AST: add Self class

ql/src/codeql_ruby/ast/Expr.qll

@@ -12,6 +12,18 @@ class Expr extends Stmt {
   Expr() { this = range }
 }
 
+/**
+ * A reference to the current object. For example:
+ * - `self == other`
+ * - `self.method_name`
+ * - `def self.method_name ... end`
+ */
+class Self extends Expr, @token_self {
+  override Self::Range range;
+
+  final override string getAPrimaryQlClass() { result = "Self" }
+}
+
 /**
  * A literal.
  *

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

@@ -47,8 +47,6 @@ module AstNode {
       or
       this instanceof Generated::BareString
       or
-      this instanceof Generated::Self
-      or
       this instanceof Generated::Float
       or
       this instanceof Generated::Superclass

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

@@ -6,6 +6,14 @@ module Expr {
   abstract class Range extends Stmt::Range { }
 }
 
+module Self {
+  class Range extends Expr::Range, @token_self {
+    final override Generated::Self generated;
+
+    final override string toString() { result = "self" }
+  }
+}
+
 module Literal {
   abstract class Range extends Expr::Range {
     abstract string getValueText();

ql/test/library-tests/ast/calls/calls.expected

@@ -74,7 +74,6 @@ callsWithNoReceiverArgumentsOrBlock
 | calls.rb:286:5:286:9 | call to super | super |
 | calls.rb:287:5:287:11 | call to super | super |
 | calls.rb:303:5:303:7 | call to foo | foo |
-| calls.rb:304:5:304:14 | call to super | super |
 | calls.rb:305:5:305:9 | call to super | super |
 callsWithArguments
 | calls.rb:14:1:14:11 | call to foo | foo | 0 | calls.rb:14:5:14:5 | 0 |
@@ -174,6 +173,7 @@ callsWithReceiver
 | calls.rb:275:7:275:12 | call to bar | calls.rb:275:7:275:7 | X |
 | calls.rb:279:11:279:16 | call to bar | calls.rb:279:11:279:11 | X |
 | calls.rb:303:5:303:13 | call to super | calls.rb:303:5:303:7 | call to foo |
+| calls.rb:304:5:304:14 | call to super | calls.rb:304:5:304:8 | self |
 | calls.rb:305:5:305:15 | call to super | calls.rb:305:5:305:9 | call to super |
 callsWithBlock
 | calls.rb:17:1:17:17 | call to foo | calls.rb:17:5:17:17 | { ... } |

ql/test/library-tests/ast/calls/calls.rb

@@ -301,7 +301,7 @@ end
 class AnotherClass
   def another_method
     foo.super
-    self.super # TODO: this shows up as a call without a receiver, but that should be fixed once we handle `self` expressions
+    self.super
     super.super # we expect the receiver to be a SuperCall, while the outer call should not (it's just a regular Call)
   end
-end
+end