make a Comment superclass

Author: erik-krogh

ql/ql/src/codeql_ql/ast/Ast.qll

@@ -156,34 +156,38 @@ class TopLevel extends TTopLevel, AstNode {
   override QLDoc getQLDoc() { result = this.getMember(0) }
 }
 
-class QLDoc extends TQLDoc, AstNode {
+abstract class Comment extends AstNode, TComment {
+  abstract string getContents();
+}
+
+class QLDoc extends TQLDoc, Comment {
   QL::Qldoc qldoc;
 
   QLDoc() { this = TQLDoc(qldoc) }
 
-  string getContents() { result = qldoc.getValue() }
+  override string getContents() { result = qldoc.getValue() }
 
   override string getAPrimaryQlClass() { result = "QLDoc" }
 
   override AstNode getParent() { result.getQLDoc() = this }
 }
 
-class BlockComment extends TBlockComment, AstNode {
+class BlockComment extends TBlockComment, Comment {
   QL::BlockComment comment;
 
   BlockComment() { this = TBlockComment(comment) }
 
-  string getContents() { result = comment.getValue() }
+  override string getContents() { result = comment.getValue() }
 
   override string getAPrimaryQlClass() { result = "BlockComment" }
 }
 
-class LineComment extends TLineComment, AstNode {
+class LineComment extends TLineComment, Comment {
   QL::LineComment comment;
 
   LineComment() { this = TLineComment(comment) }
 
-  string getContents() { result = comment.getValue() }
+  override string getContents() { result = comment.getValue() }
 
   override string getAPrimaryQlClass() { result = "LineComment" }
 }

ql/ql/src/codeql_ql/ast/internal/AstNodes.qll

@@ -90,6 +90,8 @@ class TYamlNode = TYamlCommemt or TYamlEntry or TYamlKey or TYamlListitem or TYa
 
 class TSignatureExpr = TPredicateExpr or TType;
 
+class TComment = TQLDoc or TBlockComment or TLineComment;
+
 /** DEPRECATED: Alias for TYamlNode */
 deprecated class TYAMLNode = TYamlNode;
 

ql/ql/src/queries/style/RepeatedWord.ql

@@ -9,22 +9,14 @@
 
 import ql
 
-string getComment(AstNode node) {
-  result = node.(QLDoc).getContents()
-  or
-  result = node.(BlockComment).getContents()
-  or
-  result = node.(LineComment).getContents()
-}
-
 /** Gets a word used in `node` */
-string getWord(AstNode node) { result = getComment(node).regexpFind("\\b[A-Za-z]+\\b", _, _) }
+string getWord(Comment node) { result = node.getContents().regexpFind("\\b[A-Za-z]+\\b", _, _) }
 
-AstNode hasRepeatedWord(string word) {
+Comment hasRepeatedWord(string word) {
   word = getWord(result) and
-  getComment(result).regexpMatch(".*\\b" + word + "\\s+" + word + "\\b.*")
+  result.getContents().regexpMatch(".*\\b" + word + "\\s+" + word + "\\b.*")
 }
 
-from AstNode comment, string word
+from Comment comment, string word
 where comment = hasRepeatedWord(word)
 select comment, "The comment repeats " + word + "."