From 7eced7335a1f0bc8375d8b84a606dd1456546ac1 Mon Sep 17 00:00:00 2001
From: Wolfgang Thaller <wolfgang.thaller@gmx.net>
Date: Sun, 23 Dec 2018 12:02:36 +0100
Subject: [PATCH] work around bison 3.2 bug (fixes #72)

---
 Rez/RezParser.yy      | 13 ++++++++++++-
 Rez/Test/UnitTests.cc | 22 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/Rez/RezParser.yy b/Rez/RezParser.yy
index 7563a33036..e7f5259ef0 100644
--- a/Rez/RezParser.yy
+++ b/Rez/RezParser.yy
@@ -118,7 +118,18 @@
 	{
 	public:
 		RezSymbol() = default;
-		RezSymbol(yy::RezParser::symbol_type&& x) : yy::RezParser::symbol_type(std::move(x)) {}
+		
+		// Bison 3.2 has a bug in the move constructor for basic_symbol<by_type>.
+		// Bison-generated code uses only basic_symbol<by_type>::move, which
+		// works without crashing.
+		RezSymbol(yy::RezParser::symbol_type&& x)
+		{
+			move(x);
+		}
+		RezSymbol(RezSymbol&& x)
+		{
+			move(x);
+		}
 	};
 }
 
diff --git a/Rez/Test/UnitTests.cc b/Rez/Test/UnitTests.cc
index a172a34710..fee01c864c 100644
--- a/Rez/Test/UnitTests.cc
+++ b/Rez/Test/UnitTests.cc
@@ -25,6 +25,28 @@ BOOST_AUTO_TEST_SUITE(LexSuite)
 		BOOST_CHECK_EQUAL(t.token(), TOKEN);	\
 	} while(0)
 
+BOOST_AUTO_TEST_CASE(moveBisonSymbol)
+{
+	// Bison 3.2 contains a bug in the move constructor for its symbol type.
+	// It will crash when used.
+	// Unfortunately, there is no copy constructor any more, so it's hard to avoid.
+	std::string filename = "foo";
+	yy::location loc(&filename, 0,0);
+	auto sym = RezParser::make_INTLIT(42, loc);
+	auto sym2 = std::move(sym);
+}
+
+BOOST_AUTO_TEST_CASE(moveRezSymbol)
+{
+	// This tests my workaround for the bison bug;
+	// RezSymbol derives from bison's symbol type and reimplements all move constructors
+	std::string filename = "foo";
+	yy::location loc(&filename, 0,0);
+	RezSymbol sym = RezParser::make_INTLIT(42, loc);
+	auto sym2 = std::move(sym);
+}
+
+
 BOOST_AUTO_TEST_CASE(basicInt)
 {
 	RezWorld world;