Fix in refinements: update grammar, visitor, and add regression test

Author: RajShivu

liquidjava-example/src/main/java/testMultiple/errors/ResultRefinementRegression.java

@@ -0,0 +1,34 @@
+package testMultiple.errors;
+
+import liquidjava.specification.Refinement;
+
+public class ResultRefinementRegression {
+	
+	
+	@Refinement("_ > 0")
+    static int positive() {
+        return 5;
+    }
+
+    @Refinement("return> 0")
+    static int broken() {
+        return -1; 
+    }
+    
+    @Refinement("$result > 0")
+    int testPositive() {
+        return 10;
+    }
+
+    @Refinement("$result < 0")
+    int testNegative() {
+        return -5;
+    }
+
+
+    public static void main(String[] args) {
+        int x = positive();
+        int y = broken();
+    }
+
+}

liquidjava-verifier/src/main/antlr4/rj/grammar/RJ.g4

@@ -92,7 +92,7 @@ BOOL    : 'true' | 'false';
 ID_UPPER: ([A-Z][a-zA-Z0-9]*);
 OBJECT_TYPE:
 		  (([a-zA-Z][a-zA-Z0-9]+) ('.' [a-zA-Z][a-zA-Z0-9]*)+);
-ID     	: '#'*[a-zA-Z_][a-zA-Z0-9_#]*;
+ID     	: '#'*('$')? [a-zA-Z_] [a-zA-Z0-9_#]* ;
 STRING  : '"'(~["])*'"';
 INT     : 	(([0-9]+) |	([0-9]+('_'[0-9]+)*));
 REAL   	: (([0-9]+('.'[0-9]+)?) | '.'[0-9]+);

liquidjava-verifier/src/main/java/liquidjava/rj_language/visitors/CreateASTVisitor.java

@@ -159,17 +159,12 @@ else if (rc instanceof LitContext)
         // return new Var(((VarContext) rc).ID().getText());
         // }
         else if (rc instanceof VarContext) {
-            // Normalize return-value identifiers:
-            // - "return" (legacy syntax)
-            // - "_" (current shorthand)
-            // Both are mapped to "$result", the canonical return value identifier.
             String name = ((VarContext) rc).ID().getText();
-            
-            if (name.equals("return") || name.equals("_")) {
-                name = "$result";
+            if (name.equals("$result") || name.equals("return")) {
+                name = "_";
             }
-
             return new Var(name);
+
         }
 
         else if (rc instanceof TargetInvocationContext) {