Merge parameter index validator into member existence

Resolves #18

Author: sciwhiz12

src/main/java/org/parchmentmc/compass/data/validation/impl/MemberExistenceValidator.java

@@ -1,29 +1,42 @@
 package org.parchmentmc.compass.data.validation.impl;
 
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.parchmentmc.compass.data.validation.Validator;
+import org.parchmentmc.compass.util.DescriptorIndexer;
 import org.parchmentmc.feather.mapping.MappingDataContainer;
 import org.parchmentmc.feather.metadata.ClassMetadata;
 import org.parchmentmc.feather.metadata.FieldMetadata;
 import org.parchmentmc.feather.metadata.MethodMetadata;
 import org.parchmentmc.feather.metadata.SourceMetadata;
 
+import java.util.BitSet;
+
 /**
- * Validates that classes, fields, and methods exist according to the Blackstone metadata.
+ * Validates that classes, fields, methods, and parameters exist according to the Blackstone metadata.
+ *
+ * @see DescriptorIndexer
  */
 public class MemberExistenceValidator extends Validator {
+    @MonotonicNonNull
+    private DescriptorIndexer indexer;
+
     public MemberExistenceValidator() {
         super("member existence");
     }
 
     @Override
     public boolean visit(MappingDataContainer container, @Nullable SourceMetadata metadata) {
+        indexer = new DescriptorIndexer();
         return metadata != null; // Only visit when we have metadata available
     }
 
     @Override
     public boolean preVisit(DataType type) {
-        return DataType.CLASSES.test(type) || DataType.FIELDS.test(type) || DataType.METHODS.test(type);
+        return DataType.CLASSES.test(type)
+                || DataType.FIELDS.test(type)
+                || DataType.METHODS.test(type)
+                || DataType.PARAMETERS.test(type);
     }
 
     @Override
@@ -36,19 +49,33 @@ public boolean visitClass(MappingDataContainer.ClassData classData, @Nullable Cl
     }
 
     @Override
-    public void visitField(MappingDataContainer.ClassData classData, MappingDataContainer.FieldData fieldData, 
+    public void visitField(MappingDataContainer.ClassData classData, MappingDataContainer.FieldData fieldData,
                            @Nullable ClassMetadata classMetadata, @Nullable FieldMetadata fieldMetadata) {
         if (fieldMetadata == null) {
             error("Field does not exist according to metadata");
         }
     }
 
     @Override
-    public boolean visitMethod(MappingDataContainer.ClassData classData, MappingDataContainer.MethodData methodData, 
+    public boolean visitMethod(MappingDataContainer.ClassData classData, MappingDataContainer.MethodData methodData,
                                @Nullable ClassMetadata classMetadata, @Nullable MethodMetadata methodMetadata) {
         if (methodMetadata == null) {
             error("Method does not exist according to metadata");
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public void visitParameter(MappingDataContainer.ClassData classData, MappingDataContainer.MethodData methodData,
+                               MappingDataContainer.ParameterData paramData, @Nullable ClassMetadata classMetadata,
+                               @Nullable MethodMetadata methodMetadata) {
+        final BitSet indexes = indexer.getIndexes(methodData, methodMetadata);
+        byte paramIndex = paramData.getIndex();
+
+        if (!indexes.get(paramIndex)) {
+            // When above is resolved, add special-case for index 0 and non-static method
+            error("Parameter does not exist according to descriptor");
         }
-        return false;
     }
 }

src/main/java/org/parchmentmc/compass/data/validation/impl/ParameterIndexValidator.java

@@ -22,7 +22,6 @@
 import org.parchmentmc.compass.data.validation.impl.LambdaValidator;
 import org.parchmentmc.compass.data.validation.impl.MethodStandardsValidator;
 import org.parchmentmc.compass.data.validation.impl.ParameterConflictsValidator;
-import org.parchmentmc.compass.data.validation.impl.ParameterIndexValidator;
 import org.parchmentmc.compass.data.validation.impl.ParameterStandardsValidator;
 import org.parchmentmc.compass.data.validation.impl.RecordValidator;
 import org.parchmentmc.compass.data.validation.impl.SyntheticValidator;
@@ -69,7 +68,6 @@ public ValidateData(ObjectFactory objectFactory) {
         validators.add(new SyntheticValidator());
         validators.add(new MethodStandardsValidator());
         validators.add(new ParameterConflictsValidator());
-        validators.add(new ParameterIndexValidator());
         validators.add(new RecordValidator());
         validators.add(new MemberExistenceValidator());
     }