commit 8ad67a72a4fa59efffc891e73ecf10020e3c565d
author Cherry Zhang <cherryyz@google.com> Mon Jul 09 16:06:35 2018 -0400
committer Ian Lance Taylor <iant@golang.org> Tue Jul 10 00:54:32 2018 +0000
tree 9331ec37492cce5bc21689ac2d96ade558821396
parent 94738979a3422e845acf358a766aabf8b9275d43

compiler: fix double evaluation with interface field expression

In Interface_field_reference_expression, the interface expression
is used in two places, so a temporary variable is used. Previously,
we used a Set_and_use_temporary_expression, which, when evaluated
twice, causes double evaluation of the underlying expression. Fix
by setting the temporary once and use Temporary_reference_expression
instead.

Fixes golang/go#26248.

Change-Id: Ieec464201a5498c3c8c4a1751c3bb79f4a2b515c
Reviewed-on: https://go-review.googlesource.com/122756
Reviewed-by: Ian Lance Taylor <iant@golang.org>

go/expressions.cc

diff --git a/go/expressions.cc b/go/expressions.cc
index 75b8b69..89b265b 100644
--- a/go/expressions.cc
+++ b/go/expressions.cc
@@ -11886,10 +11886,9 @@
   if (!this->expr_->is_variable())
     {
       Temporary_statement* temp =
-	Statement::make_temporary(this->expr_->type(), NULL, this->location());
+	Statement::make_temporary(NULL, this->expr_, this->location());
       inserter->insert(temp);
-      this->expr_ = Expression::make_set_and_use_temporary(temp, this->expr_,
-							   this->location());
+      this->expr_ = Expression::make_temporary_reference(temp, this->location());
     }
   return this;
 }