diff --git a/libsolidity/SolidityNameAndTypeResolution.cpp b/libsolidity/SolidityNameAndTypeResolution.cpp
index 3948a4a23..fced12848 100644
--- a/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -1889,6 +1889,93 @@ BOOST_AUTO_TEST_CASE(storage_location_local_variables)
 	BOOST_CHECK_NO_THROW(parseTextAndResolveNames(sourceCode));
 }
 
+BOOST_AUTO_TEST_CASE(assignment_mem_to_local_storage_variable)
+{
+	char const* sourceCode = R"(
+		contract C {
+			uint[] data;
+			function f(uint[] x) {
+				var dataRef = data;
+				dataRef = x;
+			}
+		}
+	)";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
+}
+
+BOOST_AUTO_TEST_CASE(storage_assign_to_different_local_variable)
+{
+	char const* sourceCode = R"(
+		contract C {
+			uint[] data;
+			uint8[] otherData;
+			function f() {
+				uint8[] storage x = otherData;
+				uint[] storage y = data;
+				y = x;
+				// note that data = otherData works
+			}
+		}
+	)";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
+}
+
+BOOST_AUTO_TEST_CASE(assignment_mem_storage_variable_directly)
+{
+	char const* sourceCode = R"(
+		contract C {
+			uint[] data;
+			function f(uint[] x) {
+				data = x;
+			}
+		}
+	)";
+	BOOST_CHECK_NO_THROW(parseTextAndResolveNames(sourceCode));
+}
+
+BOOST_AUTO_TEST_CASE(function_argument_mem_to_storage)
+{
+	char const* sourceCode = R"(
+		contract C {
+			function f(uint[] storage x) private {
+			}
+			function g(uint[] x) {
+				f(x);
+			}
+		}
+	)";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
+}
+
+BOOST_AUTO_TEST_CASE(function_argument_storage_to_mem)
+{
+	char const* sourceCode = R"(
+		contract C {
+			function f(uint[] storage x) private {
+				g(x);
+			}
+			function g(uint[] x) {
+			}
+		}
+	)";
+	BOOST_CHECK_NO_THROW(parseTextAndResolveNames(sourceCode));
+}
+
+BOOST_AUTO_TEST_CASE(mem_array_assignment_changes_base_type)
+{
+	// Such an assignment is possible in storage, but not in memory
+	// (because it would incur an otherwise unnecessary copy).
+	// This requirement might be lifted, though.
+	char const* sourceCode = R"(
+		contract C {
+			function f(uint8[] memory x) private {
+				uint[] memory y = x;
+			}
+		}
+	)";
+	BOOST_CHECK_THROW(parseTextAndResolveNames(sourceCode), TypeError);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }
diff --git a/libsolidity/SolidityOptimizer.cpp b/libsolidity/SolidityOptimizer.cpp
index 397ee6316..85a88c030 100644
--- a/libsolidity/SolidityOptimizer.cpp
+++ b/libsolidity/SolidityOptimizer.cpp
@@ -944,6 +944,14 @@ BOOST_AUTO_TEST_CASE(cse_access_previous_sequence)
 	// 0, SLOAD, 1, ADD, SSTORE, 0 SLOAD
 }
 
+BOOST_AUTO_TEST_CASE(cse_optimise_return)
+{
+	checkCSE(
+		AssemblyItems{u256(0), u256(7), Instruction::RETURN},
+		AssemblyItems{Instruction::STOP}
+	);
+}
+
 BOOST_AUTO_TEST_CASE(control_flow_graph_remove_unused)
 {
 	// remove parts of the code that are unused