Merge pull request github#9150 from tamasvajk/kotlin-MissingInstanceofInEquals

Kotlin: Add more type check casts to MissingInstanceofInEquals query

Author: tamasvajk

java/ql/src/Likely Bugs/Comparison/MissingInstanceofInEquals.ql

@@ -26,6 +26,10 @@ class CheckedCast extends CastExpr {
 predicate hasTypeTest(Variable v) {
   any(InstanceOfExpr ioe).getExpr() = v.getAnAccess()
   or
+  any(NotInstanceOfExpr nioe).getExpr() = v.getAnAccess()
+  or
+  any(SafeCastExpr sce).getExpr() = v.getAnAccess()
+  or
   exists(MethodAccess ma |
     ma.getMethod().getName() = "getClass" and
     ma.getQualifier() = v.getAnAccess()

java/ql/test/kotlin/query-tests/MissingInstanceofInEquals/MissingInstanceofInEquals.expected

@@ -0,0 +1 @@
+Likely Bugs/Comparison/MissingInstanceofInEquals.ql

java/ql/test/kotlin/query-tests/MissingInstanceofInEquals/MissingInstanceofInEquals.qlref

@@ -0,0 +1,7 @@
+data class D(val x: Int) {}
+
+data class E(val x: Int) {
+    override fun equals(other: Any?): Boolean {
+        return (other as? E)?.x == this.x
+    }
+}