Properly expand macro in ErrorPropagationExpr

gcc/rust/ChangeLog:

	* ast/rust-expr.h
	(ErrorPropagationExpr::get_propagating_expr_ptr): New member
	function.
	* expand/rust-expand-visitor.cc (ExpandVisitor::visit): Call
	maybe_expand_expr on the inner expression owned by an
	ErrorPropagationExpr.

Signed-off-by: Owen Avery <[email protected]>

Author: powerboat9

gcc/rust/ast/rust-expr.h

@@ -488,6 +488,12 @@ class ErrorPropagationExpr : public OperatorExpr
     return *main_or_left_expr;
   }
 
+  std::unique_ptr<Expr> &get_propagating_expr_ptr ()
+  {
+    rust_assert (main_or_left_expr != nullptr);
+    return main_or_left_expr;
+  }
+
   Expr::Kind get_expr_kind () const override
   {
     return Expr::Kind::ErrorPropagation;

gcc/rust/expand/rust-expand-visitor.cc

@@ -544,7 +544,7 @@ ExpandVisitor::visit (AST::MetaItemPathExpr &)
 void
 ExpandVisitor::visit (AST::ErrorPropagationExpr &expr)
 {
-  visit (expr.get_propagating_expr ());
+  maybe_expand_expr (expr.get_propagating_expr_ptr ());
 }
 
 void