C#: Add test cases that uses in/out or ref parameters.

Author: michaelnebel

csharp/ql/test/query-tests/Linq/MissedAllOpportunity/MissedAllOpportunity.cs

@@ -32,6 +32,20 @@ public void M2(NonEnumerableClass nec)
         }
     }
 
+    public void M3(List<int> lst, ref int x)
+    {
+        // GOOD: Linq can't be used here because the condition uses a ref parameter.
+        var allEven = true;
+        foreach (int i in lst)
+        {
+            if (i % 2 != x)
+            {
+                allEven = false;
+                break;
+            }
+        }
+    }
+
     public class NonEnumerableClass
     {
         public IEnumerator<int> GetEnumerator() => throw null;

csharp/ql/test/query-tests/Linq/MissedAllOpportunity/MissedAllOpportunity.expected

@@ -1 +1,5 @@
+#select
 | MissedAllOpportunity.cs:11:9:18:9 | foreach (... ... in ...) ... | This foreach loop looks as if it might be testing whether every sequence element satisfies a predicate - consider using '.All(...)'. |
+| MissedAllOpportunity.cs:39:9:46:9 | foreach (... ... in ...) ... | This foreach loop looks as if it might be testing whether every sequence element satisfies a predicate - consider using '.All(...)'. |
+testFailures
+| MissedAllOpportunity.cs:39:9:46:9 | This foreach loop looks as if it might be testing whether every sequence element satisfies a predicate - consider using '.All(...)'. | Unexpected result: Alert |

csharp/ql/test/query-tests/Linq/MissedFirstOrDefaultOpportunity/MissedFirstOrDefaultOpportunity.cs

@@ -179,6 +179,20 @@ public Operation M14(IEnumerable<Operation> operations, Func<string, bool>[] pre
         return null;
     }
 
+    public int M15(IEnumerable<int> values, ref readonly int x)
+    {
+        // GOOD: FirstOrDefault does not support a predicate that captures a ref parameter.
+        foreach (var value in values)
+        {
+            if (value > x)
+            {
+                return value;
+            }
+        }
+
+        return default;
+    }
+
     private static Task<bool> IsMatch(Operation operation, string operationId) =>
         Task.FromResult(string.Equals(operation.OperationId, operationId, StringComparison.Ordinal));
 }

csharp/ql/test/query-tests/Linq/MissedFirstOrDefaultOpportunity/MissedFirstOrDefaultOpportunity.expected

@@ -1,5 +1,9 @@
+#select
 | MissedFirstOrDefaultOpportunity.cs:10:9:14:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:12:17:12:91 | call to method Equals | predicate |
 | MissedFirstOrDefaultOpportunity.cs:22:9:28:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:24:17:24:25 | ... > ... | predicate |
 | MissedFirstOrDefaultOpportunity.cs:36:9:40:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:38:17:38:25 | ... > ... | predicate |
 | MissedFirstOrDefaultOpportunity.cs:149:9:153:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:151:17:151:32 | ... > ... | predicate |
 | MissedFirstOrDefaultOpportunity.cs:161:9:165:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:163:17:163:25 | ... > ... | predicate |
+| MissedFirstOrDefaultOpportunity.cs:185:9:191:9 | foreach (... ... in ...) ... | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | MissedFirstOrDefaultOpportunity.cs:187:17:187:25 | ... > ... | predicate |
+testFailures
+| MissedFirstOrDefaultOpportunity.cs:185:9:191:9 | This foreach loop returns the first sequence element satisfying a $@ - consider finding the element explicitly using '.FirstOrDefault(...)'. | Unexpected result: Alert |

csharp/ql/test/query-tests/Linq/MissedSelectOpportunity/MissedSelectOpportunity.cs

@@ -25,6 +25,17 @@ public async Task M2(IEnumerable<ICounter> counters)
         }
     }
 
+    public void M3(List<int> lst, out int x)
+    {
+        // GOOD: Linq can't be used here as the Select would capture an out parameter.
+        x = 2;
+        foreach (int i in lst)
+        {
+            int j = i * x;
+            Console.WriteLine(j);
+        }
+    }
+
     public interface ICounter
     {
         Task<int> CountAsync();

csharp/ql/test/query-tests/Linq/MissedSelectOpportunity/MissedSelectOpportunity.expected

@@ -1 +1,5 @@
+#select
 | MissedSelectOpportunity.cs:11:9:15:9 | foreach (... ... in ...) ... | This foreach loop immediately $@ - consider mapping the sequence explicitly using '.Select(...)'. | MissedSelectOpportunity.cs:13:13:13:26 | ... ...; | maps its iteration variable to another variable |
+| MissedSelectOpportunity.cs:32:9:36:9 | foreach (... ... in ...) ... | This foreach loop immediately $@ - consider mapping the sequence explicitly using '.Select(...)'. | MissedSelectOpportunity.cs:34:13:34:26 | ... ...; | maps its iteration variable to another variable |
+testFailures
+| MissedSelectOpportunity.cs:32:9:36:9 | This foreach loop immediately $@ - consider mapping the sequence explicitly using '.Select(...)'. | Unexpected result: Alert |

csharp/ql/test/query-tests/Linq/MissedWhereOpportunity/MissedWhereOpportunity.cs

@@ -174,6 +174,18 @@ public void M12(IEnumerable<int> elements)
         }
     }
 
+    public void M13(List<int> lst, in int x)
+    {
+        // GOOD: Linq can't be used here because the condition uses an in parameter.
+        foreach (int i in lst)
+        {
+            if (i % 2 != x)
+                continue;
+            Console.WriteLine(i);
+            Console.WriteLine((i / 2));
+        }
+    }
+
     public class NonEnumerableClass
     {
         public IEnumerator<int> GetEnumerator() => throw null;

csharp/ql/test/query-tests/Linq/MissedWhereOpportunity/MissedWhereOpportunity.expected

@@ -1,5 +1,9 @@
+#select
 | MissedWhereOpportunity.cs:10:9:16:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:12:17:12:26 | ... != ... | implicitly filters its target sequence |
 | MissedWhereOpportunity.cs:19:9:26:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:21:17:21:26 | ... == ... | implicitly filters its target sequence |
 | MissedWhereOpportunity.cs:45:9:52:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:47:17:47:26 | ... == ... | implicitly filters its target sequence |
 | MissedWhereOpportunity.cs:70:9:76:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:72:17:72:46 | ... == ... | implicitly filters its target sequence |
 | MissedWhereOpportunity.cs:120:9:126:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:122:17:122:46 | ... == ... | implicitly filters its target sequence |
+| MissedWhereOpportunity.cs:180:9:186:9 | foreach (... ... in ...) ... | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | MissedWhereOpportunity.cs:182:17:182:26 | ... != ... | implicitly filters its target sequence |
+testFailures
+| MissedWhereOpportunity.cs:180:9:186:9 | This foreach loop $@ - consider filtering the sequence explicitly using '.Where(...)'. | Unexpected result: Alert |