Improve inVoidContext to take conditional expressions into account.

Author: Max Schaefer

javascript/ql/lib/Expressions/ExprHasNoEffect.qll

@@ -38,6 +38,8 @@ predicate inVoidContext(Expr e) {
   )
   or
   exists(LogicalBinaryExpr logical | e = logical.getRightOperand() and inVoidContext(logical))
+  or
+  exists(ConditionalExpr cond | e = cond.getABranch())
 }
 
 /**

javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/ExprHasNoEffect.expected

@@ -10,4 +10,5 @@
 | tst.js:50:3:50:49 | new Syn ... o me?") | This expression has no effect. |
 | tst.js:51:3:51:36 | new Err ... age(e)) | This expression has no effect. |
 | tst.js:62:2:62:20 | o.trivialNonGetter1 | This expression has no effect. |
+| tst.js:78:24:78:24 | o | This expression has no effect. |
 | uselessfn.js:1:1:1:15 | (functi ... .");\\n}) | This expression has no effect. |

javascript/ql/test/query-tests/Expressions/ExprHasNoEffect/tst.js

@@ -73,5 +73,8 @@ function g() {
 	Object.defineProperty(o, "nonTrivialGetter2", unknownGetterDef());
 	o.nonTrivialGetter2; // OK
 
-	(o: empty); // OK.
+	(o: empty); // OK
+
+	testSomeCondition() ? o : // NOT OK
+		doSomethingDangerous();
 };