C#: Handle in arguments, and add AssignableAccess::isInArgument() predicate.

calumgrant · calumgrant · commit a5d50fc1db2b · 2018-11-13T10:58:43.000Z
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expression.cs b/csharp/extractor/Semmle.Extraction.CSharp/Entities/Expression.cs
@@ -223,6 +223,9 @@ private void PopulateArgument(ArgumentSyntax arg, int child)
                 case SyntaxKind.None:
                     mode = 0;
                     break;
+                case SyntaxKind.InKeyword:
+                    mode = 3;
+                    break;
                 default:
                     throw new InternalError(arg, "Unknown argument type");
             }
diff --git a/csharp/ql/src/semmle/code/csharp/exprs/Access.qll b/csharp/ql/src/semmle/code/csharp/exprs/Access.qll
@@ -174,6 +174,14 @@ class AssignableAccess extends Access, @assignable_access_expr {
     isOutArgument() or
     isRefArgument()
   }
+
+  /**
+   * Holds if this access passes the assignable being accessed as an `in`
+   * argument in a method call.
+   */
+  predicate isInArgument() {
+    expr_argument(this, 3)
+  }
 }
 
 /**
diff --git a/csharp/ql/test/library-tests/csharp7.2/InArguments.expected b/csharp/ql/test/library-tests/csharp7.2/InArguments.expected
@@ -0,0 +1 @@
+| csharp72.cs:18:12:18:12 | access to local variable s |
diff --git a/csharp/ql/test/library-tests/csharp7.2/InArguments.ql b/csharp/ql/test/library-tests/csharp7.2/InArguments.ql
@@ -0,0 +1,5 @@
+import csharp
+
+from AssignableAccess e
+where e.isInArgument()
+select e
diff --git a/csharp/ql/test/library-tests/csharp7.2/NumericLiterals.expected b/csharp/ql/test/library-tests/csharp7.2/NumericLiterals.expected
@@ -1,2 +1,2 @@
-| csharp72.cs:42:23:42:34 | 85 |
-| csharp72.cs:47:31:47:31 | 1 |
+| csharp72.cs:48:23:48:34 | 85 |
+| csharp72.cs:53:31:53:31 | 1 |
diff --git a/csharp/ql/test/library-tests/csharp7.2/PrivateProtected.expected b/csharp/ql/test/library-tests/csharp7.2/PrivateProtected.expected
@@ -1,2 +1,2 @@
-| csharp72.cs:47:27:47:27 | X |
-| csharp72.cs:49:28:49:28 | F |
+| csharp72.cs:53:27:53:27 | X |
+| csharp72.cs:55:28:55:28 | F |
diff --git a/csharp/ql/test/library-tests/csharp7.2/ReadonlyStructs.expected b/csharp/ql/test/library-tests/csharp7.2/ReadonlyStructs.expected
@@ -1,2 +1,2 @@
-| csharp72.cs:28:17:28:30 | ReadonlyStruct |
-| csharp72.cs:36:21:36:37 | ReadonlyRefStruct |
+| csharp72.cs:34:17:34:30 | ReadonlyStruct |
+| csharp72.cs:42:21:42:37 | ReadonlyRefStruct |
diff --git a/csharp/ql/test/library-tests/csharp7.2/RefReadonlyDelegate.expected b/csharp/ql/test/library-tests/csharp7.2/RefReadonlyDelegate.expected
@@ -1 +1 @@
-| csharp72.cs:25:31:25:33 | Del |
+| csharp72.cs:31:31:31:33 | Del |
diff --git a/csharp/ql/test/library-tests/csharp7.2/RefReadonlyReturns.expected b/csharp/ql/test/library-tests/csharp7.2/RefReadonlyReturns.expected
@@ -1 +1 @@
-| csharp72.cs:20:22:20:22 | F |
+| csharp72.cs:26:22:26:22 | F |
diff --git a/csharp/ql/test/library-tests/csharp7.2/RefStructs.expected b/csharp/ql/test/library-tests/csharp7.2/RefStructs.expected
@@ -1,2 +1,2 @@
-| csharp72.cs:32:12:32:20 | RefStruct |
-| csharp72.cs:36:21:36:37 | ReadonlyRefStruct |
+| csharp72.cs:38:12:38:20 | RefStruct |
+| csharp72.cs:42:21:42:37 | ReadonlyRefStruct |
diff --git a/csharp/ql/test/library-tests/csharp7.2/csharp72.cs b/csharp/ql/test/library-tests/csharp7.2/csharp72.cs
@@ -11,6 +11,12 @@ struct S
     void F(in S s)
     {
     }
+
+    void CallF()
+    {
+      var s = new S();
+      F(in s);
+    }
 }
 
 class RefReadonlyReturns

Original file line number	Diff line number	Diff line change
`@@ -174,6 +174,14 @@ class AssignableAccess extends Access, @assignable_access_expr {`
`174`	`174`	`isOutArgument() or`
`175`	`175`	`isRefArgument()`
`176`	`176`	`}`
	`177`	`+`
	`178`	`+ /**`
	`179`	+ * Holds if this access passes the assignable being accessed as an `in`
	`180`	`+ * argument in a method call.`
	`181`	`+ */`
	`182`	`+ predicate isInArgument() {`
	`183`	`+ expr_argument(this, 3)`
	`184`	`+ }`
`177`	`185`	`}`
`178`	`186`
`179`	`187`	`/**`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+\| csharp72.cs:18:12:18:12 \| access to local variable s \|`
Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-\| csharp72.cs:25:31:25:33 \| Del \|`
	`1`	`+\| csharp72.cs:31:31:31:33 \| Del \|`
Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-\| csharp72.cs:20:22:20:22 \| F \|`
	`1`	`+\| csharp72.cs:26:22:26:22 \| F \|`