C++: Require orphaned variables when computing compiler-generated initializers.

Author: MathiasVP

cpp/ql/lib/semmle/code/cpp/Initializer.qll

@@ -56,5 +56,13 @@ class Initializer extends ControlFlowNode, @initialiser {
   predicate isBraced() { braced_initialisers(underlyingElement(this)) }
 
   /** Holds if this initializer is generated by the compiler. */
-  predicate isCompilerGenerated() { this.getDeclaration().(Variable).isCompilerGenerated() }
+  predicate isCompilerGenerated() {
+    exists(Variable v |
+      v = this.getDeclaration() and
+      // We require the variable to be an orphan to not mark the initializer
+      // from a desugared ranged for loop as compiler generated.
+      orphaned_variables(unresolveElement(v), _) and
+      v.isCompilerGenerated()
+    )
+  }
 }

cpp/ql/test/library-tests/compiler_generated/compilerGenerated.expected

@@ -32,21 +32,15 @@
 | cpp.cpp:31:5:33:5 | declaration | Stmt |
 | cpp.cpp:31:5:33:5 | declaration | Stmt |
 | cpp.cpp:31:17:31:18 | (reference to) | Expr |
-| cpp.cpp:31:17:31:18 | vs | Expr |
 | cpp.cpp:34:1:34:1 | return ... | Stmt |
 | file://:0:0:0:0 | (__begin) | Expr |
 | file://:0:0:0:0 | (__begin) | Expr |
 | file://:0:0:0:0 | (__begin) | Expr |
 | file://:0:0:0:0 | (__end) | Expr |
-| file://:0:0:0:0 | (__range) | Expr |
 | file://:0:0:0:0 | (reference dereference) | Expr |
 | file://:0:0:0:0 | (reference dereference) | Expr |
 | file://:0:0:0:0 | * ... | Expr |
-| file://:0:0:0:0 | ... + ... | Expr |
 | file://:0:0:0:0 | array to pointer conversion | Expr |
 | file://:0:0:0:0 | array to pointer conversion | Expr |
-| file://:0:0:0:0 | initializer for (__begin) | Initializer |
-| file://:0:0:0:0 | initializer for (__end) | Initializer |
-| file://:0:0:0:0 | initializer for (__range) | Initializer |
 | file://:0:0:0:0 | operator delete | Function |
 | file://:0:0:0:0 | operator new | Function |