Ruby: Restrict CfgScope

Author: hvitved

ruby/ql/lib/codeql/ruby/controlflow/internal/ControlFlowGraphImpl.qll

@@ -76,12 +76,16 @@ abstract class CfgScopeImpl extends AstNode {
 }
 
 private class ToplevelScope extends CfgScopeImpl, Toplevel {
+  ToplevelScope() { exists(this.getAStmt()) }
+
   final override predicate entry(AstNode first) { first(this, first) }
 
   final override predicate exit(AstNode last, Completion c) { last(this, last, c) }
 }
 
 private class EndBlockScope extends CfgScopeImpl, EndBlock {
+  EndBlockScope() { exists(this.getAStmt()) }
+
   final override predicate entry(AstNode first) {
     first(this.(Trees::EndBlockTree).getBodyChild(0, _), first)
   }
@@ -95,6 +99,8 @@ private class EndBlockScope extends CfgScopeImpl, EndBlock {
 }
 
 private class BodyStmtCallableScope extends CfgScopeImpl, AstInternal::TBodyStmt, Callable {
+  BodyStmtCallableScope() { exists(this.getAStmt()) }
+
   final override predicate entry(AstNode first) { this.(Trees::BodyStmtTree).firstInner(first) }
 
   final override predicate exit(AstNode last, Completion c) {
@@ -103,6 +109,8 @@ private class BodyStmtCallableScope extends CfgScopeImpl, AstInternal::TBodyStmt
 }
 
 private class BraceBlockScope extends CfgScopeImpl, BraceBlock {
+  BraceBlockScope() { exists(this.getAStmt()) }
+
   final override predicate entry(AstNode first) {
     first(this.(Trees::BraceBlockTree).getBodyChild(0, _), first)
   }