Merge branch 'main' into literals

ql/src/codeql_ruby/ast/Pattern.qll

@@ -14,6 +14,26 @@ class Pattern extends AstNode {
   Variable getAVariable() { result = range.getAVariable() }
 }
 
+/**
+ * A "left-hand-side" expression. An `LhsExpr` can occur on the left-hand side of
+ * operator assignments (`AssignOperation`), in patterns (`Pattern`) on the left-hand side of
+ * an assignment (`AssignExpr`) or for loop (`ForExpr`), and as the exception
+ * variable of a `rescue` clause (`RescueClause`).
+ *
+ * An `LhsExpr` can be a simple variable, a constant, a call, or an element reference:
+ * ```rb
+ * var = 1
+ * var += 1
+ * E = 1
+ * foo.bar = 1
+ * foo[0] = 1
+ * rescue E => var
+ * ```
+ */
+class LhsExpr extends Pattern, Expr {
+  override LhsExpr::Range range;
+}
+
 /** A simple variable pattern. */
 class VariablePattern extends Pattern {
   override VariablePattern::Range range;
@@ -25,7 +45,12 @@ class VariablePattern extends Pattern {
 /**
  * A tuple pattern.
  *
- * This includes both tuple patterns in parameters and assignments.
+ * This includes both tuple patterns in parameters and assignments. Example patterns:
+ * ```rb
+ * a, self.b = value
+ * (a, b), c[3] = value
+ * a, b, *rest, c, d = value
+ * ```
  */
 class TuplePattern extends Pattern {
   override TuplePattern::Range range;
@@ -35,4 +60,13 @@ class TuplePattern extends Pattern {
 
   /** Gets a sub pattern in this tuple pattern. */
   final Pattern getAnElement() { result = this.getElement(_) }
+
+  /**
+   * Gets the index of the pattern with the `*` marker on it, if it exists.
+   * In the example below the index is `2`.
+   * ```rb
+   * a, b, *rest, c, d = value
+   * ```
+   */
+  final int getRestIndex() { result = range.getRestIndex() }
 }

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

@@ -29,8 +29,6 @@ module AstNode {
       or
       this instanceof Generated::RestAssignment
       or
-      this = any(Generated::RestAssignment ra).getChild()
-      or
       this instanceof Generated::Superclass
       or
       this instanceof Generated::HeredocBody

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

@@ -57,13 +57,15 @@ module ConstantWriteAccess {
 }
 
 module ConstantAssignment {
-  abstract class Range extends ConstantWriteAccess::Range { }
+  abstract class Range extends ConstantWriteAccess::Range, LhsExpr::Range {
+    Range() { explicitAssignmentNode(this, _) }
+
+    override string toString() { result = ConstantWriteAccess::Range.super.toString() }
+  }
 
   private class TokenConstantAssignmentRange extends ConstantAssignment::Range, @token_constant {
     final override Generated::Constant generated;
 
-    TokenConstantAssignmentRange() { explicitAssignmentNode(this, _) }
-
     final override string getName() { result = generated.getValue() }
 
     final override Expr::Range getScopeExpr() { none() }
@@ -75,10 +77,7 @@ module ConstantAssignment {
     final override Generated::ScopeResolution generated;
     Generated::Constant constant;
 
-    ScopeResolutionAssignmentRange() {
-      constant = generated.getName() and
-      explicitAssignmentNode(this, _)
-    }
+    ScopeResolutionAssignmentRange() { constant = generated.getName() }
 
     final override string getName() { result = constant.getValue() }
 

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

@@ -123,7 +123,7 @@ module RescueClause {
   class Range extends Expr::Range, @rescue {
     final override Generated::Rescue generated;
 
-    final Expr getException(int n) { result = generated.getExceptions().getChild(n) }
+    final LhsExpr getException(int n) { result = generated.getExceptions().getChild(n) }
 
     final Expr getVariableExpr() { result = generated.getVariable() }
 

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

@@ -246,7 +246,7 @@ module AssignOperation {
 
     final override string getOperator() { result = generated.getOperator() }
 
-    final override Expr getLhs() { result = generated.getLeft() }
+    final override LhsExpr getLhs() { result = generated.getLeft() }
 
     final override Expr getRhs() { result = generated.getRight() }
   }

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

@@ -1,6 +1,7 @@
 private import codeql_ruby.AST
 private import TreeSitter
 private import codeql_ruby.ast.internal.AST
+private import codeql_ruby.ast.internal.Expr
 private import codeql_ruby.ast.internal.Variable
 private import codeql_ruby.ast.internal.Method
 private import codeql.Locations
@@ -20,6 +21,8 @@ predicate explicitAssignmentNode(Generated::AstNode n, Generated::AstNode assign
     parent instanceof Generated::DestructuredLeftAssignment
     or
     parent instanceof Generated::LeftAssignmentList
+    or
+    parent instanceof Generated::RestAssignment
   )
 }
 
@@ -40,7 +43,7 @@ predicate implicitParameterAssignmentNode(Generated::AstNode n, Callable::Range
 }
 
 module Pattern {
-  class Range extends AstNode::Range {
+  abstract class Range extends AstNode::Range {
     cached
     Range() {
       explicitAssignmentNode(this, _)
@@ -56,8 +59,12 @@ module Pattern {
   }
 }
 
+module LhsExpr {
+  abstract class Range extends Pattern::Range, Expr::Range { }
+}
+
 module VariablePattern {
-  class Range extends Pattern::Range, @token_identifier {
+  class Range extends LhsExpr::Range, @token_identifier {
     override Generated::Identifier generated;
 
     string getVariableName() { result = generated.getValue() }
@@ -74,6 +81,14 @@ module TuplePattern {
 
   class Range extends Pattern::Range, Range_ {
     Pattern::Range getElement(int i) {
+      exists(Generated::AstNode c | c = getChild(i) |
+        result = c.(Generated::RestAssignment).getChild()
+        or
+        not c instanceof Generated::RestAssignment and result = c
+      )
+    }
+
+    private Generated::AstNode getChild(int i) {
       result = this.(Generated::DestructuredParameter).getChild(i)
       or
       result = this.(Generated::DestructuredLeftAssignment).getChild(i)
@@ -81,6 +96,8 @@ module TuplePattern {
       result = this.(Generated::LeftAssignmentList).getChild(i)
     }
 
+    int getRestIndex() { result = unique(int i | getChild(i) instanceof Generated::RestAssignment) }
+
     override Variable getAVariable() { result = this.getElement(_).getAVariable() }
 
     override string toString() { result = "(..., ...)" }