Enforce view with error for experimental 0.5.0.

test/libsolidity/ViewPureChecker.cpp

@@ -143,6 +143,16 @@ BOOST_AUTO_TEST_CASE(environment_access)
 	}
 }
 
+BOOST_AUTO_TEST_CASE(view_error_for_050)
+{
+	CHECK_ERROR(
+		"pragma experimental \"v0.5.0\"; contract C { uint x; function f() view { x = 2; } }",
+		TypeError,
+		"Function declared as view, but this expression (potentially) modifies the state and thus requires non-payable (the default) or payable."
+	);
+
+}
+
 BOOST_AUTO_TEST_CASE(modifiers)
 {
 	string text = R"(