QL: Merge pull request #29 from github/fourth-query

add `ql/override-parameter-name`

Author: erik-krogh

ql/src/codeql_ql/ast/Ast.qll

@@ -32,6 +32,7 @@ class AstNode extends TAstNode {
   /**
    * Gets the location of the AST node.
    */
+  cached
   Location getLocation() {
     exists(Generated::AstNode node | not node instanceof Generated::ParExpr |
       node = toGenerated(this) and

ql/src/queries/style/OverridingParameterName.ql

@@ -0,0 +1,31 @@
+/**
+ * @name Using a different paramater name than used in the super-predicate.
+ * @description Using another parameter can be an indication of copy-pasted code, or a mistake.
+ * @kind problem
+ * @problem.severity warning
+ * @id ql/override-parameter-name
+ * @tags correctness
+ *       maintainability
+ * @precision medium
+ */
+
+import ql
+
+pragma[noinline]
+private predicate getAnOverridingParameter(
+  ClassPredicate pred, ClassPredicate sup, VarDecl parameter, int index
+) {
+  pred.overrides(sup) and
+  parameter = pred.getParameter(index)
+}
+
+from ClassPredicate pred, ClassPredicate sup, VarDecl parameter, int index
+where
+  getAnOverridingParameter(pred, sup, parameter, index) and
+  sup.getParameter(index).getName() != pred.getParameter(index).getName() and
+  // avoid duplicated alerts with `ql/override-swapped-name`
+  not exists(int other | other != index |
+    sup.getParameter(other).getName() = pred.getParameter(index).getName()
+  )
+select parameter, pred.getParameter(index).getName() + " was $@ in the super class.",
+  sup.getParameter(index), "named " + sup.getParameter(index).getName()

ql/src/queries/style/SwappedParameterNames.ql

@@ -2,7 +2,7 @@
  * @name Swapped parameter names in overriding predicate.
  * @description Swapping the parameter names in an overriding method indicates an implementation mistake.
  * @kind problem
- * @problem.severity warning
+ * @problem.severity error
  * @id ql/override-swapped-name
  * @tags correctness
  *       maintainability
@@ -13,21 +13,18 @@ import ql
 
 pragma[noinline]
 private predicate getAnOverridingParameter(
-  ClassPredicate pred, ClassPredicate sup, VarDecl parameter, string parName, string superName,
-  int index
+  ClassPredicate pred, ClassPredicate sup, VarDecl parameter, int index
 ) {
   pred.overrides(sup) and
-  parameter = pred.getParameter(index) and
-  parameter.getName() = parName and
-  sup.getParameter(index).getName() = superName
+  parameter = pred.getParameter(index)
 }
 
-from
-  ClassPredicate pred, ClassPredicate sup, VarDecl parameter, string parName, string superName,
-  int index
+from ClassPredicate pred, ClassPredicate sup, VarDecl parameter, int index
 where
-  getAnOverridingParameter(pred, sup, parameter, parName, superName, index) and
-  superName != parName and
-  exists(int other | other != index | sup.getParameter(other).getName() = parName)
-select parameter, parName + " was $@ in the super class.", sup.getParameter(index),
-  "named " + superName
+  getAnOverridingParameter(pred, sup, parameter, index) and
+  sup.getParameter(index).getName() != pred.getParameter(index).getName() and
+  exists(int other | other != index |
+    sup.getParameter(other).getName() = pred.getParameter(index).getName()
+  )
+select parameter, pred.getParameter(index).getName() + " was $@ in the super class.",
+  sup.getParameter(index), "named " + sup.getParameter(index).getName()