QL: Merge pull request github#54 from github/aschackmull/singleton-set

New query: Singleton set literal.
erik-krogh · Oct 13, 2021 · 87910e8 · 87910e8
2 parents fed3d80 + f71acdf
commit 87910e8
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diff --git a/ql/src/codeql_ql/ast/Ast.qll b/ql/src/codeql_ql/ast/Ast.qll
@@ -1926,7 +1926,7 @@ class Set extends TSet, Expr {
   Set() { this = TSet(set) }
 
   /**
-   * Gets the ith element in the set literal expression.
+   * Gets the `i`th element in this set literal expression.
    */
   Expr getElement(int i) { toGenerated(result) = set.getChild(i) }
 

diff --git a/ql/src/queries/style/SingletonSetLiteral.ql b/ql/src/queries/style/SingletonSetLiteral.ql
@@ -0,0 +1,15 @@
+/**
+ * @name Singleton set literal
+ * @description A singleton set literal can be replaced by its member.
+ * @kind problem
+ * @problem.severity warning
+ * @id ql/singleton-set-literal
+ * @tags maintainability
+ * @precision very-high
+ */
+
+import ql
+
+from Set setlit
+where exists(unique(Expr e | e = setlit.getElement(_)))
+select setlit, "Singleton set literal can be replaced by its member."