASCII characters"
 notes: >
   String may be forced to the BINARY (ASCII-8BIT) encoding sometimes
 focused_on_node: "org.truffleruby.language.dispatch.RubyCallNode"
@@ -23,11 +23,11 @@ ast: |
           notRuby2KeywordsHashProfile = false
       children:
           arguments = [
-              StringLiteralNode
+              FrozenStringLiteralNode
                   attributes:
-                      encoding = ASCII-8BIT
+                      definition = expression
                       flags = 0
-                      tstring = echo \xFF 1
+                      frozenString = echo \xFF 1
           ]
           receiver =
               SelfNode

spec/truffle/parsing/fixtures/strings/encoding_of_backtick_literal/when_utf8_characters.yaml

@@ -23,11 +23,11 @@ ast: |
           notRuby2KeywordsHashProfile = false
       children:
           arguments = [
-              StringLiteralNode
+              FrozenStringLiteralNode
                   attributes:
-                      encoding = UTF-8
+                      definition = expression
                       flags = 0
-                      tstring = echo £ 1
+                      frozenString = echo £ 1
           ]
           receiver =
               SelfNode

src/main/java/org/truffleruby/parser/BodyTranslator.java

@@ -2888,9 +2888,9 @@ private RubyNode translateWhileNode(WhileParseNode node, boolean conditionInvers
 
     @Override
     public RubyNode visitXStrNode(XStrParseNode node) {
-        final ParseNode argsNode = buildArrayNode(
-                node.getPosition(),
-                new StrParseNode(node.getPosition(), node.getValue(), node.encoding));
+        final var stringNode = new StrParseNode(node.getPosition(), node.getValue(), node.encoding);
+        stringNode.setFrozen(true); // it's always frozen
+        final ParseNode argsNode = buildArrayNode(node.getPosition(), stringNode);
         final ParseNode callNode = new FCallParseNode(node.getPosition(), "`", argsNode, null);
         final RubyNode ret = callNode.accept(this);
         return addNewlineIfNeeded(node, ret);

src/main/java/org/truffleruby/parser/YARPTranslator.java

@@ -2832,9 +2832,8 @@ public RubyNode visitWhileNode(Nodes.WhileNode node) {
 
     @Override
     public RubyNode visitXStringNode(Nodes.XStringNode node) {
-        // TODO: pass flags, needs https://github.com/ruby/yarp/issues/1567
         // convert EncodingFlags to StringFlags
-        int flags = 0;
+        int flags = Nodes.StringFlags.FROZEN; // it's always frozen
 
         if (node.isForcedBinaryEncoding()) {
             flags |= Nodes.StringFlags.FORCED_BINARY_ENCODING;