AST: rescue modifier

ql/src/codeql_ruby/ast/Expr.qll

@@ -229,6 +229,8 @@ class Pair extends Expr, @pair {
 class Rescue extends Expr, @rescue {
   final override Rescue::Range range;
 
+  final override string getAPrimaryQlClass() { result = "Rescue" }
+
   /**
    * Gets the `n`th exception to match, if any. For example `FirstError` or `SecondError` in:
    * ```rb
@@ -271,3 +273,31 @@ class Rescue extends Expr, @rescue {
    */
   final StmtSequence getBody() { result = range.getBody() }
 }
+
+/**
+ * An expression with a `rescue` modifier. For example:
+ * ```rb
+ * contents = read_file rescue ""
+ * ```
+ */
+class RescueExpr extends Expr, @rescue_modifier {
+  final override RescueExpr::Range range;
+
+  final override string getAPrimaryQlClass() { result = "RescueExpr" }
+
+  /**
+   * Gets the body of this `RescueExpr`.
+   * ```rb
+   * body rescue handler
+   * ```
+   */
+  final Stmt getBody() { result = range.getBody() }
+
+  /**
+   * Gets the exception handler of this `RescueExpr`.
+   * ```rb
+   * body rescue handler
+   * ```
+   */
+  final Stmt getHandler() { result = range.getHandler() }
+}

ql/src/codeql_ruby/ast/internal/AST.qll

@@ -69,8 +69,6 @@ module AstNode {
       or
       this instanceof Generated::Rational
       or
-      this instanceof Generated::RescueModifier
-      or
       this instanceof Generated::Subshell
       or
       this instanceof Generated::Undef

ql/src/codeql_ruby/ast/internal/Expr.qll

@@ -290,6 +290,18 @@ module Rescue {
   }
 }
 
+module RescueExpr {
+  class Range extends Expr::Range, @rescue_modifier {
+    final override Generated::RescueModifier generated;
+
+    final Stmt getBody() { result = generated.getBody() }
+
+    final Stmt getHandler() { result = generated.getHandler() }
+
+    final override string toString() { result = "... rescue ..." }
+  }
+}
+
 module Pair {
   class Range extends Expr::Range, @pair {
     final override Generated::Pair generated;

ql/test/library-tests/controlflow/graph/Cfg.expected

@@ -1534,7 +1534,7 @@ cfg.rb:
 #-----|  -> Interpolation
 
 #  130| ... = ...
-#-----|  -> RescueModifier
+#-----|  -> ... rescue ...
 
 #  130| Constant
 #-----|  -> ... = ...
@@ -1542,7 +1542,7 @@ cfg.rb:
 #  130| 5
 #-----|  -> Constant
 
-#  133| RescueModifier
+#  133| ... rescue ...
 #-----|  -> 1
 
 #  133| ... / ...