C#: Simplify the discarding and also discard type mentions and comments.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/Overlay.qll

@@ -14,7 +14,7 @@ predicate isOverlay() { databaseMetadata("isOverlay", "true") }
  * An abstract base class for all elements that can be discarded from the base.
  */
 overlay[local]
-abstract private class DiscardableEntity extends @element {
+abstract private class DiscardableEntity extends @locatable {
   /** Gets the path to the file in which this element occurs. */
   abstract string getPath();
 
@@ -36,7 +36,7 @@ overlay[local]
 private class StarEntity = @expr or @stmt;
 
 overlay[discard_entity]
-private predicate discardStarEntity(@element e) {
+private predicate discardStarEntity(@locatable e) {
   e instanceof StarEntity and
   // Entities with *-ids can exist either in base or overlay, but not both.
   exists(DiscardableEntity de | de = e |
@@ -46,7 +46,7 @@ private predicate discardStarEntity(@element e) {
 }
 
 overlay[discard_entity]
-private predicate discardNamedEntity(@element e) {
+private predicate discardNamedEntity(@locatable e) {
   not e instanceof StarEntity and
   // Entities with named IDs can exist both in base, overlay, or both.
   exists(DiscardableEntity de | de = e |
@@ -73,155 +73,32 @@ private predicate discardLocation(@location_default loc) {
 }
 
 overlay[local]
-private class ExprEntity extends DiscardableEntity instanceof @expr {
-  override string getPath() {
-    exists(@location_default loc | expr_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class StmtEntity extends DiscardableEntity instanceof @stmt {
-  override string getPath() {
-    exists(@location_default loc | stmt_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class UsingDirectiveEntity extends DiscardableEntity instanceof @using_directive {
-  override string getPath() {
-    exists(@location_default loc | using_directive_location(this, loc) |
-      result = getLocationPath(loc)
-    )
-  }
-}
-
-overlay[local]
-private class NamespaceDeclarationEntity extends DiscardableEntity instanceof @namespace_declaration
-{
-  override string getPath() {
-    exists(@location_default loc | namespace_declaration_location(this, loc) |
-      result = getLocationPath(loc)
-    )
-  }
-}
-
-overlay[local]
-private class PreprocessorDirectiveEntity extends DiscardableEntity instanceof @preprocessor_directive
-{
-  override string getPath() {
-    exists(@location_default loc | preprocessor_directive_location(this, loc) |
-      result = getLocationPath(loc)
-    )
-  }
-}
-
-overlay[local]
-private class TypeEntity extends DiscardableEntity instanceof @type {
-  override string getPath() {
-    exists(@location_default loc | type_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class AttributeEntity extends DiscardableEntity instanceof @attribute {
-  override string getPath() {
-    exists(@location_default loc | attribute_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class TypeParameterConstraintsEntity extends DiscardableEntity instanceof @type_parameter_constraints
-{
-  override string getPath() {
-    exists(@location_default loc | type_parameter_constraints_location(this, loc) |
-      result = getLocationPath(loc)
-    )
-  }
-}
-
-overlay[local]
-private class PropertyEntity extends DiscardableEntity instanceof @property {
-  override string getPath() {
-    exists(@location_default loc | property_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class IndexerEntity extends DiscardableEntity instanceof @indexer {
-  override string getPath() {
-    exists(@location_default loc | indexer_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class AccessorEntity extends DiscardableEntity instanceof @accessor {
-  override string getPath() {
-    exists(@location_default loc | accessor_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class EventEntity extends DiscardableEntity instanceof @event {
-  override string getPath() {
-    exists(@location_default loc | event_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class EventAccessorEntity extends DiscardableEntity instanceof @event_accessor {
-  override string getPath() {
-    exists(@location_default loc | event_accessor_location(this, loc) |
-      result = getLocationPath(loc)
+private class PossibleDiscardableEntity extends DiscardableEntity instanceof @locatable {
+  override string getPath() {
+    exists(@location_default loc | result = getLocationPath(loc) |
+      expr_location(this, loc) or
+      stmt_location(this, loc) or
+      using_directive_location(this, loc) or
+      namespace_declaration_location(this, loc) or
+      preprocessor_directive_location(this, loc) or
+      type_location(this, loc) or
+      attribute_location(this, loc) or
+      type_parameter_constraints_location(this, loc) or
+      property_location(this, loc) or
+      indexer_location(this, loc) or
+      accessor_location(this, loc) or
+      event_location(this, loc) or
+      event_accessor_location(this, loc) or
+      operator_location(this, loc) or
+      method_location(this, loc) or
+      constructor_location(this, loc) or
+      destructor_location(this, loc) or
+      field_location(this, loc) or
+      localvar_location(this, loc) or
+      param_location(this, loc) or
+      type_mention_location(this, loc) or
+      commentline_location(this, loc) or
+      commentblock_location(this, loc)
     )
   }
 }
-
-overlay[local]
-private class OperatorEntity extends DiscardableEntity instanceof @operator {
-  override string getPath() {
-    exists(@location_default loc | operator_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class MethodEntity extends DiscardableEntity instanceof @method {
-  override string getPath() {
-    exists(@location_default loc | method_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class ConstructorEntity extends DiscardableEntity instanceof @constructor {
-  override string getPath() {
-    exists(@location_default loc | constructor_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class DestructorEntity extends DiscardableEntity instanceof @destructor {
-  override string getPath() {
-    exists(@location_default loc | destructor_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class FieldEntity extends DiscardableEntity instanceof @field {
-  override string getPath() {
-    exists(@location_default loc | field_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class LocalVariableEntity extends DiscardableEntity instanceof @local_variable {
-  override string getPath() {
-    exists(@location_default loc | localvar_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-
-overlay[local]
-private class ParameterEntity extends DiscardableEntity instanceof @parameter {
-  override string getPath() {
-    exists(@location_default loc | param_location(this, loc) | result = getLocationPath(loc))
-  }
-}
-// TODO: We Still need to handle commentline, comment block entities and type mentions.