Replace DeadNode with null for stub values of local variables assignings

Author: andrykonchin

spec/truffle/parsing/fixtures/rescue/capturing/with_local_variable.yaml

@@ -72,14 +72,6 @@ ast: |
                                                           frameSlot = 2 # error
                                                           sourceCharIndex = 37
                                                           sourceLength = 5
-                                                      children:
-                                                          valueNode =
-                                                              DeadNode
-                                                                  attributes:
-                                                                      flags = 0
-                                                                      reason = "YARPTranslator#visitLocalVariableTargetNode"
-                                                                      sourceCharIndex = -1
-                                                                      sourceLength = 0
                                       IntegerFixnumLiteralNode
                                           attributes:
                                               flags = 1

spec/truffle/parsing/fixtures/rescue/with_exception_and_variable.yaml

@@ -75,14 +75,6 @@ ast: |
                                                           frameSlot = 2 # error
                                                           sourceCharIndex = 37
                                                           sourceLength = 5
-                                                      children:
-                                                          valueNode =
-                                                              DeadNode
-                                                                  attributes:
-                                                                      flags = 0
-                                                                      reason = "YARPTranslator#visitLocalVariableTargetNode"
-                                                                      sourceCharIndex = -1
-                                                                      sourceLength = 0
                                       IntegerFixnumLiteralNode
                                           attributes:
                                               flags = 1

spec/truffle/parsing/fixtures/rescue/without_exception_but_with_variable.yaml

@@ -46,14 +46,6 @@ ast: |
                                                           frameSlot = 2 # error
                                                           sourceCharIndex = 24
                                                           sourceLength = 5
-                                                      children:
-                                                          valueNode =
-                                                              DeadNode
-                                                                  attributes:
-                                                                      flags = 0
-                                                                      reason = "YARPTranslator#visitLocalVariableTargetNode"
-                                                                      sourceCharIndex = -1
-                                                                      sourceLength = 0
                                       IntegerFixnumLiteralNode
                                           attributes:
                                               flags = 1

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

@@ -229,8 +229,7 @@ public AssignableNode visitSplatNode(Nodes.SplatNode node) {
     public AssignableNode visitRequiredParameterNode(Nodes.RequiredParameterNode node) {
         final String name = node.name;
         final ReadLocalNode lhs = yarpTranslator.getEnvironment().findLocalVarNode(name);
-        final RubyNode rhs = new DeadNode("YARPMultiTargetNodeTranslator#visitRequiredParameterNode");
-        final WriteLocalNode rubyNode = lhs.makeWriteNode(rhs);
+        final WriteLocalNode rubyNode = lhs.makeWriteNode(null);
 
         return rubyNode.toAssignableNode();
     }

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

@@ -2654,8 +2654,7 @@ public WriteLocalNode visitLocalVariableWriteNode(Nodes.LocalVariableWriteNode n
     public WriteLocalNode visitLocalVariableTargetNode(Nodes.LocalVariableTargetNode node) {
         final String name = node.name;
         final ReadLocalNode lhs = environment.findLocalVarNode(name);
-        final RubyNode rhs = new DeadNode("YARPTranslator#visitLocalVariableTargetNode");
-        final WriteLocalNode rubyNode = lhs.makeWriteNode(rhs);
+        final WriteLocalNode rubyNode = lhs.makeWriteNode(null);
 
         assignPositionAndFlags(node, rubyNode);
         return rubyNode;