diff --git a/libsolidity/analysis/ContractLevelChecker.cpp b/libsolidity/analysis/ContractLevelChecker.cpp
index e2208f3fb..419ebe93f 100644
--- a/libsolidity/analysis/ContractLevelChecker.cpp
+++ b/libsolidity/analysis/ContractLevelChecker.cpp
@@ -43,6 +43,7 @@ bool ContractLevelChecker::check(ContractDefinition const& _contract)
 	checkConstructor(_contract);
 	checkFallbackFunction(_contract);
 	checkExternalTypeClashes(_contract);
+	checkHashCollisions(_contract);
 
 	return Error::containsOnlyWarnings(m_errorReporter.errors());
 }
@@ -420,3 +421,18 @@ void ContractLevelChecker::checkExternalTypeClashes(ContractDefinition const& _c
 						"Function overload clash during conversion to external types for arguments."
 					);
 }
+
+void ContractLevelChecker::checkHashCollisions(ContractDefinition const& _contract)
+{
+	set<FixedHash<4>> hashes;
+	for (auto const& it: _contract.interfaceFunctionList())
+	{
+		FixedHash<4> const& hash = it.first;
+		if (hashes.count(hash))
+			m_errorReporter.typeError(
+				_contract.location(),
+				string("Function signature hash collision for ") + it.second->externalSignature()
+			);
+		hashes.insert(hash);
+	}
+}
diff --git a/libsolidity/analysis/ContractLevelChecker.h b/libsolidity/analysis/ContractLevelChecker.h
index ef1486171..f930fb60d 100644
--- a/libsolidity/analysis/ContractLevelChecker.h
+++ b/libsolidity/analysis/ContractLevelChecker.h
@@ -75,6 +75,8 @@ private:
 	/// Checks that different functions with external visibility end up having different
 	/// external argument types (i.e. different signature).
 	void checkExternalTypeClashes(ContractDefinition const& _contract);
+	/// Checks for hash collisions in external function signatures.
+	void checkHashCollisions(ContractDefinition const& _contract);
 
 	langutil::ErrorReporter& m_errorReporter;
 };
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index d107d2dcc..e411609cd 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -93,19 +93,6 @@ bool TypeChecker::visit(ContractDefinition const& _contract)
 	for (auto const& n: _contract.subNodes())
 		n->accept(*this);
 
-	// check for hash collisions in function signatures
-	set<FixedHash<4>> hashes;
-	for (auto const& it: _contract.interfaceFunctionList())
-	{
-		FixedHash<4> const& hash = it.first;
-		if (hashes.count(hash))
-			m_errorReporter.typeError(
-				_contract.location(),
-				string("Function signature hash collision for ") + it.second->externalSignature()
-			);
-		hashes.insert(hash);
-	}
-
 	if (_contract.isLibrary())
 		checkLibraryRequirements(_contract);