Swift: Add a class that's the union of struct and class.

Author: MathiasVP

swift/ql/lib/codeql/swift/elements/decl/ClassOrStructDecl.qll

@@ -0,0 +1,23 @@
+private import codeql.swift.elements.decl.ClassDecl
+private import codeql.swift.elements.decl.StructDecl
+private import codeql.swift.elements.decl.NominalTypeDecl
+
+/**
+ * A `class` or `struct` declaration. For example `MyStruct` or `MyClass` in the following example:
+ * ```swift
+ * struct MyStruct {
+ *   // ...
+ * }
+ *
+ * class MyClass {
+ *   // ...
+ * }
+ * ```
+ */
+class ClassOrStructDecl extends NominalTypeDecl {
+  ClassOrStructDecl() {
+    this instanceof ClassDecl
+    or
+    this instanceof StructDecl
+  }
+}

swift/ql/lib/swift.qll

@@ -4,3 +4,4 @@ import codeql.swift.elements
 import codeql.swift.elements.expr.ArithmeticOperation
 import codeql.swift.elements.expr.LogicalOperation
 import codeql.swift.elements.decl.MethodDecl
+import codeql.swift.elements.decl.ClassOrStructDecl