5 files changed, 37 insertions, 42 deletions

diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index 8f504ffe..8c84e4dc 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -1742,22 +1742,8 @@ bool TypeChecker::visit(FunctionCall const& _functionCall)
 						m_errorReporter.typeError(arguments[i]->location(), "Invalid rational number (too large or division by zero).");
 						errored = true;
 					}
-				if (!errored)
-				{
-					TypePointer encodingType;
-					if (
-						argType->mobileType() &&
-						argType->mobileType()->interfaceType(false) &&
-						argType->mobileType()->interfaceType(false)->encodingType()
-					)
-						encodingType = argType->mobileType()->interfaceType(false)->encodingType();
-					// Structs are fine as long as ABIV2 is activated and we do not do packed encoding.
-					if (!encodingType || (
-						dynamic_cast<StructType const*>(encodingType.get()) &&
-						!(abiEncodeV2 && functionType->padArguments())
-					))
-						m_errorReporter.typeError(arguments[i]->location(), "This type cannot be encoded.");
-				}
+				if (!errored && !argType->fullEncodingType(false, abiEncodeV2, !functionType->padArguments()))
+					m_errorReporter.typeError(arguments[i]->location(), "This type cannot be encoded.");
 			}
 			else if (!type(*arguments[i])->isImplicitlyConvertibleTo(*parameterTypes[i]))
 			{
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index c85e0522..0954fdf3 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -390,6 +390,27 @@ MemberList const& Type::members(ContractDefinition const* _currentScope) const
 	return *m_members[_currentScope];
 }
 
+TypePointer Type::fullEncodingType(bool _inLibraryCall, bool _encoderV2, bool _packed) const
+{
+	TypePointer encodingType = mobileType();
+	if (encodingType)
+		encodingType = encodingType->interfaceType(_inLibraryCall);
+	if (encodingType)
+		encodingType = encodingType->encodingType();
+	if (auto structType = dynamic_cast<StructType const*>(encodingType.get()))
+	{
+		// Structs are fine in the following circumstances:
+		// - ABIv2 without packed encoding or,
+		// - storage struct for a library
+		if (!(
+			(_encoderV2 && !_packed) ||
+			(structType->location() == DataLocation::Storage && _inLibraryCall)
+		))
+			return TypePointer();
+	}
+	return encodingType;
+}
+
 MemberList::MemberMap Type::boundFunctions(Type const& _type, ContractDefinition const& _scope)
 {
 	// Normalise data location of type.
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 474a6f33..12029a4e 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -280,6 +280,11 @@ public:
 	/// This for example returns address for contract types.
 	/// If there is no such type, returns an empty shared pointer.
 	virtual TypePointer encodingType() const { return TypePointer(); }
+	/// @returns the encoding type used under the given circumstances for the type of an expression
+	/// when used for e.g. abi.encode(...) or the empty pointer if the object
+	/// cannot be encoded.
+	/// This is different from encodingType since it takes implicit conversions into account.
+	TypePointer fullEncodingType(bool _inLibraryCall, bool _encoderV2, bool _packed) const;
 	/// @returns a (simpler) type that is used when decoding this type in calldata.
 	virtual TypePointer decodingType() const { return encodingType(); }
 	/// @returns a type that will be used outside of Solidity for e.g. function signatures.
diff --git a/libsolidity/codegen/ABIFunctions.cpp b/libsolidity/codegen/ABIFunctions.cpp
index b3f1bc7e..1ce77d67 100644
--- a/libsolidity/codegen/ABIFunctions.cpp
+++ b/libsolidity/codegen/ABIFunctions.cpp
@@ -471,13 +471,8 @@ string ABIFunctions::abiEncodingFunction(
 	bool _fromStack
 )
 {
-	solUnimplementedAssert(
-		_to.mobileType() &&
-		_to.mobileType()->interfaceType(_encodeAsLibraryTypes) &&
-		_to.mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType(),
-		"Encoding type \"" + _to.toString() + "\" not yet implemented."
-	);
-	TypePointer toInterface = _to.mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType();
+	TypePointer toInterface = _to.fullEncodingType(_encodeAsLibraryTypes, true, false);
+	solUnimplementedAssert(toInterface, "Encoding type \"" + _to.toString() + "\" not yet implemented.");
 	Type const& to = *toInterface;
 
 	if (_from.category() == Type::Category::StringLiteral)
@@ -886,13 +881,8 @@ string ABIFunctions::abiEncodingFunctionStruct(
 			solAssert(member.type, "");
 			if (!member.type->canLiveOutsideStorage())
 				continue;
-			solUnimplementedAssert(
-				member.type->mobileType() &&
-				member.type->mobileType()->interfaceType(_encodeAsLibraryTypes) &&
-				member.type->mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType(),
-				"Encoding type \"" + member.type->toString() + "\" not yet implemented."
-			);
-			auto memberTypeTo = member.type->mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType();
+			TypePointer memberTypeTo = member.type->fullEncodingType(_encodeAsLibraryTypes, true, false);
+			solUnimplementedAssert(memberTypeTo, "Encoding type \"" + member.type->toString() + "\" not yet implemented.");
 			auto memberTypeFrom = _from.memberType(member.name);
 			solAssert(memberTypeFrom, "");
 			bool dynamicMember = memberTypeTo->isDynamicallyEncoded();
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index 2d81a106..bd3ec8f5 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -333,26 +333,19 @@ void CompilerUtils::encodeToMemory(
 )
 {
 	// stack: <v1> <v2> ... <vn> <mem>
+	bool const encoderV2 = m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2);
 	TypePointers targetTypes = _targetTypes.empty() ? _givenTypes : _targetTypes;
 	solAssert(targetTypes.size() == _givenTypes.size(), "");
 	for (TypePointer& t: targetTypes)
 	{
-		solUnimplementedAssert(
-			t->mobileType() &&
-			t->mobileType()->interfaceType(_encodeAsLibraryTypes) &&
-			t->mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType(),
-			"Encoding type \"" + t->toString() + "\" not yet implemented."
-		);
-		t = t->mobileType()->interfaceType(_encodeAsLibraryTypes)->encodingType();
+		TypePointer tEncoding = t->fullEncodingType(_encodeAsLibraryTypes, encoderV2, !_padToWordBoundaries);
+		solUnimplementedAssert(tEncoding, "Encoding type \"" + t->toString() + "\" not yet implemented.");
+		t = std::move(tEncoding);
 	}
 
 	if (_givenTypes.empty())
 		return;
-	else if (
-		_padToWordBoundaries &&
-		!_copyDynamicDataInPlace &&
-		m_context.experimentalFeatureActive(ExperimentalFeature::ABIEncoderV2)
-	)
+	else if (_padToWordBoundaries && !_copyDynamicDataInPlace && encoderV2)
 	{
 		// Use the new Yul-based encoding function
 		auto stackHeightBefore = m_context.stackHeight();