Address review comments

ql/src/codeql_ruby/controlflow/BasicBlocks.qll

@@ -1,6 +1,6 @@
 /** Provides classes representing basic blocks. */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import codeql_ruby.controlflow.ControlFlowGraph
 private import internal.ControlFlowGraphImpl
 private import SuccessorTypes

ql/src/codeql_ruby/controlflow/ControlFlowGraph.qll

@@ -1,24 +1,26 @@
 /** Provides classes representing the control flow graph. */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import codeql_ruby.controlflow.BasicBlocks
 private import SuccessorTypes
 private import internal.ControlFlowGraphImpl
 private import internal.Splitting
 private import internal.Completion
 
+private class CfgScopeRange = @method or @block or @do_block;
+
 /** An AST node with an associated control-flow graph. */
-class CfgScope extends AstNode {
-  private string name;
-
-  CfgScope() {
-    name = this.(Method).getName().toString()
-    or
-    this = any(MethodCall mc | name = "block for " + mc.getMethod()).getBlock()
-  }
-
+class CfgScope extends AstNode, CfgScopeRange {
   /** Gets the name of this scope. */
-  string getName() { result = name }
+  string getName() {
+    result = this.(Method).getName().toString()
+    or
+    this instanceof Block and
+    result = "block"
+    or
+    this instanceof DoBlock and
+    result = "do block"
+  }
 }
 
 /**
@@ -276,6 +278,30 @@ module SuccessorTypes {
     final override string toString() { result = "redo" }
   }
 
+  /**
+   * A `retry` control flow successor.
+   *
+   * Example:
+   *
+   * Example:
+   *
+   * ```rb
+   * def m
+   *   begin
+   *     puts "Retry"
+   *     raise
+   *   rescue
+   *     retry
+   *   end
+   * end
+   * ```
+   *
+   * The node `puts "Retry"` is `retry` successor of the node `retry`.
+   */
+  class RetrySuccessor extends SuccessorType, TRetrySuccessor {
+    final override string toString() { result = "retry" }
+  }
+
   /**
    * An exceptional control flow successor.
    *

ql/src/codeql_ruby/controlflow/internal/AstNodes.qll

@@ -3,7 +3,7 @@
  * will likely be part of the hand-written user-facing AST layer.
  */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 
 class LogicalNotAstNode extends Unary {
   AstNode operand;

ql/src/codeql_ruby/controlflow/internal/Completion.qll

@@ -4,7 +4,7 @@
  * A completion represents how a statement or expression terminates.
  */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import codeql_ruby.controlflow.ControlFlowGraph
 private import AstNodes
 private import NonReturning
@@ -17,6 +17,7 @@ private newtype TCompletion =
   TBreakCompletion() or
   TNextCompletion() or
   TRedoCompletion() or
+  TRetryCompletion() or
   TRaiseCompletion() or // TODO: Add exception type?
   TExitCompletion() or
   TNestedCompletion(Completion inner, Completion outer) {
@@ -220,6 +221,16 @@ class RedoCompletion extends Completion, TRedoCompletion {
   override string toString() { result = "redo" }
 }
 
+/**
+ * A completion that represents evaluation of a statement or an
+ * expression resulting in a retry.
+ */
+class RetryCompletion extends Completion, TRetryCompletion {
+  override RetrySuccessor getAMatchingSuccessorType() { any() }
+
+  override string toString() { result = "retry" }
+}
+
 /**
  * A completion that represents evaluation of a statement or an
  * expression resulting in a thrown exception.

ql/src/codeql_ruby/controlflow/internal/Consistency.qll

@@ -1,7 +1,7 @@
-import codeql_ruby.ast
-import codeql_ruby.controlflow.ControlFlowGraph
-import Completion
-import Splitting
+private import codeql_ruby.ast
+private import codeql_ruby.controlflow.ControlFlowGraph
+private import Completion
+private import Splitting
 
 query predicate nonUniqueSetRepresentation(Splits s1, Splits s2) {
   forex(Split s | s = s1.getASplit() | s = s2.getASplit()) and

ql/src/codeql_ruby/controlflow/internal/ControlFlowGraphImpl.qll

@@ -31,7 +31,7 @@
  * caught up by its surrounding loop and turned into a `NormalCompletion`.
  */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import AstNodes
 private import codeql_ruby.controlflow.ControlFlowGraph
 private import Completion
@@ -501,6 +501,7 @@ private module Cached {
     TBreakSuccessor() or
     TNextSuccessor() or
     TRedoSuccessor() or
+    TRetrySuccessor() or
     TRaiseSuccessor() or // TODO: Add exception type?
     TExitSuccessor()
 

ql/src/codeql_ruby/controlflow/internal/NonReturning.qll

@@ -1,6 +1,6 @@
 /** Provides a simple analysis for identifying calls that will not return. */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import Completion
 
 /** A call that definitely does not return (conservative analysis). */

ql/src/codeql_ruby/controlflow/internal/Splitting.qll

@@ -2,7 +2,7 @@
  * Provides classes and predicates relevant for splitting the control flow graph.
  */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 private import AstNodes
 private import Completion
 private import ControlFlowGraphImpl

ql/src/codeql_ruby/printAst.qll

@@ -6,7 +6,7 @@
  * to hold for only the AST nodes you wish to view.
  */
 
-import codeql_ruby.ast
+private import codeql_ruby.ast
 
 /**
  * The query can extend this class to control which nodes are printed.