diff --git a/Changelog.md b/Changelog.md
index 3fa7c9dec99a..bbb59751ccc1 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -7,6 +7,7 @@ Compiler Features:
 
 
 Bugfixes:
+ * ABIEncoderV2: Fix internal error related to mappings as library parameters.
  * Yul: Properly detect name clashes with functions before their declaration.
 
 
diff --git a/libsolidity/codegen/ABIFunctions.cpp b/libsolidity/codegen/ABIFunctions.cpp
index 653451a6fc6e..f4c743174fa1 100644
--- a/libsolidity/codegen/ABIFunctions.cpp
+++ b/libsolidity/codegen/ABIFunctions.cpp
@@ -308,6 +308,7 @@ string ABIFunctions::cleanupFunction(Type const& _type, bool _revertOnFailure)
 			break;
 		case Type::Category::Array:
 		case Type::Category::Struct:
+		case Type::Category::Mapping:
 			solAssert(_type.dataStoredIn(DataLocation::Storage), "Cleanup requested for non-storage reference type.");
 			templ("body", "cleaned := value");
 			break;
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index a7ff7a89cb3a..c8fbbff7b8a7 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -9037,9 +9037,13 @@ BOOST_AUTO_TEST_CASE(using_library_mappings_external)
 				}
 			}
 		)";
-	compileAndRun(libSourceCode, 0, "Lib");
-	compileAndRun(sourceCode, 0, "Test", bytes(), map<string, Address>{{"Lib", m_contractAddress}});
-	ABI_CHECK(callContractFunction("f()"), encodeArgs(u256(2), u256(0), u256(84), u256(46), u256(0), u256(198)));
+	for (auto v2: {false, true})
+	{
+		string prefix = v2 ? "pragma experimental ABIEncoderV2;\n" : "";
+		compileAndRun(prefix + libSourceCode, 0, "Lib");
+		compileAndRun(prefix + sourceCode, 0, "Test", bytes(), map<string, Address>{{"Lib", m_contractAddress}});
+		ABI_CHECK(callContractFunction("f()"), encodeArgs(u256(2), u256(0), u256(84), u256(46), u256(0), u256(198)));
+	}
 }
 
 BOOST_AUTO_TEST_CASE(using_library_mappings_return)