C++: Add missing parent scope cases

Author: jketema

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

@@ -129,7 +129,7 @@ class Element extends ElementBase {
    * or certain kinds of `Statement`.
    */
   Element getParentScope() {
-    // result instanceof class
+    // result instanceof Class
     exists(Declaration m |
       m = this and
       result = m.getDeclaringType() and
@@ -138,31 +138,40 @@ class Element extends ElementBase {
     or
     exists(TemplateClass tc | this = tc.getATemplateArgument() and result = tc)
     or
-    // result instanceof namespace
+    // result instanceof Namespace
     exists(Namespace n | result = n and n.getADeclaration() = this)
     or
     exists(FriendDecl d, Namespace n | this = d and n.getADeclaration() = d and result = n)
     or
     exists(Namespace n | this = n and result = n.getParentNamespace())
     or
-    // result instanceof stmt
+    // result instanceof Stmt
     exists(LocalVariable v |
       this = v and
       exists(DeclStmt ds | ds.getADeclaration() = v and result = ds.getParent())
     )
     or
-    exists(Parameter p | this = p and result = p.getFunction())
+    exists(Parameter p |
+      this = p and
+      (
+        result = p.getFunction() or
+        result = p.getCatchBlock().getParent().(Handler).getParent().(TryStmt).getParent() or
+        result = p.getRequiresExpr().getEnclosingStmt().getParent()
+      )
+    )
     or
     exists(GlobalVariable g, Namespace n | this = g and n.getADeclaration() = g and result = n)
     or
+    exists(TemplateVariable tv | this = tv.getATemplateArgument() and result = tv)
+    or
     exists(EnumConstant e | this = e and result = e.getDeclaringEnum())
     or
-    // result instanceof block|function
+    // result instanceof Block|Function
     exists(BlockStmt b | this = b and blockscope(unresolveElement(b), unresolveElement(result)))
     or
     exists(TemplateFunction tf | this = tf.getATemplateArgument() and result = tf)
     or
-    // result instanceof stmt
+    // result instanceof Stmt
     exists(ControlStructure s | this = s and result = s.getParent())
     or
     using_container(unresolveElement(result), underlyingElement(this))

cpp/ql/test/library-tests/scopes/parents/parents.cpp

@@ -14,6 +14,13 @@ namespace foo {
   }
 }
 
+template<typename T>
+T var = 42;
 
-                        
+int g() {
+  requires(int l) { l; };
 
+  return var<int>;
+}
+
+// semmle-extractor-options: -std=c++20

cpp/ql/test/library-tests/scopes/parents/parents.expected

@@ -1,5 +1,8 @@
 | 0 | file://:0:0:0:0 | (global namespace) | file://:0:0:0:0 | __va_list_tag |
 | 0 | file://:0:0:0:0 | (global namespace) | parents.cpp:2:11:2:13 | foo |
+| 0 | file://:0:0:0:0 | (global namespace) | parents.cpp:18:3:18:3 | var |
+| 0 | file://:0:0:0:0 | (global namespace) | parents.cpp:18:7:18:7 | var |
+| 0 | file://:0:0:0:0 | (global namespace) | parents.cpp:20:5:20:5 | g |
 | 1 | file://:0:0:0:0 | __va_list_tag | file://:0:0:0:0 | fp_offset |
 | 1 | file://:0:0:0:0 | __va_list_tag | file://:0:0:0:0 | gp_offset |
 | 1 | file://:0:0:0:0 | __va_list_tag | file://:0:0:0:0 | operator= |
@@ -14,7 +17,11 @@
 | 1 | parents.cpp:4:10:4:10 | f | parents.cpp:4:19:13:5 | { ... } |
 | 1 | parents.cpp:4:19:13:5 | { ... } | parents.cpp:5:11:5:11 | j |
 | 1 | parents.cpp:4:19:13:5 | { ... } | parents.cpp:6:11:10:7 | { ... } |
+| 1 | parents.cpp:4:19:13:5 | { ... } | parents.cpp:11:18:11:18 | e |
 | 1 | parents.cpp:4:19:13:5 | { ... } | parents.cpp:11:21:12:7 | { ... } |
 | 1 | parents.cpp:6:11:10:7 | { ... } | parents.cpp:7:9:9:9 | for(...;...;...) ... |
 | 1 | parents.cpp:6:11:10:7 | { ... } | parents.cpp:7:33:9:9 | { ... } |
 | 1 | parents.cpp:7:33:9:9 | { ... } | parents.cpp:8:15:8:15 | k |
+| 1 | parents.cpp:18:7:18:7 | var | parents.cpp:17:19:17:19 | T |
+| 1 | parents.cpp:20:5:20:5 | g | parents.cpp:20:9:24:1 | { ... } |
+| 1 | parents.cpp:20:9:24:1 | { ... } | parents.cpp:21:16:21:16 | l |