C++: Update stats to add coroutines

Initial impl won't support it

cpp/ql/src/semmle/code/cpp/exprs/Expr.qll

@@ -1268,3 +1268,32 @@ class SpaceshipExpr extends BinaryOperation, @spaceshipexpr {
 
   override string getOperator() { result = "<=>" }
 }
+
+/**
+ * A C/C++ co_await expression
+ * ```
+ * co_await foo();
+ * ```
+ */
+class CoAwaitExpr extends UnaryOperation, @co_await {
+  override string getAPrimaryQlClass() { result = "CoAwaitExpr" }
+
+  override string getOperator() { result = "co_await" }
+
+  override int getPrecedence() { result = 16 }
+}
+
+
+/**
+ * A C/C++ co_yield expression
+ * ```
+ * co_yield 1;
+ * ```
+ */
+class CoYieldExpr extends UnaryOperation, @co_yield {
+  override string getAPrimaryQlClass() { result = "CoYieldExpr" }
+
+  override string getOperator() { result = "co_yield" }
+
+  override int getPrecedence() { result = 2 }
+}

cpp/ql/src/semmle/code/cpp/stmts/Stmt.qll

@@ -662,6 +662,67 @@ class LabelStmt extends Stmt, @stmt_label {
   override predicate mayBeGloballyImpure() { none() }
 }
 
+/**
+ * A C/C++ 'co_return' statement.
+ *
+ * For example:
+ * ```
+ * co_return 1+2;
+ * ```
+ * or
+ * ```
+ * co_return;
+ * ```
+ */
+class CoReturnStmt extends Stmt, @stmt_co_return {
+  override string getAPrimaryQlClass() { result = "CoReturnStmt" }
+
+  /**
+   * Gets the operand of this 'co_return' statement.
+   *
+   * For example, for
+   * ```
+   * co_return 1+2;
+   * ```
+   * the operand is a function call `return_value(1+2)`, and for
+   * ```
+   * co_return;
+   * ```
+   * the operand is a function call `return_void()`.
+   */
+  FunctionCall getOperand() { result = this.getChild(0) }
+
+  /**
+   * Gets the expression of this 'co_return' statement, if any.
+   *
+   * For example, for
+   * ```
+   * co_return 1+2;
+   * ```
+   * the result is `1+2`, and there is no result for
+   * ```
+   * co_return;
+   * ```
+   */
+  Expr getExpr() { result = this.getOperand().getArgument(0) }
+
+  /**
+   * Holds if this 'co_return' statement has an expression.
+   *
+   * For example, this holds for
+   * ```
+   * co_return 1+2;
+   * ```
+   * but not for
+   * ```
+   * co_return;
+   * ```
+   */
+  predicate hasExpr() { exists(this.getExpr()) }
+
+  override string toString() { result = "co_return ..." }
+}
+
 /**
  * A C/C++ 'return' statement.
  *

cpp/ql/src/semmlecode.cpp.dbscheme

@@ -1228,6 +1228,8 @@ funbind(
             | @builtinaddressof
             | @vec_fill
             | @un_log_op_expr
+            | @co_await
+            | @co_yield
             ;
 
 @bin_log_op_expr = @andlogicalexpr | @orlogicalexpr;
@@ -1647,6 +1649,8 @@ case @expr.kind of
 | 324 = @builtinconvertvector
 | 325 = @builtincomplex
 | 326 = @spaceshipexpr
+| 327 = @co_await
+| 328 = @co_yield
 ;
 
 @var_args_expr = @vastartexpr
@@ -1851,6 +1855,7 @@ case @stmt.kind of
 |  33 = @stmt_handler
 // ...  34 @stmt_finally_end deprecated
 |  35 = @stmt_constexpr_if
+|  37 = @stmt_co_return
 ;
 
 type_vla(

cpp/upgrades/098850d25c4e9d417eb74c1bef9deb2f9d2dc417/upgrade.properties

@@ -0,0 +1,3 @@
+description: Add some coroutines types (@co_await, @co_yield, @stmt_co_return)
+compatibility: backwards
+