C#: Remove false positives for cs/useless-assignment-to-local

Author: hvitved

csharp/ql/src/Dead Code/DeadStoreOfLocal.ql

@@ -114,7 +114,7 @@ class RelevantDefinition extends AssignableDefinition {
    */
   private predicate isDefaultLikeInitializer() {
     this.isInitializer() and
-    exists(Expr e | e = this.getSource() |
+    exists(Expr e | e = this.getSource().stripCasts() |
       exists(string val | val = e.getValue() |
         val = "0" or
         val = "-1" or

csharp/ql/test/query-tests/Dead Code/DeadStoreOfLocal/DeadStoreOfLocal.expected

@@ -16,8 +16,6 @@
 | DeadStoreOfLocal.cs:320:9:320:32 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:316:23:316:23 | b | b |
 | DeadStoreOfLocal.cs:361:13:361:20 | String s = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:361:13:361:13 | s | s |
 | DeadStoreOfLocal.cs:387:13:387:21 | ... = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:385:13:385:13 | s | s |
-| DeadStoreOfLocal.cs:395:16:395:26 | String s = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:395:16:395:16 | s | s |
-| DeadStoreOfLocal.cs:402:13:402:28 | String s = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocal.cs:402:13:402:13 | s | s |
 | DeadStoreOfLocalBad.cs:7:13:7:48 | Boolean success = ... | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:7:13:7:19 | success | success |
 | DeadStoreOfLocalBad.cs:23:32:23:32 | FormatException e | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:23:32:23:32 | e | e |
 | DeadStoreOfLocalBad.cs:32:22:32:22 | String s | This assignment to $@ is useless, since its value is never read. | DeadStoreOfLocalBad.cs:32:22:32:22 | s | s |