Refactor and rely on environments chain instead of #parent field in Translators to create flip-flop's state

Author: andrykonchin

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

@@ -33,7 +33,6 @@
 import org.truffleruby.language.control.InvalidReturnNode;
 import org.truffleruby.language.control.NotNodeGen;
 import org.truffleruby.language.control.ReturnID;
-import org.truffleruby.language.locals.FindDeclarationVariableNodes;
 import org.truffleruby.language.locals.LocalVariableType;
 import org.truffleruby.language.locals.ReadLocalVariableNode;
 import org.truffleruby.language.locals.WriteLocalVariableNode;
@@ -47,8 +46,6 @@ public final class YARPBlockNodeTranslator extends YARPTranslator {
     private final Nodes.ParametersNode parameters;
     private final Arity arity;
     private final String currentCallMethodName;
-    // used to find the nearest outer non-block lexical scope
-    private final YARPTranslator parent;
 
     public YARPBlockNodeTranslator(
             RubyLanguage language,
@@ -57,13 +54,11 @@ public YARPBlockNodeTranslator(
             Source source,
             Nodes.ParametersNode parameters,
             Arity arity,
-            String currentCallMethodName,
-            YARPTranslator parent) {
+            String currentCallMethodName) {
         super(language, environment, sourceBytes, source, null, null, null);
         this.parameters = parameters;
         this.arity = arity;
         this.currentCallMethodName = currentCallMethodName;
-        this.parent = parent;
     }
 
     public RubyNode compileBlockNode(Nodes.Node body, String[] locals, boolean isStabbyLambda,
@@ -344,10 +339,4 @@ private boolean shouldConsiderDestructuringArrayArg(Arity arity) {
         }
     }
 
-    @Override
-    // local variable will be declared in the nearest outer non-block lexical scope
-    protected FindDeclarationVariableNodes.FrameSlotAndDepth createFlipFlopState(int depth) {
-        return parent.createFlipFlopState(depth + 1);
-    }
-
 }

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

@@ -100,7 +100,7 @@
 import org.truffleruby.language.literal.ObjectLiteralNode;
 import org.truffleruby.language.literal.StringLiteralNode;
 import org.truffleruby.language.literal.TruffleInternalModuleLiteralNode;
-import org.truffleruby.language.locals.FindDeclarationVariableNodes;
+import org.truffleruby.language.locals.FindDeclarationVariableNodes.FrameSlotAndDepth;
 import org.truffleruby.language.locals.FlipFlopNodeGen;
 import org.truffleruby.language.locals.InitFlipFlopSlotNode;
 import org.truffleruby.language.locals.ReadLocalNode;
@@ -499,8 +499,7 @@ private RubyNode translateBlockAndLambda(Nodes.Node node, Nodes.BlockParametersN
                 source,
                 parameters,
                 arity,
-                currentCallMethodName,
-                this);
+                currentCallMethodName);
 
         methodCompiler.frameOnStackMarkerSlotStack = frameOnStackMarkerSlotStack;
 
@@ -1201,7 +1200,7 @@ public RubyNode visitFlipFlopNode(Nodes.FlipFlopNode node) {
         final RubyNode begin = node.left.accept(this);
         final RubyNode end = node.right.accept(this);
 
-        final FindDeclarationVariableNodes.FrameSlotAndDepth slotAndDepth = createFlipFlopState(0);
+        final var slotAndDepth = createFlipFlopState();
         final RubyNode rubyNode = FlipFlopNodeGen.create(begin, end, node.isExcludeEnd(), slotAndDepth.depth,
                 slotAndDepth.slot);
 
@@ -2014,10 +2013,13 @@ protected RubyNode defaultVisit(Nodes.Node node) {
         throw new Error("Unknown node: " + node);
     }
 
-    protected FindDeclarationVariableNodes.FrameSlotAndDepth createFlipFlopState(int depth) {
-        final int frameSlot = environment.declareLocalTemp("flipflop");
-        environment.getFlipFlopStates().add(frameSlot);
-        return new FindDeclarationVariableNodes.FrameSlotAndDepth(frameSlot, depth);
+    /** Declare variable in the nearest non-block outer lexical scope - either method, class or top-level */
+    protected FrameSlotAndDepth createFlipFlopState() {
+        final var target = environment.getSurroundingMethodEnvironment();
+        final int frameSlot = target.declareLocalTemp("flipflop");
+        target.getFlipFlopStates().add(frameSlot);
+
+        return new FrameSlotAndDepth(frameSlot, environment.getBlockDepth());
     }
 
     /** Translate a list of nodes, e.g. break/return operands, into an array producing node. It returns ArrayLiteralNode