From 56425bb2b1cb9937b7c7a6baaee5ddcdd1f2e3d1 Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Wed, 17 Oct 2018 22:07:05 +0200
Subject: [PATCH 1/2] Add a test for delete x.length

---
 test/libsolidity/SolidityEndToEndTest.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index 7a496e643..7f865aa11 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -1787,6 +1787,24 @@ BOOST_AUTO_TEST_CASE(deleteLocals)
 	ABI_CHECK(callContractFunction("delLocal()"), encodeArgs(6, 7));
 }
 
+BOOST_AUTO_TEST_CASE(deleteLength)
+{
+	char const* sourceCode = R"(
+		contract test {
+			uint[] x;
+			function f() public returns (uint){
+				x.length = 1;
+				x[0] = 1;
+				delete x.length;
+				return x.length;
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+	ABI_CHECK(callContractFunction("f()"), encodeArgs(0));
+	BOOST_CHECK(storageEmpty(m_contractAddress));
+}
+
 BOOST_AUTO_TEST_CASE(constructor)
 {
 	char const* sourceCode = R"(

From c14dfeb8c5ffcc15cff1014a39ffa425aee1430a Mon Sep 17 00:00:00 2001
From: chriseth <chris@ethereum.org>
Date: Wed, 17 Oct 2018 22:17:33 +0200
Subject: [PATCH 2/2] Removed unreachable cases in LValue.cpp.

---
 libsolidity/codegen/LValue.cpp | 49 +++++-----------------------------
 1 file changed, 7 insertions(+), 42 deletions(-)

diff --git a/libsolidity/codegen/LValue.cpp b/libsolidity/codegen/LValue.cpp
index 776846832..790ab309e 100644
--- a/libsolidity/codegen/LValue.cpp
+++ b/libsolidity/codegen/LValue.cpp
@@ -134,8 +134,7 @@ void MemoryItem::storeValue(Type const& _sourceType, SourceLocation const&, bool
 void MemoryItem::setToZero(SourceLocation const&, bool _removeReference) const
 {
 	CompilerUtils utils(m_context);
-	if (!_removeReference)
-		m_context << Instruction::DUP1;
+	solAssert(_removeReference, "");
 	utils.pushZeroValue(*m_dataType);
 	utils.storeInMemoryDynamic(*m_dataType, m_padded);
 	m_context << Instruction::POP;
@@ -460,8 +459,7 @@ void StorageByteArrayElement::storeValue(Type const&, SourceLocation const&, boo
 void StorageByteArrayElement::setToZero(SourceLocation const&, bool _removeReference) const
 {
 	// stack: ref byte_number
-	if (!_removeReference)
-		m_context << Instruction::DUP2 << Instruction::DUP2;
+	solAssert(_removeReference, "");
 	m_context << u256(31) << Instruction::SUB << u256(0x100) << Instruction::EXP;
 	// stack: ref (1<<(8*(31-byte_number)))
 	m_context << Instruction::DUP2 << Instruction::SLOAD;
@@ -498,8 +496,7 @@ void StorageArrayLength::storeValue(Type const&, SourceLocation const&, bool _mo
 
 void StorageArrayLength::setToZero(SourceLocation const&, bool _removeReference) const
 {
-	if (!_removeReference)
-		m_context << Instruction::DUP1;
+	solAssert(_removeReference, "");
 	ArrayUtils(m_context).clearDynamicArray(m_arrayType);
 }
 
@@ -521,24 +518,9 @@ unsigned TupleObject::sizeOnStack() const
 	return size;
 }
 
-void TupleObject::retrieveValue(SourceLocation const& _location, bool _remove) const
+void TupleObject::retrieveValue(SourceLocation const&, bool) const
 {
-	unsigned initialDepth = sizeOnStack();
-	unsigned initialStack = m_context.stackHeight();
-	for (auto const& lv: m_lvalues)
-		if (lv)
-		{
-			solAssert(initialDepth + m_context.stackHeight() >= initialStack, "");
-			unsigned depth = initialDepth + m_context.stackHeight() - initialStack;
-			if (lv->sizeOnStack() > 0)
-			{
-				if (_remove && depth > lv->sizeOnStack())
-					CompilerUtils(m_context).moveToStackTop(depth, depth - lv->sizeOnStack());
-				else if (!_remove && depth > 0)
-					CompilerUtils(m_context).copyToStackTop(depth, lv->sizeOnStack());
-			}
-			lv->retrieveValue(_location, true);
-		}
+	solAssert(false, "Tried to retrieve value of tuple.");
 }
 
 void TupleObject::storeValue(Type const& _sourceType, SourceLocation const& _location, bool) const
@@ -569,24 +551,7 @@ void TupleObject::storeValue(Type const& _sourceType, SourceLocation const& _loc
 	CompilerUtils(m_context).popStackElement(_sourceType);
 }
 
-void TupleObject::setToZero(SourceLocation const& _location, bool _removeReference) const
+void TupleObject::setToZero(SourceLocation const&, bool) const
 {
-	if (_removeReference)
-	{
-		for (size_t i = 0; i < m_lvalues.size(); ++i)
-			if (m_lvalues[m_lvalues.size() - i])
-				m_lvalues[m_lvalues.size() - i]->setToZero(_location, true);
-	}
-	else
-	{
-		unsigned depth = sizeOnStack();
-		for (auto const& val: m_lvalues)
-			if (val)
-			{
-				if (val->sizeOnStack() > 0)
-					CompilerUtils(m_context).copyToStackTop(depth, val->sizeOnStack());
-				val->setToZero(_location, false);
-				depth -= val->sizeOnStack();
-			}
-	}
+	solAssert(false, "Tried to delete tuple.");
 }